The Manufacture Technique of the API Steel Pipe

This new manufacture technique of a kind of API steel pipe which belongs to straight seam welded steel pipe is being widely accepted around the world. As a matter of fact, the API steel pipe is a kind of welded steel pipe that has no seams. Although the API steel pipe has not many applications like the welded steel pipe, the API steel pipe is mainly used for industry that links to the oil. And its application is increasing because of the increasing of the oil demand.

This kind of manufacture technique controls reasonably the sulfur content of carbon, phosphor as well as the sulfur and adds to a trace of alloying elements at the same time. The manufacture method of this straight seam welded steel pipe( API steel pipe) is that first, carry out pretreatment to the molten iron, and then proceed with smelt, refine, sheet stamping, hot rolling, laminar flow cooling, plate rolling, seam welding as well as test. And in the middle of welding technique, it is better to control the parameters such as welding speed, welding temperature, extrusion amount as well as the angular aperture.

This kind of manufacture technique improve the composition proportion of material that is used for producing API steel pipe and promote the welding technique at the same time. Thus, the API steel pipe has the characteristics of high dimensional accuracy, good welding toughness, good performance of the extrusion as well as easy to control the quality and low cost. At present, the seamless API steel pipe that is used in petroleum industry has the problems of large ovality, uneven wall thickness, not enough damage resistant property. Using this kind of API steel pipe severely influence the service life of the wells. The welded steel pipe and carbon steel pipe are also available. Thus, it is important to produce a kind of manufacture technique that can overcome the shortcoming of current technique.

The detail manufacture technique is as follows. First, carry out the pretreatment of the liquid iron. And then put liquid iron after pretreatment into the revolving furnace to carry out smelting. And add alloying elements in the middle of melting.  Next, put liquid steel after smelting in the revolving furnace into the refining furnace again to proceed with smelting. And make the liquid steel after smelting in the refining furnace into the steel feed. And then, turn the steel feed into banding board through blooming, precision rolling and finish rolling with hot rolling mill. And then carry out laminar flow cooling treatment to the banding board after hot rolling. Then wind the banding board after laminar flow cooling treatment into casting pipe with winding machine. Finally, weld the welding seam of the casting pipe after winding with welding machine.

If you would like to know more,pls visit:Hunan Great Steel Pipe Co.,ltd

The Type of Steel Pipe Used for Oil Transportation

The processing, transportation and storage of oil is highly complex with high pressure and corrosion. Crude oil from the underground contains substances such as sulfur and hydrogen sulfide that can oxidize the pipeline. This is a key problem during the oil transportation. Therefore, the material chosen must meet these needs. Steel is the most used material applied in the oil transporting and storage. Some technique has been invented to increase its strength and its corrosion resistance.

People have used pipes for many years. Steel pipes are long, hollow tubes. According to statistics, there are millions of tons of black steel pipe being produced each year; they are so versatile and therefore widely used in many industries. It's not difficult to find that steel pipes are used in a many places. Since they are tough and hard, they are used for transporting oil, gas, water throughout cities and towns. They can be lightweight although they are hard. Black pipe, a form of carbon steel pipe, was widely used in homes built before the 1960s. But since black pipes are durable, they are still used for applications like gas and oil line. The black appearance is formed by a black oxide scale when forging the steel pipe.

Steel pipes are used widely in petroleum industry and many other fields, so they have large consumption volume. There are many kinds of oil steel pipe; the two principle kinds are oil well pipe (drill collar, drill pipe, casing pipe, tubing pie etc.) and oil-gas transportation pipe. Steel pipelines can be buried underground for hundreds of years with little damage giving the credit to their excellent stress crack resistance. They can also be used for outside storage because of the amazing dependable performance. The well-drilling during the oil exploration and exploitation needs frill pipes and drill collars, well reinforcing needs casing, and the oil recovery need tubing. In recent years, the annual consumption of structural steel pipe is about 1.3 million tons. The pipeline transportation is the most economical and reasonable method for oil.

With the rapid development of pipeline, the demand of oil transportation line pipe increased greatly in China. The black iron pipe is a type of API steel pipe which has a black oxide scale on its surface. It is less expensive and more ductile than other iron pipes so it is popular around the world. In generally, electric resistance welded steel pipe are used for oil transmission which can guarantee assures defined quality when using it. This kind of pipe is constantly stable in hot or wet environment. The importance of oil transporting to supply energy makes the industry of steel pipeline production keep developing and more attention to it. Corrosion resistant, water based paint is used on the outer layer to prevent atmospheric corrosion during transportation and storage. You can also aid more protective layers on coating steel pipe to make them more durable.

The Difference Between the Black Steel Pipe and the Welded Steel Pipe

At present, nearly each family is equipped with different types of the pipes to deliver water, gas as well as the warm steam. They are the parts of your family, and it is necessary to repair them occasionally. Thus, how to choose the pipes you really need is important. Knowing the main differences between these two pipes will help you find out the pipes suitable for your home. The main difference between the two pipes is their basic properties. Most of the black steel pipes are iron pipes, which have high carbon as well as the ferrite.  And its name black steel pipe comes from the outer black oxide cover on the surface. Ever if the black steel pipe is a type of the welded steel pipe, they are not the same completely.

The second difference between steel pipe and black iron pipe is their applications. For example, the structural steel pipe is often used to like your water supply system to the general water supply system, while the black steel pipe is most commonly utilized to deliver gas and oil in your house. In earliest time, people used black steel pipes to deliver water. However, there is no corrosion resistant layer to keep the black steel pipe from being rusted, so people chose to use welded steel pipe that has longer service time to deliver water.

As for the usage, the carbon steel pipe is beneficial to installing all kinds of the fittings because of lacing corrosion resistant layer. Thus, it has more chance to connect with other pipes to meet different building construction demands. While there are many kinds of welded steel pipes and most of them are covered with a anticorrosion layer, so they have longer using time but are not easily to link to other pipes. In terms of maintenance, the welded steel pipes have a better durability than that of the black steel pipes. In addition, because most of the welded steel pipe has welded seams, so it is not easy to occur leakage in the middle of delivering. And some of the black steel pipes have seams, so the welded steel pipe is much safer than the black steel pipes.

And as the black steel pipes are fragile, it is easy to damage the black steel pipe in the course of production. However, the protection coverage of the welded steel pipe will flake off over time, causing blocking the pipelines. Thus, when choosing these two pipes, you need to consider carefully. Finally, the price of welded steel pipe as well as the black steel pipe is another major difference that the customers care about. As a matter of fact, the black steel pipe is usually much cheaper than that of the welded steel pipe, making it an ideal choice for those who want to cut off the cost. However, the black steel pipes need extra money to maintain and add to fittings. Thus, after carefully calculation, the welded steel pipe is much economical.

