Using 4130 for sheet metal repairs

[TnBlkC230WZ]

I'm a nube at MIG welding and the whole process of what steel to use for body repairs.

I'm about to embark on installing DSE mini tubs and a Chassiworks G-Link in my 71 Nova. Installiing the mini tubs requires patching lots of holes in the body and frame rails. I've done some research and I'm considering using annealed 4130 steel for the repair work.

My logic is that even annealed, 4130 has a much higher yield strenth than mild steel and slightly higher tensile strength.

DSE recommends patching the frame rail with 1/8 inch mild steel. I would like to use annealed .063 4130 to reinforce the inner side of the rail to attach (possibly bolt) the G-Link to and for patching the outer side of the fram rail. The frame rail is .048 from the factory, but it will get narrowed for the mini tubs. Is this a good idea or should I use a heavier guage or different material?

I plan to patch the other smaller holes with .040 or .050 4130.

[Ratfink]

Is this like a unibody type construction? I work with 4130 plates quite a bit and Yes in it's annealed state it is very much like a 1010, or 1018 mild steel. The thicknesses you are talking about generally scare me though, especially when you are talking suspension. To answer our question, Yes, you can use 4130, but in the end you will never know the difference.

[parsonsj]

I think 4130 would probably work fine too. But it will cost a lot more for very little gain. I'd recommend standard low-carbon steel, like 1018. 1018 is easier to cut, form, and weld.

Free advice, and worth every penny. :)

jp

[DynoDon]

Unless you are going to normalize it after you weld it in, you are going to end up with pretty much just expensive 1012 mild steel with potentially brittle weld joints.

[TnBlkC230WZ]

Thanks guys. I'll stick with the 1018 or 1012.

[DRJDVM's '69]

Dont make it more complicated than it needs to be....

[TnBlkC230WZ]

Looks like most of the 1008 - 1018 sheets conform to either cold rolled A366 or hot rolled A36 standard. Should I pick the one with the highest carbon content or stay with what is cheapest since they all have a similar yield and tensile strength?

[parsonsj]

I like CR steel. Easier to weld, since you don't have to grind or sand off the outer scale, plus CR steel usually has tighter manufacturing tolerances.

jp

[LowBuckX]

Dont make it more complicated than it needs to be.... best advice ive heard in a while