Q345 alloy tube

Q345 alloy tube is a low alloy series - high strength low alloy structural steel (GB/T1591-1994).

Q345A alloy tube, grade Q345B alloy tube usually say 16 mn steel, the material is the most common; Q345 alloy tube said methods: Q represent the material yield, behind the 345, is refers to the material yield value, at around 345 (analogous to the naming of Q235 method) would be increased with the increase of the thickness of the material and the yield value decreases.

Q345 alloy tube formula: [] - wall thickness (diameter) * wall thickness * = 0.02466 kg/m (weight of per meter)

High strength low alloy structural steel pipe in addition to the basic elements contain a certain amount or silicon manganese, also contain other suitable elements resources situation in our country. Such as vanadium (V), niobium (Nb), titanium (Ti), aluminum (Al), molybdenum (Mo), nitrogen (N) and rare earth (RE), and other trace elements. According to chemical composition and performance requirements, its brand by the Q295A, B, Q345A, B, C, D, E, Q390A, B, C, D, E, Q420A, B, C, D, E, Q4, 60 C, D, E grade steel, said the meaning with carbon structural steel .

Such steel Q345 seamless tube with carbon structural steel, has high strength, good comprehensive performance, long service life, wide application range, comparative economic advantages. The steel rolled into sheet, profiles, welded steel pipe, etc., are widely used in Bridges, ships, boilers, vehicles, and important building structure.

Q345A, Q345B, Q345C, Q345D, the level of Q345E is this distinction, represented mainly by the impact of temperature is different.

Q345A, don't do impact;

Grade Q345B, impact is 20 degrees at room temperature;

Grade Q345C, impact is 0 degrees;

Q345D grade, is 20 degrees - impact;

Q345E level, it is - hit 40 degrees.

In the impact of different temperature, impact value is also different. Due to the implementation of standards, this kind of steel plate allows the minus tolerance of delivery.

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The Development of API Steel Pipe

API steel pipes are rather sought after in those projects that require high strength, resistance to erosion. And they are widely used in gas transportation projects across cities, towns and even nations. As a matter of fact, such inherent properties as durability and corrosion-resistance make API steel pipes ideal for such industries as oil and gas companies, pipelines, and chemical companies. The techniques for manufacturing API steel pipes were derived from the making of seamless steel pipes which can be traced back to the early 1900s. At the time the London government made the decision to install a coal burning system in the city. Therefore, quality, durable pipelines were needed badly to link various supply station and to transfer gas. Thanks to the great efforts of a group of scientists and technicians, the earliest mild steel pipe were introduced and put to mass production.

Traditionally, to make a seamless steel pipe, workers need to drill a hole through a round billet and has it melted down in the furnace. Then the melting iron was poured into the mold and was elongated to the length as required by customers. Although this method used in the old days was hardly cost-effective, it is still inspiring and creative for later inventors and scientists. During 1960s and 70s, API steel pipes were introduced to transfer gas across regions. Since then, the manufacturing techniques of API steel pipes have undergone remarkable development.

In general, there are three steps in the making of API carbon steel pipe. To begin with, round billets of carbon steel are cut into suitable length according to customers' requirements and are heated in the furnace where the temperature can reach as high as 2400℃. Quenching and tempering control the hardness of the pipes and yield certain physical qualities. Therefore, different grades of API steel pipes undergo different types of quenching and tempering in order to change their micro-structure to improve strength or other properties. Next the billet is rolled over a reel, producing curled hollow shells at one end, which is sent to be cooled. Then the surfaces of the semi-products are pickled, coasted and lubricated to accelerate the following drawing process. Depending on the requirements, the pipes may be subjected to single, double or even triple drawing, after which the pipes are straightened and cut to the required sizes. Finally, API steel pipes are sent to be tested for quality before delivery.

Nowadays in many major API DSAW steel pipe plants, high-end technology is adopted to manage every aspect of the production. For instance, real-time communication between the control room and machine operators guarantees precise regulation of each step, from charging furnaces with raw materials to timing, testing and transport. And most manufacturers carefully monitor their production process according to the standards made by ASTM or ISO to meet diversified customer demands.

Welded Steel Pipe Pressure Grade

The pressure welded steel pipe consists of pipe, pipe fittings which include elbow, tee joint, taper pipe and other fittings, valve, flanged joint (flange, spacer as well as bolts), and these composition pieces are generally standard components, which can be fully decided by several factors such as their nominal pressure, texture of material, nominal diameter as well as wall thickness of the Welded steel pipe. And the nominal pressure of all the piping components in the same pipeline pressure grade. Thus, the nominal pressure grade of the piping components are called pipeline pressure grade in engineering.

