welding spring steel to mild steel

[Laughing Dog Forge]

Hi Everyone,

I have a customer who wants me to build some bench legs out of a pair of forks from a farm cultivator.

I believe the cultivator forks are spring steel.

My questions are;

1) can I weld the cultivator fork to mild steel for the brackets for the seat?

2) can I heat the forks to straighten them a little without causing a weak area?

 

 

[Frosty]

It shouldn't be a problem but spark test the forks first they may be high enough carbon to need to be normalized after you do what you  need to. 

Without knowing alloy specifics I'd run a test bead with 7018, weld a shortish piece of mild to to a hidden spot on the forks and after it cools smack it with a hammer. Lay a piece of cloth over it to prevent it or pieces from flying. If it snaps right off try it again but warm the fork to about 400f and after welding chip the weld vigorously bring it back up to 400-450f and let it cool slowly. Do the hammer test again.  If you don't have a 400f. Tempil stick a piece of white card stock business card works fine laid on the hot steel will toast pretty quickly you don't want to get it hot enough to char quickly though. And yes, a piece of paper will ignite at 451f.

Heating the forks enough to straighten before you weld should handle any preheat necessary if you weld it while it's still hot. 

Frosty The Lucky.

[Irondragon Forge ClayWorks]

What Frosty said. I have welded normalized coil spring to mild with E6011 rod and it is still holding after lifting a lot of weight. I don't have a picture but this is welded to the bucket of my tractors front loader.

Edited November 28, 2020 by Irondragon ForgeClay Works
correct fubar on rod

[Steve Sells]

you welded using 1018?

[Irondragon Forge ClayWorks]

Nope (memory fog) it was E6011... what can I say bad boy bad.

[Laughing Dog Forge]

I should have said I am MIG welding this, I don't have a stick welder.

I did the spark test and it is defiantly high carbon.

I did a test weld with a scrap piece (1/4") to mild steel 3/8" cold and let it cool and hit it with a hammer and it broke off on the first blow.

Second I heated both pieces to 450 f and then let cool to ambient temp after welding. Then hit with hammer repeatedly, took several swings but finally broke taking more of the spring steel the the first test.

I'm just worried that someone will set on this bench years from now and have it crack, I'm leaning towards forging bands around the fork out of mild steel and then welding to them.

[Frosty]

So bend a couple inches of the end of the HC steel in a 90* where it's to be welded to the mild, a 2" bend will give it 4" of bead to resist bending and breaking. 

Maybe put a weight limit on the bench? 

I'm not a fan of gmaw it's too easy to make pretty welds that aren't sound, they almost want to cold lap one side of the joint. I have a Hobart 120 Handler GMAW and use it more than stick by 50-1. But if a weld has to be sure I fire up the stick welder. I don't know if anybody is teaching stick welding anymore. 

Frosty The Lucky.

[bluerooster]

GMAW is just fine if done properly.  But as you mentioned, it's too easy to make a pretty bead that doesn't hold.