Stainless steel tubes/tubing Manufacturers&Suppliers

 

What are stainless steel tubes?

The stainless steel tubes is a kind of hollow long stainless steel. The shape can be round, square, rectangular, oval, hexagonal, etc. In some sense, stainless steel tube is an unnormal shape pipe, It also includes round. The tube is widely used in various structural parts, tools, and mechanical parts. building materials, etc. It is also commonly used for furniture, kitchenware, doors, and windows,  stair railings, etc. It is very common in daily life.

 

 

Hardness

 

Stainless steel pipe/tube is generally used to measure its hardness by Brinell, Rockwell, and Vickers hardness indicators.

 

Brinell hardness

In stainless steel pipe/tube standards, Brinell hardness is the most widely used, often with indentation diameter to indicate the hardness of the material, both intuitive and convenient. But for harder or thinner steel pipes/tubes of steel do not apply.

 

Rockwell hardness

Stainless steel tube/pipe Rockwell hardness test is the same as Brinell hardness test, are indentation test method. The difference is that it measures the depth of the indentation.

Rockwell hardness test is a widely used method, in which HRC in the steel tube standards used next to Brinell hardness HB. Rockwell hardness can be applied to determine the metal material from very soft to very hard, it makes up for the Brinell method is not, easier than the Brinell method, can be read directly from the dial of the hardness machine hardness value. However, due to its small indentation, the hardness value is not as accurate as the Brinell method.

 

Vickers hardness

Stainless steel tube/pipe Vickers hardness test 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, Rockwell method while overcoming their basic shortcomings, but not as easy as Rockwell method, Vickers method is rarely used in the steel pipe/tube standards.

 

Hardness testing

 

Stainless steel pipe/tube inside diameter of 6.0mm or more, the wall thickness of 13mm below the annealed stainless steel pipe/tube, you can use W-B75 type Wechsler hardness tester, it is very fast and easy to test, suitable for stainless steel pipe/tube to do a rapid non-destructive qualified inspection. Stainless steel pipe/tube inner diameter greater than 30mm, wall thickness greater than 1.2mm stainless steel pipe/tube, using Rockwell hardness tester, test HRB, HRC hardness. Stainless steel pipe/tube inner diameter greater than 30mm, wall thickness less than 1.2mm stainless steel pipe, using the surface Rockwell hardness tester, test HRT or HRN hardness. The inner diameter of stainless steel pipe/tube less than 0mm, more than 4.8mm stainless steel pipe/tube, the use of pipe special Rockwell hardness tester, test HR15T hardness. When the inner diameter of stainless steel pipe/tube is greater than 26mm, you can also use Rockwell or surface Rockwell hardness tester to test the hardness of the inner wall of the pipe/tube.

 

Properties

Surface resistance less than 1000 megawatts; abrasion protection; stretchable; excellent chemical resistance; good resistance to alkali metals and acids; toughness; flame retardant.

 

Classification

There are many types of stainless steel tubes, with different uses, different technical requirements, and different production methods. To distinguish their characteristics, usually according to the following method of classification of stainless steel tube.

 

Production method

Stainless steel tube according to the production method is divided into seamless and welded tube two categories.

The seamless steel tube can be divided into hot-rolled tube, cold-rolled tube, cold-drawn tube, and extruded tube, cold-drawn, cold-rolled is the secondary processing of stainless steel tube; the welded tube is divided into straight seam welded tube and spiral welded tube, etc.

 

Section shape

Stainless steel tubes according to the cross-sectional shape can be divided into rectangular tubes, diamond-shaped tubes, oval tubes, hexagonal tubes, eight square tubes, and a variety of cross-sectional asymmetric tubes. they are widely used in various structural parts, tools, and mechanical parts. Compared with round tubes, tubes generally have a larger moment of inertia and cross-sectional modulus, have greater resistance to bending and torsion, can greatly reduce the weight of the structure, saving steel.

Stainless steel tube according to the shape of the longitudinal section can be divided into equal section tube and variable section tube. Variable section tube has a tapered tube, stepped tube, and periodic section tube.

