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Stainless steel tube

Stainless steel tube is typically measured by its outer diameter and can be used in a variety of applications including a number of structural applications.

Stainless Steel Tube is a hollow steel bar, a large number of pipes used for conveying fluids, such as oil, gas, water, gas, steam,heat exchanger,mechinical machine. In addition, engaging in bending, torsional strength of the same, lighter, and they are also widely used in the manufacture of mechanical parts and engineering structures. Also used in producing all kinds of conventional weapons, the barrel, artillery shells and so on.

Tube Specifications
  • A213 – Seamless Stainless Steel Boiler, Super heater, and Heat-Exchanger Tubes
  • A249 – Welded Stainless Steel Boiler, Super heater, Heat Exchanger, and Condenser Tubes
  • A268 – Seamless and Welded Stainless Steel Tubing for General Service
  • A269 – Seamless and Welded Austenitic Stainless Steel Tubing for General Service
  • A270 – Seamless and Welded Stainless Steel Sanitary Tubing
  • A688 – Welded Austenitic Stainless Steel Feedwater Heater Tubes
  • A789 – Seamless and Welded Stainless Steel Tubing for General Service

Custom Grades of Stainless Steel Tube

  • Austenitic: 201, 304/304L, 316/316L, 317/317L, 347/347H, 321/321H, 904L
  • Ferritic: 409, 430, 439, 441, 434, 436, 444, 446
  • Martensitic: 403, 410, 410S, 414/L, 441, 418, 420, 440, 416
  • Duplex: 2205/S31803, S32750, S32760
Delivery requirment:
  • Marking: SunnySteel, material grade, standard, specification, heat no.
  • Surface Treatment: Bright annealed, polished outside and inside surface.
  • Package: knitting strip bundle, wooden box or steel box
  • Mill test certificate: according to EN 10204 3.2
  • Inspection: Third party inspection, or by clints

Range of Application

Common Applications for Stainless Steel Tubing Stainless steel tubing has a number of uses in a wide variety of industries. It can be used during manufacturing in processing plants or can become part of a final product. Stainless steel tubing can also be used in pipelines to transport oil, gas, water, or chemicals.

Stainless steel tube is typically measured by its outer diameter and can be used in a variety of applications including a number of structural applications. Stainless steel tubing is extremely durable and able to withstand corrosion. This tubing will not rust, even if exposed to the elements, heat, and other extreme conditions. Because of these factors, stainless steel tubing can be used for a wide variety of applications.

The stainless steel tubing that is supplied by SunnySteel can used in a variety of industries, including:

Considering the importance of outside and inside surface of stainless steel tubes for fluid power industry, Our mills are providing tubes that are free from scale, rust, seams, laps.

  • Machinery Parts
  • Food and Beverage Processing
  • Pharmaceutical
  • Biotechnology
  • Automotive
  • Marine
  • Construction
  • Chemical
  • Oil and Gas

the main requirement for stainless steels is that they should be corrosion resistant for a specified application or environment. The selection of a particular “type” and “grade” of stainless steel must initially meet the corrosion resistance requirements.

Additional mechanical or physical properties may also need to be considered to achieve the overall service performance requirements.

Ferritic Stainless Steel Tubes

Ferritic Stainless Steel Tubes, in principle, ferrite at all temperatures. This is achieved by a low content of austenitic forming elements, mainly nickel, and a high content of ferrite forming elements, mainly chromium. Ferritic types, such as 4003 and 4016, are mainly used for household utensils, catering equipment and other purposes where corrosion conditions are not particularly demanding.

Steel with high chromium content, such as 4762 with 24% chromium, are used at high temperature where their resistance to sulphurous flue gages is an advantage. However, the risk of 475 °C embrittlement and precipitation of brittle sigma phase in high-chromium steel must always be taken into consideration. Ferritic stainless steel, such as 4521 with extremely low carbon and nitrogen contents, find greatest use where there is a risk of stress-corrosion cracking.

Ferritic stainless steel have slightly higher yield strength (Rp 0.2) than austenitic steels, but they have less elongation at fracture. Another characteristic that distinguishes ferritic steel from austenitic material is that ferritic steel have much lower strain hardening.

