Stainless Steel Pipe
Stainless steel pipe product introduction
Stainless steel pipe is a kind of hollow long round steel, widely used in petroleum, chemical, medical, food, light industry, mechanical instrumentation, and other industrial transmission pipeline and mechanical structure parts. In addition, it is lighter in weight with the same bending and torsional strength, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also often used as furniture and kitchen utensils.
Custom Size 4 10 Inch Ss 304 Sch 10 Stainless Steel Pipe
Custom Size 4 10 Inch Ss 304 Sch 10 Stainless Steel Pipe Outer Diameter：6-2500mm， (3/8″-100″)Thickness：0.3-150mm，(SCH10-XXS)Material: 304,304L,309S,310S,316,316Ti,317,317L,321,347,347H,304N,316L, 316N,201,202Surface：BA，2B，NO.1，NO.4，4K，HL，8KStandard：ASTM，AISI，JIS, GB，DIN, ENLength：2000mm, 2500mm, 3000mm, 5800mm, 6000mm,12000mm， etc or as
China Factory Supplier Customize 4 Inch 304 Stainless China Factory Supplier Customize 4 inch 304 Stainless Steel Flexible Exhaust Pipe
China Factory Supplier Customize 4 inch 304 Stainless Steel Flexible Exhaust Pipe Outer Diameter：6-2500mm， (3/8″-100″)Thickness：0.3-150mm，(SCH10-XXS)Length：2000mm, 2500mm, 3000mm, 5800mm, 6000mm,12000mm， etcSurface：BA，2B，NO.1，NO.4，4K，HL，8KStandard：ASTM，AISI，JIS,GB， DIN,ENProducts can be customized Send Email
Hot Rolled Inox Tubes 304 Stainless Steel Pipe
Hot Rolled Inox Tubes 304 Stainless Steel Pipe Outer Diameter：6-2500mm， (3/8″-100″)Thickness：0.3-150mm，(SCH10-XXS)Material: 304,304L,309S,310S,316,316Ti,317,317L,321,347,347H,304N,316L, 316N,201,202Surface：BA，2B，NO.1，NO.4，4K，HL，8KStandard：ASTM，AISI，JIS, GB，DIN, ENLength：2000mm, 2500mm, 3000mm, 5800mm, 6000mm,12000mm， etc or as request Send Email Request
Cheaper High Quality 3 Inch S32654 S32520 S32304 Super Duplex Stainless Steel Seamless Square Tube
Cheaper High Quality 3 Inch S32654 S32520 S32304 Super Duplex Stainless Steel Seamless Square Tube Steel coil, also known as coil steel. Hot pressing and cold
stainless steel pipe
Place of Origin:
ASTM, AiSi, DIN, EN, GB, JIS
Chemical, electric power, boiler
3-6meters or as customized
Seamless or Welded
Bending, Welding, Decoiling, Punching, Cutting
Terms of price：
FOB, CIF, CFR, EXW
TT, Irrevocable LC at sight, Western union, Ali trade assurance
Application of stainless steel pipe
Stainless steel pipe is an economic profile of steel, which is an important product of the steel industry. It can be widely used in life decoration and industry. Many people in the market are used to making stair handrails, window guards, railings, furniture, etc. The common materials are 201 and 304.
Widely used in furniture, petroleum, chemical, boiler gas, plumbing fixtures, aerospace, paper, automotive, food, packaging machinery, medical, decoration, furniture, railings, and other engineering, hardware processing, shipbuilding, power plants, and other industries.
1. What are the advantages of thin-walled stainless steel pipes?
Thin-walled stainless steel pipe is durable and recognized by the engineering community, and the parties concerned are starting with the wall reduction and price reduction, so as to facilitate further promotion. In particular, the price of small-diameter stainless steel pipe is not high, so the supporting connection method, the reliability, and the price of pipe fittings are the main factors determining its development.
The particularity of thin-walled stainless steel pipe is that it thins the pipe, and on this basis, develops and innovates a simple and safe connection mode. Compared with ordinary stainless steel pipe, the utility of thin-walled pipe is added a lot. Especially when used as a water pipe. Because of the corrosion resistance of stainless steel pipes, the safety of water quality is guaranteed to a certain extent. This shows that thin-walled stainless steel pipe, as new pipe material, can play a good role in energy conservation and environmental protection. Therefore, it can be widely used in engineering construction. In addition, in terms of cost control, if the wall thickness of stainless steel pipe is thin, its weight is light and the relative cost is low; With low cost, high performance, and environmental protection, it is a pipe that people are willing to accept.