More information,pls visit:Hunan Great Steel Pipe Co.,ltd

Mobile Coating Plant is Great News for Black Steel Pipe Producers

Most of the world's pipelines are constructed with steel pipes. To protect the pipelines from any possible failure, the piping industries around the world as well as a number of scientists have made great efforts to improve the properties and strength of steel pipes. In doing so, news methods of applying external coatings are invented to equip the pipes with the capability of anti-corrosion, thermal insulation, and even buoyancy control. One of the most traditional steel pipes, black steel pipe is not galvanized. Because of its dark colored iron-oxide on the external surface, it is also named as black pipe. In general, black steel pipes are applied in the oil industry for the transportation of large amount of oil or petroleum across different areas or regions.

The coating steel pipe is typically applied in fixed pipe coating machines which in most cases are located close to the pipe plants. Some manufacturers of black steel pipes use simple anti-corrosion coatings while some others may need to have more specialized coatings, such as concrete-weight coatings or thermal insulation coatings since the pipes may be used in demanding situations. Black welded steel pipe producers either hire workers to complete coating in the plant or outsource the coating job to professional pipe coaters or independent coating suppliers. After the coating procedures and before the pipes are transported to the destinations, thorough and careful examination of the coating quality is usually carried out by the directors of the pipe plants to ensure that their black steel pipes is in line with international standards and with customers' requirements.

The traditional fixed coating plant model works when the black steel pipes are transported to areas not so far from the structural steel pipe plants. However, for cross-region or even overseas destinations, the traditional way no longer works well. Luckily, cutting-edge scientific and technological development breeds dramatic changes in the coating facilities. Nowadays, mobile coating plants for black steel pipes are available in many parts of the world, attracting a large number of pipe producers as well as independent coating suppliers.

A mobile coating plant can be easily moved to a new location where the coating services are needed. Obviously mobile coating facilities are beneficial for carbon steel pipe producers in many aspects. To begin with, more jobs will be created at the communities where the facilities are located, mobilizing locals to work in the pipe plants. Moreover, the flexibility of mobile coating facilities has proved to be efficient and cost-effective, which surely help reduces the production costs for the producers. For independent coating suppliers, mobile coating facilities undoubtedly help optimize the utilization of their professional skills and coating equipment, which may greatly promote their business. In addition, the quality of the API steel pipe and black steel pipes can be guaranteed just as those produced in fixed coating plants, which is also great news for customers.

The Differences between Welded Steel Pipe and Iron Pipe

The following are the differences between the welded steel pipe and the iron pipe. Iron pipe are poured and molded with cast iron. Iron pipe is used for water supply, dewatering as well as gas transfer line. In addition, it includes cast iron straight pipe and pipe fittings. And it has smaller labor strength. And depending on the different casting process, the iron pipe has two different types: continuous iron pipe and centrifugal iron pipe. And the difference between iron pipe and welded steel pipe can be told from the lumen of the pipe. If there are apparent longitudinal threads which stand out, it is wedding collar. And we can recognize it as welded steel pipe, while if there are not, then it is seamless pipe or iron pipe.

In terms of material, iron pipe is cast by pig iron, which will break into lumps after oxidation as well as corrosion for a long time, and extrusion of external force. However, the welded steel pipe will only come off some scum or cracking on both sides of flattening after being flattened. And the welded steel pipe is made of materials that have corrosion resistant feature, so it has corrosion resistance. Therefore, it is used in corrosively environment or occasions that need high purity. And welded steel pipe is divided into spiral welded pipe with large diameter as well as straight welded pipe with small diameter , while iron pipe is generally non-pressure bearing pipeline which has large diameter and iron pipe is always used for manufacturing exhaust water pipes.

Longitudinal welded steel pipe has simple manufacturing technique, high production efficiency, low production cost as well as fast development and other advantages. Mild steel pipe with small bore adopts mainly straight welding, while welded steel pipe with large bore use partly spiral welding. Otherwise, the strength of spiral welded pipe is higher than that of longitudinal welded steel pipe. And it also can manufacture welded pipes with different diameter through processing blanks that have the same width. However, when compared with straight welded steel pipe, the length of welding line expand 30~100% with lower production rate. And welded steel pipe is connected with strip steel, so it has brief production technology. Thus, its price is not as expensive as that of the iron pipe.

The nominal caliber of the iron pipe is 80~2200mm. and compared with gray iron pipe, it has the characteristics of large intensity, good toughness, thin pipe wall, less metal dosage as well as higher pressure suffering ability. Thus, it becomes the development direction of cast iron pipe. What the iron pipe uses is low phosphorous and low sulfur cast molten iron with high quality produced by iron making shaft furnace. And mould into iron pipe through centrifugal casting, annealing process and centrifugal pipe casting machine that belongs to water cooling metal mold which are advanced in the world. And then carry out elaborately conducting of multiple working procedures such as annealing, finishing bell and spigot, hydrostatic test, packing block cement of inner walls, cement packing block to preserve nature, water mill cement liner, coating asphalt paint on outer surface, baking asphalt paint, rust prevention of mouthing, shipping mark as well as package, making it become iron skin with high intensity, high extension as well as corrosion resistance. Through the differences between the welded steel pipe and API carbon steel pipe, you will understand them better.

Avoid Spiral Welded Steel Pipe Rupture In Long Pipeline

Spiral pipe with big diameter, high strength and practical features make it the first choice of many long-distance pipeline. With the spiral steel pipe rupture has a method for base metal and weld flattening test, guided bend test, a number of indicators of landing inspection toughness test, Charpy impact test. Not only for the gas pipeline has a higher toughness requirements for oil pipelines in recent years also made a high impact toughness requirements.

Currently, the project is widely used annealed after welding cooling to eliminate residual stress, while cooling after welding residual stress is an important process, this approach is not a waste of energy and easy to produce larger welding residual stresses. Post weld heat treatment is a new technique to eliminate residual stress.

After the material is preheated before welding to heat treatment temperature and the welding process to maintain continuous heating of the weld member that temperature after soldering using its thermal insulation cotton allowed to cool slowly. This method can effectively reduce the welding residual stress, improve resistance to stress corrosion of metals. Post weld heat treatment can effectively reduce the welding residual stress, and heat treatment temperature is higher, the residual stress better. After the heat treatment can be effectively improved resistance to stress corrosion spiral welded steel pipe, the higher the heat treatment temperature, stress corrosion resistance increased more significant. Pipeline Industry Development of China's second climax will surely come. Spiral welded steel pipe (ssaw steel pipe) will be put into research, and enhance the pipeline capacity. Improve and increase the diameter of the intensity level, due to the importance of the people's lack of understanding of the impact toughness of the material, in many parts of the world have occurred fragility and fracture toughness of pipeline accidents. Through the analysis of these incidents, research, and "fracture mechanics" as the development of a new discipline and practical application in the pipeline industry, increasing the awareness of the importance of understanding the impact toughness of the pipe. Toughness index has actually become a pipe line pipe important indicator.

