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|Stainless steel is a long hollow circular steel, mainly used in petroleum, chemical, medical, food, light industry, machinery and instruments, and other industrial Transportatio structural components such as pipes and machinery. In addition, bending, torsional strength of the same, lighter, so it is widely used in manufacture of mechanical parts and engineering structures. Also used in producing all kinds of conventional weapons, the barrel, shells and so on.
Stainless steel market
Stainless steel industry town of Foshan Lanshi
Lanshi Town, Foshan City, is a professional production of stainless steel products the town, and its stainless steel products mainly include: stainless steel cold rolled strip steel, stainless steel welded pipe, stainless steel products.
Cold rolled stainless steel strip Lanshi existing production lines and more than 100, the annual production of stainless steel cold-rolled strip steel 20 million to 30 million tons.
Lanshi nearly in stainless steel welded pipe production line section, yield nearly 30 million tons. Mainly produce stainless steel decoration pipe, fluid transport stainless steel welded pipe, stainless steel pipe with a mechanical structure, the food industry stainless steel pipe, welded stainless steel heat exchange and so on. The main representative enterprises in Foshan City Real Stainless Steel Pipe Co., Ltd. (Tel :400 -188-0757) and Lanshi Aerospace Stainless Steel Pipe Co., Ltd. production.
Lanshi stainless steel slitting, cross brushed stainless steel, mirror processing processing industry is very prosperous, and its output is also 20 million to 30 million tons.
Lanshi town has four large stainless steel professional market, with distribution of hundreds of stalls, selling stainless steel coil, plate, stainless steel welded pipe, stainless steel doors, windows, decorative accessories and stainless steel and stainless steel products, from the sales Lanshi to the country, is the leading steel distribution center.
Stainless steel industry in Wenzhou
Wenzhou stainless steel industry is an emerging industry, originated in the 20th century, early 80s, after 20 to develop and explore the coming year, in the domestic market has been quite well known and influential.
Currently more than 130 production enterprises, with good development, and expand the momentum. Piercing equipment, the industry is now 38. Rolling, drawing more than 500 equipment, metallurgical equipment, six, all with refining, and other equipments are complete. The production capacity and scale are in constant expansion and enhancement. 2001, the output value of over 5 million enterprises and 10 enterprises as the city and district-star business. In order to ensure product quality, water pressure, eddy current and ultrasonic flaw detection, direct-reading spectrometer and other detection equipment are constantly increasing and improving. 2001, by the higher sampling technology supervision department, with a pass rate of 80% or more. Intermediate grade with all kinds of high technology and management staff of 300 people, is gradually standardized enterprise production, management track. Wenzhou stainless steel industry is the production of stainless steel tubes and stainless steel rods, varieties, specifications, models have reached more than 400 kinds. 2001 sales of 1.715 billion yuan of stainless steel, production reached 106,000 tons. Stainless steel rods 222 million, yield 2,11 million tons, and paid state taxes of 1 million yuan. Steel exports increased year by year, 2001 5000T, the export volume this year 8000 ~ 10000T, there have been 10 to the right to import and export companies. Stainless steel pipe exported to Southeast Asia, the European Union in dozens of countries and regions, by the appreciation of foreign merchants and customers.
Stainless steel tube industry in Wenzhou, the original is blank, is now developing rapidly expanding, but there is a certain gap between production capacity still can not meet the needs of the domestic market. Wenzhou stainless steel industry in the future development ideas and specific practices are:
1, to improve product yield as the center, strengthen internal management, and improving the size and grade as the goal, to further improve Wenzhou stainless steel tube and corporate reputation, encourage enterprises to group development, strengthening of technical personnel, introduction and training of management personnel strengthen the building of production equipment, to ensure and improve product quality.
2, to brand development, the number of entrepreneurs in Wenzhou stainless steel industry and credit, build brand awareness in China.
3, Establishing the Park production of stainless steel, stainless steel producers gather to make on the size, grade, a leading brand name, form a group of production; by merger, affiliation, equity participation, joint, etc., to achieve Zhejiang Economic and Trade Office "key development" planning objectives.
4, good Wenzhou stainless steel professional market. Stainless steel industry is developing rapidly, but with no certain amount of professional market, not attracting visitors all over the world, so manufacturers can only set point operating throughout the country, not only increasing business costs, hinder the development of enterprises. If the completion of the professional market, production, sales and service in one, will enable the production companies based in the real sly, to the country, out of the country.
