Yes it is possible to use induction heating plus quenching to harden 20MnCr5. The maximum hardness will be less than 45 HRC.

Alliedtrans--you do understand that the results will not be comparable to carburized 20MnCr5, don't you?

I know that the results will not be comparable but the items I am talking about are synchronizer components for a gearbox and some manufacturers have been using induction with changed alloy steel chemistry to fasten their production. Hence I wanted to know if it can be done and some details as to how.


Thanks
Ankur

Addition of surfactants to the quench water to prevent steam blanketing of the parts aids in hardening low carbon steel.

Thanks TheBlacksmith for your reply.. i had heard something of the same nature.. Can you please let me know which surfactant to add to water for hardening 20MnCr5 to achieve a hardness of 50-53 HRC.

I don't think you are going to get it that hard unless the steel has a bit higher carbon content, no matter what you try.

Yes, look at CoryPad's response.

In order to quench to 50-53 HRC, the steel needs to have an absolute minimum C content of ~ 0.25%, and more like 0.27%. 20MnCr5 just doesn't have sufficient C content even at the upper end of the spec. The two closest grades that are standard in the European system are 30MnB5 (1.531) and 27MnCrB5-2 (1.7182) according to EN 10083-3. In the +H condition, they have maximum hardenability of 55 HRC up to 5 mm from the quenched end in a Jominy test. So, for thin rings and composition restricted to the high end of the hardenability range, you could water quench after induction heating and achieve hardness > 50 HRC. The water temperature would need to be relatively low as well as the polymer concentration, which means cracking and distortion are more likely.