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309S stainless steel tube

Stainless steel pipe is a kind of hollow long circular steel, mainly widely used in petroleum, chemical, medical, food, light industry, mechanical instrumentation and other industrial transportation pipes and mechanical structural components. In addition, the bending and torsional strength are the same, and the weight is light, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also commonly used for the production of various conventional weapons, barrels, shells, etc.

Stainless steel pipes are divided into ordinary carbon steel pipes, high-quality carbon structural steel pipes, alloy structural pipes, alloy steel pipes, bearing steel pipes, stainless steel pipes and bimetal composite pipes, coatings and coated pipes to save precious metals and meet special requirements. There are many kinds of stainless steel pipes, different uses, different technical requirements, and different production methods. The current production of steel pipe diameter range 0.1-4500mm, wall thickness range 0.01 ~ 250mm. In order to distinguish its characteristics, the steel pipe is usually classified according to the following method.

Mode of production

Stainless steel pipe according to the production method is divided into seamless pipe and welded pipe two categories, seamless steel pipe can be divided into hot rolled pipe, cold rolled pipe, cold drawn pipe and extrusion pipe, cold drawing, cold rolling is the secondary processing of steel pipe; The welded pipe is divided into straight seam welded pipe and spiral welded pipe.

Section shape

Stainless steel pipe according to the cross-section shape can be divided into round pipe and shaped pipe. The special-shaped pipe has rectangular pipe, diamond pipe, oval pipe, hexagonal pipe, eight pipe and a variety of cross-section asymmetric pipe. Shaped tubes are widely used in various structural parts, tools and mechanical parts. Compared with the round tube, the shaped tube generally has a larger moment of inertia and section modulus, and has a larger bending and torsional resistance, which can greatly reduce the weight of the structure and save steel.

Stainless steel pipe according to the profile shape can be divided into equal section pipe and variable section pipe. The variable section pipe has conical pipe, stepped pipe and periodic section pipe.

Pipe end shape

Stainless steel pipe can be divided into light pipe and wire pipe (with rebar steel pipe) according to the state of the pipe end. Wire pipe can also be divided into ordinary wire pipe (conveying water, gas and other low pressure pipe, using ordinary cylindrical or conical pipe thread connection) and special thread pipe (oil, geological drilling pipe, for important wire pipe, using special thread connection), for some special pipe, in order to make up for the impact of thread on the strength of the pipe end, Tube end thickening (internal thickening, external thickening or internal and external thickening) is usually carried out before wire drawing.

Use classification

According to the use can be divided into oil well pipe (casing, tubing and drill pipe, etc.), pipeline pipe, boiler pipe, mechanical structure pipe, hydraulic support pipe, gas cylinder pipe, geological pipe, chemical pipe (high-pressure fertilizer pipe, oil cracking pipe) and ship pipe.

Stainless steel industry

Stainless steel industry is a new industry, originated in the early 1980s, after 20 years of development and exploration, in the domestic market has been quite well-known and certain influence.

At present, there are more than 130 production enterprises, with a good momentum of development and expansion. The whole industry perforating equipment 38. More than 500 sets of cold rolling and cold drawing equipment, 6 smelting equipment, all using the furnace refining, other equipment is relatively complete. The production capacity and scale of enterprises are constantly expanding and strengthening. In 2001, there were 5 enterprises with an output value of over 100 million yuan, and more than 10 enterprises were rated as star-rated enterprises in the city and district. In order to ensure product quality, hydraulic pressure, eddy current and ultrasonic flaw detection, direct reading spectrometer and other analytical testing equipment are constantly increasing and improving. In 2001, the superior technical supervision department sampled and tested, and the pass rate reached more than 80%. There are more than 300 technical and managerial personnel with various senior and intermediate titles, and the enterprise has gradually embarked on the track of standardized production and management. Wenzhou stainless steel industry is mainly the production of stainless steel pipes and rods, varieties, specifications, models have reached more than 400 kinds. In 2001, the sales of stainless steel reached 1.715 billion yuan, and the output reached 106,000 tons. The stainless steel rod is 222 million yuan, the output is 2,110 thousand tons, and the national tax is more than 100 million yuan. The export volume of steel pipe is also increasing year by year, in 2001 was 5000T, it is expected that the export volume this year is 8000~10000T, and more than 10 enterprises have obtained the right to import and export. Stainless steel pipes are exported to dozens of countries and regions in Southeast Asia and the European Union, and are highly appreciated by foreign businesses and users. Future development ideas and specific practices are as follows:

To improve product output as the center, strengthen the internal management of enterprises, improve the scale and grade of enterprises as the goal, further improve the visibility of Wenzhou stainless steel pipe and enterprises, encourage enterprises to develop into groups, strengthen the introduction and training of technical personnel and management personnel, strengthen the construction of production equipment, ensure and improve product quality.

To the road of brand development, the number of stainless steel industry and the credit of entrepreneurs, shaping Chinese brand awareness.

The establishment of stainless steel pipe production park, gathering stainless steel production enterprises, so that on the scale, grade, create a leader, create a brand, the formation of group production; Through mergers, affiliations, equity participation, joint and other ways to achieve the "key development" of Zhejiang Economic and Trade Department planning goals.

Do a good job in the stainless steel professional market. Stainless steel industry is developing rapidly, but because there is no certain scale of professional market, can not attract customers from all over the country, so the production enterprises can only set up operations all over the country, which increases the cost of enterprises and hinders the development of enterprises. If a professional market is built, integrating production, sales and service, it will enable production enterprises to really base themselves on the background, go to the whole country and rush out of the country.