Ferritic grades have been developed to provide a group of stainless steel to resist corrosion and oxidation, while being highly resistant to stress corrosion cracking. These steels are magnetic but cannot be hardened or strengthened by heat treatment. They can be cold worked and softened by annealing. As a group, they are more corrosive resistant than the martensitic grades, but generally inferior to the austenitic grades. Like martensitic grades, these are straight chromium steels with no nickel. They are used for decorative trim, sinks, and automotive applications, particularly exhaust systems.

Mainly Standard include:

  • ASTM A268 Standard Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service
  • JIS G3463 Stainless Steel for Boiler and Heat Exchanger Tubes
  • GB/T 30065 Welded ferritic stainless steel tubes for feedwater heater
  • GB/T 30066 Welded ferritic stainless steel tubes for heat-exchanger and condenser

The stainless steel tubing that is supplied by SunnySteel can used in a variety of industries, including:

  • Type 430 The basic ferritic grade, with a little less corrosion resistance than Type 304. This type combines high resistance to such corrosives as nitric acid, sulfur gases, and many organic and food acids.
  • Type 405 Has lower chromium and added aluminum to prevent hardening when cooled from high temperatures. Typical applications include heat exchangers.
  • Type 409 Contains the lowest chromium content of all stainless steels and is also the least expensive. Originally designed for muffler stock and also used for exterior parts in non-critical corrosive environments.
  • Type 434 Has molybdenum added for improved corrosion resistance. Typical applications include automotive trim and fasteners.
  • Type 436 Type 436 has columbium added for corrosion and heat resistance. Typical applications include deep-drawn parts.
  • Type 442 Has increased chromium to improve scaling resistance. Typical applications include furnace and heater parts.
  • Type 446 Contains even more chromium added to further improve corrosion and scaling resistance at high temperatures. Especially good for oxidation resistance in sulfuric atmospheres.

Comparison Chart

GB ISO Unified
Digital Code
ASTM / ASME UNS Code EN Code Company
Commercial Grade
06Cr13Al S11348 405 S40500 1.4002
409 409L S40900 1.4512
0Cr13SiAl 1.4724 SIC9(Sanyo)/
1C256(Sandvik)
10Cr17 S11710 430 S43000 1.4016
022Cr18Ti S11863 439 S43035 1.451
019Cr19Mo2NbTi S11972 444 S44400 1.4521
0Cr18SiAl 1.4742 SIC10(Sanyo)/
1C356(Sandvik)
0Cr24SiAl 1.4762 SIC12(Sanyo)
16Cr25N S12550 TP446-1/TP446-2 S44600 1.4762 2C52/2C48(Sandvik)
1Cr25Ti QS25T(Sanyo)
00Cr27Mo3Ni2TiNb S44660 S44660 Sea-Cure(Plymouth Tube)
00Cr29Mo4TiNb S44735 S44735 AL29-4C(ATI)
00Cr29Mo4Ni2TiNb S44736 S44736 AL29-4-2(ATI)
S44300 S44300 1.4522 443

Ferritic Stainless Steel, which are part of the 400 series of stainless alloys, have chromium as their major alloying element and are typically low in carbon content. Ductility and formability are less than that of the austenitic grades. The corrosion resistance is comparable to that of the austenitic grades in certain applications. Thermal conductivity is about half that of carbon steels.

Ferritic stainless steel are magnetic, they generally have good ductility and can be welded or fabricated without difficulty. These grades can be processed to develop an aesthetically pleasing, bright finish and, hence, are sometimes used for automotive trim and appliance molding. They also find use in functional applications where cost is a major factor, e.g., automotive exhaust systems, catalytic converters, radiator caps, and chimney liners. These grades can be hardened by cold rolling, but cannot be hardened as much as the austenitic alloys.

See the full data for Stainless steel pipes

Stainless steel pipes are used mainly for industrial use, plants, sanitation, heat exchangers, and machine structures.