Another advantage of thin-walled stainless steel pipe is the connection mode. Stainless steel pipe has a variety of connection modes. Compared with traditional welding, the flange connection mode of thin-walled pipe is not only firm but also has no welding scar, which looks more beautiful. Stainless steel pipe has always had the advantages of stability, safety, green environmental protection, and low economic success, On this basis, thin-walled stainless steel pipe has made more advantages through the renewal of scientific and technological methods. Therefore, as common pipe material, thin-walled pipe plays a great role in life and industrial use.
2. What are the advantages of stainless steel water pipes?
◆ Safe and non-toxic. The selected stainless steel material is a food-grade health material, so for the water supply pipe, the selection of stainless steel pipe is the most beneficial to health. The immersion water test shows that all indexes meet the requirements of relevant international drinking water standards. The inner wall of the stainless steel pipe is smooth. It will not accumulate scale and is not easy to be contaminated by bacteria after long-term use. There is no need to worry about the impact of water quality, and it can eliminate the secondary pollution of water.
◆ Long service life. The thin and dense chromium-rich oxide film on the surface of stainless steel makes the stainless steel water pipe has good corrosion resistance in all water quality, including soft water, and even buried; The field corrosion test data show that the service life of stainless steel water pipe can reach 100 years, and there is almost no need for maintenance in the service life cycle, which avoids the cost and trouble of pipe replacement, and the comprehensive use cost is low.
◆ Energy-saving and environmental protection. The inner wall of the stainless steel pipe is smooth and the water resistance is very small, which reduces the pressure loss and the transportation cost. Due to the low coefficient of thermal expansion of stainless steel, the heat loss in the hot water pipelines is effectively reduced. Stainless steel is a 100% renewable material, which will not cause public hazards to the environment.
◆ Wide application range. Stainless steel pipes can be widely used in cold water, hot water, drinking water, air, gas, medical gas, petroleum, chemical industry, water treatment, and other pipeline systems.
◆ Economical and practical. Since the invention of stainless steel in the 20th century, stainless steel has become an ordinary material. At present, in the performance-price ratio of water pipes of various materials, the best is stainless steel water pipes. This is related to the superior properties of stainless steel, such as corrosion resistance, high strength, and strong impact resistance. Its service life can be said to be the same as that of buildings. Once invested, you will benefit all your life. It can be described as “once and for all”.
3. How to maintain stainless steel water pipes?
◆ Before installing the stainless steel water pipe, the surface of the water supply pipe can be coated with a layer of vegetable oil, and then slightly dried over low fire. The purpose of this is to prolong the service life of stainless steel water pipes and make them easier to clean.
◆ If there are signs of rust on the outer surface of the stainless steel water pipe, the stainless steel wax specially used for rust removal shall be applied at the rusty place in time. After a period of waxing, it can be polished and cleaned. After washing the wax, the outer surface of the water pipe will change luster again.
◆ In daily life, try not to use sharp objects to collide with stainless steel water pipes.
◆ When transporting stainless steel water pipes, they should be packed and fixed with things to avoid collision between water pipes or other sharp objects, which is easy to cause dents on the surface of water pipes and is not beautiful enough.
◆ Once the outer surface of the stainless steel water pipe is scratched, use a dry towel to dip a little stainless steel care agent, and then wipe the scratched place. After wiping, gently polish it with a grinding wheel until the scratch disappears.
4.The application prospect of stainless steel pipe
Stainless steel pipe is an economic cross-sectional steel. It is an important product of the steel industry. It can be widely used in life decoration and industry. Many people in the market are used to making it into stair handrails, window sills, railings, furniture, etc. The common materials are 201 and 304. It accounts for about 8%-16% of the total steel, and is widely used in the national economy. Because of its hollow cross-section, steel pipe is most suitable for pipelines for the transportation of liquids, gases and solids. Stainless steel pipe is an economical steel that saves metal. It is an important part of high-efficiency steel, especially in petroleum drilling, smelting, transportation and other industries. Secondly, geological drilling, chemical industry, construction industry, mechanical industry, aircraft and automobile manufacturing, boilers, medical equipment, furniture, bicycle manufacturing, etc. also need a large number of various steel pipes. With the development of new technologies such as atomic energy, rockets, missiles, space industry, stainless steel pipe plays an increasingly important role in the defense industry, science and technology and economic construction.
Stainless steel pipe is safe, reliable, sanitary, environmental protection, economic and applicable. The thin wall of the tube and the successful development of new reliable, simple and convenient connection methods make it irreplaceable advantages of other tubes. It will be increasingly popular and promising for engineering applications.
Because stainless steel has many of the desirable properties needed in a construction material, it is arguably unique among metals, and its development continues. Improvements have been made to existing types in order to make stainless steel more neutral in traditional applications, and new types of stainless steel are being developed to meet the exacting requirements of advanced architectural applications. Due to continuous improvements in production efficiency and quality, stainless steel has become one of the most cost-effective materials chosen by architects.