These can be divided into stainless steel seamless pipe and tube stainless steel welded pipe (pipe joints) two categories, according to the different manufacturing processes can
Is: hot rolling, extrusion, cold drawing and cold rolling it several basic types, according to section shape can be divided into tubes and shaped tubes, circular steel is widely used, but there are some square, rectangular, semicircular, hexagonal, triangular, octagonal shaped stainless steel pipe, etc..
For the steel pipe under fluid pressure test should be carried out to test the pressure of hydraulic capacity and quality, in the required pressure without leakage, wet or expansion of qualified, some steel but also according to the requirements of the standard or demand side, curling trials , flaring test, flattening test.
Seamless stainless steel tube, also known as stainless steel seamless pipe, tube or solid steel ingot is made of wool by the perforated pipe, and then by the hot-rolled, cold-rolled or cold call is made. Specifications of seamless steel tubes with wall thickness mm diameter * number indicates.
304 full SUS304 stainless steel tube stainless steel tube
SUS304 grade stainless steel materials are stainless steel United States, the domestic equivalent of 0Cr19Ni9 grade stainless steel tube, usually 0Cr18Ni9 instead.
The mechanism of anti-rust stainless steel alloy elements form a dense oxide film, cut off from contact with oxygen, to prevent any further oxidation. So stainless steel is not a "stainless."
304 rusty phenomenon occurs, there may be several reasons:
1. Using the chloride ions present in the environment.
Cl widespread, such as salt, sweat, sea water, wind, soil and so on. Stainless steel in the presence of chloride ions in the environment, corrosion quickly, even more than ordinary mild steel.
Therefore, the use of stainless steel environment requirements, and require regular cleaning to remove dust, clean and dry.
316 and 317 stainless steel (317 stainless steel performance see below) is a stainless steel containing molybdenum species. Molybdenum content of 317 stainless steel in a little clever in 316 stainless steel. Molybdenum in the steel, the steel is superior to total 310 and 304 stainless steel, high temperature conditions, when the sulfuric acid concentration lower than 15% and higher than 85%, 316 stainless steel with a wide range of uses. 316 stainless steel has good corrosion performance of the chloride, it is usually used in the marine environment.
Stainless steel tube with the social and economic development, its application has also been more widely popular. In all areas will bring about a new change.
Theoretical weight of stainless steel: W = (OD - thickness) x Length of wall thickness x0.02491x
Stainless steel seamless pipe production technology
Stainless steel welded pipe production process: raw materials - Slitting - welded pipe - repair side - polishing - Inspection (printing) - Packaging - Shipping (warehousing) (decorative pipe) material - min Article - welded tube - heat treatment - correction - straightening - repair side - pickling - pressure test - test (printing) - Packaging - Shipping (warehousing) (pipe industry piping tube)
The application prospects of stainless steel pipe
Stainless steel safe, reliable, environmental health, affordable, thin wall of the pipe and the new, reliable, simple and convenient connection method developed, it can not be replaced with more advantages other pipe, engineering will be more and more use will become increasingly popular, a good prospect.
As China's reform and opening up policy, economy for rapid growth, urban housing, public buildings and tourist facilities for the construction of water supply and domestic water supply proposed new requirements. In particular, water quality, there is growing attention to increasing demands. Galvanized steel pipe because of this common and easy corrosive impact of relevant policies in the country, will gradually fade into history, plastic pipe, composite pipe and copper pipe became the common piping system. However, in many cases, stainless steel pipe more advantages, especially the wall thickness of only 0.6 ~ 1.2mm thin-walled stainless steel pipe in high-quality drinking water systems, hot water systems and the safety and health in the first place water supply system, with safe, reliable, environmental health, economical and so on. Domestic and international engineering practice has been proved to be the best water system performance, new, energy-saving and environmental protection is one type of pipe, but also a very competitive water pipe, is bound to improve water quality and improve the living standards of people to play without comparable role.
Water supply system in the building, because of galvanized steel over a hundred years glorious history, a variety of new plastic pipes and composite pipe rapid development, but also to varying degrees, all kinds of pipe there are some deficiencies, far can not fully meet the water supply needs and the state Department of drinking water and the water quality requirements. Therefore, the experts predicted: building water supply pipes will eventually return to the era of the metal tube. According to the application of foreign experience in the metal tube was identified in thin-walled stainless steel pipe one of the best overall performance.
Promote the use of thin-walled stainless steel tube of domestic time is ripe
Thin-walled stainless steel tube, China in the 20th century began late 90s production, use, is the emerging field of new pipe family, have been widely used in building the pipeline water supply and drinking water.
