Yield strength change in welded heat affected zone!
Yield strength change in welded heat affected zone!
(OP)
Hello, I have a part that has three metal sheets made of 1075 steel laser welded together on the outer edges to form an enclosed volume of air that is compressible to take care of some pressure waves in a tube and regulate the dynamics. The question I have is how does the yield strength and poisson's ratio of the standard 1075 steel change in the heat affected zone of the weld? I am not sure what the melting temperature of this steel is that needs to be acheived to fuse the molten metal together. But the metal in the weld zone does get very hot and once it cools down, it becomes very brittle and hard, because of untempered martensite. Any help would be greatly appreciated. Thanks.





RE: Yield strength change in welded heat affected zone!
RE: Yield strength change in welded heat affected zone!
Is this really the question you wanted to ask?
If you have to make bellows out of 1075 (shakes head) use a diffused pre-pass to preheat the area before the weld so that the weld metal and austinitized heat affected zone do not quench too fast.
Or, if you are going for production rate and have money for tooling you could build a resistance coil into your backup tooling to warm the part up before welding.
This will allow you to get the bellows together, then you still have to austinitize, quench and temper the parts to get the ductility and fatigue strength you need.
If you can not subsequently heat treat the assembly, run a couple of low power postweld laser passes to temper the weld and heat affected zone.
Life would be simpler if you could switch to a precipitation hardenable alloy such as A286.
RE: Yield strength change in welded heat affected zone!
RE: Yield strength change in welded heat affected zone!