Stainless steel combines performance, appearance, and use characteristics. Stainless steel will remain one of the best building materials in the world.
5.304 stainless steel pipe rust corrosion resistance principle
Steel rust in the atmosphere is iron ionization to form unprotected iron oxide (rust) corrosion phenomenon, while 304 stainless steel pipe rust is also a corrosion phenomenon. The difference lies in the atmosphere. The ionization of iron and chromium in stainless steel forms a protective chromium-rich oxide (passivation film). The difference between them is only the nature of the chemical reaction products.
It is generally accepted that steel rusting in the atmosphere is severe corrosion, while stainless steel rusts because stainless steel does not rust. This is visible to the naked eye, the formation of reddish-brown rust on the surface of the steel and a thin passivation layer on the surface of stainless steel. The colorless and transparent film is invisible to the naked eye. What people can see is the passivation film under the surface of the metal shiny and beautiful caused by misunderstanding.
It is conceivable that if the passivation film on the surface of 304 stainless steel pipe is not colorless and opaque, what will be the result? 304 stainless steel tube rust resistance is determined by the chromium content of the steel (steel contains enough chromium to ensure the formation of chromium-rich oxide film on the surface, so the higher the chromium content, the better its corrosion resistance) stainless steel, and stainless steel tube has no relationship with the magnetic properties, there is no chromium there is no stainless steel tube. A large number of studies and practices at home and abroad show that chromium is the only element that can passivate steel, making steel stainless, corrosion resistant, and has industrial value. The so-called chromium-free stainless steel pipe does not exist. The only characteristic of stainless steel pipe is that it does not rust in the atmosphere and fresh water (i.e., it is rust-resistant. It should be distinguished from steel that is corrosion resistant but rusts in the atmosphere, fresh water and acids, alkalis, salts and other media.
6.304L stainless steel pipe rust removal method
Clean the steel surface with solvents and emulsions to remove oil, grease, dust, lubricants and similar organic substances, but cannot remove rust, oxide, flux, etc. on the steel surface, so it can only be used as an auxiliary means in anti-corrosion production.
◆ Rust removal tools
Mainly using tools such as steel wire brush to polish the steel surface, it can remove loose or warped oxide, rust, welding slag, etc. Manual tools can remove rust up to Sa2 level, and power tools can remove rust up to Sa2 level. Up to Sa3 grade. If there is solid oxide skin attached to the steel surface, the effect of rust removal by tools is not ideal and does not reach the depth of anchor pattern required for anti-corrosion construction.
Both chemical and electrolytic methods are generally used for pickling. Only chemical pickling is used for pipeline corrosion protection, which can remove oxide, rust and old coating. Sometimes it can be used as reprocessing after sandblasting rust removal. Although chemical cleaning can make the surface reach a certain degree of cleanliness and roughness, its anchor pattern is shallow and easy to pollute the environment.
◆ Spray (polishing) descaling
Spraying (throwing) rust
removal is driven by high power motor to rotate the spray (throwing) knife at high speed, so that abrasives such as steel sand, steel shot, wire segments and minerals can be sprayed (thrown) away. Under the action of centrifugal force, on the surface of steel pipe. Not only can thoroughly remove rust, oxides and dirt, but also under the effect of violent impact and friction of abrasives, the steel pipe can also achieve the required uniform roughness.
After spraying (throwing) rust removal, not only can expand the physical adsorption on the surface of the pipe, but also can enhance the mechanical adhesion of the anti-corrosion layer to the surface of the pipe. Therefore, spray (blasting) rust removal is the ideal way to remove rust from the pipe. Generally speaking, shot (sand) descaling is mainly used for inner surface treatment of pipes, and shot (sand) descaling is mainly used for outer surface treatment of pipes.
7.316L stainless steel pipe reliability
Selection of austenitic stainless steel should be the whole machine with indirect contact with solids (i.e., where Cl precipitation), especially the injection pipeline, 316L and other ultra-low carbon austenitic stainless steel should be used; the whole machine with indirect contact with liquid objects (i.e., where no Cl precipitation) can be used ordinary austenitic stainless steel; when the friction between the anti-corrosive agent and insoluble particles is controlled, the following should be mastered on the image first , and then change the method. Other aspects are properly addressed while analyzing and considering the selection. Select austenitic stainless steel is the end of corrosion prevention. Do not assume that you can rest easy or comply with GMP. it is more important to ensure that the processing technology and passivation solutions can be reliably responded to. When stainless steel is not available in the above requirements, it can be pre-selected among other materials. From development and consumption to commissioning for military use, several experiments related to the reliability of 316L stainless steel tubes must be stopped. To ensure that the requests made by the user can be met, compliance with the commissioning cycle, resource conservation, and enhanced error governance are often redundant. Experimental governance is to improve the effectiveness of experiments to ensure the validity of the goods reliability outline. The secondary task of governance is to develop and implement the test plan. Therefore, it is necessary to arrange more analytical experiments. A rare approach is to organize, harmonize, and supervise.
