347/347H Stainless Steel

347 stainless steel plate, 347 stainless steel sheet, TP 347H steel tubing

Alloy 347 and 347H is a kind of high carbon Niobium Stabilized Austenitic stainless steel with the addition of Niobium. The addition of element Nb, makes TP347H have good intercrystalline corrosion resistance, especially to corrosive media such as acid, alkali, and salt. It is widely used in the heat exchangers, superheater pipes, reheater pipes, steam pipe in boilers of power generation, petroleum, chemical industry, synthetic fiber, food, and paper industry. The element Nb is less vulnerable to burning loss than Ti, so it can be used as the welding rod for Cr-Ni Austenitic stainless steel. Similar to 18-8 Austenitic stainless steel which contains Ti, Grade 347H has higher high-temperature strength and better oxidation resistance than 316 stainless steel.

Stainless steel 347/347H equivalent grade:

1.4550/ 1.4912

UNS S34700/ S34709

AISI 347/347H

TP 347/347H

SUS 347/347H

X6CrNiNb18-10/ X7CrNiNb18-10

GB 0Cr18Ni11Nb/ 1Cr19Ni11Nb

Available Forms and Specifications:

Grade 347H steel pipe & tube: ASTM A 213, A312, A 269; AMS 5556,  5558, 5575, 5571

Grade347H sheet & plate: ASTM A240; AMS 5512

Grade 347H round bar: ASTM A 276, A479

Grade 347H forging: ASTM A182

Chemical composition:

Grade C Mn Si P S Cr Ni Nb
347 0.08 max <2.0 <1.0 <0.045 <0.030 17.0-19.0 9.0-13.0 0.8-1.00
347H 0.04-0.10 <2.0 <1.0 <0.045 <0.030 17.0-19.0 9.0-13.0 0.8-1.00

Type 347H Mechanical Properties:

Density,g/c㎡ 7.93 Kg/m³
Melting range,℃ 1398-1427℃
Tensile strength, min, Mpa 515MPa
Yield strength, 0.2% offset, min, Mpa 205 MPa
Elongation, A5% 35
Hardness, Brinell 192 Max


Alloy 347 and 347H are generally used where require severe corrosive conditions such as superheater pipe, reheater pipe, steam pipe for large boiler and heat exchanger, and oil refineries for petrochemical processing.

LKALLOY is an industry-leading supplier of the Cr-Ni series and other high-quality stainless steel alloys. LKALLOY supplies 347H stainless steel pipe and tube, and 347 filler rods which are used for several applications such as condensers, heat exchangers, filters, and more.

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