Dredging Steel Pipe

Dredging mild steel pipe is mainly used for cleaning conveying silt, mud and other mixed sundry steel pipe. Flood drainage, dredging steel pipe is widely used in summer beach, river, channel, urban environmental protection, construction and other fields.

Dredging for steel pipes is nominally dredging dredge, expanding or dig deep lakes and other water, underwater conditions by human or mechanical excavation engineering. Generalized dredging including water next to the reef blasting method, blast beach, etc. Artificial excavation is only applicable to small rivers can block construction.

Mechanical construction is widely used all kinds of dredger, sometimes with rope shovel on land construction machinery.

Mechanical dredging began in 1600, in the construction of the port of Rotterdam, the Netherlands bucket dredger. In 1889, China began to huangpu river by dredger construction. New waterway dredging engineering is widely used in: (1) excavation, ports, and the canal. (2) be deepened and widened and clean up the waterway and port. (3) dredge channel, channel and reservoir dredging. (4) of excavated dock, the dock, lock the hydraulic structural steel pipe such as foundation pit. (5) of reclaimed stretched with dredging, reclamation and other projects. 6. Remove underwater obstacle.

Physical Test Methods of Structural Steel Pipe

There are many kinds of steel pipe quality physical test methods of steel structural steel pipe, including physical method which is the most commonly used inspection method, physical test some physical phenomena is used for measurement or test methods. Internal defects of materials or the workpiece inspection, are generally adopt the method of nondestructive flaw detection. Current NDT magnetic testing, ultrasonic testing, X-ray flaw detection, penetration testing, etc.

First is the magnetic testing can only be found in magnetic metal surface and near surface defects, and can only do quantitative analysis of defects, for the nature of the defect and depth can only estimate according to the experience. Magnetic inspection is magnetized ferromagnetic metal parts of the magnetic fields generated by the magnetic flux leakage to find defects. According to the different method of measurement of magnetic flux leakage, the magnetic particles can be divided into method, induction method and magnetic recording, of which the most widely used method of magnetic powder.

Followed by some liquid penetrant inspection is to use the physical properties such as permeability to find and display defects, including two fluorescent dye penetrant inspection and testing, can be used to check the ferromagnetic and the defects on the surface of the ferromagnetic materials.

Followed by X-ray detector is to use the rays can penetrate and attenuation in the material properties to found a flaw detection method. According to the detection of radiation is different, can be divided into X ray flaw detection and gamma ray flaw detection and high-energy X-ray detector. Due to the different methods display the defect, each ray flaw detection and ionization method, screen method of observation, photography and industrial television method. Ray test is mainly used to test the inside of the weld crack, lack of penetration, porosity, slag inclusion and other defects.

Followed by ultrasonic wave in the metal and other homogeneous medium propagation, due to the different medium interface will produce reflection, thus can be used for internal defect inspection. Ultrasound can test any welding materials, any part of the defects, and is more sensitive to find defect position, but the nature of defects, shape and size are difficult to determine. So ultrasonic testing is often used with X-ray inspection for carbon steel pipe.

Heating Conditions To Be Met of SSAW Steel Pipe

Before hot rolling of  steel plate, to heating not only improve the metal and plastic raw materials, reduce the deformation force, and convenient in rolling. In addition, the steel in the process of heating, the ingot can also eliminate the ingot bring some tissue defects and stress. Spiral welded steel pipe manufacturer for steel heating should be put forward requirements:

1. In the section of billet temperature uniformity and the length direction;

2. The steel temperature should meet the requirements of rolling technology;

3. The heating furnace's accident, long service life;

4. The furnace has a good technical and economic indicators;

5. Reduce the oxidation of the metal and decarburization, to prevent overheating and burning;

Main Points of Large Diameter LSAW Steel Pipe Processing Technology

Large diameter LSAW welded steel pipe processing technology main points: (1) processing of reinforced thread of large diameter pipe, wire head  teeth form and pitch and other necessary and cohesive set of teeth form and pitch, and form a complete set of gauge to check the qualified. (2) the steel bar thread machining, should choose water soluble cutting fluid lubrication; When temperature is lower than 0 ℃, should be mixed with 15% - 15% of large-diameter structural steel pipe sodium nitrite, shall not be made lubricants or without lubricant oil set of silk. (3) the operator should check each steel wire head the appearance quality and make the operator symbols. (4) a steel wire head through self-inspection, respond to each 10% random sampling inspection of large diameter square in jiangsu standard manufactured, and not less than 10, if there is a, namely the batch processing full view, unqualified silk head should be heavy processing, the after inspection qualified can be used again. (5) mild steel pipe has inspection qualified wire head, put on the maintenance cap should be maintained, and according to the standard classification of neat.

Requirements of SSAW Used for Piling Driving

What requirements are required to spiral welded steel pipe used for pile driving

Piling with spiral steel pipe is hot rolled steel coil tube billet, often spiral shape, made of double-sided submerged arc welding or high frequency welding, used in civil construction, port, bridge pile foundation with steel pipe. So what requirements are required to piling with spiral steel pipe? Here give you a detailed analysis of spiral tube mill.

1, raw material is steel strip coil, wire, flux. Have to pass strict physical and chemical inspection before investment.

2, the head and tail docking strip, use single or double wire submerged arc welding, after rolled steel tube adopts automatic submerged arc welding repair welding.

3, have continuous acoustic detection of weld mark parts, after manual ultrasonic and X-ray check, if there are defects, after repair, again through the nondestructive inspection, until defects have been eliminated.

4, strip steel butt weld and fellowship with spiral weld d joint in the tube, all pass X-ray films and television inspection.

5, each carbon steel pipe after hydrostatic pressure test, radial sealing for the pressure. Test pressure and time are controlled strictly by steel pipe hydraulic microcomputer testing device. The parameters automatically printed out.

6, after welding the weld passes the online continuous ultrasonic automatic meter check, ensure spiral weld nondestructive testing coverage of 100%. If there are defects, automatic alarm and spray tags, production workers to adjust process parameters, in a timely manner to eliminate defects.

After 7, cut into single pole, the head of every batch of steel pipe should be strictly check system, check the weld mechanical properties, chemical composition, amalgamation, structural steel pipe surface quality, and through the nondestructive flaw detection, ensure that qualified pipe process, can be formally put into production.

Epoxy Coal Tar Anti-corrosion Coating

Epoxy coal tar anti-corrosion paint is composed of epoxy coal tar with two main components, is a (epoxy) b (hardener) a two-component coating steel pipe, has excellent adhesion, toughness, resistance to moisture, water resistance, resistance to chemical media, have prevent various ions through the performance of the paint film with the coated objects with the characteristics of expansion and contraction. It never falls off and cracking.