In fact, the spiral steel pipeline transportation has many advantages, is the resilience of poor transmission capacity shortage. For just freezing point, high waxy crude oil, higher than the designed capacity, the pipeline will be constrained by existing capacity and pressure pumping capacity; below the designed capacity, the pipeline will be constrained by existing thermal conditions. To overcome this fixed point, only with the DRA and depressant. Spiral structural steel pipe and ductile crack extension instability instability expansion.

How to avoid pipeline breaks have a way of base metal and weld flattening test, guided bend test, a number of indicators of landing inspection toughness test, Charpy impact test. Not only for the gas pipeline has a higher toughness requirements for oil pipelines in recent years also made a high impact toughness requirements. For long-distance pipeline, it should completely avoid crack initiation is very difficult, in fact, at home and abroad are difficult to fully achieve. This is because the long-distance pipeline hundreds of kilometers long and some even more than a thousand kilometers long welds, weld too much, plus the damage caused during construction and transportation, etc., so that increases the chances floor room.

Currently, the project is widely used to eliminate residual stress annealed after welding cooling, and cooling after welding residual stress is an important process, this approach is not a waste of energy and easy to produce larger welding residual stresses. Post weld heat treatment is a new technique to eliminate residual stress. After the material is preheated before welding to heat treatment temperature and the welding process to maintain continuous heating of the weld member that temperature after soldering using its thermal insulation cotton allowed to cool slowly. This method can effectively reduce the welding residual stress, improve resistance to stress corrosion of metals. Post weld heat treatment can effectively reduce the welding residual stress, and heat treatment temperature is higher, the residual stress better. After the heat treatment can be effectively improved resistance to stress corrosion spiral welded steel pipe, the higher the heat treatment temperature, stress corrosion resistance increased more significant. Pipeline Industry Development of China's second climax will surely come. Spiral welded steel pipe will be put into researchFree Articles, and enhance the pipeline capacity.

Advantage Of Galvanized Steel Square Tube

Introduction: hot dip galvanized square tube in place is very widely used in building construction, it has advantages of what? Fiber we together to get to know what are the advantages of it. Pass first, hot dip galvanized square pipe is galvanized and the building materials, so its performance is very good, it has the very good anti-corrosion performance, the advantages of it to make it in easily corrupt environment use, also can have very good waterproof properties, so it can guarantee the time in contact with the water quality will not because rust phenomenon caused by water, making it the service life of the guaranteed; Second, the density of hot dip galvanized square pipe is very good, no matter from the material itself or from its structure is better than other steel materials, can make it at the time of use is not affected by the outside world

Hot dip galvanized square tube in place is very widely used in building construction, it has advantages of what? Fiber we together to get to know what are the advantages of it.

Pass first, hot dip galvanized square pipe is galvanized and the building materials, so its performance is very good, it has the very good anti-corrosion performance, the advantages of it to make it in easily corrupt environment use, also can have very good waterproof properties, so it can guarantee the time in contact with the water quality will not because rust phenomenon caused by water, making it the service life of the guaranteed;

Second, the density of hot dip galvanized square pipe is very good, no matter from the material itself or from its structure is better than other steel materials, can make it at the time of use is not affected by the outside world of material damage; Has the very strong abrasion resistance, when using, can literally put and transportation;

Finally, stretchability is hot dip galvanized square tube is very good, to make it in bending, stretching, to ensure that will not break; At the time of production and processing workmanship is very good, so it looks very smooth.

Low pressure fluid conveying with straight seam square tube (GB/T3092-1993) is also called general welded pipe, commonly known as the clarinet. Is used to transport oil, gas, air, water and heating steam general low pressure fluid and other purposes such as welded square tube. Square tube wall thickness is divided into ordinary square pipe and thickening; To take over the side form is divided into without thread square tube (light pipe) and the square tube with screws. The specifications of the square tube in nominal diameter (mm), nominal diameter is the inner diameter of approximation. Traditionally used in said, such as 1 1/2. Low pressure fluid conveying with welded square tube in addition to directly used for conveying fluid, also used as a low voltage large amounts of fluid conveying with galvanized welded steel pipe. Low pressure fluid conveying with galvanized welded square tube (GB/T3091-1993), also known as galvanized welded square tube, commonly known as the white tube. Is used for transporting oil, gas, air, water and heating steam, warm water generally low pressure fluid or other purposes such as hot dip galvanized welded square tube (furnace welding and welding). Square tube wall thickness is divided into ordinary galvanized square tubes and thickening galvanized square tubes; To take over the side form is divided into without threaded galvanized coating steel pipe and galvanized square pipe with screws. The specifications of the square tube in nominal diameter (mm), nominal diameter is the inner diameter of approximation. Traditionally used in said, such as 1 1/2.

Ordinary carbon steel pipe is an industrial and civil construction, machinery and equipment such as electric installation engineering of square mild steel pipe is used to protect the wire.

Main Application Of Sprial Welded Steel Pipe

Spiral welded steel pipe main use: widely used in houses, Bridges, roads and other civil engineering construction. Main origin: spiral pipe manufacturers in China are mainly distributed in north and northeast, north China, such as shougang, tangshan, xuanhua, ChengGang northeast Westwood, north Taiwan, stroke, such as steel and so on, the two regions more than about 50% of the total output of rebar.

Spiral welded pipe is widely used in natural gas, petroleum, chemical, electric power, heat, water supply and drainage, steam heating, hydropower station with the pressure steel pipe, thermal power, water and other long-distance pipeline and piling, dredging, Bridges, steel structure engineering field. Quality stand or fall of spiral welded pipe transverse reinforcement and low, often appear phenomenon of discontent, because manufacturers to achieve big minus tolerance, finished product quantity of the previous way slants big, small iron type, groove filling.

With the development of national economy and the improvement of people's living standard, the spiral welded pipe has become home to the new trend of developing the pipeline system. The company has always believed in "quality first, customer first, sincere friends, science and technology enterprise". Hebei tianyuan steel pipe manufacturing co., LTD., the idea of "cooperation, innovation, seek progress and development. I founded the company, always pay attention to the quality of products and processing management of complex products, at the same time, external to undertake a variety of difficult processing production of welded pipe business. Realize the user the value of the perfect, is our goal.

