[Sal Monella]

building up shaft, thinking 316L but want to be sure.
All help appreciated.

[Braehill]

Sal,
There's a rod made for 17-4 called ER630 and it should be used if you need to maintain the 17-4's mechanical properties, but if you're just building up the shaft for say a sealing surface then you should be able to use 316. Your welds should be convex and if you use 300 series rod it doesn't require a post weld heat treat, the 630 rod does. I would use 308L if it's a large shaft to lessen the chances of checking within the welds. They call for a 250* interpass temp. and I personally would cool it with compressed air in between passes.

Len

[Sal Monella]

Sal,
There's a rod made for 17-4 called ER630 and it should be used if you need to maintain the 17-4's mechanical properties, but if you're just building up the shaft for say a sealing surface then you should be able to use 316. Your welds should be convex and if you use 300 series rod it doesn't require a post weld heat treat, the 630 rod does. I would use 308L if it's a large shaft to lessen the chances of checking within the welds. They call for a 250* interpass temp. and I personally would cool it with compressed air in between passes.

Len

Thank you. Maintaining integrity is critical.
What is involved in the post weld heat treat and how critical are the temperature ranges? (for post weld treatment)?

[Braehill]

Sal,
17-4 is a precipitation hardened martensitic stainless and needs to be returned to that phase after welding if you need it to remain 17-4. I would be lying if I told you I knew what all was involved in the post weld heat treatment but maybe others here might know, I'll let someone with more understanding of that process answer that.

I would say if you line up somebody to do the heat treatment then they would be able to tell you how important the interpass temps would be to the final product.

Len

[Sal Monella]

I meant the post welding temp for heat treating but that is fine, you have been very helpful. It is for my son's fishing boat,
the main propeller shaft. If it were to break at the weld the boat could flood and he fishes the North Atlantic in the winter.

Now that I have a direction I can find the heat treating process. Thanks for your help.