Welding 4140 Q&T to 1026 Seamless Tube 2

[chk68]

We need to weld a premachined 4140 Q&T (131,000 psi yield) pin into a 1026 hrs seamless tube. The pin is shrunk fit into the tube before welding, and the weld is just a secondary means to assure the pin does not work loose or spin in the bore.

Since the 4140 is quenched and tempered and premachined for bearings, I don't think PWHT is plausible. In the past they have preheated to 400-450F and slow cooled and used E71T-1 wire. Is this acceptable? Sketch attached.

 

[stanweld]

E7018 H4R low hydrogen coated electrodes are also recommended with your stated preheat. A dehydrogenation heat treatment at 600F min for 2 hrs is recommended when using E71T-1 or its cousins, E71T-1M, E71T-12C, E71T-12M.

 

[metengr]

Agreed. Make sure after welding you NDT the fillet weld using wet fluorescent MT.

 

[stanweld]

Finally, the weldment could be locally tempered using properly designed induction heating coils and frequencies.