Filler Metal for Unknown Tool Steel?

[Weldo]

Hey, I'm seeking advice on filler selection for a part from an Atlas shaper.

There's a pin pressed into a plate. The back side is welded and ground flush.

In the pic below I've already begun pressing it out. The flushed off weld had cracked around 90% of the circumference.




The front side receives no weld.




The pin is most likely some kind of tool steel.




I'm not sure about the plate being tool steel. It probably should be for the service it does, but none of the surfaces are finished as finely as the pin. Some scoring can be seen in the sliding fit parts so it may not be a very hard steel.




In the little research I've done some have suggested specialty tool steel rods. Others say 309L is a good choice. Some have said 7018. Most agree that pre/post heating and ample peening is a good idea. I've even heard that you could avoid all the metallurgical intricacies by brazing instead of welding when it comes to tool steel.

So what are your thoughts?

 

[b4autodark]

Kind of a poor design for a weldment in my opinion, but it is what it is. I would try to chamfer the back side of the plate until all the original filler material is gone so you won't be dealing with that as well and to give your new weld more surface area, also dress off the end of the pin.

Pre and post heating is a good practice for a "unknown material procedure" like this especially to prevent cracking of the weld which in my experience is more likely than with a straight line fillet weld. Stress relieving is also recommended.

A plug weld with a 3/32" 309L electrode at 90 amps would be my choice.

Good luck.

 

[General Zod]

Other good choices are Harris 03SMW Super Missile Weld TIG rod, and Hastelloy-W. I could sell you small quantities of either rod if you wish.

 

[Weldo]

Oh, a dealer, eh?

I may take you up on that. Over in the shaper section there's at least one other guy who had this same problem with old weld cracking. Maybe it's a common problem but I'd like to ensure I don't have it again later on.

 

[Ulma Doctor]

don't forget about E312 !

 

[General Zod]

Oh, a dealer, eh?

I may take you up on that. Over in the shaper section there's at least one other guy who had this same problem with old weld cracking. Maybe it's a common problem but I'd like to ensure I don't have it again later on.

ER312 is also a good choice.

No, I'm not a dealer of anything. I just happen to have lots of stuff.

I have (in various sizes)

Hastelloy-W
Hastelloy-X
ER312
ER309L
ER308L
ER321
ER347
ER70S-2
Inconel-625
ERCuSi-A
Super Missile Weld
ER4043
ER5356
ER4943
ER-Ti-5 6Al-4V
ER-Ti-23 6Al-4V ELI
ER80SD-2
Inconel 718 (on-order)
Inconel x750 (on-order)

 

[Lo-Fi]

I'm currently having really good results TIG brazing unknown tool steel. Knowing now how easy it is, I'd put some hefty prep chamfers in and get brazing - tig or otherwise! You can probably get a stronger joint than original if you're cunning with the prep

 

[Weldo]

No, I'm not a dealer of anything. I just happen to have lots of stuff.

Thanks for the offer, man! I'll definitely file that away for future!

I'm currently having really good results TIG brazing unknown tool steel. Knowing now how easy it is, I'd put some hefty prep chamfers in and get brazing - tig or otherwise! You can probably get a stronger joint than original if you're cunning with the prep

This was something I'd run across in my searching. You can avoid some of the drawbacks of welding by not actually melting the base metal. I may give that a try. I bought some brazing rods years ago but never played with 'em. Now's the time I guess. I forget what type they were...

 

[rwm]

Be careful. I find it very hard not to melt any base metal with TIG braze. I have had some very weak bonds. Torch brazing is more reliable if you have a torch hot enough. Personally, I would just TIG weld it.
Robert

Jodi says it here:

TIG Welding/Brazing with Silicon Bronze

Video on Tig welding/brazing using sil-bro - silicon bronze filler rod

www.weldingtipsandtricks.com

 

[Weldo]

I've never actually TIG brazed but I expect there to be a very fine line between getting the base hot enough but not melting. I'll try it out on some scraps first.

Thanks for the advice. It seems to be a poorly designed part that is prone to cracking so I want to do the best repair possible. The pin only presses in about 0.250" or a little more and it's under heavy load.