 

 

Application classification

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

 

Material classification

Stainless steel tubes can be divided into Cr series (400 series), Cr-Ni series (300 series), Cr-Mn-Ni (200 series), and precipitation hardening series (600 series) by composition.

200 series ----- Cr-Ni-Mn austenitic stainless steel 300 series - Cr-Ni austenitic stainless steel.

301 ----- has good ductility and is used for forming products. Can also be rapidly hardened by mechanical processing. Good weldability. Wear resistance and fatigue strength are better than 304 stainless steel.

302 ----- has the same corrosion resistance as 304, but is stronger due to its relatively high carbon content.

303 ----- is easier to machine than 304 by adding small amounts of sulfur and phosphorus.

304----- is 18/8 stainless steel. GB grade is 0Cr18Ni9.

 

309----- has better temperature resistance than 304.

316 ----- is the second most widely used steel grade after 304, mainly used in the food industry, pharmaceutical industry, and surgical equipment, with the addition of molybdenum to give it a special structure that resists corrosion. SS316 is commonly used for nuclear fuel recovery devices. 18/10 grade stainless steel tubes are also usually qualified for this application.

Type 321 ----- similar to 304 except that the addition of titanium reduces the risk of corrosion in the material 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 automotive exhaust, ferritic stainless steel (chromium steel).

410-----Martensitic (high strength chromium steel), good wear resistance, poor corrosion resistance.

416 ----- added sulfur to improve the processing properties of the material.

420-----"Cutting tool grade" martensitic steel, similar to Brinell high chromium steel, the earliest stainless steel. Also used for surgical knives and can be made very bright.

430 ----- Ferritic stainless steel, used for decorative purposes, e.g. for car accessories. Good formability, but less resistance to temperature and corrosion.

440 ----- High strength cutting tool steel, slightly higher carbon content, after appropriate heat treatment, can be obtained after high yield strength, hardness can reach 58HRC, belong to the hardest stainless steel among. The most common application example is "razor blade". There are three common types: 440A, 440B, 440C, and 440F (easy to work with).

500 Series ----- Heat-resistant chromium alloy steel.

600 Series ----- Martensitic precipitation hardening stainless steel tubes.

 