The difference between the spiral welded steel pipe and straight seam welded pipe
The metallurgical properties of materials

Straight seam submerged arc welding pipe is made of steel plate production, and the spiral weld pipe is made of hot-rolled coil plate production. Unit of hot rolling steel strip rolling technology has a series of advantages, has obtained in the production of high grade pipeline steel metallurgy process ability. For example, in the output on the bench is equipped with water cooling system to speed up the cooling, this allows to use low alloy to special strength grade and low temperature toughness, to improve the weldability of the steel. But this system in the basic no steel factory. Rolled plate alloy content (carbon equivalent) are often lower than similar grades of steel, it also improves the weldability of the spiral welded pipe.
More to be sure, as a result of the spiral welded pipe coil plate rolling direction is not perpendicular to the pipe axis direction (the spiral Angle of solution depends on the steel pipe), and straight seam steel pipe steel rolling direction perpendicular to the pipe axis direction, thus, anti-cracking performance of spiral welded pipe material is better than that of straight seam steel pipe.

Welding process,
From the welding process, the sprial welded steel pipe and DSAW steel pipe welding method is consistent, but the straight seam welded pipe will inevitably have a lot of t-shaped weld, so the probability of weld defects is also greatly improved, and the t-shaped seam welding residual stress is larger, the stress state of the weld metal are often in a three-way increases the possibility of a crack.

And, according to the regulations of submerged arc welding process, each weld shall have arc and arc in, but every straight seam welded pipe when weld girth, can not meet the conditions, thus there may be more at arc welding defects.

More information,pls visit:Hunan great steel pipe co.,ltd

20g Steel Pipe

20 G boiler carbon steel pipe and 20 g high pressure boiler tube, belongs to the high quality carbon structural steel pipe.
(1) the high quality carbon structural steel grade 20 g, MNG, 20 MNG.
(2) 15 mog, alloy structural steel pipe grade 20 crmog mog, 12, 15 crmog, 12 cr2mog, 12 cr1movg, 12 cr3movsitib, etc.
(3) corrosion and heat resistant steel used cr18ni9, 1 cr18ni11nb boiler tubes, in addition to ensure that the chemical composition and mechanical properties by root do water pressure test, flaring, flattening test. Steel tube to heat treatment state delivery.
In addition, the microstructure and grain size of finished steel pipe, the decarburization layer also has certain requirements.
High quality carbon structural steel is rely on adjust the amount of carbon (C) to improve the mechanical properties of steel, therefore, according to the carbon content of high and low, this kind of steel can be divided into:
Low carbon steel, carbon content less than 0.25% generally, such as 10, 20 steel, etc.;
Medium carbon steel, carbon content is in commonly between 0.25 ~ 0.60%, 35, 45 steel, etc.;
High carbon steel, carbon content is generally greater than 0.60%. This kind of steel is generally not used in the manufacture of steel pipe.
In fact, carbon content and no obvious boundaries between them.
Such steel production is bigger, USES broad, rolling (forging) more commonly made into round, square, flat profiles, such as plate and seamless steel tube. Mainly used in the manufacture of general structure and the mechanical structure parts, components and building structure and pipe conveying fluid. According to the requirement, sometimes need to heat treatment (normalizing or conditioning) after use.
High pressure boiler seamless steel tube (GB5310-2008) is used in the manufacture of high pressure and over pressure of the water tube boiler heating surface quality carbon steel pipe, alloy steel and heat resistant stainless steel seamless steel tube.
Specifications and appearance quality: GB5310-08 the high pressure boiler seamless steel tube of hot-rolled tube 22 ~ 530 mm outside diameter, wall thickness ranging from 20 to 70 mm. Cold drawn 10 to 108 mm (cold rolled) pipe diameter, wall thickness range 2.0 ~ 13.0 mm.
High quality carbon structural steel pipe is rely on adjust the amount of carbon (C) to improve the mechanical properties of steel, therefore, according to the carbon content of high and low, this kind of steel can be divided into:
Low carbon steel, carbon content less than 0.25% generally, such as 10, 20 steel, etc.;
Medium carbon steel, carbon content is in commonly between 0.25 ~ 0.60%, 35, 45 steel, etc.;
High carbon steel pipe, carbon content is generally greater than 0.60%. This kind of steel is generally not used in the manufacture of steel pipe.

Specific surface measurement of ERW Steel Pipe

Specific surface measurement of ERW carbon steel pipe

1, clean

Using solvent, emulsion steel surface cleaning, to remove oil, grease, dirt, lubricants, and similar organic matter, but it cannot remove rust, scale, such as welding flux on the surface of the steel, so only as auxiliary means in the anti-corrosion coating steel pipe production.

2, tools, cleaning

Main USES steel wire brush tool for steel surfaces such as grinding, can remove loose or cock scale, rust, slag, etc. Hand tools can achieve derusting Sa2 level, power tool cleaning can reach grade Sa3, if solid iron oxide adhered on the surface of the steel, tool cleaning effect is not ideal, anchor pattern depth of anticorrosion construction requirements.

3, pickling

Commonly used chemical and electrolytic pickling process, two methods do use only pipeline anticorrosion chemical pickling, can remove scale, rust, old coating, sometimes can be used as sandblasting derusting after reprocessing. Chemical cleaning while can make the surface reaches a certain cleanness and roughness, but the anchor lines shallow, and easy to damage to the environment.

4, shot derusting spray (left)

Spray (cast) shot derusting spray is driven by high-power motor (cast) shoot high-speed rotating blades, make steel grit, steel shot, segment, minerals and other abrasive wire under the action of centrifugal force on steel pipe surface spray (cast) processing, not only can thoroughly remove rust, oxides and dirt, and steel pipe under the action of abrasive violent impact and friction, also can achieve the required uniform roughness.

After shot derusting spray (left), not only can enlarge the physical adsorption on the surface of the pipe, and can enhance anti-corrosion layer and mechanical adhesion on the surface of the coating steel pipe. Therefore, shot derusting spray (cast) is an ideal cleaning pipeline corrosion protection method. In general, shot peening (sand) cleaning is mainly used for the pipe inner surface treatment and shot (sand) is mainly used for pipe derusting outside surface treatment.

Cold drawing and hot rolled seamless steel pipe

Seamless steel pipe cold drawing (rolling) : round billet - heat - punch to heading, annealing and pickling to apply oil (copper), multi-channel time cold drawing (cold) and billet tube - heat treatment - straightening to hydrostatic test (NDT) - > tag, put in storage.

Hot rolled (extrusion seamless steel tube) : the circular tube billet - heat - punch - three-roll skew rolling, rolling, or pressing - to take off the tube and sizing (or reducing) - cooling - the tube billet - straightening - hydrostatic test (or inspection) to tags, put in storage.

Two kinds of structural steel pipe process steps

Cold drawn steel tube with hot rolled steel coils as raw material, after acid pickling to remove oxide skin for cold rolling, the finished product is hard, because of cold work hardening caused by deformation of continuous cold rolling hard roll strength, increase hardness, toughness and plastic index decreased, so the stamping performance will deteriorate, can only be used for simple deformation of the parts. Hard coil can be used as a raw material, hot dip galvanized factory for hot dip galvanizing unit Settings are annealed wire. Hard coil weight generally in June to 13.5 tons, coil diameter is 610 mm.

