Welding On Chassis

[AvinashJagtap]

Hi.
We are planning to make our chassis of two different materials.
Pure Mild Steel and other with bit of Chromium content.
I have a doubt regarding welding on these two materials.
Would there be any problem if we weld both metals on each other with Tig welding?

[AvinashJagtap]

Hi.
We are planning to make our chassis of two different materials.
Pure Mild Steel and other with bit of Chromium content.
I have a doubt regarding welding on these two materials.
Would there be any problem if we weld both metals on each other with Tig welding?

[Drew Price]

If your "...bit-of-Chromium-content..." steel means a stainless steel, you will have to read carefully about what filler metal you should use to join the two specific alloys you're considering, but it is definitely possible, though possibly not recommended.

It's very easy for the joint between the two dissimilar metals to have many un-desireable properties for a structure like the frame, such as very high hardness, get yourself a welding text and read up on welding dissimilar metals together.

TIG will work.

You may also want to read about using brazing to connect the two pieces, but there is a LOT of skill and a lot of prep to make a safe enough joint for the car, but something to consider.

[KyleD]

Could this bit of chromium content steel possibly be Chro-Moly? If so then you can indeed weld it to mild steel. We have some 4130 welded to 1020 on our current chassis and it works just fine. Like Drew said read up on proper filler rods and preparation/finishing procedures (i.e. normalizing your welds).

[Jersey Tom]

Why not make it out of 1 spec steel and not have to worry about the metallurgy of your weld zone?

[Adambomb]

I know for us it was a matter of simplicity, ie the place that does our laser cutting can simply make everything out of one sheet of 4130. I haven't heard of any problems with it.

[Xeilos]

Good tip for those who have ever worked with a good welder that you trust.

Just ask the welder and trust what he has to say and knows. He will know infinitely more about welding than you can ever hope to learn from a textbook. Even if you wanted to know about what is actually happening, talk to the welder (and if you are not arrogant) and genuinely want to learn, than he should help and teach you some of what he knows.

Bear in mind, that you have to trust this welder and be sure he is experienced/good at what he does. You can look at his welds as an example, especially on thinner sheet material and 18 ga. aluminum.

Textbooks only get you so far in the real world. There is never a replacement for practical experience as those on a FSAE team know quite well.