Stainless Steel Tube Standards

Spec. No. Title Scope
ASTM A 213
ASME SA 213
Seamless Ferritic Stainless Steel and Austenitic Stainless Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes. Pressure tubes, made from 16 grades of austenitic stainless steel and from 12 grades of ferritic Cr-Mo Alloy Steel.
ASTM A 249
ASME SA 249
Welded Austenitic Stainless Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes. Pressure tubes, made from austenitic stainless steels, (Types 304, 304H, 304L, 305, 309, 310, 316, 316H, 316L, 317, 321, 321H, 347, 347H, 348, 348H, and XM grades.)
ASTM A 268
ASME SA 268
Seamless and Welded Ferritic Stainless Steel Tubing for General Service. 15 grades of ferritic stainless steel tubing for general corrosion resistance and high-temperature service. (Types 329, 405, 409, 410, 429, 430, 430Ti, 443, 446, XMs & others).
ASTM A 269 Seamless and Welded Austenitic Stainless Steel Tubing for General Service. 13 grades of austenitic stainless steel tubing for general corrosion-resisting and high-temperature service. (Types 304, 304L, 316, 316L, 317, 321, 347, 348 and XM grades).
ASTM A 270 Seamless and Welded Austenitic Stainless Steel Sanitary Tubing. Austenitic stainless steel tubing intended for use in the dairy and food industry in sizes up to and including 4 in. in outside diameter.
ASTM A 312
ASME SA 312
Seamless and Welded Austenitic Stainless Steel Pipe. Austenitic stainless steel pipe intended for high temperature and general corrosive service. 22 grades are covered.
ASTM A 358
ASME SA 358
Electric-Fusion-Welded Austenitic Chromium-Nickel Alloy Steel Pipe for High-Temperature Service. For corrosion and high-temperature service, normally not less than 8 in. nominal diameter. Types 304, 316, 309, 310, 321, 347, 304L, 316L, 304H, 316H.
ASTM A 376 
ASME SA 376
Seamless Austenitic Stainless Steel Pipe for High-Temp Central-Station Service. Austenitic stainless steel pipe intended for high temperature and general corrosive service. Better surface than A312 pipe.
ASTM A 409 
ASME SA 409
Welded Large Outside Diameter Light Wall Austenitic Chromium-Nickel Alloy Steel Pipe for Corrosive or High-Temperature Service. Nominal diameter 14-30 in. in Schedules 5S and l0S. Types 304, 309, 310, 316, 317, 321, 347, 348, 304L, 316L.
ASTM A 450 
ASME SA 450
General requirements for Alloy Steel Tubes. Common requirements for ASTM tubular specifications.
ASTM A 511 Seamless Stainless Steel Mechanical Tubing. 27 grades are covered for mechanical applications. Primarily round tubing.
ASTM A 530
ASME SA 530
General Requirements for Carbon, Ferritic Alloy, and Austenitic Alloy Steel Pipe. Common requirements for ASTM pipe specifications as listed.
ASTM A 554 Welded Stainless Steel Mechanical Tubing. Nineteen grades are covered for mechanical applications. Rounds, squares, rectangles, and special shapes are included.
ASTM A 632 Seamless and Welded Austenitic Stainless Steel Tubing for General Service. Small Diameter. 9 grades of austenitic stainless steel tubing for general corrosion-resisting and high-temperature service.
AMS 556 Steel Tubing, Corrosion and Heat Resistant 18 Cr; 11 Ni; (Cb + Ta) (SAE 30347) Hydraulic. Annealed type 321 hydraulic line tubing. Type 1-Seamless Type 2-Welded & Drawn
AMS 5557 Steel Tubing, Corrosion, and Heat Resistant 18 Cr; 11 Ni; Ti (SAE 30321)Hydraulic Annealed type 347 hydraulic line tubing. Type 1-Seamless Type 2-Welded & Drawn
AMS 5558 Steel Tubing, Welded, Corrosion and Heat Resistant 18 Cr; 11 Ni, (Cb + Ta)(SAE 30348) Thin Wall. High pressure ducting, wall thickness 2% of O.D. or less. Weld bead controlled, X-ray.
AMS 5559 Steel Tubing, Welded, Corrosion, and Heat Resistant 18 Cr, 10 Ni, Ti, (SAE 30321) Thin Wall. High pressure ducting, wall thickness 2% of O.D. or less. Weld bead controlled, X-ray.
