Metallurgy Questions

[jeremesh]

Ok, so I have started welding again after a 20 year break and have some questions to see if I remember things right or not. If I remember my high school metal shop class properly, when you heat metal and let it cool slowly, it softens the metal. If you heat metal and cool it rapidly by quenching it in water, the metal becomes harder but also more brittle. Am I right so far??

Assuming that above is correct.

1) When I am using my angle grinder with a metal cutoff wheel to cut steel, should I quench it after the cut?

2) Same question for a weld... if I quench a weld while it is still hot will that make the weld stronger or will it just make it more brittle and easier to break?

 

[ShafferNY]

I believe you are right.

I suggest never quenching, it will make it more brittle and easier to break, especially with a weld.

 

[jeremesh]

I believe you are right.

I suggest never quenching, it will make it more brittle and easier to break, especially with a weld.

Thanks, that was what I was thinking but wanted to get some expert advice

 

[Corwyyn]

Not that it isn't called for in some situations but I have never seen a welder throw water/liquid on a weld to quench it - to me that is just an invitation to premature failure of the weld. Now for tool making (and sword-making too) quenching is nescessary, and it also makes a difference when you quench depending on the qualities you are looking for.

 

[jsc7002]

I dont put water on my welds or cuts when im done, I might blow on a weld somethimes if Im in a hurry but I normally just let it cool from the air