Welding SMO 254

[DFilardi]

Hi guys,
I have to weld a sheet of S32254 (ASTM A240) to a casting made of the same material CK-3MCuN (ASTM A744). From several readings it seems it's possible to use both 5.11 E-NiCrMo-3 and 5.11 E-NiCrMo-12 consumable electrodes. Does anyone have some experience and knows advantages/disadvantages for the two solution?

Thanks in advance

Domenico

 

[metengr]

Domenico;
I would advise you visit the web sites below for all welding information regarding 254 SMO. These are some of the best sites for welding consumables and base metal information on 254 SMO;

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

http://www.outokumpu.com/applications/documents/start.asp

 

[GRoberts]

The main disadvantage of using Nb bearing alloys to weld either the 254SMo and the CK3MCuN is that the Nb in the filler metal combines with the N in the base metal to form nitrides that can be embrittling. It is contained in some of the Avesta literature. However, it is commony done. I have experience the most problem when a customer specified that NiCrMo-3 was mandatory, and solution annealing was also required for repairs of CK3MCuN. There were many tensile and bend failures on weld test due to that. In the as-welded condition, it isn't as much of a problem. However, if I have a choice, I choose NiCrMo-10, which has plenty of Mo and no Nb, and avoid the risk all together. It is a bit more expensive though.