metalergy

J

jhowes

Well-known member
A post some time ago showed a frame being straightened by heating the frame below the motor mount to rather high temperature and then letting it cool and shrink back to it's correct place making the frame straight again. My question has to do with the temperature and cooling with oil or water, what does the cooling do to the metal? I can measure the temperature with my infrared temperature gun. If I gas weld the old frame horns on the front of the frame, do I use a more rapid cooling technique or not. Why did I hear some 70 years ago about people hammering charcoal into red hot iron? Was this only done to make a edge that could be sharpened? How about springs, can they be heated without taking away from the spring of the steel? Just an old man curious. Thanks, Jack
 
The answer is in your title. Different alloys respond to the heating and cooling, water vs. oil in their own predictable way. I think it's only science if you know what the metallurgy (alloy) is.
 
You're mixing two different processes. The "heat and quench" and carbon deposition (case hardening) are to change the hardness and strength of the metal. Straightening isn't really dependent on the cooling rate so much as the shape of the area you heat. I'd scan some welding or metalworking books or even Utube for a good description. I've seen it done on angles and I beams, but I'd think a C channel would need a slightly different technique. Also, I've usually seen it done to take a "wow" out of a flange, not to take out a bend across the whole area of a beam. I'm not saying it can't be done, just haven't seen it.
 
If you look at the 12-23-Res731 post #5, you sill see what has prompted my question. It was mentioned in that thread that the cooling process had not been done (or something like that) so I questioned if oil, water, or air cooling is the way to go and why, what happens to the metal? Sorry I am stupid on this subject, thanks for your reply. Jack
 
Thanks Mike, I think I am ready to give it a try. I still don't know about cooling with water, salt water, oil, or anything else. I think I will let it air cool. Jack
 
As a general rule, I never cool metal with any oil, water or any other artificial means. In nearly every case, it will induce brittleness. Springs and other heat treated items are a different kettle of fish. The best advice for these sorts of parts is, don't.
 
Last edited:
jhowes said:
A post some time ago showed a frame being straightened by heating the frame below the motor mount to rather high temperature and then letting it cool and shrink back to it's correct place making the frame straight again. My question has to do with the temperature and cooling with oil or water, what does the cooling do to the metal? I can measure the temperature with my infrared temperature gun. If I gas weld the old frame horns on the front of the frame, do I use a more rapid cooling technique or not. Why did I hear some 70 years ago about people hammering charcoal into red hot iron? Was this only done to make a edge that could be sharpened? How about springs, can they be heated without taking away from the spring of the steel? Just an old man curious. Thanks, Jack
Click to expand...

Do an internet search for "flame straightening technology". Gobs of info!
 
jhowes said:
Thanks Mike, I think I am ready to give it a try. I still don't know about cooling with water, salt water, oil, or anything else. I think I will let it air cool. Jack
Click to expand...

All I can do is point you to those that do this for a living. You can do it any way you like.
 
You must log in or register to reply here.
Back
Top