General cold rolling plate, coil shall be continuous annealing unit (CAPL) or bell type annealing furnace eliminate cold work hardening and rolling stress, corresponding mechanics performance index prescribed by the standard.

Cold rolled steel plate surface quality, appearance, dimension precision are better than that of the hot rolled plate, and its products right rolling thin thickness to 0.18 mm or so, so favored by the users. For the substrate to cold rolled steel coils products deep processing, become the high value-added products. Such as electric galvanized, hot dip galvanized, electric galvanized fingerprint resistant steel plate and vibration compound steel plate, belt, PVC compound steel plate, etc., make the product is beautiful and fine qualities such as high corrosion, has been widely applied. Must be annealed cold rolled steel coils for finishing, including cutting head, tail, trimming, leveling, leveling, heavy volume, or longitudinal shear plate, etc. Cold-rolled products are widely used in automotive, home appliances, instrument switch, building, office furniture and other industries. Steel strapping after each bag is 3 ~ 5 tons in weight. Flat volume classification is commonly 3 ~ 10 tons/volume. Coil diameter 610 mm.

Hot-rolled carbon steel pipe of continuous casting slab or slab as raw material, by step heating furnace, high pressure water descaling after entering the roughing mill, roughing expected by the cutting head, tail, and then into the finishing mill, and the implementation of computer control rolling and finishing after through laminar cooling and the winder, become straight hair volume. Straight hair volume of head and tail often show tongue shape and fish shape, thickness and width accuracy is poorer, side often exists defects such as wave shape, folding, tower. The volume weight is heavier, coil diameter is 760 mm. (general pipe industry like to use. To pass through the cutting head and cutting tail straight hair volume, trimming and straightening, level off of multichannel time after finishing line processing, cutting board or heavy volume, again become namely: hot rolled steel plate, flat hot-rolled coil, slitting and belt and other products. Hot rolling finishing if volume after acid pickling to remove scale and greased the hot-rolled pickling plate volumes. This product has a tendency to be local alternative manufacture, price moderate, loved by the masses of users.

If you would like to know more about this,pls visit:Hunan great steel pipe co.,ltd

Detection Technology of Large Diameter Steel Pipe

In the field of detection technology, large diameter seamless steel tube refers to the steel pipe diameter greater than 160 mm. Large-diameter seamless steel tube is petroleum, chemical, thermal, important material, boiler, machinery, hydraulic industry, etc. With the development of national economy, our country during the period of "11th five-year plan", greatly increasing demand for seamless carbon steel pipe, and presents the development trend of large diameter significantly. Especially for corrosion resistance, resistance to squeeze oil well pipe and large diameter high pressure boiler tube and high quality oil cracking pipe, petroleum and petrochemical pipeline, etc., will be as countries increase as demand for energy infrastructure investment hot spot. Thus, to ensure the quality of products nondestructive testing put forward the methods and techniques on the new topic.

At present, China's metallurgical industry for high pressure boiler seamless steel pipe detection mainly applied in phi 160 mm below the specification, and adopting the traditional eddy current flaw detection coil or independent water trough type ultrasonic testing method. For more than 160 mm seamless steel tube through the traditional type eddy current method is used for testing, there exist many problems, also not allowed to the national standard. If use the ultrasonic testing of independence, due to the ultrasonic detection mechanism of the existence of certain depth on the surface of blind area, can't be guaranteed the reliability of test results as a whole.

Through the coil of eddy current detection is a circle on the surface of the mild steel pipe surface. In use through the coil, eddy current flaw detection of tested steel tube diameter, the greater the coil detection, the greater the peripheral area of the lower SNR. It is for this reason, steel pipe eddy current inspection standard, adopt through the coil, eddy current flaw detection of its foreign economic size shall not be greater than 140 mm. In addition, in the large diameter steel pipe through the type testing, the steel tube of magnetization and demagnetization, there is certain difficulty.

Water tank type ultrasonic testing is to use steel pipe spiral advancing, ultrasonic probe fixed. By the sink and checked the characteristics of the steel pipe full of water at the bottom of the coupling, ensure that the thickness of the coupling layer remains the same. But for ultrasonic detection of internal defects on the surface of main surface defects exist blind area and time, lead to cannot detect, coupled with the spiral advancing, 30 m to 12 m long steel pipe need to occupy a space of venue, etc, have been affect the choice of the steel pipe detection method and promotion.

Therefore, testing for large diameter steel pipe at home and abroad, generally using the magnetic flux leakage method or the water pressure experiment. At home, it is no good performance for large diameter DSAW steel pipe produced by the magnetic flux leakage detection device, once used to import. Imports of magnetic flux leakage detection device is expensive, difficult to accept for most of the domestic enterprises; And low efficiency of water pressure test, the intensity of labor is big, especially when the operator the sense of responsibility is not high, the water pressure test. Visible, realization of large diameter seamless steel tube inspection has become a subject urgently to be solved in metallurgical steel pipe industry.

Large diameter steel pipe is characteristic of large diameter, wall thickness are relatively thick and so according to this characteristic makes full use of ultrasonic testing and internal eddy current testing and the characteristics of the surface and sub-surface, which can realize "no blind area" inspection. Through the adoption of "steel tube spin around, the combination of test probe forward way", not only solve the problem of detection, also solve the occupied space of space.
More information,pls visit:Hunan great steel pipe co.,ltd

Trump Added Pressure for China's Iron and Steel Trade

Chinese people just finished celebrating the Spring Festival, the President of the United States Trump insisted on "difficult" to China, the U.S. department of commerce ruling China enterprise anti-dumping tax rate of 63.86% 76.64% and 63.86% - 190.71% anti-subsidy tax rate. From the point of view, China's steel exports, the proportion of exports to the United States plummeted, a very important part of reason is that from the trade friction factors.

As a production services supplier which supply carbon steel pipe, welded steel pipe, line pipe, galvanized pipe, scaffolding, and other products , Shinestar group is very concerned about China-U.S trade, we believe that China's steel exports to the us fell so much, the most important factor is the United States on China's export restrictions may play a role. The U.S. steel industry used to dominating the world, reached its zenith, but now they need a lot of imports. Trump advise to bring manufacturing back to the United States, to  revitalization of manufacturing industry, also revitalization of the steel. According to the data showed last year, China's steel exports to the United States in 1.13 million tons, a year earlier to 2.42 million tons. Trump on Chinese steel "hate" is self-evident, and because of that, industry experts predict the short-term steel trade friction is not going to stop.

In the United States "double reverse" survey of iron and steel enterprises in China, the United States ignored the evidence of  material submitted by  enterprises in China, in the case of no or doubt, in the final stage suddenly forced to improve the rate of countervailing duties. China express  disapointment to the U.S for China iron and steel products cut out high taxes , questioned the unfair investigation method, will take the necessary measures to safeguard enterprise rights fairly.