8. Stainless steel pipe connection
There are many different ways to connect stainless steel pipes. Common types of pipe fittings include compression, compression, articulation, push-in, push-in thread, socket welding, articulated flange connection, welding welding and traditional connection. Combined conductor tandem method. These connection methods have different scope of application according to their principles, but most of them are easy to install, solid and reliable. Connection using the seal or gasket materials mostly meet the national standard requirements of silicone rubber, nitrile rubber and EPDM rubber to avoid user worries.
◆ Break the tube: cut the tube according to the required length. When the tube is broken, do not force too hard to avoid the tube is not round.
◆ Deburring: After the tube is cut off, the burr should be removed so as not to cut the seal.
◆ Mark the line: In order to make the steel pipe completely inserted into the pipe fitting socket, the insertion length must be marked and drawn at the end of the pipe.
◆ Assembly: The seal should be correctly installed in the U-shaped groove of the pipe fitting, insert the pipe into the pipe fitting socket and wait for crimping.
◆ Crimping: When crimping, the projection of the tube is placed in the groove of the mold, and the jaws are kept perpendicular to the axis of the tube.
◆ Check: After crimping is completed, check the crimp size with special gauges.
9. Identification method of stainless steel pipe
① with international chemical element symbols and national symbols to indicate the chemical composition, with Arabic letters to indicate the composition content.
Such as: China, Russia 12CrNi3A.
② with fixed numbers to indicate the steel system or number; such as: United States, Japan, 300 series, 400 series, 200 series.
③ serial number consists of Latin letters and sequence, only to indicate the use.
① the use of elemental symbols.
② Hanyu Pinyin, flat-furnace steel: P; boiling steel: F; sedimentation steel: B; Grade A steel: A; T8: Special 8; GCr15: ball.
◆Composite steel, spring steel, such as: 20CrMnTi 60SiMn, (with a few thousandths to indicate the C content).
◆Stainless steel, alloy tool steel (with a few thousandths to indicate the C content), such as: 1Cr18Ni9 thousandths (i.e. 0.1% C), stainless steel C ≤ 0.08% such as 0Cr18Ni9, ultra-low carbon C ≤ 0.03% such as 0Cr17Ni13Mo.
The American Iron and Steel Institute uses three digits to indicate the various standard grades of malleable stainless steel. In.
① Austenitic stainless steels are marked with 200 and 300 series numbers. For example, some common austenitic stainless steels are labeled 201, 304, 316 and 310.
② Ferritic and martensitic stainless steels are indicated by numbers in the 400 series. Ferritic stainless steels are labeled 430 and 446, martensitic stainless steels are labeled 410, 420 and 440C, duplex (austenitic-ferritic).
③ stainless steel, precipitation-hardening stainless steel and high alloy with less than 50% iron content are usually named by a patented name or trademark.
① national standard GB ② industry standard YB ③ local standard ④ enterprise standard Q/CB
① product standards ② packaging standards ③ method standards ④ basic standards
4-3 Standard level (divided into three levels)
Y level: international advanced level I level: international general level H level: domestic advanced level
4-4 National standards.
GB1220-84 stainless steel bar (I level) GB4241-84 stainless steel welded plate (H level)
GB4356-84 stainless steel welded plate (Class I) GB1270-80 stainless steel pipe (Class I)
GB12771-91 Stainless steel welded pipe (Y grade) GB3280-84 Stainless steel cold plate (I grade)
GB4237-84 stainless steel hot plate (Class I) GB4239-91 stainless steel cold strip (Class I)
10. What is the classification of stainless steel pipe?
Stainless steel pipe is divided into ordinary carbon steel pipe, high quality carbon structural steel pipe, alloy structural pipe, alloy steel pipe, bearing steel pipe, stainless steel pipe, bimetallic composite pipe, plated pipe, saving precious metals and meeting special requirements. . There are many types of stainless steel tubes, different uses, different technical requirements and different production methods. Currently produced steel pipe outer diameter range of 0.1-4500mm, wall thickness range of 0.01-250mm. in order to distinguish its characteristics, steel pipe is usually divided into the following categories.
