254 SMO Stainless

[WeldGk]

I have been unable to establish a hardness limit for 254 SMO welds. ANyone have any commonly used limits for sour service (NACE MR0175/ISO 15156)?

 

[metengr]

KimberleyS;
The only information I have seen related to hardness for weld metals is on the Outokumpu (Avesta) web site

http://www.avestawelding.com/?msg=404

You can navigate your way around this site and locate welding 245 SMO austenitic stainless steel. The suggested filler metal using the GTAW process is SFA 5.14 ERNiCrMo-3 (P12). In their literature, for the P12 filler metal the stated hardness is 220 BHN.

 

[TVP]

254 SMO®/(1.4547)/UNS S31254 can be used in the annealed condition or cold worked to hardness of 35 HRC maximum. See page 7 of the following Outokumpu brochure:

http://www.avestapolarit.com/upload/documents/technical/datasheets/AVPHighAlloyed.pdf

 

[bruv]

One of our clients requests a hardness survey on the PQR coupon, in accordance with the survey maps shown in NACE MR0175-2003 part 2 para 7.3.3.3. Limits imposed on us are 250HV10, 22HRC and 100HRB.

This material is destined for sour service use.

 

[metengr]

bruv;
Good information. However, is this applicable to superaustenitic stainless steel base materials that traditionally will not harden from welding? I would be curious to know if NACE MR0175-2003 part 2 para 7.3.3.3 applies to austentic base materials.

 

[strider6]

Kimberley

254 SMO SS is covered in NACE/ISO 15156 part 3 in para A.3 "Highly Alloyed austenitic stainless steel". The only limit that i've found is a 100 HRB for cast 254SMO.

S.

Corrosion Prevention & Corrosion Control

 

[WeldGk]

The application is for welding. Hardness surveys, in Rockwell and Vickers were performed.

 

[metengr]

KimberleyS;
Yes, I understood your OP. Without further information, I would treat the weld hardness acceptance criteria the same as the hardness for the cast 254 SMO at 100 HRB.

 

[EdStainless]

Since 100RB is also the limit in the ASTM material specs it sounds like a good place to start.

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Plymouth Tube

 

[bruv]

metengr (Materials) 28 Oct 08 12:03
bruv;
Good information. However, is this applicable to superaustenitic stainless steel base materials that traditionally will not harden from welding? I would be curious to know if NACE MR0175-2003 part 2 para 7.3.3.3 applies to austentic base materials.

Metengr,

strider 6 is correct in that this material is only covered in part 3 of MR0175. The weld hardness survey is a client requirement only, but it does ensure that the entire weld meets MR0175. Our client requests this for all austenitic alloys that they buy from us and others.

 

[metengr]

bruv;
Thanks for the clarification to my question. This confirms my suspicion that the reason welds are not specifically mentioned in part 3 of MR0175 is that for austenitic materials welded with austenitic filler metals hardening does not ocurr, and the only condition for use in sour service is the condition of the base metal (with or without welding).