Considering the signs of economic recovery in the world is unclear, as the Trump to power and inverse globalization trend, in 2017 the foreign trade situation is still not optimistic, steel trade friction is likely to be more, the number of steel products is still the trade friction of the hardest-hit areas this year. For Chinese companies, this is such a high "double reverse" tariffs means that Chinese enterprises will face higher prices and lower market recognition, severely weakened the competitiveness of the Chinese iron and steel products in the United States market, squeeze the Chinese iron and steel products exports to the us space.

 Although exports is falling , no need too scared. Now should timely adjust the relevant policies and strategies, put more focus on the domestic market. Of course, for own problems, we cannot turn a blind eye. China's steel exports are mainly low value-added, low technology content products, lack of competitiveness, the price is low. Of course will be considered by other countries as dumping, result intrade friction. Therefore, China should improve the value of steel products, increase the added value, enhance competitiveness, not just to preempt the market by low price products.

Shinestar group will analysis of international trade situation scientificly, seize the opportunity, meet the challenge, strive to produce more high quality carbon steel pipe, welded steel pipe, line pipe, galvanized pipe, scaffolding, and other products, for the Chinese brand in the international arena made positive noises.

Heat the Iron and Steel Industry Will Continue in 2017?

In 2017, China's steel industry will still in a critical period of transformation and upgrading, the situation is still grim. As the welding steel pipe, seamless steel pipe, galvanized pipe, straight seam submerged arc welding pipe, carbon steel pipe, scaffolding, and other products production services vendors, Shinestar group thinks, although in 2016 iron and steel enterprise profitability, a successful counter attack, but it is not optimistic.

Industry fundamentals, the situation of oversupply of steel market is not a fundamental change, iron and steel enterprise's profit foundation is still not strong enough. On the one hand, the high volatility in the prices of raw materials, such as coke, ore, iron and steel enterprise profit control to bring greater pressure. Since this year social inventory exploded on the other hand, the first week of Spring Festival domestic steel inventories rose to 50%, high inventory needs certain time, may be longer than expected time before industry. And monetary policy fine-tuning since this year, before the Spring Festival, the central bank raised lending facilities (MLF) interest rates after the mid, and after the central bank raised its multiple deadline reverse repurchase and stock lending facilities (SLF) interest rates, interest rates from the long side interest rates to short end, up market interest rate curve, liquidity tightening signs for a more cautious attitude to the futures market operation, greatly influenced by phase current linkage. There are some unclear structural steel pipe spot market direction.

The ministry released earlier this month the first announcement to cancel the specification of 35 list of iron and steel enterprise, this is the 2012 years since its steel industry standard management, start list by "addition" change "subtraction" for the first time. Means that dissolve the iron and steel industry in 2017 will further strengthening its excess capacity.

Recently, the five ministries jointly issued by the "about further implement pressure balance policy promotes the steel market has kept running notice. "Notice" pointed out that before the recovery period of steel prices, show that the serious problem of excess steel production capacity in our country have a certain degree of improvement. Recently appeared steel prices of spot and futures markets and rapid rise in the short term, but China's steel industry oversupply problem has not been fundamentally solved. Also notice again, to crack down on illegal production and sales "groud of steel" behavior, before the end of June 2017 in accordance with the law to ban the production of construction steel power frequency furnace, intermediate frequency furnace capacity, manifests the country determined to clean up behind the capacity determination.

Clean up 2017 "groud of steel" as an important content to work capacity. Provinces such as guangdong, jiangsu, hebei, sichuan also have issued relevant documents, determined to crack down on illegal production "groud of steel" production and sales. Iron and steel industry in China has developed from incremental into the stage of development, reducing the overall production capacity surplus part of the advanced capacity are resolve, "groud of steel" must clean up all.

As a based in China, service global steel production enterprises, Shinestar group will work hard to realize the transformation and upgrading, combined with their own situation to make strategic plan, produce the high quality of welded steel pipe, seamless steel pipe, galvanized pipe, straight seam submerged arc welding pipe, carbon steel pipe, scaffolding, and other products, promote the competitiveness of the enterprise.

How to Drill Galvanized Steel Pipe

Differed from the API carbon steel pipe, the galvanized steel pipe is a kind of steel pipe in nature with a zinc layer. Therefore, drilling a galvanized steel pipe is generally the same as drilling into a API steel pipe. However, there is no protection zinc layer on the drilled hole, so it may rust. Thus, the extra corrosion resistant measures should be taken. First, you should put on protection glasses to make your eyes safe. Make a sign on the center of the galvanized steel pipe where you will drill a hole later. Put the center punch towards the center of the galvanized steel pipe. And then strike center punch with the aid of the hammer to make a pit as the center sign. Thus, the sign will not be disappeared. Utilize the right size drill bits in accordance with different holes of the galvanized steel pipe. If you want to drill a large diameter into the galvanized steel pipe, you need to use a smaller drill bit first to as a leading for latter drilling. Thus, the drilling will be accurate and efficient.

In the process of drilling galvanized coating steel pipe which is unlike the API steel pipe, there will be friction and spark appearing. That is the reason way we should put on the protection glasses first. And in order to reduce this friction, you can use cutting fluid, which is sprayed on the drill bit to lessen the friction and protect your drill bit from being blunt. And then adjust the drill bit, putting it just towards the center signed on the galvanized steel pipe instead of the API steel pipe.

Put forth your strength on the drill and press the trigger to start drilling a hole on the galvanized steel pipe. If you find the drill bit is a little bit too hot, you can use the trigger on the drill motor to control the drill speed in the process of drilling a hole. Reduce the strength that you have on the drill motor when you are close to the discharge gate of the hole. Eliminate the bur of both sides of the hole of the mild steel pipe with the help of the grinder and clear up the nearby of the hole, such as dirt and metal filings.

Sway the spray can for one minute to fully make the liquids in the can blended. What this spray can have is the cold galvanizing. Put off the hat of the spray can. The distance between the spray can and the surface of the galvanized steel pipe which is different from the API steel pipe should be 8-15 inches. The function of the cold galvanizing is to cover a thin protection layer on the hole as well as the nearby of the drilled hole. And keep in mind that there is another hole on the opposite end of the galvanized steel pipe, which needs the cold galvanizing as well. Thus, repeat the above processes on the other side of the galvanized steel pipe.