The thickness of 0.5 ~ 1.0 mm.

Epoxy coal asphalt is a kind of anticorrosive form of high cost performance, engineering measurement show that the use of epoxy coal asphalt plus cathodic protection. Oil and gas pipelines using 20 years almost no corrosion occur.

Recommended use

The product can be used as the water of the sea or fresh water pipeline outer wall corrosion, the outer wall of underground pipelines, the outer wall of heat carbon steel pipe, sluices anti-corrosion paint, also can be used as a treatment tank, storage tank, coal mine shaft headframe anticorrosive paint, such as in the outer wall of pipeline coating, and glass fiber cloth bandage, become strengthen level and strengthen the level of coating, anticorrosive performance.

Welded Steel Pipe and Flammable Vapors

When using carbon steel pipe tools, we might as well avoid frequent contact with skin and eyes. In case of contact, flush with plenty of water should not last long since if irritation persists, welded steel pipe might be eroded. The beveled pipe end helps spread the solvent easily as the welded steel pipe is joined to the fitting. By doing so, all burrs should be removed from the inside as well as the outside, of the pipe ends with the help of steel pipe tools. Special pipe tools can be used quickly and efficiently along with wrenches. The special woven nylon straps are extra strong and are specially treated for slip resistance so they can provide gripping power for turning steel pipe tools. This can be achieved without scratching or deforming the pipe as long as we follow the precautionary statement of welded steel pipe.

What is more, we may use the pipe system with caution due to the welding torches at construction sites. In those locations, welded steel pipe is being installed and special caution should be taken when we are using welding torches or other equipment. This is because sparks might be involved when using steel pipe tools. Flammable vapors from welded steel pipe joints sometimes linger within or around a piping system for some time. What is more, special care of structural steel pipe tools must be taken for much lower emissions per event. In addition, it is useful to define a potential flow back and the average number from the national inventory is slightly higher at 151 Mg.

Such an approach would be grounded in observable welded steel pipe patterns since it has robust physical variables. Thus, we can connect the demand or input with the secondary resource supply so that the output has a potential to significantly improve economic profits of the welded steel pipe. The iron cycle consists of transformation and market processes and is connected by flows of goods. It can be quantified for the period 1900–2004 and rough estimates are made so as to obtain reasonable initial conditions for welded steel pipe.

Data sources and model assumptions are also available based on mass flows of goods and steel pipe tools. Where no statistics could be obtained, data can be derived from mass balances and model assumptions without any doubt. The processes of welded steel pipe manufacturing can be divided into a range of categories. Industry stocks are neglected because of their small size but iron can be incorporated for

Corrosion Resistance of API Steel Pipe

All stainless steel pipe coating contains principally iron and a certain rate of chromium. At this level, such elements as chromium will not react with oxygen and moisture in the environment so API steel pipe will not be corroded. This is largely because mild steel pipe coating forms a protective and coherent layer. What is more, oxide film can envelop the entire surface of API steel pipe and the passive or boundary layer is very thin. To be more specific, the passive layer and steel pipe coating on stainless steels exhibits a truly remarkable property in many applications. For instance, when API steel pipe is damaged or abraded, the chromium in the steel pipe coating reacts can reform the oxide layer.

Thus if we increase the chromium content in steel pipe coating beyond the minimum of ten percent, the API steel pipe will have greater corrosion resistance. In terms of steel pipe coating, corrosion resistance may be further improved and a wide range of properties are offered by API carbon steel pipe producers. What is more, the addition of more nickel in steel pipe coating will further increase the corrosion resistance of API steel pipe. In particular, the API steel pipe resistance to pitting corrosion will be on the increase as long as nitrogen increases. Due to this reason, the mechanical strength of API steel pipe will be enhanced along with the resistance to pitting. In fact, steel pipe coating in use is in accordance with the metal cycles. Tens of thousands of workers rely on the steel pipe coating industry to support their lives. In some cases, API steel pipe is considered as a source for future secondary metal resources.

At the same time, it has been noticed that the market demand for API steel pipe generates demand for better coating steel pipe . Despite their great importance and their impacts on other parts of the API steel pipe, the study of in-use steel pipe coating has been widely neglected. Thus, we need to investigate this issue by analyzing the steel pipe coating cycle and its development in recent years. This is marked by the same order of magnitude on a global scale even though steel pipe coating is less significant compared with other steps in making API steel pipe. But their relative importance is increasing without any doubt so that API steel pipe will function well in various conditions. With a perfect API steel pipe recycling system, many developed nations could substitute scrap utilization for industry usage. In addition, steel pipe coating is also applicable to other metals as well and it could allow a significant improvement in the long term.

Decision on Whether Using Seamless or Welded Pipe

The wall thickness or diameter ratio and the specified carbon steel pipe tolerances are the two mainly factors influence people choose in using seamless pipes or welded pipes. Next we will introduce some factors which influence whether using seamless or welded Pipe. Availability is the first factor which can influence people whether using seamless or welded pipe. Therefore, from wide material in stock we may only provide a limited number of alloys when manufacture the seamless hot rolled pipes. We may not use the steel plates or coils for they are shortage. These plates or coils are mainly used to produce welded pipes with numbers of different material grades. We can recover from special alloys and service stores with the small quantities of raw materials. Alloy C4 is also a kind of service stores or special alloys and we can cut them and get them from wide material which is in stock. This is the first factor which can influence people whether using seamless or welded pipe.

Tolerances are the second factor which can influence people whether using seamless or welded mild steel pipe. The hot rolled seamless pipes have f 12.5 percent of wall thickness tolerance. In ASTM A999 or EN ISO 1127 T2, the hot rolled seamless pipes are fundamentally specified. However, the manufacturing procedure can cause differences in thickness of the wall. We can use the wall thickness differences to lead a possible eccentricity. In the other word, we can use the wall thickness differences to form a deviation which is from symmetry. The tolerance of welded pipes wall thicknesses usually is ASTM A999 to EN ISO 1127 T3. In order to make sure that the wall thickness tolerance are very constant when pass through the entire pipe body and make sure that the wall thickness tolerance are the best tolerance, we should take the evenness of the coil thickness or the steel plate into consideration. They are the second factor which can influence people whether using seamless or welded pipe.

Pipe lengths and quantities are factors which can influence people whether using seamless or welded pipe. We may produce the length of seamless pipes relying on the weight a meter or a rod. From this, we can know that the lengths of pipe would maximum 13 meters when the lengths of pipe up to NB 100. While the lengths of pipe would maximum 4 meters when they are up to NB 200. Then we can produce the lengths of pipe with maximum 4 meters. Coil is the main material to make the minimum production. Those are factors which can influence people whether using seamless or welded steel pipe.