AMS 5560 Steel Tubing, Seamless Corrosion Resistant 19 Cr; 9 Ni (SAE 30304). Annealed type 304 aircraft hydraulic fine tubing. (Not subject to high pressure). Structural.
AMS 5561 Steel Tubing, Welded and Drawn Corrosion Resistant 21 Cr; 6 Ni; 9 Mn High-Pressure Hydraulic. For parts and assemblies such as fluid lines subject to high pressure and requiring corrosion resistance. 1/8 - 1/4 Hard.
AMS 5562 Steel Tubing, Seamless Corrosion Resistant 21 Cr; 6 Ni; 9 Mn Annealed. Parts and assemblies requiring both corrosion and heat resistance, and having higher strength than 18-8 types.
AMS 5565 Steel Tubing, Welded, Corrosion Resistant 19 Cr; 6 Ni (SAE 30304). Annealed type 304 aircraft hydraulic line tubing. (Not subject to high pressure), Structural.
AMS 5566 Steel Tubing, Seamless or Welded Corrosion Resistant 19 Cr; 10 N (SAE 30304) High-Pressure Hydraulic Cold drew type 304, high pressure, aircraft hydraulic line tubing. 1/8 hard. 
Type 1óSeamless 
Type 2óWelded & Drawn
AMS 5567 Steel Tubing, Seamless or Welded Corrosion Resistant 19Cr; 10 Ni (SAE 30304) Hydraulic, Solution Treated. Fluid lines subject to medium-high pressures requiring corrosion resistance. Annealed. (1) Seamless (2) Welded & Drawn
AMS 5570 Steel Tubing, Seamless Corrosion and Heat Resistant 18 Cr; 10 Ni; Ti (SAE 30321). Annealed Structural. Parts and assemblies requiring both corrosion and heat resistance especially when such parts are welded during fabrication. Requiring oxidation resistance up to approximately 1500F, but useful at that temperature only when stresses are low.
AMS 5571 Steel Tubing, Seamless Corrosion, and Heat Resistant 18 Cr; 11 Ni; (Cb + Ta) (SAE 30347). Annealed Structural. Parts and assemblies requiring both corrosion and heat resistance especially when such parts are welded during fabrication. Requiring oxidation resistance up to approximately 1500F, but useful at that temperature only when stresses are low.
AMS 5572 Steel Tubing, Seamless Corrosion, and Heat Resistant 25 Cr; 20 Ni (SAE 30310). Annealed Structural. Parts and assemblies requiring both corrosion and heat resistance especially when welded during fabrication, Requiring oxidation resistance up to approximately 2000F, but useful at that temperature only when stresses are low.
AMS 5573 Seamless Type 316 Annealed Structural Parts & assemblies requiring, both corrosion and heat resistance up to 1600F.
AMS 5574 Seamless Type 309S Annealed Structural Parts & assemblies requiring both corrosion and heat resistance up to 2000F especially welded assemblies.
AMS 5575 Steel Tubing, Seamless Corrosion, and Heat Resistant 18 Cr; 11 Ni; (Gb + Ta) (SAE 30347). Annealed Structural. Parts and assemblies requiring both corrosion and heat resistance especially when such parts are welded during fabrication. Requiring oxidation resistance up to approximately 1500F, but useful at that temperature only when stresses are low.
AMS 5576 Steel Tubing. Welded, Corrosion and Heat Resistant 18 Cr; 10 Ni; Ti (SAE 30321). Annealed Structural. Parts and assemblies requiring both corrosion and heat resistance especially when such parts are welded during fabrication. Requiring oxidation resistance up to approximately 1500F, but useful at that temperature only when stresses are low.
AMS 5577 Steel Tubing, Welded, Corrosion, and Heat Resistant 25 Cr; 20 Ni; (SAE 30310). Annealed Structural. Parts and assemblies requiring both corrosion and heat resistance especially when welded during fabrication. Requiring oxidation resistance up to approximately 2000F, but useful at that temperature only when stresses are low.