Durable thin-walled stainless steel tube, has been recognized engineering, and the parties concerned are from the reduced wall thickness, and lower prices aspects, in order to facilitate further promotion. Particularly small diameter stainless steel tube, the price is not high, so supporting the connection method, the reliability of pipe and the price is the main factor to determine its development. China in Sichuan, Guangdong, Zhejiang, Jiangsu and developers have developed technologies and the connection pipe, the pipe is very promising. Ministry of Construction and relevant departments attach great importance to this new type of pipe, according to China Technology Market Management and Promotion Center, the National Science City  No. 71 document, on the application "of height to diameter ratio of high-precision stainless steel wall, high pressure water pipes and related pipe fittings and special technology "the notice informed, thin-walled stainless steel pipe and products that promote the use of technology to improve the quality of modern architecture, improve and protect water quality are of great significance.
Meanwhile, the Ministry of Construction attached great importance to promote the use of thin-walled stainless steel tubing. "Thin-walled stainless steel pipes," the industry standard was issued in 2001 executed. Relevant technical specification and installation of pipeline engineering Atlas, Ministry of Construction has issued a document, is responsible for the preparation by Tongji University. Currently, Sichuan, Guangdong, Zhejiang, Jiangsu and other places to have the professional manufacturers of stainless steel thin-walled tube, the product has become mature, therefore, promote the use of the time has come.
Prospects for the domestic market
¢Ù demand for water supply pipeline
According to "building business" Ninth Five-Year "Plan and Goals for Vision 2010," estimated that from 2001 to 2010, annual demand for 50 to pipe 60 million km, including hot and cold water demand in residential construction area of 40 million km . Some people think that the development of stainless steel pipes, to improve the quality of modern architecture the city is significant.
¢Ú the rapid development of direct drinking water
With the development of national economy, direct drinking water in China, Beijing, Shenzhen, Shanghai, Chongqing and other cities developed rapidly, economically developed medium-sized cities are also actively planning to catch the last straight. In drinking water, the stainless steel piping is no doubt second to none. Currently on the grade of the hotels, public places or have been configured in the configuration drinking water pipes.
¢Û the future of a vast domestic import substitution
To promote the stainless steel tube, China since the 90s from the 20th century from the reduced wall thickness, reduce costs begin to address the "wall of height to diameter ratio of high-precision," the problem of thin-walled stainless steel tubes, stainless steel pipe used widely to develop quickly . A pipeline to be able to fully promote the use of, and ultimately domestic. At present, domestic manufacturers have been part of the production and further development of thin-walled stainless steel pipe and tube capacity.
Variety of stainless steel pipe connections
Variety of stainless steel pipe connections, the common types of compression fittings, compression type, live fit, push, push threaded, socket welded, live access flange connection, welding and welding with traditional connection derived from a combination of series connections. These connections, according to its principle is different, its scope of application are different, but most are easy to install, solid and reliable. Connection with the seal or gasket material, most of them selected in line with national standards of silicon rubber, nitrile rubber and EPDM rubber, from the user's worries.
Identification method for stainless steel
The number and representation of steel
¢Ù chemical element with the symbol of international and national symbols to represent the chemical composition, with the Arabic alphabet to represent the component content:
Such as: China, Russia 12CrNi3A
¢Ú fixed digit number to represent the steel type series or digital; such as: the United States, Japan, the 300 series, 400 series, 200 series;
¢Û composition of the Latin alphabet and the order number, saying only that purpose.
