Welding on spring steel

Date 11-02-2000 21:07

The problem I am having is welding Cold formed A-36 to 1065-1075 oiltempered spring steel (information from the vendor). The A-36 is 2" bar stock that is drilled and tapped (to attach threaded adjusters) then fits inside the spring and is welded to the first wrap of the coil spring. It welds fine but the springs are breaking off anywhere from the end of the weld to 3 to 4 wraps down. It seems like maybe a HAZ problem but that is my question. Could it be something else? If it is what? and what can be done to remedy this problem. We have been welding them with 7018 (not as many broke) then with 71M. We also have L-50 but haven't tried it. Are any of these acceptable or do we need to consider using something else? Or is there really no good way to weld springs steel? These springs are stretched approximately 8" inches so there is certainly alot of strain on them. Thank you for your time and input it is greatly appreciated.
Thanks again,
Marc

By R. Johnson (**)

Date 11-03-2000 22:36

Any welding process is going to ruin the temper of the springs and cause a very hard heat affected zone. I would not feel comfortable with the spring welded and would worry about a future failure that could cause an injury or even death.
Can you mechanically fasten the spring to the A36 steel? If not you will have to work out a postweld heattreatment procedure, and subquent quenching and tempering the springs all over again after welding. Or better yet buy untempered spring steel and then temper it after welding.

By Jorge Giraldo (**)

Date 01-02-2001 19:48

I am absolutely agree with Mr. Jhonson's reply too. You can't avoid the very hard heat affected zone caused for the high carbon content (0.65%-0.75%) of the spring steel and is very susceptible to hydrogen cracking (or cold cracking). Particularly, I prefer to make modifications (improvements) on the designe instead use welding.

Jorge Giraldo
Medellín, Colombia

By G.S.Crisi (****)

Date 11-09-2000 12:33

I agree entirely with Mr. Johnson's reply.
Giovanni S. Crisi