This kind of steel pipe can be divided into stainless steel seamless steel pipe and stainless steel welded steel pipe (welded pipe) two categories, according to the different manufacturing process can be: Hot rolling, extrusion, cold drawing and cold rolling these basic types, according to the section shape can be divided into round pipe and shaped pipe, widely used is round steel pipe, but there are also some square, rectangular, semicircular, hexagonal, equilateral triangle, octagonal and other shaped stainless steel pipe.

For the steel pipe under fluid pressure to carry out hydraulic tests to test its pressure resistance and quality, under the specified pressure does not leak, wet or expansion qualified, some steel pipe also according to the standard or the requirements of the demander flange test, flaring test, flattening test.

Seamless stainless steel pipe, also known as stainless steel seamless pipe, is made of steel ingot or solid tube blank perforated into a tube, and then made of hot rolled, cold rolled or cold drawn. The specifications of the seamless steel pipe are expressed by the outer diameter * the wall thickness of millimeters.

201 Stainless Steel pipe --S20100 (AISI.ASTM)

304 stainless steel pipe full name SUS304 stainless steel pipe

SUS304 stainless steel pipe belongs to the American grade of stainless steel pipe, the domestic grade is equivalent to 0Cr19Ni9 stainless steel pipe, usually replaced by 0Cr18Ni9.

The mechanism of stainless steel rust prevention is that the alloying element forms a positive potential and no longer has the ability to transport electrons to the oxidizer.

304 material rust phenomenon, there may be the following reasons:

Chloride ions are present in the use environment.

Chloride ions are widely present, such as salt, sweat, sea water, sea breeze, soil and so on. Stainless steel in the presence of chloride ions in the environment, corrosion quickly, even more than ordinary mild steel, chloride ions and alloy elements in the Fe to form a complex, the Fe positive potential is reduced, and then oxidized by oxidizing agents to take away electrons.

Therefore, there are requirements for the use of stainless steel environment, and it is necessary to wipe frequently, remove dust, and keep clean and dry.

316 and 317 stainless steels are molybdenum containing stainless steels. The molybdenum content in 317 stainless steel is slightly higher than 316 stainless steel. Because 316 stainless steel contains molybdenum, the overall performance of the steel is better than 310 and 304 stainless steel, under high temperature conditions, when the concentration of sulfuric acid is lower than 15% and higher than 85%, 316 stainless steel has a wide range of uses. 316 stainless steel also has good resistance to chloride erosion, so it is usually used in Marine environments.

With the development of social economy, the application of stainless steel pipe has also been more and more widely popularized. Will bring new changes in every field.

The theoretical weight formula of stainless steel pipe: W= (outer diameter - wall thickness) x wall thickness x0.02491x length, where the W unit is kg, the outer diameter and wall thickness units are mm, and the length unit is meters (m).

Production technology

Stainless steel welded pipe production process:

Raw materials -- strip -- welded pipe -- repair end -- polishing -- inspection (printing) -- packaging -- shipping (warehousing) (decorative welded pipe)

Raw material - article points - welding pipe, heat treatment, correct, straightening, fix the end, pickling, water pressure test, inspection (spurts India) - packaging - shipment (transport) (tube) for piping weld pipe industry


Stainless steel pipes are generally used to measure the hardness of Brinell, Rockwell, Vickers three hardness indicators.

Brinell hardness

In the stainless steel pipe standard, Brinell hardness is the most widely used, and the indentation diameter is often used to indicate the hardness of the material, which is both intuitive and convenient. However, it is not suitable for steel pipes of harder or thinner steel.

Rockwell hardness

The Rockwell hardness test of stainless steel pipe is the same as the Brinell hardness test, which is an indentation test method. The difference is that it measures the depth of the indentation. Rockwell hardness test is a widely used method at present, and HRC is second only to Brinell hardness HB in steel pipe standards. Rockwell hardness can be applied to the determination of very soft to very hard metal materials, it makes up for the Brinell method is not, is simpler than the Brinell method, can directly read the hardness value from the dial of the hardness machine. However, due to the small indentation, the hardness value is not as accurate as the Brinell method.

Vickers hardness

The Vickers hardness test for stainless steel tubes is also an indentation test method that can be used to determine the hardness of very thin metal materials and surface layers. It has the main advantages of Brinell and Rockwell method, and overcomes their basic shortcomings, but it is not as simple as Rockwell method, and Vickers method is rarely used in steel pipe standards.

Hardness testing

For annealed stainless steel pipes with inner diameter above 6.0mm and wall thickness below 13mm, W-B75 Wechsler hardness tester can be used, which is very fast and simple to test and suitable for rapid and non-destructive qualification inspection of stainless steel pipes. For stainless steel pipes with inner diameter greater than 30mm and wall thickness greater than 1.2mm, Rockwell hardness tester is used to test HRB and HRC hardness. Stainless steel pipes with inner diameter greater than 30mm and wall thickness less than 1.2mm are tested for HRT or HRN hardness using a surface Rockwell hardness tester. For stainless steel pipes with inner diameter less than 0mm and greater than 4.8mm, Rockwell hardness tester for pipes is used to test HR15T hardness. When the inner diameter of the stainless steel pipe is greater than 26mm, the hardness of the inner wall of the pipe can also be tested with Rockwell or surface Rockwell hardness tester.


Zhishang Steel Co., Ltd

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