[4x4ish]

if metal is heated and bent into a new shape, does it weaken?

I have a tow hook from a nissan pathfinder i think and it is to go on the back of my vitara but it has a angle in it as the pics show. i need this angle to go the other way basically so if it heated and bent will it weaken its strength as a recovery hook? It seems to be hollow but still thick metal.

[SuziBlu]

Not sure of the grade steel its made of, I assume mild, and if so, there is not enuf carbon in mild to change its structure during heating/cooling. Put it on a grinder, if its a dull spark, its mild, another test, hit it, if its mild it will give off a dull thud, where as any form of tensile will give off a ring, higher pitch.

Give a cold chisel a hit n listen to the noise of high tensile, similarly, hit it with the grinder and see the hotter sparks. Also, a file will cut mild very easily.

I do not have recover hooks on any of my cars sorry, so can only surmise.

[MacDaddy]

I am pretty sure if you heat and bend, it will weaken it... tempering it may help some... or just make it brittle and even more weak... i am guessing it would only be mild steel... so you might get away with it... maybe...

[BlueSuzy]

Pajero's have similar.

I would move it to a better position where i could use it, or i would not bother, and buy a new recovery hook.

[4x4ish]

since im not getting a difinate no it will not weaken, i will not touch it and mount it in another spot. i will now have to grind off the old tow hook but i was hoping i could put it on the other side where i would not have to grind anything. better safe than sorry.

[wharf]

If you heat it up enough to bend it the metal needs to be properly cooled/tempered again.

[Llewellyn92]

If done correctly you would have nothing to worry about, If you simply heated till it was white hot and bent it and allowed for it to cool slowly in the air the steel would be anealed to a fairly soft state which means it would bend easily befor it breaks. Ive learned that a good way of tempering steel thats goint to be subject to both shock loading and tensile stresses is once the workpiece has been shaped and while it is still white hot to then quickly quence it in a bucket of water to harden the workpiece. The problem here is its then quite brittle so to combat this you reheat the workpiece to a point where it turns a straw colour and keep it at this temp and allow to "soak" for a minute or two befor quencing for a second time. This technique usually gives a good balance between hardness, brittleness and strength. Mind you aftermarket tow hooks arnt that expensive are they?