Stainless steel pipes are divided into seamless pipes and welded pipes according to the production method. Seamless steel pipe can be divided into hot-rolled pipe, cold-rolled pipe, cold-drawn pipe and extruded pipe. Cold-drawn and cold-rolled are the secondary types of steel pipe. Processing; welded pipe is divided into straight seam welded pipe and spiral welded pipe.
Stainless steel tubes can be divided into round tubes and shaped tubes according to the cross-sectional shape. Shaped tubes include rectangular tubes, diamond-shaped tubes, oval tubes, hexagonal tubes, octagonal tubes and a variety of asymmetric cross-sectional tubes. Shaped tubes are widely used in various structural parts, tools and mechanical parts. Compared with the round tube, shaped tube generally has a larger moment of inertia and cross-sectional modulus, and has a larger bending and torsion resistance, can greatly reduce the weight of the structure, saving steel.
Stainless steel tube according to the shape of the longitudinal cross-section can be divided into equal-section tube and variable-section tube. Variable-section tubes include tapered tubes, stepped tubes and periodic section tubes.
Tube end shape
Stainless steel pipe according to the end state can be divided into glossy pipe and threaded pipe (threaded steel pipe). Threaded pipe can be divided into ordinary threaded pipe (pipeline conveying water, gas and other low pressure, with ordinary cylindrical or tapered pipe connection) and special threaded pipe (oil, geological drilling with pipe. Important threaded pipes, connected with special threads). For some special pipes, the pipe ends are usually thickened (inside thickening, outside thickening or inside and outside thickening) before turning the threads in order to compensate for the effect of the threads on the strength of the pipe ends.
11. What are the new products of stainless steel pipes?
200 series D7S
Product description: The nickel content of D7S is around 2.5%, which is slightly lower than D11, and the price is lower. Stainless steel pipes with 1% nickel content will be the key to D7S market supply to a certain extent. Therefore, the high use rate of competitive and high-quality stainless steel will also be an important part of the sales plan.
Application areas: The target market for new products, such as stainless steel kitchen appliances and equipment, has launched a marketing plan for stainless steel pipes.
Product description: The tensile strength of this material is 980～1180MPa, and the maximum working temperature can reach 90℃.
Application field: Pipeline for the harsh submarine environment.
Product description: Ultra (super) critical unit is the basis for the modernization of power generation equipment and energy-saving and emission reduction. Among the important pressure components of ultra (super) critical boilers, the components with the highest working temperature and the worst working environment are the superheater and the reheater. Previously, these materials used in China were imported from abroad. However, there are only 10 steel material manufacturers in the world with limited capacity. Such materials have a large gap, high import prices, difficult procurement, and short supply, which has seriously affected China’s supermarkets. The production of supercritical boilers and the development of electric power. China’s current demand for power plant boiler tubes is about 30,000 tons per year, and with the continuous improvement of ultra (super) critical power generation technology, the demand is increasing year by year. Several large domestic companies have invested a lot of manpower and financial resources in the research and development and production of such products, and have achieved considerable results. On the one hand, it has made its own contribution to the development of the country’s electric power industry, and at the same time, it has also brought considerable economic benefits to the enterprise.
Application field: power station boiler industry, mainly in key parts such as superheater and reheater high-temperature section.
12. What is the executive standard of stainless steel pipe?
GB/T14976-2012 Stainless steel seamless steel pipe for fluid transportation.
(Instead of GB/T14976-2002 instead of GB/T14976-1994 instead of GB2270-1980).
GB/T14975-2012 Stainless steel seamless steel pipe for structure (instead of GB/T14975-2002).
GB13296-2013 Stainless steel tubes for boiler tubes and heat exchangers.
(GJB2608-96) (YB676-73) Structural and thick-walled seamless steel tubes for aviation.
(GJB2296-95) (YB678-71) Stainless steel tubes for aviation.
(YB/T679-97) (YB679-71) 18A hollow rivet aviation thin-walled seamless steel pipe.
(GJB2609-96) (YB680-71) Structural tubes for aviation, thin-walled. Seamless steel pipe.
(YB/T681-97) (YB681-71) 20A Air duct, thin-walled seamless steel pipe.
GB3090-2000 small diameter stainless steel pipe.
GB5310-2017 Seamless steel pipe for high pressure boiler.
GB3087-2008 Medium and low pressure boiler tubes.
GB3089-2008 Seamless steel pipe with very thin wall for stainless acid resistance.
GB9948-2013 Seamless steel pipe for petroleum cracking.
ASTM A213 Ferritic and austenitic alloy tubes for boilers and heat exchangers.
ASTM A269 General purpose austenitic stainless steel tubes and welded tubes.
ASTM A312 Seamless austenitic stainless steel tubes and pipes welded tubes and pipes.