Welding Frequency Influences the Quality of Welded Steel Pipe

In general, the influence on welded steel pipe quality because of high welding frequency is as follow.

Steel weld gap control
When the welded steel pipe is in the process of welding, please ensure the opening angle of the weld flush is in 7degree or smaller, and the gap is between 1-3 mm. Otherwise, the welding of the steel pipe may be poor, such as the weld crack produced on the surface of the welded steel pipe is incompletely fusion. On the contrary, if the weld control is too small, there are also severe problems caused by excessive heating, for example, weld burning, molten metal splash, and in turn influence the quality of welded steel pipe. Why the molten metal splashes is because the pressure of the internal is greater than the pressure on the weld surface when the melt is out of the pipe side.

Regulation of high-frequency induction loop position
Usually, the induction coil loop should be placed in the same center line pipe. When the loop is distant from the squeeze, the squeeze rollers will not burn. Whether it will burn or not depends on the size between the induction loop and the welded structural steel pipe. If the size is too big, and then the induction loop is too far away from the welded steel pipe, the strength of welding will decrease. The tighter the coupled induction coil, the better the welding strength. In addition, the diameter of a single circle must be equal to the width of the induction coil pipe. The oscillation frequency and output efficiency can be affected by optional lap or two laps.

Magnet position control
The magnet, which is also called impedance, is one of the most important parts of the cross-sectional area of the welded steel pipe. It can be used to strengthen the electromagnetic induction, and concentrate the heat weld edges. If the temperature is lower, then the permeability of the magnet will be higher. Besides, where to place the magnet may have an great influence on the efficiency and quality of the carbon steel pipe welding, so it is better to place the magnet in the heating section V-zone, which is front of the roll center.

Shinestar Won 2016 Alibaba Hundreds of Millions ISPS Award

Dec 23, 2016, looking for new foreign trade in Hunan and 2016 annual Hunan network business awards ceremony held in Changsha, about a hundred foreign trade enterprises attended the meeting, Shinestar won 2016 "Hundreds of Millions ISPS Award ", the Executive Director of Shinestar Wang Li was invited to attend and receive the award.

The awarding activity is hosted by the Kaifu District People's Government, supported by Alibaba. The activities summed up the development of 2016 Hunan foreign trade business model, commended some foreign trade enterprises' outstanding achievement in e-commerce. It has promulgated the "Annual Top Ten ISPS," "Special Contribution Award", "Ten Million ISPS Award" and "Hundreds of Millions ISPS Award " and other eight awards. Shinestar won "Hundreds of Millions ISPS Award " with excellent sales performance, as well as the special contributions to develop Hunan e-commerce, which has been warmly concerned by the on-the-spot guest.

Shinestar is based in China,service global production of large steel enterprises, is committed to global customers with high quality steel products and services.In 2016, although the environment is not good, many companies have encountered had difficulties and challenges, but Shinestar has successfully bucked the trend,Steel sales exceeded 4 billion yuan, more gains of the 2016 "Hunan top 100 enterprises "award.Behind these achievements, the role played by e-commerce is pivotal. E-commerce for Shinestar to create more business opportunities to help brands better open visibility, but also to bring effective and convenient management of the Shinestar, in terms of reducing the cost of marketing is playing a significant role.

Shinestar Steel Group CEO Wang Li said Shinestar either from capital investment or talent reserves have attached great importance to the development of E-commerce,  has achieved preliminary results,2016 through the electric business platform for sales performance is proved by leaps and bounds.But e-commerce in the steel industry is  still in the early stages of development, great potential, in the end how to do, how to do a good job, is a very worthy of study. Shinestar also in unceasing exploration,  hope can be in the future and electricity business elite, industry experts to explore and research.

The Shinestar won "Hundreds of Millions ISPS Award "  honor,both a positive result of the past, but also an encouragement for future development. Shinestar will take this as a new starting point, continue to promote the development of e-commerce, and continuously enhance the core competitiveness of enterprises.To create "century of  steel enterprises in the field of overall service bench marking", and continuous efforts.

Coal Mine Steel Market volatility in 2017, You Must Guard Against the Risk

Review of China's steel prices in 2016, has experienced a rise in the first quarter, falling in the second quarter, third quarter concussion rose slightly, began shock rise into the fourth quarter, the overall profit has got improvement. According to the current raw material product price comparison relations, steel mills have a small profit, the coal industry profits in good condition.   

Shinestar steel research institute predicted that next year the domestic economy stabilises, turned to the steady monetary policy, focus on inhibition of asset bubbles and guard against financial risks. As a result, the market game could turn into a policy game, black tie commodity market volatility will increase. External aspect, the depreciation pressure will be largger; Internally, the supply side gradually accelerate structural reform; And infrastructure construction has a great potential demand in Asia, Europe and the United States and emerging economies developed economies infrastructure upgrades will bring more opportunities, black series product prices logic could be evolved from the supply side of booster for the push on consumer demand.

At the same time, the uncertainty of Trump was elected President of the United States, the European Union member states factors such as bankruptcy, or will lead to global debt or local financial crisis, demand side can lead to weak, which affects commodity prices. In addition, real estate is one of the largest terminal black series product demand, real estate speculation are suppressed, "area" construction is expected due to investment, long cycle, more difficult to make up for short time and replace the real estate market needs of rapid change. Domestic and social excess liquidity will be poured into the futures market, fry high spot market at the same time, the need to guard against a periodic extreme raw material market.

Black series products especially coal, in the second half of this year the price rise is bigger, brought together a certain risk. But become a relative shortage of coking coal resources, especially after a market-oriented elimination in recent years, the state-owned coal enterprises in improving the assets and liabilities, expansion willingness and ability is not strong, difficult to apply for a loan from the bank, on the verge of bankruptcy private enterprises cannot fast recovery capacity, supply increased dramatically, hard coking coal supply and demand is expected to relative balance as a whole. Iron and steel enterprise operation situation is not optimistic at the same time. With the advancement of environmental protection and nature to capacity, the steel supply is hard to continue to effectively increase like this year, iron and steel enterprises is expected to present certain improvement in operating performance. Shinestar steel group will make persistent efforts, and constantly provide customers with more high-quality carbon steel pipe, spiral welded steel pipe, stainless steel pipe, scaffolding, etc.

Shinestar steel research institute believes that the iron and steel enterprises in the procurement, need to scientific research market, grasp the market opportunities and benefits, positive for purchasing and make the effect; Steel sales department must be good at seize effective order, the production department to keep steady production, continue to produce line pipe, submerged arc weld spiral welded steel pipe, stainless steel pipe, scaffolding, etc. The company which have conditional and basic, could participate in hedging appropriately, but must keep smooth operation, watch the market risk.

