Welding Question: MS to CM

[janjon]

Can mild steel plates, brackets, tabs, etc. be properly and effectively welded to chromemoly tubing of my FED chassis? I am needing to relocate the gas pedal mounting on my car and need a plate welded between two crossmembers to do this, I have ms plate laying around but do I need to get 4130? 

[rooman]

There are no problems welding mild steel to moly. Just make sure that the ms is reasonable quality, not some junk hot rolled full of impurities. The cheap stuff will weld to the moly but you take the chance of impurities in the plate contaminating the weld puddle. Also be wary of welding heavy plate to the thin moly as that can introduce a potential fatigue point. In other words don't try to weld a 3/8" thick bracket to .058 moly tubing--it can be done but is not good engineering practice.

Roo

[janjon]

Thanks, Roo for the response and your input. Would you say that cold-finished steel strip is either inherently, or more likely, to be of better quality than hot-rolled stock?

[rooman]

Yes,
       unless you run across some Chinese junk you will usually find that cold rolled is better quality. I try to use 1018 cr when I use mild steel.

Roo