The pipeline material grade is the piping components selecting and using regulations established by the designing institute or the engineering companies. And it is always given in the form of the excel sheet. In addition, the engineering and technical staff can make sure the detail specific provision of all kinds of dimensions and specifications of the piping components on the conditions of some certain pressure, temperature as well as fluid media which are correspond to these detail specific regulations according to the pipeline material grade sheet. When the engineering as well as technical staffs choose piping components, they base on this pipeline material grade sheet. Every letter and every number in the pipeline material grade codes represents different meanings. And it is usual that there are two grade codes that represent pressure grade in the welded steel pipe and texture of material respectively.

On the technological process map that draws the piping and instruments diagram, there are labels of pipeline pressure grade codes for every black steel pipe. Pipeline pressure grade codes usually consist of a couple of units, and every unit is represented by the letters as well as numbers. And they show the piping pressure grade in the welded steel pipe the main texture of material of the pipelines, seal or types of connection, corrosion allowance and other quality parameter separately. Except for that, every designing institute as well as engineering company has its own expressive method for piping pressure grade codes. Although different letters and different numbers are symbols of different meaning, the contexts they express are the same.

Branch pipe connection table is a sheet given by engineering companies as well as designing institute, stipulating the types of connection of the main pipes as well as the branch pipes. Technological staffs are able to find out what kind of connection methods the different main pipes and different branch pipes should adopt easily under every different piping pressure grade in the carbon steel pipe according to this sheet. The main types of connection consist of connection of the welded pipes, API steel pipe, tee joint (isometric or reducing tee), direct connection of main pipes as well as branch pipes or connection of tee joint plus reducing pipe transition.

The Profiles of the Black Steel Pipe

Black steel pipe used for conveying fluid and solid, not only to exchange heat, manufacturing machinery parts and container, it is also a kind of economic steel. With black steel pipe manufacturing space truss structures, pillar and mechanical support, can reduce light weight, saving metal 20 ~ 40%, and can realize the mechanization of factory construction. Carbon steel pipe manufacturing highway Bridges not only can save steel, simplify construction, and can greatly reduce the area of the coating layer, save investment and maintenance costs.

So, any other types of steel cannot completely replace steel tube, but the steel tube can replace part of the profile and bar. Black steel pipe to the national economic development and improvement of quality of human life, is far better than the other steel products. From People's Daily appliances, furniture, water supply and drainage, gas supply, ventilation and heating facilities to various kinds of agricultural machinery equipment manufacturing. The development of underground resources, defense and aerospace used guns, bullets, missiles, rocket is inseparable from the steel tube and so on.

Because of the structural steel pipe is closely connected with human life and production activities, production technology of black steel pipe industry has developed rapidly, not only bring forth the fresh, Also black steel pipe production in iron and steel industry occupies an irreplaceable position. Black steel pipe and welded pipe, is to use steel plate or steel strip after crimp molding made of welded steel pipe. The technology of producing black steel pipe is simple and the production efficiency of it is high, but the general strength of the black steel pipe is lower than that of the seamless steel tube. This can increase the profiles of the black steel pipe. The seamless steel tube is instead in the field. The welded steel pipe formed according to the weld seam welded pipe and the spiral welded pipe.

The technology of straight seam welded pipe production is also simple, and with high production efficiency, low cost and rapid development. The strength of the straight seam API steel pipe is lower than that of the black steel pipe, which uses a narrow billet production with a smaller diameter welded pipe. Also you can adopt the production of the same width of billet with different pipe diameter welded pipes. If compared with the same length of straight seam pipe, its length is 30~100 percent and its production speed is low. As a result, a small diameter mild steel pipe is mostly with straight seam welding, large diameter welded pipe for the most part adopts spiral welded. These profiles of black steel pipe are used for transporting oil, gas, air, water, heating steam and so on.

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Big Differences between ERW Steel Pipe and Seamless Pipe

Nowadays, with quick construction of society and rapid development of technology, more and more different kinds of steel pipes are created, such as welded steel pipe, seamless steel pipe, ERW steel pipe and so on, and more and more steel pipes are needed. In the competitive market of steel pipe, ERW steel pipe, seamless pipe and welded steel pipe are well sold thanks to their specific characteristics.

