Weld Metal Heat Treating for 4140 1

[dengmech]

I am trying to weld 4140 to 4140 and then heat treat to achieve 120 ksi yield of the base metal as well as the weld metal. I'm not a welding engineer, therefore I am looking for a pre-qualified procedure or method which lays out how to do this. I have been working with AWS D1.1 although in para 3.14 it disallows heat treatment to achieve a base metal strength of greater than 50ksi. Can anyone point me in a direction where I could find the correct procedure or let me know if what I am doing is even possible or sound.

Secondly the weld area is the least stressed area of the entire part. The weld undergoes reversing cycles between tension and compression. I only need a PJP groove weld to meet the allowable stress of 0.3 times the weld wire strength as defined by AWS D1.1. Should I use the heat treated strength of the weld wire or the as deposited strength of the weld wire? Is it advisable to use a PJP groove weld in tension? The total cycles for the life of the weldment is only 100, so I'm not terribly concerned about cycle life.

 

[Guest102023]

Overall I don't get a good feeling about the weld you are describing or its service application.

The kinds of questions and the way you are asking them suggests you need to retain a welding engineer from the realosphere.

"If you don't have time to do the job right the first time, when are you going to find time to repair it?"

 

[weldstan]

There is no "prequalified" WPS for your requirements. You will need to determine the correct process, filler metal, preheat, PWHT, etc. through qualification and require your welder(s) to be qualified using the procedure. Hire a welding metallurgist to help you out.

 

[Duwe6]

D1.1 has NOTHING to do with hardening steels like 4130 and 4140. Neither does ASME. Only resource I know of is aircraft - some tubular frames on small planes are made from 4130 tubing, and the welds are made with 60 or 70-series filler metal and NOT heat treated. They use the joint designs to reinforce the soft area caused by welding on a heat-treated and hardened area.