I was thinking about bending up some steel tube to make into a bumper for the rear of my truck, along the lines of Allpro's or marlins. But, i don't have a tube bender, so my question is, if i heat it with the torch enough, will it bend without comprimising it, and can it be bent to 90 degrees?

My feeling is that this is a no, and that i'll need a bender, but i wanted to be sure.

 

even if you heat it, it will still kink, i dont think that it would change the properties of mild steel that much, it depends how you cool it

 

Yeah I would agree, it will kink even if you bend it over something round it will just flaten. It's a good idea not to heat steel more than you have too, the property's of the steel can change and depending how it's cooled, it can be better or most likly worst. Mandrel bender is your best bet for strong bends.

 

i highly doubt a 90 degree bend is possible without a bender... even with a bender thats quite much... you would need to pack it with sand and do all that stuff otherwise the tube will msot likely collapse

 

Yeah, that's what i thought...i'm thinking cut and weld, since that's all beyond what i can do in the shop...thanks

 

You could get away with bending tube with a torch but not a 90 it would flatten out on the outside of the bend and possibly kink the inside. When you heat steel it's called Anealing and makes the properties of the affected area weaker. When you mandrel bend using cold forming it increases the tinsel strength of the affected area (bend) by up to 30% by stretching and shrinking the tube while bending yielding no kinks and a smooth surface inside and out.

Cuttin' and weldin' can look real nice too

 

A point of clarification regarding annealing. In general annealing refers to a heating process that changes the microstructure and properties a metal causing it to be softer and weaker. While making it weaker sounds like a bad thing it isn't necessarily. Annealing is often necessary to make further cold working or machining possible. Annealing is also used to reduce brittleness in a welded or previously heat treated part. In terms of annealing a HREW tube for bending, the affects would be dependent on the intensity and length of the heating.

Cheers.