How to Pile up Spiral Welded Steel Pipe?

Spiral welded steel pipe manufacturer produces spiral steel pipe are generally mass production, and the specifications of the various production, the production of spiral steel tube how to pile up? Correct stacked spiral steel pipe is conducive to protect the quality of the spiral steel pipe, prolong the life of the spiral steel pipe, prevent deformation, erosion, do well organized stacked spiral steel pipe, but also to the loading of late spiral steel pipe, inventory. Spiral steel pipe buyers should also be stacked spiral steel pipe according to request.

Below small make up to you to introduce spiral steel pipe right stacking principle.

1) spiral steel pipe, deposited in the open air under the required by wood or stone, crib shall be slightly tilted, and to facilitate drainage, and pay attention to material placed flat, prevent caused by bending deformation.

2) the principle of spiral steel pipe stacking requirements is in the pallet, ensure safe premise, do according to the varieties, specifications of pallet, different kinds of materials to pallet respectively, prevent muddied and mutual erosion, also facilitate outbound loading.

3) ban on spiral steel pipe pile a deposit of steel erosion things around.

4) spiral steel pipe pile bottom should be higher, solid, smooth, prevent the material to be affected with damp be affected with damp or deformation,

5) the same material in warehouse stacking respectively.

6) structural steel pipe stacking height, artificial homework no more than 1.2 m, the mechanical work no more than 1.5 m, crib for no more than 2.5 m wide,

7) between pile and pile should have certain channels, check way for o. commonly 5 m, access depending on the material size and transport machinery, general is 1.5 ~ 2. Om,

8) Angle steel and channel steel should be deposited in the open air, over the mouth down, beams should be made to put, steel tank I face up, not to avoid water accumulation of rust.

9) pile bottom cushion is high, if the warehouse to the cement ground, higher o. 1 m, if the mud, to cushion high o. 2 ~ 0.5 m. If the open area, cement floor mat high o. 3 ~ 5 m o., sand and mud surface mat high 0.5 ~ o. 7 m.

Above is the right spiral carbon steel pipe pile up principle, to ensure the quality of the spiral steel pipe, must according to the principle of piles.

Structure and usage of Sprial Welded Steel Pipe

(1) the raw material is steel strip coil, wire, flux. Have to pass strict physical and chemical inspection before investment. (2) the strip head to tail docking, use single or double wire submerged arc welding, after rolled steel tube adopts automatic submerged arc welding repair welding. (4) on both sides of the electric contact pressure gauge control conveyor under the pressure of oil cylinder pressure, ensure the smooth delivery of strip steel. (5) the use of external control or internal control roll forming. Spiral steel pipe/spiral welded steel pipe/spiral steel pipe factory price (6) the weld gap control device to ensure that meet the requirements of welding seam clearance, pipe diameter, and quantity of the wrong side of weld gap are tightly controlled. (7) welding and welding are used within the United States Lincoln welding machine for single or double wire submerged arc welding, to obtain the stable welding specification. (8) after welding the weld passes the online continuous ultrasonic automatic meter check, ensure the spiral weld nondestructive testing coverage of 100%. If there are defects, automatic alarm and spray tags, production workers in accordance with the adjuster art parameters at any time, in a timely manner to eliminate defects. (9) by air plasma cutting machine to cut the steel tube into single. After cut into single pole (10), the head of every batch of structural steel pipe should be strict inspection system, can check weld mechanical properties, chemical composition, amalgamation, steel tube surface quality and the nondestructive flaw detection, ensure that qualified pipe process, can be formally put into production. (11) have continuous acoustic detection of weld mark parts, after manual ultrasonic and X-ray check, if there are defects, after repair, again through the nondestructive inspection, until defects have been eliminated. (12) strip steel butt weld and fellowship with spiral weld d joint in the tube, all pass X-ray films and television inspection of mild steel pipe.

OCTG Steel Pipe

OCTG is mainly used for oil and gas well drilling and oil and gas transportation. It includes oil drill pipe, casing, pumping tubing. Oil drilling mild steel pipe are mainly used to connect the drill collar and bit and pass the drilling power. Oil casing is mainly used for drilling and completion of the sidewall of the support in order to ensure the normal operation of the wells in the conduct and completion of the drilling process. The pumping tubing wells at the bottom of the oil and gas transmission to the ground. According to strength of steel,casing can be divided into different grade of steel, that is, J55, K55, N80, L80, C90, the T95, P110, Q125, V150. And so on. Well conditions, different depth of the steel grade is also different. Also requires the casing in corrosive environments with corrosion resistance. Casing with anti-collapsing performance in complex geological conditions. Oil Casing is the lifeline to maintain a well run. Due to different geological conditions, underground stress state of tension and compression, bending, and the combined effects of torsional stress acting on the carbon steel pipe, which has put forward higher requirements on the quality of the casing itself. Once the casing is damaged for some reason, may lead to the production of the wells, or even scrapped.

Welded Steel Pipe for Pipeline

Pipeline is put oil,gas,water out of the ground, transported to the oil and gas industry enterprises through the line pipe including seamless pipe and welded steel pipe. With the development of the pipeline steel plate and pipe forming，welding and technological progress, and gradually expand the scope of application of the pipeline with the pipe, especially the advantages become more pronounced wet group within the distance range of large diameter pipe, in addition, the cost factors pipe,which has a dominant position in the field of structural steel pipe, limiting the development of stainless steel seamless line pipe. Seamless line pipe production in 2004 about 400 000 t steel grade X42-70, the varieties of line pipe on land and undersea pipeline. Production of high grade steel line pipe micro-alloying heat treatment process, stainless steel seamless pipe production costs are significantly higher than the pipe, and with the improvement of the steel grade, such as the above-X80 steel grade pipeline restrictions on carbon equivalent difficult for the conventional process of seamless steel pipe to meet user requirements; the 12Cr1moV alloy coating steel pipe production plant in order to improve its pipeline corrosion resistance, low temperature, high-temperature environments the use of stable performance and carry out research work.

