The difference between 347 and 347H stainless steel.

347 is a niobium-containing austenitic stainless steel, while 347H is its high carbon version. In terms of composition, 347 can be seen as an alloy derived from adding niobium to the base of 304 stainless steel. Niobium is a rare earth element that functions similarly to titanium. When added to the alloy, it can refine grain structure, resist intergranular corrosion, and promote age hardening.

Ⅰ.Corresponding to national standards

China GBIT 20878-2007 06Cr18Ni11Nb 07Cr18Ni11Nb(1Cr19Ni11Nb)
US ASTM A240-15a S34700,347 S34709,347H
JIS J1S G 4304:2005 SUS 347 -
DIN EN 10088-1-2005 X6CrNiNb18-10 1.4550 X7CrNiNb18-10 1.4912

Ⅱ.CHEMICAL COMPOSITION OF S34700 Stainless steel bar

Grade C Mn Si S P Fe Ni Cr
347 0.08 max 2.00max 1.0 max 0.030max 0.045 max 62.74 min 9-12max 17.00-19.00
347H 0.04 – 0.10 2.0 max 1.0 max 0.030 max 0.045 max 63.72 min 9-12max 17.00 – 19.00

Ⅲ.347 347H Stainless steel bar Mechanical Properties

Density Melting Point Tensile Strength (MPa) min Yield Strength 0.2% Proof (MPa) min Elongation (% in 50mm) min
8.0 g/cm3 1454 °C (2650 °F) Psi – 75000 , MPa – 515
Psi – 30000 , MPa – 205

Ⅳ.Material properties

①Excellent corrosion resistance comparable to 304 stainless steel.
② Between 427~816℃, it can inhibit the formation of chromium carbide, resist sensitization, and has good resistance to intergranular corrosion.
③It still has a certain creep resistance in a strong oxidizing environment with a high temperature of 816℃.
④Easy to extend and form, easy to weld.
⑤Good low temperature toughness.

Ⅴ.Application occasions

The high-temperature performance of 347&347H stainless steel is better than that of 304 and 321. It is widely used in aviation, petrochemical, food, paper and other industries, such as exhaust main pipes and branch pipes of aircraft engines, hot gas pipes of turbine compressors, and in small loads and temperatures not exceeding 850°C. Parts that work under the conditions, etc.

Post time: May-11-2024