More information,pls visit:Hunan Great Steel Pipe Co.,ltd

Development Innovation of Welded Steel Pipes

"The development compendium during twelfth-five period" puts forward clearly, oil and gas pipelines' total length will exceed 150000 km until 2015, representing a 90% growth in 2010. According to this, it is calculated that in the next four years we will need about 700-800 million tons of welded steel pipe to transmit oil and gas each year, which means in the next four years the length of the increased pipelines is equivalent to the sum of the past fifty years, increasing at more than 14% growth rate, providing the great opportunity for the oil and gas pipeline company. The import of China's oil is likely to exceed 3 tons until 2020, surpassing Japan, which makes China become the largest oil importing country of the world. It is essential to produce a lot of oil pipelines. At present most of the domestic gas and oil pipelines are structural steel pipe. Therefore, the using amount will increase greatly. The industry of welded steel pipes is booming.

In recent years, the steel enterprise of China in the international market is very competitive, mainly thanks to the two advantages of Chinese enterprises in the international competition. On one hand, the energy price is low in our country. The raising energy price worldwide makes the cost of the structural steel pipe steel pipe enterprises worldwide increasing constantly, but in our country, energy price is still lower than the international market, which is a cost advantage of Chinese carbon steel pipe industry. On the other hand, the environmental cost is low in our country. The environmental cost of developed countries in Europe is increasing, which weaken their competitiveness. The two advantages decide that the welded steel pipe enterprises in China have certain competitiveness in the cost of production.

However this situation will not last long in our country. First of all, the cost of energy such as oil price and gas price will increase. The electricity price is low. It is estimated that the price will also improve. Electricity is abundantly used in the industry of welded steel pipes. Therefore, the increasing energy price will impact to the entire industry. Second, the Chinese government puts forward energy-saving task. Each enterprise must implement the policy, which will improve environmental cost. If so, this will put up the price of the welded steel pipe. The difference between domestic price and foreign price will be further narrowed, that will weaken the international competitiveness of the welded steel pipe enterprise in our country.

In summary the welded steel pipe enterprise should get ready. It should actively seek technological innovation, especially the core technology innovation. Innovation is the strategic direction of welded steel pipe. The development of low carbon economy widens the welded steel pipe industry market space. The enterprise should transform the development mode and adjust the industrial structure, in order to adapt to the low carbon economy. The development direction of welded API steel pipe industry is seeking technical innovation, promoting the stable and sustainable development of Chinese welded steel pipes.

More information,pls visit:Hunan Great Steel Pipe Co.,ltd

Seamless welding technology application and development

The application of seamless welding technology:

Seamless welding technology in welding mold welding shows excellent performance, improve the accuracy of the parts, smoothness and appearance of the handsome sex, shorten the mould manufacturing cycle. Overcome the appear in the welding process has the defects of seam and effect the beauty of the mould.

Now with the global market's growing demand for high quality parts, can improve the parts precision seamless welding technology is more and more favour. The seamless welding technology, not only can help eliminate mold weld, also enhances the precision of parts accordingly, smoothness and appearance is considerable. At the same time, the  welding technology of welded steel pipe implemented effective control in the process of plastic injection forming, shorten the mould processing cycle. Due to the production of the product has excellent surface finish, so there is no need to use the secondary plating and annealing, also avoids the size change due to secondary shrinkage.

In the mold production technology of the past, near the surface of the cooling pipe layout in the mold, the product surface finish is not uniform. In some relatively new technology, through the mold core and cavity cooling pipeline of water near the resin injection area, can make the products have good quality assurance.

The development of the seamless welding technology:

New seamless welding technology adopted modern machine tools and some of the new technology. According to the technological requirements of the new technology, processing similar mesh mold core and cavity, in order to avoid its mobile and the second clamping, use the fourth axis milling machine tool, so that we can improve the tolerance dimension precision. Plate finned and water chamber cooling mild steel pipe have been more widely used, further improve the product quality and seamless welded finish.

The emergence of new seamless welding technology using a die channel design of a variety of changes and polyhedron vertical machining center milling is possible. In the actual mold forming process, the change of the die channel design can help to control the best temperature change mould heating and cooling.

Through to the important pitch diameter infiltration room for milling, can keep temperature fluctuations within 60 ℃. These infiltration room at the back of the cavity are milling, shape and cavity is consistent, can be used as high pressure steam and cooling water channel, can have cavity on the surface of the heat conduction effect, make temperature distribution more uniform, to maintain the change of temperature, to control the rate of temperature fluctuations.

Application seamless welding technology will not make workpiece warping and deformation occurs, the cavity and the mold core mold side matching don't cause any problems. In addition, due to the workpiece can be tilted, avoid using only the ball milling cutter for face processing, prolong the service life of the cutter.

If you would like to know more about carbon steel pipe,pls visit:www.great-pipe.com

Difference of seamless steel pipe and seamless copper tube

Seamless steel pipe:

In the production pipeline, refrigeration, medical air with steam, natural gas and liquefied petroleum with the progress of structural steel pipe made of copper into a residential, commercial and industrial buildings use the material of choice.

Seamless copper tube:

From a historical point of view, first is through the process of piercing seamless copper tube production will be a solid billet into a shell. Extrusion with thin wall thickness of shell is introduced in the 20th century 50 s market, at that time, already had large extruder, the extruding machine has higher extrusion speed.

In addition, the shell is also suitable for cold drawn on the cold drawing and cold drawn than they used to work on a larger unit weight on the tank drawing roller drum of cold drawn. In the cold drawing machine design is a major progress in spinner or continuous block in the pipe is widely used, the principle of which is from the wire industry development.

High speed machine according to a certain size of the pipeline cleaning, straightening, testing, marking and cutting, then transfer the product by strapping equipment based on the size of the strict processing, or is the product rewind, its purpose is to users of the cord to carry on the annealing treatment. Irregular wall thickness in the ASTM B88 and seamless copper pipe specification into 0% in a few years ago. People now are into engineering assessment basis to study again. As air conditioning applications seamless tube is more and more is produced through Schumag program, during the need to use a carbide floating plug for a straight through. This procedure with a high degree of attention to improve the control of the wall thickness. As a medical or the application of the LP steam pipelines require high inner surface cleanliness.

This requirement is implemented through the following process: dip tube to contain the appropriate chemical cleaning machine, and then by using B819 rules of procedure to detect tubular products, these provisions are specially suitable for medical air seamless copper tube, B837, natural gas and liquefied petroleum gas fuel distribution system of seamless copper tube.

If you would like to know more about carbon steel pipe,pls contact :hunan great steel pipe co.,ltd

Boiling steel plates and composed plate

1, boiling steel plates

Boiling steel plate is made of ordinary carbon structural steel pipe rimmed steel hot rolled steel plate. Rimmed steel is a steel deoxidized incomplete, only use a certain amount of weak deoxidizer of steel fluid deaeration, liquid steel oxygen content is higher, after the steel ingot mould injection, carbon and oxygen reaction produces a large amount of gas, liquid steel caused by boiling, rimmed steel hence the name. Rimmed steel carbon content is low, because of no silicon deoxidation, silicon content in steel is low (Si < 0.07%). Rimmed steel outer in boiling liquid steel caused by vigorous agitation under the conditions of crystallization, so the surface of pure, dense, good surface quality, has good plasticity and stamping performance, no big shrinkage cavity, less cutting head, high yield, and the steel production process is simple, less consumption of ferroalloy, steel cost is low. Boiling steel plate used in the manufacture of various kinds of stamping parts, architecture and engineering structure and some of the less important parts of machine structure. But rimming steel heart of impurity is more, segregation more serious, the organization is not dense, uneven mechanical properties. At the same time because the gas content in steel is more, so the toughness is low, ductile-brittle and aging sensitivity is larger, the welding performance is poor. So the boiling steel is not suitable for manufacturing work under impact load, under the condition of low temperature of welded structure and other important structures.