ASTM A450 General requirements for carbon, ferritic and austenitic alloy steel tubes and pipes.
ASTM A530 General requirements for special purpose ferritic and alloy steels.
ASTM A789 General requirements for seamless and welded steel tubes of carbonitic austenitic stainless steel.
JIS G3456-88 Stainless steel pipes for mechanical structures.
JIS G3448-88 Stainless steel pipes for general pipelines.
JIS G3459-88 Stainless Steel Pipes and Tubes for Pipelines.
JIS G3463-88 Stainless steel pipes for boilers and heat exchangers.
Q/HYAD Seamless steel pipe for chemical industry.
(0Cr18NI11T) Q/HYAD Cr18Ni5MO3Si2 Duplex stainless steel. Seamless steel pipe.
13. What are the material classifications of stainless steel tubes?
Stainless steel pipe can be divided into Cr series (400 series), Cr-Ni series (300 series), Cr-Mn-Ni (200 series) and precipitation hardening series (600 series) according to the composition.
200 series – Cr-Ni-Mn austenitic stainless steel 300 series – Cr-Ni-Mn austenitic stainless steel.
301 —– Good ductility for molded products. Can also be hardened by machining. Good weldability. Wear resistance and fatigue strength better than 304 stainless steel.
302 —– Same corrosion resistance as 304, better strength due to higher carbon content.
303 —– is easier to cut than 304 with the addition of small amounts of sulfur and phosphorus.
304 —– is 18/8 stainless steel. GB grade is 0Cr18Ni9. 309 – has better temperature resistance compared to 304.
316 —– The second most versatile steel grade after 304, used mainly in the food industry, pharmaceutical industry and surgical instruments. The addition of molybdenum makes it an exceptional corrosion resistant structure. It is also used as a “marine steel” because it has better resistance to chloride corrosion than 304 stainless steel tubing. SS316 is commonly used in nuclear fuel recovery installations. Grade 18/10 stainless steel tubing also typically meets this application grade.
Type 321 – Similar properties to 304 except that titanium is added to reduce the risk of corrosion in the material’s welds.
400 Series – Ferritic and martensitic stainless steels.
408-Good heat resistance, weak corrosion resistance, 11% Cr, 8% Ni.
409-The cheapest type (British and American), usually used as an automotive exhaust, is a ferritic stainless steel (chromium steel).
410-Martensitic (high strength chromium steel), good wear resistance, poor corrosion resistance.
416 – Sulfur is added to improve the machinability of the material.
420 – A “tool grade” martensitic steel, similar to the earliest stainless steels such as Brinell high chromium steel. It is also used in scalpels and can be very bright.
430 – Ferritic stainless steel, used for decorative purposes, such as automotive parts. Good formability, but less temperature and corrosion resistance.
440- High strength tool steel with slightly higher carbon content. With proper heat treatment, higher yield strength can be obtained. With a hardness of up to 58 HRC, it is one of the hardest stainless steels. The most common application example is “razor blades”. Three types are commonly used: 440A, 440B, 440C, 440F (easy to work with).
500 series – heat resistant chromium alloy steel.
600 series – martensitic precipitation hardening stainless steel tube.
14.The cause of rusting of 304 steel
Chlorine ions are widely distributed, such as salt, sweat, seawater, sea breeze, soil, etc.. Stainless steel corrodes rapidly in the presence of chloride ions, even more than ordinary low carbon steel. Chlorine ions and alloying elements in the formation of iron complexes, reducing the positive potential of iron, and then oxidized by taking electrons from the oxidizer.
Therefore, there are requirements for the stainless steel to be used in an environment that requires frequent wiping to remove dust and keep it clean and dry.
316 and 317 stainless steels are molybdenum-containing stainless steels. The molybdenum content of 317 stainless steel is slightly higher than that of 316 stainless steel. Because 316 stainless steel contains molybdenum, the overall performance of this steel is better than 310 and 304 stainless steel. Under high temperature conditions, when the sulfuric acid concentration is below 15% and above 85%, 316 stainless steel is widely used. 316 stainless steel also has good resistance to chloride corrosion and is therefore commonly used in marine environments.
15. Stainless steel tube application requirements
(1) Automotive industry
Stainless steel is mainly used in the exhaust system, accounting for more than 1/2 of the total stainless steel of the car, 80% of ferritic stainless steel. The exhaust gas produced by the car engine through the exhaust gas intake pipe, front pipe, hose, converter, center pipe out of the muffler. Commonly used steel grades for exhaust system are 409L, 436L, etc. Automotive muffler mainly adopts stainless steel welded pipe. According to estimates, the automotive stainless steel pipe accounts for about 1.5% of the total downstream consumption of stainless steel pipe, the use of stainless steel seamless pipe and welded pipe ratio of about 2:1.
including the fertilizer industry
Stainless steel pipe is in great demand. The industry mainly uses stainless steel seamless tubes. Specifications are: 304, 321, 316, 316L, 347, 317L, etc., the outer diameter of about ￠18-¢610, wall thickness of 6mm-50mm or so (generally choose Φ159mm or more specifications of low and medium pressure transport pipe), the specific application areas are: furnace tube, material transport tube, heat transfer tube, etc.
