About Type 347 Stainless Steel By yaang.com

347 stainless steel is variant of the basic austenitic 18/8 Grade 304 with added Columbium – the introduction of Columbium stabilizes the steel and eliminates carbide precipitation which subsequently causes intergranular corrosion. 

The steel has excellent forming and welding qualities and excellent toughness even at cryogenic temperatures.

Benefits of 347 Stainless Steel

• Higher creep stress and rupture properties when compared with 304
• Ideal for high temperature service
• Overcomes sensitization and intergranular corrosion concerns
• Can be used in elevated temperature applications for ASME Boiler and Pressure Vessel Code applications
• Due to stabilisation the material offers better overall corrosion resistance when compared to 304/304L
• Excellent mechanical properties
• A high carbon version (347H) is also available

Typical Uses

• Heat exchangers
• High temperature steam service
• High temperature chemical process

Both 347H/347 Stainless Steel are used primarily in elevated temperature applications. 

Chemical Composition

UNS No	Grade	C	Si	Mn	P	S	Cr	Mo	Ni	N	Other
S34700	347	0.08	0.75	2.00	0.045	0.030	17.00/19.00	–	9.00/13.00	–	Cb:10xC1.00

Mechanical Properties

UNS No	Grade	Proof Stress 0.2% (MPa)	Tensile Strength (MPa)	Elongation A5(%)	Hardness Max
					HB	HRB
S34700	347	205	515	40	201	92

Source: Yaang Pipe Industry (www.yaang.com)