The number of rules
¢Ù using element symbols
¢Ú use Hanyu Pinyin, open-hearth steel: P, boiling steel: F, killed steel: B, A steel: A, T8: Special 8
¡ô structural steel, spring steel, such as: 20CrMnTi 60SiMn, (with very few that C content)
¡ô Stainless steel, alloy tool steel (indicated by a few thousandths of C content), such as: 1Cr18Ni9 thousandth (ie,
0.1% C), such as stainless steel C ≤ 0.08% 0Cr18Ni9, ultra-low carbon C ≤ 0.03% as 0Cr17Ni13Mo
International Stainless Steel Plate Method
American Iron and Steel Institute is a three-digit number used to mark a variety of standard grade wrought stainless steel. Of which:
¢Ù austenitic stainless steel with 200 and 300 series digital mark,
¢Ú ferritic and martensitic stainless steel with a 400 series numerals. For example, some of the more common austenitic stainless steel
Is 201, 304, 316 and 310 for the tag,
¢Û ferritic stainless steel is marked 430 and 446, is 410,420, and 440C martensitic stainless steel as standard
In mind that two-phase (austenite - ferrite),
¢Ü stainless steel, precipitation hardening stainless steel and iron content of less than 50% of the high-alloy is usually ordered by the patent or trademark name
Classification and grading standards
4-1 grade category:
National Standard GB ¢Ú ¢Ù industry standard YB ¢Û ¢Ü local standard enterprise standard Q / CB
¢Ù ¢Ú product standard method of packaging standard ¢Û ¢Ü basic standards standards
4-3 standard level (three levels):
Y-level: the international advanced level I level: the general level of H international level: the domestic advanced level
GB1220-84 stainless steel bars (I grade) GB4241-84 stainless steel welded plate Park (H level)
GB4356-84 stainless steel welded plate garden (I grade) GB1270-80 stainless steel pipe (I grade)
GB12771-91 stainless steel pipe (Y class) GB3280-84 stainless steel cold plate (I grade)
GB4237-84 stainless steel hot plate (I grade) GB4239-91 stainless steel cold strip (I level)
New stainless steel
200 Department of D7S
Manufacturer: Hyundai Steel
Product Description: D7S about 2.5% nickel content, nickel content is slightly lower than the D11, namely, the price is relatively low. 1% nickel content stainless steel is D7S to some extent, the key market supply, and therefore competitive, high quality stainless steel integrated areas of high usage rate will also be an important part of the marketing plan.
Application: The target market of new products such as stainless steel kitchen appliances, stainless steel equipment, and other fields of sales and marketing plans.
SandvikSAF3207HD duplex stainless steel tube
Manufacturer: Sandvik Materials Technology
Description: The tensile strength of the material 980 ~ 1180MPa, maximum working temperature of up to 90 ¡æ, relative to the standards developed by the company before the super duplex stainless steel SAF2507 is concerned, in terms of tensile strength and has a maximum operating temperature greatly improved. SAF2507 the tensile strength of 800 ~ 1100MPa, the maximum temperature of 65 ¡æ in the environment. SandvikSAF3207HD is used in deepwater, high temperature and high pressure and specially designed.
Applications: harsh undersea environment pipes
Supercritical boiler with stainless steel tube / seamless pipe
Manufacturer: TISCO, Baosteel, Huzhou long-established, Changzhou Wujin
Product Description: super (super) critical power generation equipment unit is the basis for the modernization and energy conservation.
In the ultra (ultra) supercritical pressure boilers important parts, the working temperature of the highest parts of the working environment is worst superheater and reheater. Before, my kind of materials used in domestic all imported from abroad, and now only a few international manufacturers of iron and steel capacity is limited, the larger the gap of such materials, imports expensive and procurement difficulties, shortage, seriously affecting the country Ultra-supercritical boiler production and energy development. For China's current demand for power plant boiler tube about three million tons per year, and with the (ultra) supercritical power generation technology continues to improve, demand has expanded each year. A few large enterprises have invested in recent years, a lot of manpower and financial resources dedicated to such product development, production, and achieved considerable results. On the one hand the development of the country's power industry has made its own contribution, but also to the enterprise has brought considerable economic benefits.
Application: boiler industry, mainly superheater and reheater heat section and other key parts.
400 series stainless steel tubes for air conditioning
Manufacturer: Nippon Sumikin Stainless
Product Description: This product is Nippon Steel Sumikin first developed in the global stainless steel pipe used in air conditioning, with high processing performance, weight can be reduced by 60% than the copper price lower than copper, brass can be used as alternative products.
Application: air-conditioning industry
DP28W duplex stainless steel
Manufacturer: Sumitomo Metal
Product Description: This stainless steel in urea - carbamate solution with good corrosion resistance in chloride environments has a high resistance to stress corrosion cracking. Meanwhile, the excellent mechanical properties of duplex stainless steel, high security requirements can be applied to the plant construction.
Application: chemical industry, construction industry.
