3CR12 stainless steel?

By Kix

Date 06-08-2007 13:19

This is a very magnetic stainless steel that were working with. I don't know if you can call it duplex stainless or not. We weld this to it self and to 304 stainless. What filler material would be a good all around filler for doing both? Right now we're using 308L and 309L. The guys are saying they're haveing probs mig welding with the 309L filler with the 98/2 argon/CO2 gas i told them to use. They are telling me they want the tri mix back for the 309L wire and i was wondering if there was some other wire i can use on the 3cr12 stainless with the 98/2 gas mix. Thanks

Kix

By js55

Date 06-08-2007 13:42

Kix,
To be honest with you, I have never met the welder who can tell the difference between 309 and 308. And I've worked with the best. I'm sure they think they can but only because they've read the label. It could logically be argued that the greater alloy content would create more viscosity in the puddle, but you can't see it. You're more likely to notice variances in S or Si than you are the alloy increase from 308 to 309.
If they don't like the gas, they don't like the gas, but don't let em bull you about it working with 308 and not 309 or vice versa. 308, 309, and 316 are acceptable for 3Cr12.
I'm guessing the Tri mix you used had a greater volume percent of CO2/O2 combined. This is most likely the difference they're seeing. And this is valid. The greater oxidation potential, thermal energy, broader penetration pattern, and edge wetting will definately be noticable.

By Kix

Date 06-08-2007 14:11

Yeah i did some looking around and found that under one code the 309L was prequalified and it wasn't D1.1. Like you said it also stated 308 has been succesfully used in joining this material. So i think we'll go to the 308L, but can you get away with joining carbon steel to stainless with 308L. I allways use 309L when welding stainless to carbon, but could you use 308L and have it be mechanically sound? If so then i can scap the 309L wire all together and just have 308L ordered in.

By js55

Date 06-08-2007 14:24

Kix,
You can use 308 to weld CS, but don't. I say that because theoretically if you keep dilution low enough you reduce the likelyhood of martensite formation. But why chance it. The higher alloy of 309 is necessary. And actually if you dilute 309 too much with CS you can still get martensite. The only way you can eliminate the possibility of martensite altogether is to use nickel base alloys.

By Kix

Date 06-08-2007 17:11 Edited 06-11-2007 12:01

Yeah there mig welding stainless bungs to carbon pipe fittings with GMAW spray arc. I'd say that you would be taking a chance with the 308L with that application. I'll keep em using the 309L for that application.