AMS 5639 Seamless Type 304 Cold Finished Mechanical Tube Rockwell 90B max Hardness Corrosion Embrittlement Capability
AMS 5645 Seamless Type 321 Cold Finished Mechanical Tube Rockwell 90B max Hardness Corrosion Embrittlement Capability
AMS 5546 Seamless Type 347 Cold Finished Mechanical Tube Rockwell 90B max Hardness Corrosion Embrittlement Capability
AMS 5647 Seamless Type 304L Cold Finished Mechanical Tube Rockwell 90B max Hardness Corrosion Embrittlement Capability
AMS 5648 Seamless Type 316 Cold Finished Mechanical Tube Rockwell 90B max Hardness
MIL-T-5695 Tubing, Steel, Corrosion Resistant, (304) Cold Drawn (1/2 or 1/4 Hard) Smls or W&D. Intended for use in the fabrication of aircraft structural parts requiring a high degree of resistance to corrosion.
MIL-T-6737
(T 321)
Tubing, Steel, Corrosion and Heat Resistant (18-8 Stabilized), Welded. Annealed. Type 321 and 347 tubings intended for use in the manufactured exhaust stacks, manifolds, blast tubes, ring collectors, and similar applications where weldable corrosion and heat-resisting steel is required or for use at 8000 - 1500F.
MIL-T-6845
(T304)
Tubing, Steel, Corrosion Resistant (304) Aerospace Vehicle Hydraulic System. 1/8 Hard, Seamless, Welded & Drawn. Intended for use in high pressure hydraulic and pneumatic systems in which corrosion-resistant materials are required. The tubing is not suitable for use in applications assembled by welding or brazing or exposed to temperatures higher than 800F, because of impaired resistance to corrosion, where subsequent anneal not possible.
MIL-T-8504
(T 304)
Tubing, Steel, Corrosion Resistant (18-8) Annealed, Aircraft Hydraulic System. Seamless, Welded. Intended for use in high pressure hydraulic and pneumatic systems in which corrosion-resistant materials are required. This tubing is of lower strength and higher ductility than tubing to Specification MIL-T-6845. It may be used to replacing MIL-T-6845 tubing but heavier wall thicknesses must be used: Same qualifications regarding welding, brazing & temperature.
MIL-T-8506
(T 304)
Tubing, Steel, Corrosion Resistant, (304) Annealed, Seamless, Welded. Intended for use in the fabrication of aircraft parts requiring a high degree of resistance to corrosion. Not to be used in high-pressure hydraulic control systems.
MILT 8606
(T 304L)
(T 321)
(T 347)
Tubing, Steel, Corrosion Resistant (18-8 Stabilized). Annealed. Seamless, Welded & Drawn. Intended for use in applications that require a high degree of resistance to corrosion or to temperatures in the range of 800?F-1500?F. or in applications that involve welding. Suitable for use in tank-automotive equipment for hydraulic and mechanical applications.
MlL-T-8808
(T 321)
(T 347)
Tubing, Steel, Corrosion Resistant (l8-8 Stabilized), Aircraft Hydraulic Quality. Annealed, Seamless, Welded & Drawn. Intended for use in high-pressure hydraulic and pneumatic systems where corrosion and heat resistance are required and in which welding or brazing may be involved during fabrication. Resists oxidation at temperatures to 1200F, but is useful at that temperature only when stresses are low.
MIL-T4973
(T 304L)
(T 316L)
(T 321)
(T 347)
Tubing, Steel, Corrosion Resistant, Aerospace Vehicle Hydraulic System. 1/8 Hard. Seamless, Welded & Drawn. Intended for use in high-pressure hydraulic and pneumatic systems where corrosion and heat resistance are required and in which welding or brazing may be involved during fabrication. Suitable for use in temperatures to 1200F, when stresses are low.
MIL-P-1144
(T 304) (T 304L)
(T 316) (T 316L)
(T 321) (T 347)
Pipe, Stainless Steel, (Corrosion Resisting). Seamless or Welded. Annealed. The pipe is intended for high-temperature and hydraulic and other pressure services under general corrosive conditions.