(3) water, gas and other fluid transportation
Equipment manufacturing and maintenance
Stainless steel pipe annual consumption of 20,000 tons or more. Such industries mainly use sanitary or antibacterial grade stainless steel pipe. Sanitary seamless tubes made of imported SUS304 and 316L can meet the special requirements of various media in the food and biopharmaceutical fields. Antibacterial stainless steel has the advantages of stainless steel and good antibacterial properties. The demand for kitchen equipment, workbenches and utensils in the food industry, medical equipment in daily life, tableware and towel racks, and freezer supports is increasing.
16.Analysis of the development trend of stainless steel pipe industry
（1）Environmentally friendly products have become new favorites.
With the continuous emergence of environmental protection issues, consumers’ awareness of environmental protection and health continues to increase, and more attention is paid to the environmental protection and safety of stainless steel tube products, and products that do not meet environmental protection standards will gradually be eliminated by the market. Therefore, if stainless steel tube shops want to maintain long-term development, they must follow the market demand and take the route of environmentally friendly products.
（2)Market demand has changed
With the development of the times, young consumer groups are gradually becoming the main force of market consumption. The young people born in the 1980s and 1990s have more and higher requirements for stainless steel pipes, and the demand for personalized products also forces stainless steel. Store management should keep abreast of consumer needs.
（3）Internet e-commerce channels are becoming more and more obvious
In today’s era, with the rapid development of the Internet and the advent of the mobile Internet era, earth-shaking changes have taken place in all walks of life. With the continuous development of the market, the subjective awareness of consumers continues to increase, and there are higher requirements for stainless steel pipe products. Therefore, the stainless steel pipe industry conforms to the consumer market and expands new channels such as the Internet and e-commerce, and consumption upgrades have become an inevitable trend.
As a basic material in the industrial field, industrial stainless steel pipes are widely used in my country’s equipment manufacturing industry. The equipment manufacturing industry is a strategic industry that provides technical equipment for various industries in the national economy. An important guarantee for upgrading and technological progress and a concentrated expression of the country’s comprehensive strength.
17. Four main points of stainless steel water pipe selection
(1) Product details
Some product details are easy for us to find, such as the gloss of the surface of the stainless steel pipe, the hand feels, whether the cut is flat, whether there are burrs, black spots, etc., such details are easy for us to find. If such basic requirements are not met, it is obvious that this kind of stainless steel pipe is basically a relatively poor product. A good stainless steel water pipe is a thin-walled seam pipe, which is welded by a pipe-making machine. The internal welding seam of the pipeline is smooth, and there is no obvious color change around the welding seam. The wall thickness of the stainless steel pipe is uniform, especially the welding seam, and there should be no dislocation or depression. Therefore, it is not a good product with thick walls. Stainless steel water pipes should be thin-walled pipes with seams.
The raw material determines the quality of the finished product. The quality of stainless steel pipes is greatly related to the material of stainless steel pipes. At present, the materials of stainless steel pipes are generally used in four categories: 201, 304, 316, and 316L. Among them, in terms of comprehensive cost performance, 304 has the most drinking water pipes, and food-grade 304 stainless steel water pipes are recommended. The corrosion resistance of 316 stainless steel is better than that of 304 stainless steel. 316L has lower carbon content than 316 and better corrosion resistance, but the price is more expensive than 304 stainless steel, so you can choose according to your needs.
At present, the national standard thickness of stainless steel water pipes in the domestic stainless steel water pipe market and manufacturers is 0.8~2mm. The wall thickness of the stainless steel water pipe is the key to determining its connection strength, and the wall thickness must meet the standard. Only in this way can it maintain the seismic performance and the performance of resisting external impact in various environments.
If you want to control the quality of stainless steel pipes at the source, the best way is to find the right manufacturer. The quality of stainless steel pipes produced by unqualified manufacturers varies. Although the price may be cheaper, the quality of the product cannot be guaranteed. Therefore, it is necessary to choose a large stainless steel pipe manufacturer with rich production experience.