Normal Standard

Item ASTM A213/A213M ASTM A312/A312M
Grade TP304 TP304L TP304 TP304L
TP316 TP316L TP316 TP316L
TP317 TP317L TP317 TP317L
TP347 TP310S TP347 TP310S
TP309H* TP310H* TP317* TP310H*
  TP321HΔ   TP321HΔ
Yield Strength
σ0.2 (Mpa)
≥170; ≥205 ≥170; ≥205
Tensile Strength
σb (Mpa)
≥485 ≥515 ≥485; ≥515
Elongation %
≥35 ≥35 ≥35 ≥35
Flattening Test H=1.09t/(0.09+t/D) H=1.09t/(0.09+t/D)
Flange Test 21-68%  
Intergranular corrosion
“*”“Δ” ASTM E112
“Δ” min 7#, “*” min 6#
“*”﹑”Δ”ASTM E112, min 6#
Hydraulic test(Mpa) D P max P=220.6t/D D P max ASTM A530/A530M
D≤270MM P=2Rt/D
R=50%σ0.2
<25.4 7 ≤88.9 17
25.4-<38.1 10
38.1-<50.8 14 >88.9 19
50.8-<76.2 17
76.2-<127 24
≥127 31
Metallograph Analysis STM A262 E ASTM A262 E
Non-Destructive Test ASTM E213 E309 E426 ASTM E213 E309 E426
Hardness HRB<90 RB<90

Chemical composition

Grade Chemical Composition
C (max) Si (max) Mn (max) P (max) S (max) Ni Cr Mo Other
TP 304 0.08 0.75 2 0.04 0.03 8-11 18-20
TP 304H 0.04-0.10 0.75 2 0.04 0.03 8-11 18-20
TP 304L 0.035 0.75 2 0.04 0.03 8-13 18-20

TP 309S

0.08 0.75 2 0.04 0.03 8-13 18-20
TP 310S 0.08 0.75 2 0.045 0.03 12-15 22-24
TP 316 0.08 0.75 2 0.04 0.03 19-22 24-26
TP 316L 0.035 0.75 2 0.04 0.03 10-15 16-18
TP 316Ti 0.08 0.75 2 0.04 0.03 11-14 16-18
TP 317 0.08 0.75 2 0.04 0.03 11-14 16-18
TP 321 0.08 0.75 2 0.04 0.03 9-13 18-20
TP 321H 0.04-0.10 0.75 2 0.04 0.03 9-13 17-20
TP 347 0.08 0.75 2 0.04 0.03 9-13 17-20
TP 347H 0.04-0.10 0.75 2 0.04 0.03 9-13 17-20

Tolerance grade

Grade Outside diameter tolerance Grade Wall thickness tolerance
D1 ±1.50% but at least ±0.75mm T1 ±15% but at least ±0.60mm
D2 ±1.00% but at least ±0.50mm T2 ±12.5% but at least ±0.40mm
D3 ±0.75% but at least ±0.30mm T3 ±7.5% but at least ±0.15mm
D4 ±0.50% but at least ±0.10mm T4 ±5.0% but at least ±0.10mm

Tolerance standard

Item ASTM A213 ASTM A312 ASTM A269
O.D. tolerance O.D. tolerance O.D. tolerance
Outside diameter tolerance(mm) <25.4 ±0.10 10.3-48.3 +0.4/-0.8 12.7 < +0.13/-0.13
25.4-≤38.1 ±0.15 >48.3-114.3 +0.8/-0.8 12.7-38.1 +0.13/-0.13
>38.1-<50.8 ±0.20 >114.3-219.1 +1.6/-0.8 38.1-88.9 +0.25/-0.25
50.8-<63.5 ±0.25 >219.1-457.2 +2.4/-0.8 88.9-139.7 +0.38/-0.38
63.5-<76.2 ±0.30 >457.2-660.4 +3.2/-0.8 139.7-203.2 +0.76/-0.76
76.2-≤101.6 ±0.38 >660.4-864 +4/-0.8    
>101.6-≤190.5 ±0.38/-0.64 >864-1219.2 +4.8/-0.8    
>190.5-≤228.6 ±0.38/-1.14        
Thickness 
tolerance(mm)
O.D. tolerance ±12.5%t O.D. tolerance
≤38.1 +20%t/0 ≤38.1 ±15%t
>38.1 +22%t/0 >38.1 ±10%t