Commonly Quality Problems of Mild Steel Pipe

In recent years, China's pipeline construction ushered in a new development of the peak. At the same time, the world market for steel pipe demand increases rapidly, so a large number of Chinese steel pipe exports. Behind the production and application of this prosperity, there have been some quality issues, some of the problems is indeed worrying. Quality of domestic mild steel pipe  Size deviation Size deviation in the straightness of the steel pipe, roundness and wall thickness uneven aspects. In most cases, little straightness tolerance of steel pipe used in the manufacture of standard steel pipe straightness requirements, if you exceed the specified value, will constitute a return of reason, therefore, the factory should be attention.  The roundness of the ultra-poor will affect the use of steel pipe, mainly on the wrong side of the group of welded joints. Will not only welded joints by the circular degree of tolerance resulting from the wrong side of bearing capacity of reduced also produce stress concentration. On-site group, some roundness of the steel pipe can be rectified, and some thick-walled steel pipe is not easily corrected. The outside diameter deviation and roundness of steel pipe used in a considerable difference.  The wall thickness of the uneven and generally easy to be ignored, and not clearly defined in many steel pipe standards. If the wall thickness and severe uneven, not only will cause the wrong side of the group on the joint, but also the secondary deformation processing (such as welded steel pipe manufacturing pipe fittings) adversely affect. Construction site feedback information on, serious non-uniform wall thickness steel pipe  Welding is very difficult. Therefore, many users started to pay attention and limit the wall thickness of the non-uniform bias. Structural steel pipe of uneven thickness deviation level of control actually reflects the level of manufacturing of the steel mills. Chemical composition .

DIN30670 Standard of Coating Steel Pipe

DIN 30670 refers to polyethylene coating steel pipe and fittings –Requirements and testing.

This standard specifies requirements for factory-applied three-layer extruded polyethylene-based coatings, and one- or multi-layered sintered polyethylene-based coatings for the corrosion protection of steel pipes and fittings. The coatings are suitable for the protection of buried or submerged steel pipes at design temperatures of –40 °C up to +80 °C. The present standard specifies requirements for coatings that are applied to longitudinally or spirally welded or seamless steel pipes and fittings used for the construction of pipelines for conveying liquids or gases. Applying this standard ensures that the PE coating provides sufficient protection against the mechanical, thermal and chemical loads occurring during operation, transport, storage and installation. DIN EN ISO 21809-1 specifies requirements at international level for three-layer extruded polyethylene- and polypropylene-based coatings for carbon steel pipe for petroleum and natural gas pipeline transportation systems. The following fields of application are not covered by DIN EN ISO 21809-1: ─ all polyethylene-based coatings for steel pipes and fittings used for the conveyance and distribution of water and wastewater, ─ all polyethylene-based coatings for steel pipes and fittings in distribution pipelines for gaseous and liquid media, ─ single- and multi-layer sintered polyethylene-based coatings for steel pipes and fittings used for transport pipelines and distribution pipelines The present standard remains valid for the above fields of application. Two-layer polyethylene-based coatings are standardized at European level in DIN EN 10288 which was published in December 2003.

Materials shall be selected at the discretion of the coater because, depending on the installation and coating procedure, various materials can be used to comply with the minimum requirements specified in this standard for the finished coating. Any deviating requirements of the purchaser regarding the materials to be used shall be subject to agreement.The surface shall be prepared by removing rust by means of blast cleaning. Blast cleaning and any necessary subsequent work shall not result in the reduction of the minimum wall thickness specified in the technical delivery standards for the structural steel pipe. Residual abrasive dust shall be removed prior to coating.

Pickling Technics for Carbon Steel Pipe

Carbon steel pipe pickling method currently are used in the construction and management of two trough pickling pickling inner loop. 

(1) trough pickling. The installed piping removed after decomposition into pickling bath soak treatment after passing their secondary installation. This method is suitable for larger diameter tube short, straight, easy to disassemble, piping and a small amount of on-site piping system hydraulics hydraulic piping construction of small amounts of occasions, such as pumping stations, valve stations inside, can be used trough pickling method. 
(2) structural steel pipe loop pickling. In the installed hydraulic components in the hydraulic lines disconnected or removed with a hose, receivership, rinse cover joints, constitute rinse loop. Acid pump acid into the circulating loop pickling. The pickling method is more advanced construction technology in recent years, with the pickling speed, good effect, the process is simple, easy to operate, reducing pollution on the human body and the environment, reduce labor intensity and shorten the pipeline installation period, resolve long lines and complex piping pickling difficult problem, and to avoid secondary pollution problems trough pickling easy assembly occurs, has been widely used in the construction of large hydraulic system piping. 

Pickling formula and process piping will cause unreasonable tube wall can not be completely ex oxide, wall over corrosion, corrosion of the coating steel pipe wall and the tube again residual chemical reactions sediment and other phenomena.

Lamination Defect Control Measures of LSAW and DSAW Steel Pipe

Lamination defect control measures of DSAW steel pipe is following below:
1, to improve the toughness of plastic tube
Improve the cleanliness of molten steel, to reduce the harmful inclusions; increase the proportion of the slab crystal axis, to reduce the center segregation and center porosity; the use of reasonable cooling system to avoid cracks occur within the slab; billet or rolling slab to be taken offline slow cooling process, reduce internal stress, thus ensuring the microstructure and mechanical properties of the finished tube and pipe meet the technical standards.

2, the reasonable control of the heating temperature
By measuring the thermoplastic curve, choose the best heating temperature. Note also that there is enough heating tube holding time, in order to reduce and improve plastic deformation resistance and toughness.
 
3, lower roll speed
Roll speed is a key parameter piercing process, the roll speed from low to high variations in the process, there is a critical stratification began the roll speed. Lower roll speed, easy to form tube bore; higher roll speed, tube and capillary easily form a layered defects. In order to eliminate delamination defects and capillary tube, roll speed should be reduced to the beginning of the critical delamination roll speed of these mild steel pipe.

Limitations of DSAW Steel Pipe

DSAW steel pipe also has its own shortcomings, spiral steel hollow section is used as a large number of pipeline fluids, such as transportation of oil, natural gas, gas, water and some solid materials, pipes and so on. Compared to other steel and solid steel bar, the same torsional strength in bending, lighter, is an economic cross-section steel, widely used in the manufacture of structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle rack and construction using steel scaffolding.

Structural steel pipe manufacturing annular parts, can improve material utilization, simplify the manufacturing process, saving material and machining time, such as bearing rings, jack sets, has been widely used to make steel. Steel or a variety of conventional weapons indispensable material, barrel, barrel would have to make steel. Pipe according to different cross-sectional shapes can be divided into tube and shaped tubes. Because in the perimeter of equal conditions, the largest area of a circle with a circular tube can carry more fluid. In addition, the circular cross section to withstand internal or external radial pressure, the force is uniform, so the vast majority of pipe is pipe.

However, the mild steel pipe also has some limitations, such as under the conditions by plane bending, tube as good as square, rectangular tube large flexural strength, the skeleton of some farm machinery, steel and wood furniture on the popular square, rectangular tube. According to different uses should also have other special-shaped pipe cross-sectional shape.

