On one of my weird T related projects, I would like to join a piece into a object that is case hardened 8620. The piece I would be inserting will be new. I am thinking maybe making it from D2? But case hardened 8620 is a option? I am thinking of drilling a hole right through and then silver brazing it in. Any insight would be appreciated
Brazing will most likely draw the case out. And it will certainly draw the temper out of D2. You'll be right up there at about the same temperature for 8620 case unless you do use 50+ silver rod and watch the temperature really close. You can't re-harden either since the brazing will melt out.
Any chance of jointing the parts by threads?
Forgot to ask: Do you have or have access to a heat-treat oven? You could set the temp to brazing temp and let the brazing paste/powder flow. I the oven is accurate, you should be ok. But I wouldn't use D2.
Your problem is that the surface as you describe it is probably carburized. That alone would make it more difficult to weld if welding was an option.
So you are joining two pieces, eh? If you share for what purpose final function I may be able to guide you. For starters it would be a lot simpler to use identical stock. Whatever happens to the one will also happen to the other. Makes it easier.
If the surface is carburized to get that case hardening, it will actually behave like a 4130 when brazed or welded...preheats, puddle should solidify near instantly when laid on, post treat air temper. Don't plan it out it will crack....if you share, even thru PM what you expect of the joint, I can probably help. Also, knowing what you actually have or prefer...braze, weld, would help.
The problem is a machine shop goofed on a dimension. Yes certainly their error and yes they would make new parts if I insist.
BUT I want work with them and I am trying to see if there is a easier solution.
So yes the original part is carburized and case hardened. The part that needs to be moved needs to be hardened as well. So we can remove the part that is incorrectly located. And then add a new part that is moved about 3/16".
Ken Your comment is precisely my concern. I can probably gain access to a quality heat treat oven locally, so your suggestion is worth consideration.
George The joint design will not be highly stressed. I am after wear resistance on the part that has to be moved and the original part has to work inside a needle roller bearing elsewhere.
Another option is just to press the two parts together (a light fit would be sufficient).
I do appreciate the help very much. I don't profess to be a expert in metalurgy
What type of wear resistance are you trying to achieve with the D2 component? It can be rather unfriendly stuff with which to work, especially if any of the machining operations are to take place after heat treating (unless machining by EDM).
No machining would be done after