Stress relief before quenching

[stanislasdz]

It's necessary to do a stress relief heat treatment after homgeneizing and before the quenching a part of steel casting with 500 of thickness.

Thanks for answers !

 

[swall]

What alloy is the part? Does it have abrupt section changes?
I assume you are worried about potential quench cracking?

 

[stanislasdz]

Yes it's a steel part in 18CrNiMO

This part have aprubt changes

 

[swall]

You have a couple of options. One would be an interrupted quench into 1000F salt just long enough to equalize the temperature, followed by an oil quench. The other option would be to quench into 400F salt instead of oil.

 

[stanislasdz]

we use only water quenching !

 

[swall]

This is a carburizing grade of steel, correct?

 

[dbooker630]

Looks like the SAE equivalent would be 4320H. But it should be quenched in a 'medium-hot' oil, perhaps something in between conventional and marquench, about 225-250F. The salt options whether interrrupted or direct to Ms temp are good options also.