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.

Stainless Steel Type 347 Information By yaang.com

Stainless Steel Type 347 is a columbium/tantalum stabilized austenitic stainless steel. Like Type 321, it has superior intergranular-corrosion resistance compared to typical 18-8 type alloys. Since columbium and tantalum have stronger affinity for carbon than chromium, carbides of those elements tend to precipitate randomly within the grains instead of forming continuous patterns at the grain boundaries. Type 347 should be considered for applications requiring intermittent heating between 800ºF (427ºC) and 1650ºF (899ºC).

347 Stainless Steel should be considered for use in aircraft collector rings and exhaust manifolds, expansion joints and high temperature chemical process equipment.

347 Stainless Steel AMS 5646 By yaang.com

347 Stainless Steel Bar

Spec: AMS 5646

347 Stainless Steel Bar AMS 5646
UNS S34700

Nominal Composition

• Iron 68%
• Chromium 18%
• Nickel 11%
• Columbium+Tantalum 10 x Carbon minimum

Type 347 Stainless Steel (AMS 5512 / AMS 5646) Technical Data Sheet By yaang.com

Chemical Composition Limits

Weight%

C

P

Si

Ni

Mn

S

Cr

Cb + Ta

Fe

Co

Mo

Cu

347

0.08 max

0.040 max

1.00 max

9-12

2.0 max

0.030 max

17-19

10 x C min

Bal

1.00 max only AMS 5646

0.75 max

0.75 max

347H

0.04-0.10

0.040 max

1.00 max

9-12

2.0 max

0.030 max

17-19

10 x C min

Bal

Type 347 Stainless Steel is a chromium nickel stainless steel which has been modified by the addition of columbium and tantalum. The main advantage of this is an excellent resistance to intergranular corrosion which is common to other austenitic stainless steels following exposure to temperatures of 800° to 1500°F. Type 347 Stainless Steel has about the same general corrosion resistance as Type 302.

UNS S34700 347 Stainless Steel Pipes, Flanges, Pipe Fittings By yaang.com

347 Stainless Steel Detailed Description

Type 347 stainless steel is a stabilized austenitic stainless steel similar to type 304 with an addition of Columbium and Tantalum. The columbium serves to produce a stabilized type of stainless steel which is immune to chromium carbide precipitation. This type of grades are thus recommended for parts fabricated by welding which cannot be susequently annealed or for parts which must operate in service between 800 – 1600°F.

Alloy 347 Stainless Steel Data By yaang.com

Alloy 347 (S34700) is stabilized stainless steel which offers as its main advantage an excellent resistance to intergranular corrosion following exposure to temperatures in the chromium carbide precipitation range from 800 to 1500°F (427 to 816°C). Alloy 347 stainless steel is stabilized by the addition of columbium and tantalum.

Alloy 347 stainless steel is also advantageous for high temperature service because of its good mechanical properties. Alloy 347 stainless steel offers higher creep and stress rupture properties than Alloy 304 and, particularly, Alloy 304L, which might also be considered for exposures where sensitization and intergranular corrosion are concerns.

Stainless Steel 347 (UNS S34700) By yaang.com

Type 347 stainless steel has slightly improved corrosion resistance over type 321 stainless steel in strongly oxidizing environments. Type 347 stainless steel is stabilized with columbium, it is preferable for aqueous and low temperature environments due to its good resistance to intergranular attack. Both 347 stainless steel and 321 stainless steel offer good resistance to polythionic acid stress corrosion cracking, encountered in oil refineries. The high temperature oxidation resistance of 347 stainless steel is similar to that of 304 stainless steel. Useful to 1500°F.