Welding 1215 splined drive coupling into 17-4PH shaft

[JohnNabors]

We purchase a 17-4PH pump shaft that has a splined drive coupling that is press fitted into the shaft and then welded in place. The coupling and the bore for the press fit are both chamfered approximately .125". The supplier is using E309 as a filler. Could anyone tell me if that is the ideal filler material and if there are any special measures to be taken when welding 17-4 to 1215 in this application? I would be very grateful for any help.

Thanks -John

 

[metengr]

JohnNabors;
I presume by your post that the splined drive coupling is seal welded to the pump shaft, correct? If so, why must it be seal welded?

First off, 1215 is a rephosphorized and resulferized free machining steel. This material exhibits poor weldability because of the added phosphorus and sulfur content to promote enhanced machinability. The 17-4 PH stainless is definitely weldable, and requires no preheat. Typically, E309 is used for dissimilar metal welding, which would apply here.

However, my question still remains, why take the risk of seal welding a material (1215) with poor weldability to a pump shaft that is fabricated of precipitation hardened stainless steel? If you need to prevent the splined coupling from rotating under torque, use a mechanical method to stake the splined coupling.