 

Stainless steel tube and pipe Application



Stainless steel tube is economic section steel, is an important product in the steel industry, can be widely used in life decoration and industry, many people on the market for the production of stairs handrails, window guards, railings, furniture, etc. Commonly available are 201, 304, 316 three kinds of materials.

 

Because the stainless steel pipe has a hollow section, and therefore the most suitable for liquid, gas, and solid transport pipeline; at the same time with the same weight of round steel, steel pipe section coefficient, bending, and torsional strength, so also become a variety of machinery and building structure on the important material.

 

Structures and components made of stainless steel tubes have a larger cross-sectional modulus than solid parts under equal weight. Therefore, the stainless steel tube itself is metal-saving economic section steel, it is an important part of efficient steel, especially in the oil drilling, smelting, and transmission industries are in greater demand, followed by geological drilling, chemical industry, construction industry, machinery industry, aircraft, and automobile manufacturing, as well as boilers, medical equipment, furniture, and bicycle manufacturing also need a large number of various steel tubes.

 

With the development of new technologies such as atomic energy, rockets, missiles, and space industry, stainless steel tube in the defense industry, science and technology, and economic construction has become increasingly important.

 

Stainless steel tube is safe, reliable, sanitary and environmentally friendly, economical, thin-walled pipes and new reliable, simple and convenient connection methods are developed successfully so that it has more irreplaceable advantages of other tubes, the application of engineering will be more and more, the use of more and more popular, the prospects are good.

 

As stainless steel has many of the ideal properties required for building materials, it can be said to be unique in the metal, and its development continues. To make stainless steel perform better in traditional applications, improvements have been made to the existing types, and new stainless steels are being developed to meet the stringent requirements of advanced architectural applications.

 

Due to increasing production efficiency and improving quality, stainless steel has become one of the most cost-effective materials chosen by architects.
Stainless steel combines performance, appearance, and use characteristics, so stainless steel will remain one of the best building materials in the world.

 

Marking Method

 

Indication method

① Use the international chemical element symbols and the symbols of the country to indicate the chemical composition, using Arabic letters to indicate the content of the composition.
Such as China, Russia 12CrNi3A

② with a fixed number of digits to indicate the steel series or numbers; such as the United States, Japan, 300 series, 400 series, 200 series.

③ with Latin letters and order to form a serial number, only to indicate the use.

Labeling method

American Iron and Steel Institute is a three-digit number to indicate the various standard grades of malleable stainless steel. Among them.

① austenitic stainless steel with 200 and 300 series of numbers marked, for example, some of the more common austenitic stainless steel is marked with 201, 304, 316, and 310.

② Ferritic and martensitic stainless steels are indicated by numbers in the 400 series. Ferritic stainless steel is marked by 430 and 446, martensitic stainless steel is marked by 410, 420 as well as 440C, duplex (austenitic-ferritic).

③ Stainless steels, precipitation-hardening stainless steels, and high-alloys containing less than 50% iron are usually named using patented names or trademarks.

 

Standard classification

4-1 classification
① national standard  ② industry-standard  ③ local standard ④ enterprise standard Q/C

4-2 Classification.
①Product standards ②Packaging standards ③Method standards ④Basic standards

 

Tube Weight calculation

W = Circumference×wall thickness(m) × Pm(density of tube matertail kg/m3 )×length×1000= KG/M 

 

Round tube weight

Circumference = π(314)× outer diameter

W = π(314)×outer diamemter(m)×wall thickness(m) × Pm(density of tube mertail kg/m3 )×1000= KG/M (weight per meter).

SS304 Pm is 7.93, SS316 Pm is 7.96

Example

Round 38.1mm, wall 2.5mm, length 1m, 304material

W=3.14×0.0381×0.0025×7.93×1×1000=2.37KGS

 

Square tube weight

Circumference = size×4

W = Size(m)×4×wall thickness(m) × Pm(density of tube mertail kg/m3 )×1000= KG/M (weight per meter).

SS304 Pm is 7.93, SS316 Pm is 7.96

Example

Square 40×40mm tube, wall 2.5mm, length 1m, 304material

W=0.04×4×0.0025×7.93×1×1000=3.172KGS

 

Rectangular tube weight

Circumference = (W+L)× 2

W = (W+L)× 2 ×wall thickness(m) × Pm(density of tube mertail kg/m3 )×1000= KG/M (weight per meter).

SS304 Pm is 7.93, SS316 Pm is 7.96

Example

Rectangular 25×50mm, wall 2.5mm, length 1m, 304material

W=(25+50)×2×0.0025×7.93×1×1000=2.97KGS

 

Application requirements

Equipment manufacturing and maintenance

This type of industry mainly uses sanitary or antibacterial grade stainless steel tubes. Sanitary seamless tubes made of SUS304 and 316L can meet the special requirements of various media in the food and biopharmaceutical fields. Antimicrobial stainless steel has the advantages of stainless steel and good antimicrobial properties, and the demand is increasing in the fields of kitchen equipment, workbenches and utensils for the food industry, medical equipment, tableware and hanging towel holders in daily life, and brackets for refrigerated cabinets. 



 

Stainless steel tube price $500-10000/ton