rehardening 4140HT after flame bending 1

[AlexCLE]

I need to make some hook-shaped parts from 3/4" OD 4140HT round bar and I'm using an oxy-acetelene torch to heat the rods for bending. Would letting these air cool afterwards just anneal them? Can I re-heat treat and temper them to bring back some strength; what would be the procedure? I don't have a way to measure their temperature. Thanks!

 

[redpicker]

Yes, you will have to quench and temper these at a commercial heat treating facility. Your heating for bending has not only annealed the material, but could possibly left it in a brittle condition that would make it unsuitable for use as a hook.

rp