18.What is the difference between the price of 304 stainless steel pipe
The technological level of the product also has a great influence on the price of the product, and the stainless steel tube rolling process is one of the more important processes. Generally speaking, the thickness of 304 stainless steel pipe has a great relationship with the rolling of strip steel, because the specific charging standards of the rolling plant are divided according to different thicknesses, and the thinner the thickness of the strip, the rolling processing cost of one ton The higher it is, this is why the level of the calendering process affects the price, because after the overall cost has risen, the price will naturally be different.
Generally, stainless steel pipe factories will keep some general 304 stainless steel pipe specifications and models with a thickness of about 0.5 mm and above. The 304 stainless steel pipes of these specifications and models have a high yield during pipe making and grinding and polishing, so they are easy to manufacture. However, it is not difficult for us to find in the process of contacting customers that the current needs are diversified, and many stainless steel pipes are customized in a large amount, especially some thin stainless steel pipes. The yield is relatively low because of the need for pipe making and polishing. The process specification is relatively high, and the yield is relatively low. So the overall cost goes up, and the price is naturally expensive.
The corrosion resistance of stainless steel coils decreases as the carbon content increases. Therefore, the carbon content of most stainless steels is low, up to 1.2%, and some steels have a low ωC (carbon content) of even less than 0.03% (such as 00Cr12). The main alloying element in stainless steel coil is Cr (chromium). Only when the Cr content reaches a certain value, the steel has corrosion resistance. Therefore, the goods Cr (chromium) content of at least 10.5%. Stainless steel coil also contains Ni, Ti, Mn, N, Nb, Mo, Si, Cu and other elements.
Most of the requirements for use are to maintain the original appearance of the building for a long time. In determining which type of goods to choose, the main considerations are the required aesthetic standards, the corrosiveness of the local atmosphere and the cleaning system to be used. However, other applications are increasingly seeking structural integrity or impermeability. Examples include roofs and sidewalls of industrial buildings. In these applications, construction cost to the owner may be more important than aesthetics, and the surface may not be very clean. The use of 304 stainless steel coils in dry interior environments is quite effective.
Weldability. Different product uses have different requirements for weldability. A class of tableware generally does not require weldability, even including some cookware companies. However, most products require raw materials with good weldability, such as second-class tableware, insulation cups, steel pipes, water heaters, water dispensers, etc.
Corrosion resistance. Most stainless steel coil products require good corrosion resistance, such as Class I or Class II tableware, kitchen utensils, water heaters, water dispensers, etc.
Polishing performance. In today’s society, stainless steel coil products in the production process are generally polished, only a few products such as water heaters, drinking fountains, etc. do not need to be polished. Therefore, this requires raw materials with good polishing performance.
1. The need for pre-treatment
Pretreatment is an important treatment step before the surface of stainless steel coil parts enter surface treatment (including pickling, chemical polishing and electrochemical polishing, electroplating, passivation, black coating, coloring, chemical treatment, etc.). During the forming process of goods parts, the surface may adhere to oil stains, burrs, rough surfaces and oxides. Therefore, before surface treatment, oil stains, burrs, uneven surfaces and oxides must be removed in order to obtain subsequent satisfactory results through processing.
2. Treatment of removed dirt
Stainless steel coil surface pretreatment in the need to remove the dirt can be divided into two categories: organic and inorganic substances.
(1) organic dirt. Including mineral oil (such as diesel, oil, paraffin, gypsum, etc.) and animal oil, vegetable oil (such as soybean oil, camellia oil, rapeseed oil, lard, butter, etc.). These oils are mainly from the stainless steel coil zero cattle processing process used in the lubricant. , cutting oil, quenching oil, polishing paste and polishing paste, and fingerprints.
(2) Inorganic dirt. Including dirt, dust particles, oxides and other contaminants generated during the heat treatment process.
3. Pretreatment steps for stainless steel coil parts
(1) The surface is mechanically leveled. Eliminate the roughness of the stainless steel coil surface, through mechanical polishing and grinding to achieve a surface finish.
(2) Degreasing. Remove the surface oil and dirt.
(3) Acid washing. Remove the oxides on the surface.
(4) Weak corrosion. Activates the surface to be treated, removes the surface passivation film, and exposes the metal crystal structure.
Stainless steel is a high-alloy steel, with a large resistance to rolling deformation. In order to carry out high-efficiency and high-precision rolling, rigid rolling mills should be used, generally multi-roller cold rolling mill.
Special welding process is also a feature of cold-rolled stainless steel coil production.
In the production process of cold rolled stainless steel coil, the raw material (hot rolled coil) should be annealed, intermediate annealing should be carried out in the cold rolling process, and the final product should be annealed, so annealing is an important part of the production.
Cold-rolled stainless steel is a high-grade steel products, there are strict requirements for surface quality. Not only are metallurgical defects caused by the previous process not allowed, but also obvious defects caused by the cold rolling process.