Collar to "S" Steel

[knots43]

I need to weld or braze steel collars to S7 steel tooling . In service the tool may reach 400 to 500 degrees F. Will silver braze hold in shear at these temperatures ? Alternately will a preheated weld hold. The collars are to be A36 steel. If welded I will use my mig.

Any alternative sugestions will be appreciated.

[Dipsomaniac]

I don't think you will be happy with the collar material (A36) but on some of our in-shop lathe tooling it is recommended to TIG weld 4140 or 4150 on S7 tooling.

[knots43]

Collar

I don't think you will be happy with the collar material (A36) but on some of our in-shop lathe tooling it is recommended to TIG weld 4140 or 4150 on S7 tooling.

Thank you for your reply. Normally I would use my TIG to weld this collar however I have just moved my shop and the circuit for my Hobart has not been installed so I am stuck with MIG or silver braze for now. Therefore it seemed that the A36 seemed a reasonable choice if not ideal. I guess the question is am I wasting my time if so I will just outsource. I was hoping that preheat would result in a weld good enough to get me by for now.