Composition and properties of stainless steel 347/347H

Composition and properties of stainless steel 347/347H

Type 347/347H stainless steel
347 stainless steel plate, 347 stainless steel plate, TP 347H steel pipe
Alloys 347 and 347H are high carbon niobium stabilized austenitic stainless steels with added niobium. The addition of element Nb makes TP347H have good intergranular corrosion performance, especially for corrosive media such as acids, alkalis, and salts. It is widely used in heat exchangers, superheater tubes, reheater tubes, and steam tubes in industries such as power generation, petroleum, chemical industry, synthetic fiber, food, and papermaking. The element Nb is less susceptible to burning than Ti, so it can be used as a welding rod for Cr-Ni austenitic stainless steel. Similar to Ti-containing 18-8 austenitic stainless steel, 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

Stainless steel 347/347H

X6CrNiNb18-10/ X7CrNiNb18-10

National standard 0Cr18Ni11Nb/ 1Cr19Ni11Nb

Available forms and specifications:
Grade 347H steel pipe: ASTM A 213, A312, A 269; AMS 5556, 5558, 5575, 5571

Grade 347H plate: ASTM A240; AMS 5512

Grade 347H Round Rod: ASTM A 276, A479

Grade 347H Forging: ASTM A182

chemical composition:
Grade C Manganese Silicon Phosphorus Seconds Chromium U Niobium
347 0.08 Maximum <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/cubic meter
Melting point range, ℃ 1398-1427℃
Tensile strength, min, Mpa 515MPa
Yield strength, 0.2% offset, min, MPa 205MPa
Elongation, A5% 35
Hardness, Brinell 192 max.
application:
Alloys 347 and 347H are generally used in applications requiring severe corrosion conditions, such as superheater tubes, reheater tubes, steam tubes for large boilers and heat exchangers, and refineries for petrochemical processing.