Pipe Size and tolerance
Standard deviation OD tolerance level
D1 ± 1.5%, minimum ± 0.75 mm
D2 ± 1.0%. Minimum ± 0.50 mm
D3 ± 0.75%. Minimum ± 0.30 mm
D4 ± 0.50%. ± 0.10 mm minimum
Stainless steel related presentations
Features stainless steel
All metals and the reaction of oxygen in the atmosphere, in the surface oxide film. Unfortunately, the iron oxide formed on carbon steel continue to oxidation, corrosion constantly expanding, and ultimately the formation of holes. Can use paint or oxidation-resistant metals (eg, zinc, nickel and chromium) plating to ensure the steel surface, but, as people know, this protection is only a film. If the protective layer is damaged, the steel began to rust the following
Resistance of air, steam, water and other weak corrosive media and acid, alkali, salt and other chemical attack by corrosion of steel media. Also known as acid-resistant stainless steel. Practical applications, often the weak corrosion resistance as stainless steel, corrosion medium, and the chemical resistance of steel known as acid corrosion of steel. As the two differences in the chemical composition, the former does not necessarily chemical resistance corrosion, while the latter are generally of a stainless steel. The corrosion resistance of stainless steel depends on the alloying elements contained. Chromium is to corrosion resistance of stainless steel to obtain the basic elements, when the chromium content in steel is 1.2%, the chromium and corrosive media, the role of oxygen in the steel surface to form a thin oxide film (from the passive film) , can prevent further corrosion of the steel substrate. In addition to chromium, the commonly used alloying elements nickel, molybdenum, titanium, niobium, copper, nitrogen, etc., to meet the various uses and properties of stainless steel requirements.
Stainless steel is usually divided by the matrix:
1, ferritic stainless steel. 12% Chromium 30%. Its corrosion resistance, toughness and weldability with the increase of chromium content increased resistance to chloride stress corrosion better than other types of stainless steel.
2, austenitic stainless steel. More than 18% chromium, 8% also contains a small amount of nickel and molybdenum, titanium, nitrogen and other elements. Comprehensive performance, and can be resistant to a variety of media corrosion.
3, austenitic - ferritic duplex stainless steel. Both austenitic and ferritic stainless steel, the merits, and has superplasticity.
4, martensitic stainless steel. High strength, but poor ductility and weldability.
5, precipitation hardening stainless steel. With good formability and good weldability, high strength materials can be used as the nuclear industry, aviation and aerospace industry applications.
Cr components can be divided according to Department (SUS400), Cr-Ni system (SUS300), Cr-Mn-Ni (SUS200) and the precipitation hardening systems (SUS600).
Corrosion resistant stainless steel
All metals and the reaction of oxygen in the atmosphere, in the surface oxide film. Unfortunately, the iron oxide formed on carbon steel continue to oxidation, corrosion constantly expanding, and ultimately the formation of holes. Can use paint or oxidation-resistant metals (eg, zinc, nickel and chromium) plating to ensure the steel surface, but, as people know, this protection is only a film. If the protective layer is damaged, the following steel began to rust.
Stainless steel corrosion resistance depends on the chromium, but because the chromium is one of the components of steel, so the protection methods vary.
The addition of chromium 10.5%, the atmospheric corrosion resistant steel increased significantly, but the chromium content higher, although still improve corrosion resistance, but not obvious. The reason is steel with a chromium alloy processing, the type of change in the surface oxide into the metal is similar to pure chromium oxide formed on the surface. This tight adhesion of chromium-rich oxide to protect the surface against further oxidation. This very thin oxide layer, through which you can see the surface of the natural sheen of steel, the stainless steel has a unique surface. Moreover, if the damaged surface, the exposed steel surface and atmospheric response to self-repair, re-formation of such a "passive film" and continue to play a protective role.
Therefore, all stainless steel have a common characteristic, namely, chromium content of 10.5% or more.
And building construction steel-related applications are usually only six. They contain 17 to 22% chromium, a better steel also contains nickel. Adding further to improve the atmospheric corrosion of molybdenum, in particular resistance to atmospheric corrosion with chloride.
Atmospheric corrosion resistant stainless steel
Experience has shown that atmospheric corrosion from region to region. For illustration purposes, proposed to be divided into four regions, namely: rural, urban, industrial area and coastal areas.
Is essentially pollution-free rural area. Low population density area, only non-polluting industries.
A typical urban residential, commercial and light industrial areas, there is light pollution in the area, such as traffic pollution.
Industrial air pollution caused by heavy industry area. Contamination may be due to the formation of fuel gases such as sulfur and nitrogen oxides, or the release of chemical or processing plant other gases. Particles suspended in air travel, such as iron and steel dust generated in the production process or the deposition of iron oxide corrosion will also increase.
Coastal areas is usually less than a mile from the beach area. However, deep ocean-atmosphere can be spread to the inland, especially on the island, the prevailing winds from the ocean, and bad weather. For example, the British climate is the case, so the entire country belongs to the coastal area. If the wind mixed with the ocean mist, especially due to evaporation caused by deposition of salt concentration, coupled with less rain, less often by rainfall, coastal areas is even more unfavorable conditions. If there is industrial pollution, then the greater the corrosion.
United States, Britain, France, Italy, Swe