Solutions of Oil Casing Folding Defects

Casing mild steel pipe in the production prone to outer folding defects, affect product quality improvement, it needs to be controlled.

There are several outer folding edge oxide particles cause segregation of elements, with a folding, an oxide middle folding, the presence of an excess of Al, Mg, Ca, S, P, Mn, Si outer folding element, particularly at the grain boundaries have 20μm so brittle inclusions SiO2 and silicates, intergranular fracture occurs, and said brittle inclusions is the main reason for the formation of the outer fold.

Smelting process:
1) To ensure that a pull carbon hit, after avoiding blowing carbon control endpoint> 0.10%;
2) Increase the effect of converter slag, slag under strict control, the departure process using slag, a steel ladle slag after thickness <50mm;
3) Double slag operation, control phosphorus content of the molten steel.

Refining process:
1) LF refining processing time ≥20min;
2) Strengthening deoxy go mixed results. Requirements refining slag basicity ≥2.5, slag ≤1%, white residue retention time ≥15min;
3) After the end of the bottom blowing argon refining to ensure soft blowing time ≥10min, to facilitate removal of molten structural steel pipe inclusions.

Casting process:
1) Using a ladle, tundish, protective casting and seal argon, oxidation-free protective casting;
2) Casting temperature: tundish superheat less than 20 ℃;
3) The use of mold level brake control, electromagnetic stirring;
4) Using special flux, to ensure the quality of the slab surface.

Finishing processes:
To reduce the white spots caused by hydrogen induced cracking deal billets and bars the use of slow cooling process with carbon steel pipe.

The Basic Information of Steel Pipe ASTM Standards

As known to all that steel pipes contains API carbon steel pipe, black steel pipe ,welded steel pipe,but whether you know the knowledge of ASTM Steel Pipe Standards. Today,we can discuss the problem of ASTM Steel Pipe Standards.

When it comes to ASTM Steel Pipe Standards,the first thing we need to consider is that what is ASTM. From the wiki,we can find that ASTM is a large organization that develops standards for different materials which are manufactured and generally used in construction or industry. And the organization is what is called a voluntary standards development company and they are independent of the manufacturers. Standards for each type of pipe can be downloaded or purchased in print from ASTM and several other website which host their documentation.
The mild steel pipe grading will be divided Depends on ASTM standards and ASME standards. And ASTM's steel standards are instrumental in classifying, evaluating, and specifying the material, chemical, mechanical, and metallurgical properties of the different types of steels, which are primarily used in the production of mechanical components, industrial parts, and construction elements, and other accessories related to them. The steels can be of the carbon, structural steel pipe, stainless, ferritic, austenitic, and alloy types. These steel standards are helpful in guiding metallurgical laboratories and refineries, product manufacturers, and other end-users of steel and its variants in their proper processing and application procedures to ensure quality towards safe use.

There are a lot of category of ASTM standards available,such as A514 steel,ASTM A325,ASTM A354,ASTM A490,ASTM A500,ASTM A53,ASTM C 1112 and so on. However,how to decide a steel pipe's grade? And ASTM conducts testing in controlled conditions, such as mechanical tests that include bending, hydrostatic and flattening by machine. When testing welded steel pipe for welding purposes, the ASTM takes into consideration standard, tungsten arc welding techniques.

What Should You Know About API Steel Pipe?

There are various kinds of steel pipes both in domestic and international markets for your selection. For example, the API steel pipe is one of the popular steel pipes actually. They are widely used to transport gas, oil or water. The API pipe can be classified into seamless steel pipe, ERW steel pipe, submerged arc welded steel pipe and so forth.
The API is short for American Petroleum Institute actually. The API pipe is very popular among oil and gas exporters across the world for their reliability. There are also various kinds of API pipes which are designed to satisfy different kinds of requirements in diverse areas.
The API pipe is different per size, length, thickness and so forth. They are created to satisfy different petroleum industry requirements, like production, refinement, distribution and so forth. It is the ideal choice for use in gas lines actually. Such kind of mild stee pipe is very popular among gas and oil exporters for their reliability. The pipe should be provided with high quality, robustness and mechanical toughness actually. And API pipe should be strong enough to withstand all kinds of harsh weather and the temperature conditions in the petroleum industry for production, distribution and so forth.
Nowadays, with the development of science and technology, and with the development of communication, it is not difficult for you to find a reliable API carbon steel pipe supplier. You can choose it from physical suppliers and online suppliers actually. There are various kinds of steel pipes every nook and corner of the world. And most of the suppliers or manufacturers provide added services like cutting, beveling, threading, sand blasting, coating, testing and so forth.

How to Prevent Steel Pipe From Rust

As we all know that mild steel pipe is widely used in homes and constructions as railings, or guardrails for different purposes. There are various kinds of steel pipe, like API steel pipe, or American Petroleum Institute steel pipe. Like other steel products, the steel pipe will rust after exposure to moisture for long time. So, to prevent steel pipe from rust, some measures should be taken, like painting the surface with an exterior paint that seals out moisture. Follow me to get more details.
First of all, prepare things you will need, like cleaner, rags, mineral spirits, primer, rustproof exterior paint, 200-grit sandpaper. Then clean the pipe thoroughly to remove grease, dirt, grime and salt deposits. Clean the pipe by using a heavy-duty cleaner and rags. Then use mineral spirits and rag to clean it again to remove remaining grease left on the pipe.
Second, if the carbon steel pipe has a sheeny surface that may affect the adhesion, you are advised to rough sand it. Rough the steel pipe surface lightly with metal abrasive sandpaper. A towel will be needed to wipe away all residue from sanding.
Third, add a primer to the steel pipe surface. Spray the primer to the pipe and allow it to dry naturally. The primer is not required if you are using a metal spray-paint system designed specially for steel. Then, apply the final coat of paint to the steel pipe as directed by the instructions. The welded steel pipe and structural steel pipe are also available. For more detailed information about steel pipe, you can visit Hunan Great Steel Pipe Co.,ltd. We are dependable manufacturer of steel pipe and we have great reputation among consumers both at home and abroad for high quality and competitive price.

Seamless Line Pipe

Seamless Line steel pipe refers to use seamless steel pipe production technology to produce. Pipeline steel tube is put out oil, steam, water, pipeline through the pipeline to oil and gas industry enterprise. Line pipe including seamless pipe and welded steel pipe, the pipe end with flat end, with threaded end and socket end; Its connection way as the end of welding, coupling connection, socket connection, etc.

