4130 stress relief

[Claytonsilva]

Welding on 4130.

How do I know the necessity of stress relief?

 

[unclesyd]

A little more information please. You will get some hardening adjacent to the weld so a lot depends of the physical parameters. More information is needed as 4130 is welded everyday without any stress relief or PWHT.

What is the weld metal?

what is the part for?

How large is the part?

Was the original part heat treated?

 

[Tmoose]

Here's Lincoln's recommendation for thin wall tubing, as in car and motorcycle applications.

http://www.lincolnelectric.com/knowledge/articles/content/chrome-moly.asp

Here's some other guys opnions

http://www.netwelding.com/Heat_Treated_4130.htm

 

[Claytonsilva]

The weld metal is inconel 625 for a corrosion-resistant overlay. Here, all part is treated. But, It has some code that requests stress relief? ´cause this material it´s not listed in ASME.

 

[Vestveit]

Depending on the code there may be PWHT requirements for certain materials or PWHT requirements based on yield strength and plate thickness combo.

Usually PWHT forces itself (code, or no code requirement) when your required to qualify a welding procedure. If that is the case you need to determine the hardness requirements, ie sour service requirement and calculate expected hardness based on welding method, heat input, preheat, thickness and carbon equivalent. Having determined that PWHT is indeed neccesary for 4130, the soak temperature should be set at 25 deg C below the original tempering temperature for quenched and tempered steel or if its not a QT steel, 125 deg C below A1. Soaking time should be 2min/mm and heating rate should be max 200 degC/h, cooling rate should be max 100 degC/h.

In my experience with inco 625 cladding of 4130 forgings for subsea installations PWHT has always been neccesary. Engineering almost always modified the material spec and forging to a higher strength makes it more difficult to meet the PQR requirements

 

[Claytonsilva]

Unclesyd, Tmoose and Vestveit,

Thank you the attention,

New questions will appear.


Regards,

Clayton da Silva