Pre weld HT regarding welding 4130 onto Inconel 625. 1

[noviceEng]

My guys intend to (Argon weld) 4130 onto Inconel-625, I know that post weld heat treatment isn't required but I need confirmation that pre weld HT isn't required for the 4130.
I don't think its required, am I wrong?

 

[metengr]

noviceEng;
Preheat is required for 4130 base metal because this is an alloy steel that has increased hardenability over carbon steel. I would use the following;

350 deg F for thickness at or below 1".

400 deg F for thickness greater than 1".

 

[unclesyd]

What are are going to use for filler metal?

 

[metengr]

It had better be either Inco weld A or similar Ni-base filler metal. Also, watch your heat input.

 

[noviceEng]

Thanks for responding guys, I really appreciate it, I see I still have a lot to learn. I intended to use Nickel-Chromium-Molybdenum low iron bare welding wire as the filler. Any other advise?

 

[metengr]

Do you have a qualified welding procedure? If not, I would seek assistance to qualify a welding procedure for your welders.

 

[noviceEng]

That's the interesting part of this whole scinario. I have a WPS for the 4130 and another for the inconel-625 but the Customer wants one procedure to cover both materials. Funny huh.

 

[metengr]

No, it is not funny because your Customer is absolutely correct in requesting a specific weld procedure to join two dissimilar materials. This is routinely done in industry.