High grade pipeline steel tube heat treatment process

With the development of the pipeline steel plate technology and the progress of welded pipe forming, welding technology, the application range of the pipe with welded pipe in gradually expanding, especially in the large diameter welded pipe class scope the advantage of more wet, and cost factors, welded pipe has been dominant in the field of line pipe, which limits the development of stainless steel seamless steel line pipe. About 2004 t 2004 seamless line pipe production, steel grade including X42-70, varieties have a seabed pipeline onshore pipeline steel pipe and carbon steel pipe.

Of high grade pipeline steel production is currently a micro alloying heat treatment process, the production cost of stainless steel seamless tube was obviously higher than that of welded pipe, and with the improvement of steel grade, such as the above X80 grade pipeline steel pipe for the limitation of carbon equivalent, seamless steel tube of conventional technology is difficult to meet user requirements; Now every 12 cr1mov alloy pipe factory in for the improvement of line pipe corrosion resistance, the use of stable performance and low temperature, high temperature environment to carry out the scientific research work.

Mild steel pipe weight calculation formula: [] - wall thickness (diameter) * wall thickness * = 0.02466 kg/m (weight of per meter)

At present in our country, the use of oil and gas transmission pipe of the main technical standards are API SPEC 5 l, GB/T 9711, DNV OS - F101, often involves the standard and ISO 3183, CSAZ662, roughly as follows:

(1) the API 5 l line pipe specification is beautiful because of the development of the petroleum institute a widely adopted standard. Specification only for steel pipe products, not including design, selection and installation of pipelines. Traditionally API 5 l is reasonable, the technical requirements for both the technical requirements of pipeline steel and factory's actual production possibilities, but the relative of pipeline and pipe technology development, the technical requirements of API 5 l appear to be loose, has rarely alone is suitable for the pipeline to the requirement of structural steel pipe.

(2) the DNV OS - F101 seabed pipeline (system) is a det norske veritas formulating specifications for subsea pipeline. Involves the content is very extensive, including pipeline design, material, manufacture, installation, testing, operation, maintenance and other aspects. Alone on the technical requirements for steel pipe are usually more strict than API 5 l.

(3) the ISO 3183 - l (- 2, 3) - (oil and gas industry conveying pipe delivery technical conditions in the first part: grade A steel pipe/second part; B steel pipe/third part; grade C steel) is established by the international organization for standardization about the standard of oil and gas transmission pipe delivery condition, according to the different service conditions of steel tube, divided into A, B, C three levels. The standard is not involved in pipeline design and installation, etc. Develop more comprehensive and detailed technical terms.

(4) GB/T 9711.1 (2) is China committee for standardization of tubing just standard committee equivalent adopting IS03183 "l (- 2) standard set by the oil delivery pipe used in industry technical conditions of delivery. API SPEC 5 l line pipe specification and the ISO 3183 (conveying pipe technical conditions of delivery) is the international has a great influence on the line pipe specification, in contrast, most of the world's oil companies are used to using the API SPEC 5 l specification as the basis of pipeline steel pipe procurement specification. Domestic according to the requirements of API SPEC 5 l standards and engineering design production pipeline steel is only 20 years of history. But the API SPEC 5 l is a common standard, geography, climate and other natural conditions vary widely from all over the world, the nature of the medium is different, therefore, many oil companies to call for the nature of the API are also different, therefore, many oil companies will API SPEC 5 l as a basic standard, on the basis of the standard, according to the requirements to the local actual situation or pipeline, formulate quality technical supplementary specification (technical conditions). West-east gas pipeline "technical conditions" of steel tube with API SPEC 5 l line pipe specification, as the foundation, combined with the specific situation of the west-east gas pipeline to develop.

The Use of Welded Steel Pipe or Application Range(2)

Transformer tube: for the manufacture of transformers and other caron steel pipe heat exchanger, using ordinary carbon steel, require flattening, flaring, bending, hydraulic tests. Pipe to length or double length delivery, bending the steel pipe has certain requirements.
Mild steel pipe: from general carbon structural steel and welded steel 16Mn, square tube, rectangular tube, cap -shaped tube, empty plastic steel doors and windows with steel, mainly for agricultural machinery components, steel window doors.
Welded thin-walled tube: mainly used to make furniture, toys, lamps, etc. In recent years, the production of thin-walled stainless steel tube with a very wide application, fine furniture, decoration, fences and so on.
Spiral welded pipe : It is the low-carbon carbon structural steel pipe or low alloy steel strip at a certain angle of the helix ( called molding angle ) rolled into a tube, then welded together to form the tube, it can be used narrower strip production of large diameter steel pipe. Spiral welded pipe is mainly used for oil and gas pipelines, and its diameter * thickness expressed. Spiral welded single-sided and double-sided welding, pipe should ensure that hydrostatic test, weld tensile strength and cold performance to meet the requirements.

The Use of Welded Steel Pipe or Application Range

General Pipe: Average welded steel pipe used to transport low pressure fluid. With Q195A, Q215A, Q235A steel. Easy welding may also be used in other soft steel. Pipe to carry water pressure, bending, flattening and other experiments, there are certain requirements for surface quality, delivery is usually a length of 4-10m, often required length (or double length) delivery. Pipe specifications expressed with nominal diameter (mm or inch) nominal diameter different from the actual, pipe wall thickness according to the provisions of ordinary steel and thicker steel are two forms of steel pipe end divided by threaded and non- threaded two kinds.
Galvanized steel pipe: To improve the corrosion resistance of steel, steel pipe for general (clarinet) galvanized. Galvanized coating steel pipe hot galvanized and zinc two kinds of electrical steel, hot dip galvanized thick galvanized, electro-galvanized and low cost.
Oxygen pipe: as steelmaking oxygen tube, usually with a small -diameter welded steel pipe, specification consists of 3 /8 inch -2 inch eight kinds. With 08,10,15,20 or Q195-Q235 steel is made. To corrosion, and some for aluminized.
Wire casing: also ordinary carbon steel welded pipes, used in a variety of structural concrete and distribution projects, common nominal diameter from 13-76mm. Wire condom wall is thinner, mostly used for coating or galvanized, cold bend test requirements .
Mild steel pipe: seamless form of specifications, with the diameter * thickness in millimeters of welded steel, with ordinary carbon steel, high carbon steel or low alloy steel Prudent Energy tropical, cold strip welding, soldering or tropical then by cold call method is made. To ensure the strength and bending test tube, metric walled pipe of universal energy and ordinary as structural components, such as shafts, or transmission fluid, for the production of thin-walled furniture, lamps, etc.
Roller tube: welded structural steel pipe or API steel pipe for belt conveyor idlers, usually with Q215, Q235A, B steel and 20 steel, diameter 63.5-219.0mm. On the tube bending, end with the vertical centerline, there are certain requirements joviality, ordinary pressure and flattening test.

