Induction Hardening for Low Carbon Steel 3

• Apr 23, 2014

1
• #2

CoryPad

Materials

Apr 15, 2002

5,192

US

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

 

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• Apr 23, 2014

• #3

swall

Materials

Sep 30, 2003

2,767

US

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

 

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• Apr 24, 2014

• Thread starter
• #4

alliedtrans

Automotive

Mar 22, 2012

12

IN

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

 

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• Apr 24, 2014

1
• #5

TheBlacksmith

Mechanical

May 18, 2001

1,286

US

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

 

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• Apr 24, 2014

• Thread starter
• #6

alliedtrans

Automotive

Mar 22, 2012

12

IN

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.

 

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• Apr 24, 2014

• #7

BrianPetersen

Mechanical

Apr 1, 2006

4,449

Ontario, Canada

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.

 

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• Apr 24, 2014

• #8

swall

Materials

Sep 30, 2003

2,767

US

Yes, look at CoryPad's response.

 

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• Apr 25, 2014

1
• #9

TVP

Materials

Apr 12, 2002

4,592

US

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.

 

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