The Test Requirements of Standards

Standard Chemical Composition Tensile Strength Yeild Point Tension Test Rockwell Hardness Flattening Test Flaring Test Hydrostatic
ASTM A312 X X X X X
ASTM A213 X X X X X X X X
ASTM A269 X X
ASTM A511 X X X X
ASTM A789 X X X X

Standard Ultrasonic Eddy Current Intergranular Corrosion Grain size α/γ Surface Quality Tolerance
ASTM A312 X X X
ASTM A213 X X X
ASTM A269 X X X
ASTM A511 X X
ASTM A789 X X X X

ASTM Mechanical Properties

Grade Tensile Strength
Min(Mpa)
Yeild Point
Min(Mpa)
EL. Min(%) Rockwell
Max
TP 304 515 205 35 90
TP 304H 550 240 35 90
TP 304L 485 170 35 90
TP 309S 515 205 35 90
TP 310S 515 205 35 90
TP 316 515 205 35 90
TP 316L 485 170 35 90
TP 316Ti 515 205 35 90
TP 317 515 205 35 90
TP 321 515 205 35 90
TP 321H 515 205 35 90
TP 347 515 205 35 90
TP 347H 515 205 35 90

Heat treatment technology of stainless steel pipe surface

For the heat treatment technology of the surface of stainless steel pipes, non-oxidation continuous heat treatment furnaces with protective gas are generally used abroad for intermediate heat treatment and final heat treatment of finished products. As a bright surface without oxidation can be obtained, the traditional pickling process is eliminated. The adoption of this heat treatment process not only improves the surface of stainless steel pipes, but also overcomes the environmental pollution caused by pickling.

According to the manufacturer of stainless steel pipes, according to the current world development trend, bright annealing continuous heat treatment furnaces are basically divided into the following two types:

(1) Roller-type bright annealing heat treatment furnace.

This bright annealing furnace type is suitable for heat treatment of large-size and large-volume special-shaped stainless steel pipes, with an hourly output of above 1.0 Tons. The protective gases that can be used are high-purity hydrogen, decomposed ammonia and other protective gases. It can be equipped with a convection cooling system to cool the special-shaped stainless steel tube faster.

(2) Mesh belt type bright annealing heat treatment furnace.

This bright annealing furnace type is suitable for small-diameter thin-walled precision special-shaped stainless steel pipes. The hourly output is about 0.3 to 1.0 Tons. The length of the steel pipe can be up to 40m. It can also be used to process capillary tubes in coils. Equipped with convection cooling system for fast cooling. Using gas fuel or electric heating, various protective gases can be used. The stainless steel pipe after this furnace-type heat treatment has no scratches and good brightness surface.

Tensile test and hardness test of stainless steel pipe?

Tensile strength test is to make a sample of stainless steel pipe, pull the sample to break on a tensile testing machine, and then measure one or several mechanical properties, usually only the tensile strength, yield strength, elongation after fracture and section are measured Shrinkage. Tensile strength test is the most basic test method for mechanical properties of metal materials. Almost all metal materials require tensile test as long as they have requirements for mechanical properties. Especially for those materials whose shape is not convenient for hardness test, tensile strength test becomes the only means of testing mechanical properties.

The hardness test is to slowly press a hard indenter into the surface of the sample with a durometer under specified conditions, and then test the depth or size of the indentation to determine the hardness of the material. Hardness test is the simplest, fastest and easiest method in material mechanical property test. The hardness test is non-destructive, and there is an approximate conversion relationship between the material hardness value and the tensile strength value. The hardness value of the material can be converted into the tensile strength value, which has great practical significance.

Because the tensile strength test is not easy to test, and it is convenient to convert the hardness to the strength, more and more people only test the hardness of the material and less test its strength. In particular, due to the continuous advancement of hardness tester manufacturing technology and innovations, it is now possible to directly test the hardness of some materials that could not be directly tested before, such as stainless steel tube, stainless steel sheet and stainless steel strip. Therefore, there is a tendency for hardness tests to gradually replace tensile tests.

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