There are a few aspects of differences between ERW steel pipe and seamless steelpipe. ERW pipe, which is short for electric resistance welding, is used in delivery of liquid, such as fuel, gas and so on, regardless the requirement of pressure, which plays an important role in the conveying tube all over the world, while seamless pipe is a kind of mild steel pipe shaping square and rectangle and having no seam around with hollow cross-sections, which is used in conveying liquid but also making structural members and machine parts, due to its surprisingly high anti-bending and anti-torque strength and impossibly lightness. All in all, ERW pipe and seamless steel pipe is quite different in use.

What's more, the biggest difference between ERW pipe and seamless steel pipe is that ERW pipe has welding line, which is the same as welded steel pipe, but seamless carbon steel pipe doesn't have, either does the welded steel pipe. Furthermore, the welding line of ERW pipe is the key to the quality of ERW steel pipe. The more unrecognizable the welding line of ERW pipe is, the higher quality ERW pipe has. As an old saying goes ‘hard work pays off', with scientists' continuous hard study, a huge success in eliminating the welding line of ERW pipe has been achieved. There are two ways to eliminate the welding line: geometric seamlessly and physical seamlessly. Geometric seamlessly is to eliminate the burr both inside and outside while physical seamlessly is to take steps to make base metal and metallographic structure uniform and consistent, which seems more complicate to achieve, however, a ERW pipe without a welding line can be successfully attained through which. Compared with processing technique of ERW pipe, the processing technique of seamless steel pipe is much simpler. There are two entirely different types of processing technique: cold-drawing and hot rolling. Compared with hot rolling, the technological process of cold-drawing is more complicated. Moreover, in the appearance, cold-drawn seamless stainless steel pipe is shorter than hot-rolled one and the wall thickness of cold-drawn seamless stainless steel pipe is generally smaller than the wall thickness of hot-rolled one. What's more, the technological process of hot rolling needs high temperature which reduces the resistance of deformation so that a big deflection is achieved. Generally speaking, the technological processing of ERW pipe and seamless steel pipe are quite different, due to the different appearance.

In general, although ERW pipe and seamless steel pipe both play an important role as well the welded steel pipe do in the construction of society, ERW pipe and seamless API steel pipe has different use and different making progress thanks to their different appearance. Scientists have always been paying a lot to improve their property, which is aimed to make them more multifunctional and to reduce the cost of processing. Maybe one day, ERW pipe and seamless steel pipe will have little differences.

The classification of the elbow

The classification of the elbow

According to its radius of curvature to points, can be divided into long radius elbow and short radius elbow. Long radius elbow refers to its radius of curvature is equal to 1.5 times the pipe diameter, R = 1.5 D. Short radius elbow refers to its radius of curvature is equal to the pipe diameter, namely R = D. Type D bend diameter of R for the radius of curvature.

If according to the grades of pressure points, about 17 species, and the United States, the carbon steel pipe standard is the same, there are: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, one of the most common is two kinds of STD and XS. According to bend Angle, has 45 elbow, elbow bend and 180 90. So there are a lot of kinds of elbow, an order when the order is often said to take the following methods: such as "LR STD 90 8", said the long radius, pressure rating for STD, 8 "elbow; another example," 90 SR XS 45 o 4, "said short radius, the pressure levels for XS, 45 o 4" elbow. More about classification for the elbow.

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Gangsu composite tube, large diameter coated steel pipe

Inspecting &controlling in hot dip galvanized structural steel pipe as substrate, the molten powder spraying technology in the lining (to the outer wall can be) coated plastic, performance. Compared with the galvanized pipe, corrosion, rust, scale, smooth smooth, clean and non-toxic, long life and other advantages. According to the test, the service life of inspecting &controlling for three times more than galvanized pipe. Compared with the plastic pipe, has high mechanical strength, high voltage, as well as good heat resistance. Because of the matrix is steel tube, so there is no embrittlement, aging problem. Can be widely used in tap water, gas, chemical products, such as fluid transportation and heating engineering, is an upgraded version of galvanized pipe. Because of its installation method and the traditional basic same galvanized pipe, pipe fittings form also are exactly the same, and can take the place of aluminous model multiple tube on the large diameter water conveying, welcomed by users, has become a pipe market one of the most competitive new products.

Coating steel pipe is in the ERW steel 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.

Large-diameter coating steel pipe is widely used in tap water, natural gas, petroleum, chemical industry, medicine, communication, electric power, ocean engineering, etc.