Heating & Bending Metal

Spencer · Feb 18, 2004

I have a Kasco Uni-Hitch adapter on my FEL. It allows me to use standard skid steer type quick-attach implements. There are two levers on the Uni-Hitch that are used to lock-in or unlock the quick-attach implements. I bent one of the levers last week when I was hooking up my pallet forks. The lever got caught in the fence on the back of the pallet forks. These levers have always been too close to the adapter and I have smashed my knuckles more than once when trying to move them. I got out my oxy-acetylene torch and heated up the levers and then bent them both further away from adapter. I just heated up a lever until it was getting orange and then I put my 24" Crescent wrench on it and slowly bent it to its new position. I slowly moved the torch further and further away from the lever until it was no longer orange. I then let the cold winter air cool the lever off the rest of the way. It's too late now to get advice on how I should have done this in the first place. I would however, like to know the best proceedures for future use.

Did I significantly weaken the lever by heating it up this way?

Is there a certain way to cool off the metal so that it retains as much strength as possible?

Is there a way to heat and/or cool the metal to make it harder?

Would it have been better for the metal to just beat with a hammer instead of heating it up?

I've attached a picture of one of the levers.

rdln · Feb 18, 2004

I think you did just fine. Hammering it cold could cause cracks and weakening.

The heat changes you grain structure to be perpendicular to your bends.

water quenching will harden the surface but I believe cause embrittlement, Oil quenching is slower but better.

The part did become weaker for sure but for what it does you are fine.

Heat and Beat Baby.

DAP · Feb 18, 2004

Spencer, if I understand this lever's function, it never comes under any load except when it is articulated (by hand I assume). If my assumption is right, I wouldn't worry about having taken the torch to it.

Nonetheless, with respect to weakening, you would have to know what its composition was and a fair idea of hot you got it in order to say one way or the other.

'sides, rather IT breaks than one of your knuckles methinks.

my centavos

jmc · Feb 18, 2004

Spencer,

I think you did OK. There's probably been worse done on parts for race cars. If the steel was hardened to begin with, you probably annealed it to some extent. But I doubt the manufacturer would go to the trouble or expense to make it from a hardeable alloy when he could just use a bigger piece of inexpensive steel. If you're curious, try using a file on an unheated section. If it digs in, its made of soft steel,. If it skates across the surface or hardly digs it. it was hardened.

Incidently, you can't harden and temper a steel that doesn't have some minimum carbon content. Plain old angle iron and most of what implements are made of won't harden by normal practice. Low carbon steel can be case hardened though but its just a hard skin with a soft inside. The technique involves letting carbon soak into the steel surface to change the surface chemistry into a hardenable alloy.

John