Welding 17-4 pH to 304

[sammybrock]

Current design has a 2"x2"x200"long bar of 17-4 pH welded to top of SS304 I beam. If we skip welded or spot welded, would the difference in heat shrinkage still cause warpage beween the 2 materials? If so, any solutions? The 17-4 is for 2 rails holding 2 wheels each at 10,000 lb/wheel.

 

[Goahead]

The outcome of this project is difficult to anticipate.
I understand that 17-4 PH is in fully heat treated condition and that the weld has no strength function.
If this is correct, then skip welding small fillet welds with ductile 300 series filler metal should be adequate.
Deformation would probably be reduced using a proper sequence from the center symmetrically towards the ends.
If this is not acceptable would a mechanical fastening system without welding be feasible?

http://www.welding-advisers.com/

 

[stanweld]

How thick is the stainless steel I-beam flange? Proper welding technique can mitigate distortion during welding. The rails are quite rigid; however if the I-beam flange is quite thin, you may distort it and loose some bearing surface between it and the rail between the stitch welds.

 

[sammybrock]

A little more clarification. The 17-4 has to be seal welded all along the top of the I beam. Maybe we could stitch weld the bar onto the I beam then come back and seal weld between the stitches. The stitch welding would take care of calculated seismic forces and the smaller seal welding would prevent any contamination seepage between the bar and the beam. If we seal weld one at a time and allow cooling between welds we think we can control warping.

 

[stanweld]

You may also wish to incorporate back step sequencing as well.