Heat treating steel?

I'm looking to fabricate some sway bar links for my brother's car. The stock one's have a decent bend in them to get around the suspension A-arm. I can easily make a new link using heim rod ends and either threaded tube to solid rod.

Question is this - I'll have to bend the tube or rod to the stock shape. I know this will weaken the metal and worried about it failing over time. Should I heat the metal before bending and then quench it to harden it up again? Not quite sure how all that works but want to end up with a rigid piece that will resist flexing. I'm sure the stock unit was heat treated or some alloy.

Related question - If I weld a grade 8 nut onto the end of steel tubing to use it as a threaded weld bung (non-critical part here, don't worry), have I weakened the properties of that nut?

Would it be better to weld and then quench it in oil or water, or better to let air-cool?

I think it'd be pretty hard for the home shop builder to get the temper back right. I've seen people make sway bars using spring straight stock and fabricating arms that come off the straight stock at a 90 and attach to the A frames etc. I guess they ground the ends square to mount the arms..

I bet junk yard bars could be adapted that way.. I wonder if you could use torsion bar suspension rods to fab up sway bars--they already have attaching points on the ends. The reststance could be adjusted by the arm lengths.

I usually chop saw my springie stuff when I can to keep the temper, but I've blown holes in leaf springs with my plasma cutter when I couldn't drill them, and it didn't heat them up enough to loose the temper.

About welding the grade 8 bolt/nut--I'm pretty sure you loose the temper, but It seems the quality of the grade 8 metal is better--I've seen some awful ungraded bolts that are junk to start with that look like they'd kill someone if used incorrectly --or at all!! So a nice #8 bolt as a started feels better. Might just be in my head though..

PA41

What you want to be careful with is 'drawing it down' or annealing it, Thats taking the temper out.
Heat it to bend it where you need it....then throw it in your sandbox and cover it up.....so it'll cool off slowly.....the sand will hold the heat in.....
Depending on the steel....you can oil quench, water quench, sand box it, or even use diff. chemicals to submerge it into to keep it from getting soft OR too hard....
There is a art to it....I usually spark test it to see how much carbon is in it and how hard it is to start. My tools of choice is a 4 1/2 angle grinder, a rockwell hardness tester, and a file....[[P

You re-arch springs 'cold' and 'form' spring steel cold, ie, using a press and/or bending dies....[[P

Sorry guys I wasn't clear - I'm not actually making a sway bar, just the link that connects the sway bar to the suspension. It isn't made of spring steel, just normal steel, but I have to put a bend in it. I'm just concerned that putting a bend in it will weaken it, so trying to figure out a way to strengthen it again.

BigIrish said:

Sorry guys I wasn't clear - I'm not actually making a sway bar, just the link that connects the sway bar to the suspension. It isn't made of spring steel, just normal steel, but I have to put a bend in it. I'm just concerned that putting a bend in it will weaken it, so trying to figure out a way to strengthen it again.

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id say you can bend it -- get a big enough tub to fit all of the heated area in, fill it with oil or boiled or distilled water , heat the metal and bend it how you want your looking for a nice deep red color - dont let it get to orange or bright orange red -- after you submerge it you can check and make sure it hardened to what you want -- if not, repeat the process when it has fully cooled ...

to answer your bolt question, yes it will change its strength - the amount it changes is up to you -- anytime you heat a metal youre changing the physical properties of that metal -- the less its heated, the less its affected. -- are you welding with rod or wire?
if youre using a rod - you could go with a low hy and probably be on the safe side, if youre going with wire just treat it like its sheet metal and wait for it to cool completely on its own between welds... it would take a good amount of heat to change the bolt so significantly that you would ever need to worry about it -- grade 8 bolts are almost always overkill but never a bad idea

heating mild steel

if you use mild steel. then when you quench it, you end up with case hardning. that is just on the surface. it will reduce the flex. when you heat, bright red is the best and will let you bend without stressing the metal.
thats my 2 cents