ASTM A268 TP410 / TP430 / TP439 Stainless Steel Tubing

ASTM A268 is Standard specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service, the grades contain TP410, TP405, TP420, TP430, TP430Ti, TP403, TP409, TP444, TP439 and TP446, it covers standard specification for a number of grades of nominal-wall-thickness, welded ferritic and martensitic stainless steel tubing for general corrosion-resisting and high-temperature service, ASME SA268 is alternative standard.

The tubes shall be made by the seamless or welded process with no filler metal added, tubes shall be reheated to a temperature of 1200F [650澳门凯发娱乐C] or higher and cooled to meet the requirements of this specification, All tubes shall be free of excessive mill scale, suitable for inspection. A slight amount of oxidation will not be considered as scale.

ASTM A268 Stainless Steel Tubing Specification

Standard ASTM A268, ASME SA268
Tube Type Both welded and seamless
Grades ASTM A268 TP 410, ASTM A268 TP 430, ASTM A268 TP 439
Outside diameter 1/4″ (6.25mm) to 8″ (203mm)
Wall thickness 0.02″ (0.5mm) to 0.5″(12mm)
Application Heat Exchanger, Heater, Condenser

ASTM A268 TP410, TP430, TP439 Chemical Composition

The steel shall conform to the required chemical composition for carbon, manganese, phosphorus, sulfur, silicon, nickel, chromium, molybdenum, aluminum, copper, nitrogen, titanium, and columbium, most of these grades are commonly characterized by being ferromagnetic.

Grade: TP410 TP430 TP439
UNS S41000 S43000 S43035
C, max 0.15 0.12 0.07
Mn,max 1.00 1.00 1.00
P, max 0.04 0.04 0.040
S, max 0.03 0.03 0.030
Si, max 1.00 1.00 1.00
Ni 0.50max
Cr 11.5-13.5 16.0-18.0 17.00-19.00
Al 0.15
N 0.04
Ti 0.20+4(C+N)min, 1.10max

ASTM A268 mainly contains 400 series Ferritic and Martensitic stainless steel grades, without or with slight Nickel element, so they have advantages on price compared to 304 or 316L stainless steel, that is the common used grade。

ASTM A268 Stainless Steel Tubing Sizes Tolerance

Variations in outside diameter, wall thickness, and length from those specified shall not exceed the amounts prescribed below。

Outside Diameter, in.[mm] OD Tolerance, in.[mm] Wall Thickness, % Thin wall tubes
Up to1⁄2, [12.7], excl ±0.005 [0.13] ±15
1⁄2 to 11⁄2 [12.7 to 38.1], excl/td>

±0.005 [0.13] ±10< less than 0.065 in. [1.6 mm] nominal
11⁄2 to 31⁄2 [38.1 to 88.9], excl ±0.010 [0.25] ±10 less than 0.095 in. [2.4 mm] nominal
31⁄2 to 51⁄2 [88.9 to 139.7], excl ±0.015 [0.38] ±10 less than 0.150 in. [3.8 mm] nominal
51⁄2 to 8 [139.7 to 203.2], incl ±0.030 [0.76] ±10 less than 0.150 in. [3.8 mm] nominal


The steel shall conform to the following tensile properties: tensile strength, yield strength, and elongation.

Grade Tensile strength, min, ksi [MPa] Yield strength, min, ksi [MPa] ELONGATION. MIN, %
TP410 55 [380] 30 [205] 20
TP430 60 [415] 35 [240] 20
TP439 60 [415] 30 [205] 20

The tubes shall have a hardness number that will not exceed the prescribed Brinell and Rockwell hardness values, TP410, TP430 and TP439 max Rockwell hardness 90, Test report required certification conform to Specification A1016/A1016M。

Several mechanical tests shall be conducted, namely:

  • Tension test;
  • Flaring test (for seamless tubes);
  • Flange test (for welded tubes);
  • Hardness test;
  • Reverse flattening test;
  • Intergranular corrosion test; and
  • Hydrostatic or nondestructive electric test.
ASTM A268 / A268M-10 (2016)
Standard Specification for Seamless and Welded Ferritic and Martensitic Stainless Steel Tubing for General Service
This specification covers a number of grades of nominal-wall-thickness, stainless steel tubing for general corrosion-resisting and high-temperature service. Most of these grades are commonly known as the “straight-chromium” types and are characterized by being ferromagnetic. Two of these grades, TP410 and UNS S 41500 in the specification (Table 1), are amenable to hardening by heat treatment, and the high-chromium, ferritic alloys are sensitive to notch-brittleness on slow cooling to ordinary temperatures. These features should be recognized in the use of these materials. Grade TP439 is used primarily for hot-water tank service and does not require post-weld heat treatment to prevent attack of the heat affected zone.
TP410 Stainless Steel
Grade 410 stainless steels is general-purpose martensitic stainless steel containing 11.5% chromium, which provide good corrosion resistance properties. However, the corrosion resistance of grade 410 steels can be further enhanced by a series of processes such as hardening, tempering and polishing. Quenching and tempering can harden grade 410 steels. They are generally used for applications involving mild corrosion, heat resistance and high strength
TP430 Stainless steel
Stainless steel 430 combines good corrosion resistance with good formability and ductility, also has excellent resistance to nitric attack, which makes it well suited to use in chemical applications. The most popular applications for 430 are in domestic appliances and decorative trim.
TP439 Stainless Steel
Stainless steel grade 439 is capable of being made into complex shapes such as tubular manifolds and exhaust system components, where temperatures tend to go beyond the oxidation limit of grade 409 steel. It is also preferred where wet corrosion resistance especially to chlorides is needed.

Stainless steel grade 439 has good weldability, brightness, and pitting corrosion resistance. It polishes well, and is good for deep drawing.

Other ASTM A268 Stainless Steel Grades
ASTM A268 TP 405, ASTM A268 TP 409, ASTM A268 TP 409S, ASTM A268 TP 410S, ASTM A268 TP 416, ASTM A268 TP 420, ASTM A268 TP 422, ASTM A268 TP 420, ASTM A268 TP 430F, ASTM A268 TP 430TI, ASTM A268 TP 440C, ASTM A268 TP 444, ASTM A268 TP 446
ASTM A268 TP 410 stainless steel tube
ASTM A268 TP 430 stainless steel tube