2, composed plate

Calm steel plate is made of ordinary carbon structural steel killed steel hot rolled steel plates. Killed steel is deoxidized steel, steel liquid before pouring with sufficient ferromanganese, ferrosilicon and aluminium deoxidation, liquid steel oxygen content is low (0.002-0.003%), the liquid steel in the ingot mould is calm, do not produce the boiling phenomenon, killed steel. Under normal operating conditions, no air bubbles in the killed steel, uniform organization; Because of the low oxygen levels, oxide inclusions in steel is less, high purity, ductile-brittle and aging tend to be small; At the same time, killed steel segregation is small, uniform performance comparison, quality is higher. Killed steel disadvantage is that the concentration of shrinkage cavity, yield is low, the price is higher. Therefore, composed of steel is mainly used in low temperature under impact of artifacts, and other components requiring high strength of welded structure.

Low alloy steel plate is composed of steel and half killed steel plate. Because of the high strength, superior performance, can save a large amount of steel, reduce the structure weight, its application has more and more widely.

Hunan Great Steel Pipe Co.,ltd is your best choice for steel plates and carbon steel pipe.

Introduce different type and type of mild steel pipe

Introduce different type and type of mild steel pipe

Steel pipe is open on both ends and has a hollow section, the length and the surrounding larger steel, specifications (such as the diameter or length) with dimension and wall thickness, says can be used in the pipeline, thermal technology equipment, industrial machinery, petroleum geological exploration, containers, chemical industry, and special purpose. In terms of steel prices, steel mills ex-factory prices continued to rebound. As of last weekend, the mainstream steel product factory price, the continuation of a week before the rally, gains from widened. Long products varieties increase higher than the flat material, proportion Gao Changcai companies such as jisco, steel prices many times recently. "chase after go up." Seamless steel tube is to point to by the whole piece of metal on the surface without seam steel pipe, according to the production methods can be divided into hot rolling pipe, cold rolled, cold drawn tubes, extruded tube, according to the cross section shape can be divided into round and shaped two kinds, according to the different wall thickness can be divided into thick wall pipe and thin wall pipe. Seamless tube diameter of 650 mm (hole diameter tube), minimum diameter is 0.3 mm (capillary), mainly used for petroleum geological exploration tube, petroleum chemical industry with cracking pipe, boiler tube, bearing and auto, aviation with high precision steel tube structure, etc.

Simple straight seam steel pipe forming process and USES

Welded steel pipe refers to the steel belt or steel plate bending deformation shapes such as round, square, jointed on the surface of steel pipe welding. According to different welding methods can be divided into electric arc welding tube, high frequency or low frequency electric resistance welded pipe and gas welding tube, furnace welding pipe, bondi pipe, etc., according to the weld shape can be divided into straight seam welded pipe and spiral welded pipe. In terms of cost, the price of iron essence pink rose slightly, coal prices basically stable, the sea freight rebound, scrap steel price rise is bigger. Data show that by the end of last week, the major domestic iron ore mines are price is 1160 yuan/ton, compared with the previous week rose 25 yuan/ton, or 2.42%. Welded steel tube used in oil drilling and machinery manufacturing, etc., the furnace pipe can be used as water, gas pipe and so on, the DSAW steel pipe used in high pressure oil and gas transportation, etc.; Spiral welded pipe used in oil and gas transportation, pipe pile, piers, etc. Welded steel pipe seamless steel tube of low cost, high production efficiency. Last week, China's major cities long plank material and total inventory is 14.078 million tons, 515000 tons, or 3.70% drop in the previous week. The long products 5.8797 million tons of inventory, weeks dropped 450000 tons, or 7.64%. Total inventory decline continues to expand, and plate 8.1983 million tons, week dropped 66000 tons. Rebar inventories hit a year low key cities for the society, for the first time is less than 5 million tons.

High frequency straight seamless steel pipe up.the welding manufacturing

Straight seam steel pipe to periodically check and test the reliability of the grounding system. DSAW steel pipe of high frequency welding is using ac electrical skin effect and proximity effect, steel (strip) after rolling forming, the formation of a cross section of broken circular tube billet, inside the tube billet near the center of induction coil rotating around one or a set of impedance (magnet) and impedance and pipe opening form a electromagnetic induction loop, under the action of skin effect and proximity effect, the pipe opening edges produce powerful and concentrated heat effect, make the weld edge rapidly heated to required after roller extrusion temperature, welding metal molten state to realize the joint between the crystal, after cooling to form a firm butt weld. To ensure that the fluid contained in the straight seam steel pipe's largest particle does not exceed the maximum security of pump a particle diameter standard. Straight seam steel pipe in high frequency is high frequency welding process  Pipe unit. The highest allowed 2 don't more than the pump inlet pressure Make use of pressure. Straight seam steel pipe ground demands in accordance with local laws and regulations and the requirements of the scene of some of the special requirements. Straight seam welded steel pipe pneumatic diaphragm pump through the reciprocating diaphragm deformation caused by volume changes in the volume of pumps, pneumatic diaphragm pump with pressure air as power. High frequency welded pipe units are usually made of roll forming, high frequency welding, extruding, cooling and sizing, flying saw cutting parts, such as the front of the unit is equipped with the loading loop, turned back end of the unit is equipped with steel frame; Electrical parts are mainly high frequency generator, dc excitation generator and instrument automatic control device, etc. Straight seam steel pipe, according to the need to use enough large cross-sectional area of the wire 4 an explosion caused by spark may cause personal casualty and property loss. 11 when flammable and poisonous liquid. High frequency welding is a kind of induction (or contact pressure welding) welding, it need to weld filler, no welding spatter, narrow welding heat affected zone, weld moulding beauty, weld merit such as mechanical performance is good, so is widely used in steel production. Straight seam steel pipe is made by high frequency welding machine to certain specifications of the long bar steel coil into circular tube shape and straight seam welding and straight seam steel pipe. Material of welded steel pipe are mainly: low carbon steel and sigma acuities were 300 n/s was, sigma acuities were 500 n/s was of low alloy steel and other steel products.

If you would like to know more about this,pls contact:hunan great steel pipe co.,ltd