Submerged Arc welded steel pipe

Submerged arc welded steel pipe: steel strip coil is as raw material, often warm extrusion molding, two-wire double-sided submerged arc welding process automatically welded spiral seam steel pipe. Submerged arc welded steel submerged arc welded pipe Features: welded pipe production process is simple, high efficiency, low cost, rapid development. The strength of the spiral welded structural steel pipe is generally higher than the Longitudinal, can narrow the billet production of large diameter pipe, you can also use the same width of the billet production of different diameters of pipe. However, compared with the same length of straight seam pipe, the weld length increased by 30 to 100%, and lower production rate. Therefore, smaller diameter pipe mostly straight seam mild steel pipe of large diameter are mostly spiral welded.

Welded steel pipe for pipeline

Pipeline is put oil,gas,water out of the ground, transported to the oil and gas industry enterprises through the carbon steel pipe including seamless pipe and welded steel pipe. With the development of the pipeline steel plate and pipe forming，welding and technological progress, and gradually expand the scope of application of the pipeline with the structural steel pipe, especially the advantages become more pronounced wet group within the distance range of large diameter pipe, in addition, the cost factors pipe,which has a dominant position in the field of line pipe, limiting the development of stainless steel seamless line pipe. Seamless line pipe production in 2004 about 400 000 t steel grade X42-70, the varieties of line pipe on land and undersea pipeline. Production of high grade steel line pipe micro-alloying heat treatment process, stainless steel seamless pipe production costs are significantly higher than the pipe, and with the improvement of the steel grade, such as the above-X80 steel grade pipeline restrictions on carbon equivalent difficult for the conventional process of seamless mild steel pipe to meet user requirements; the 12Cr1moV alloy pipe production plant in order to improve its pipeline corrosion resistance, low temperature, high-temperature environments the use of stable performance and carry out research work.

Notes of carbon steel pipe pickling

Pickling is oxide washed with hydrofluoric acid + nitric acid solution on steel surface after heated treatment. which used in the solution composition and ratio values​​: HF (3-8%), of HNO3 (10-15%), H2O (remaining amount), the processing solution temperature of 40-60 ℃. Notes of carbon stee pipe pickling process: The first point is the acceptance of incoming materials listed, specifications, quantity and straightening cutting quality, acceptance of failure to suspend pickling and timely notice of the quality inspection department or workshop. The second point is ready to work. First, in accordance with the ratio of the value of shop floor control add acid, add acid should be evenly distributed in the pickling tank, rather than add in a certain part of the acid tank; then control the size of the volume of steam to control the temperature of the acid the general control of the temperature of the acid to slightly steaming (about 60 degrees) should not control the temperature is too high and even the feeling of acid boiling; the rest is to organize the process of site steel pipe card, the distinction between different frame of steel because of the differences of steel the pickling time. The third point for the pickling process control, and also the most important step. Vary in the products, mild steel pipe and finished steel pickling and degreasing. The fourth point inspection after pickling. Finished pickling steel pipe inspection focused primarily on steel pipes inside and outside surface of the oxide cleanliness, especially the cleanliness of the bore, the best yarn Brad over inspection, sampling should be not less than 10%. Followed by inspection of the steel pipe surface acid blotting and steel color case, the test failed to re-pickling; away oil structural steel pipe surface should be no significant oil pollution, with particular attention to the steel pipe at both ends should be no residual acid outflow.

Large Diameter Piling Structural Steel Pipe

Large diameter piling structural steel pipe is more than 1000 mm diameter steel pipe, large diameter seamless steel tube is made from solid tube ingot or the perforation capillary, then through hot rolling and cold rolling or cold dial. Large-diameter coating steel pipe is in the high frequency welded pipe of large diameter spiral welded pipe and coating on the basis of plastic, the most great mouth diameter of 1200 mm, according to the needs of the different coating of polyvinyl chloride (PVC), polyethylene (PE), epoxy resin (EPOZY), and other various plastic coating performance, good adhesion and corrosion resistance is strong, can resist the corrosion of strong acid, strong alkali and other chemical, non-toxic, does not rust, wear resistance, impact resistance, resistance to permeability is strong, the pipe surface is smooth, does not adhere to any material, can reduce the transmission of resistance, improve the efficiency of traffic and transportation, reduce the pressure loss. Coating without solvent, no leakage material, so that it can't be polluted by conveying medium, so as to ensure the purity of fluid and health, in 40 ℃ to + 80 ℃ range can be used cold heat cycles, not aging, not cracking, thus it can be used in cold zone and other harsh environment.

Pile structural steel pipe manufacturing method

(1) the raw material is steel strip coil, wire, flux. Have to pass strict physical and chemical inspection before investment.

(2) the strip head to tail docking, use single or double wire submerged arc welding, after rolled steel tube adopts automatic submerged arc welding repair welding.

(3) before shaping, strip after flattening, cutting edge, edge planing, transmission and cleaning the surface to the flanging process.

 (4) on both sides of the electric contact pressure gauge control conveyor under the pressure of oil cylinder pressure, ensure the smooth delivery of strip steel.

(5) the use of external control or internal control roll forming.

(6) the weld gap control device to ensure that meet the requirements of welding seam clearance, pipe diameter, and quantity of the wrong side of weld gap are tightly controlled.

(7) welding and welding are used within the United States Lincoln welding machine for single or double wire submerged arc welding, to obtain the stable welding specification.

(8) after welding the weld passes the online continuous ultrasonic automatic meter check, ensure the spiral weld nondestructive testing coverage of 100%. If there are defects, automatic alarm and spray tags, production workers to adjust process parameters, in a timely manner to eliminate defects.

(9) by air plasma cutting machine to cut the steel tube into single.

Cut into single pole (10), after each batch of mild steel pipe in the first three root must carry on the strict inspection system, check the weld mechanical properties, chemical composition, amalgamation, steel tube surface quality and the nondestructive flaw detection, ensure that qualified pipe process, can be formally put into production.

(11) have continuous acoustic detection of weld mark parts, after manual ultrasonic and X-ray check, if there are defects, after repair, again through the nondestructive inspection, until defects have been eliminated.

(12) strip steel butt weld and fellowship with spiral weld d joint in the tube, all pass X-ray films and television inspection.

(13) each carbon steel pipe after hydrostatic pressure test, radial sealing for the pressure. Test pressure and time are controlled strictly by steel pipe hydraulic microcomputer testing device. The parameters automatically printed out.

(14) pipe end machining, make the end verticality, slope Angle and the blunt edge to get accurate control.