12L14 heat treat

[multiproducts]

We currently carbon nitride our 12L14 pinions to provide a case hardening. We would like to get more strength from this material. Is there a way to induce carbon into the part during the heat treat to increase strength? We would like to match the strength of 4140 thru HT to Rc30.

Thanks

 

[swall]

You will have to change the base material to get more strength. Change to 8620 or 5120 and carburize instead of carbo nitride. With a carburized case, you can obtain deeper hardening. You need to change base materials in order to obtain a core hardness high enough to support the case hardened layer.

 

[CoryPad]

While swall's suggestion is good from a strength perspective, the machinability will be horrid compared with 12L14. That will need to be a major consideration.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[TVP]

It will entail a major change to the current manufacturing process, but cold forming the pinions out of 8620 or 5120 and then carburizing as swall mentioned would be one possibility for increasing strength. Another option would be to cold form the pinions out of a through hardening grade that can attain the necessary hardness. If the section size is not that big, perhaps a lower alloyed grade like 15B35, 51B35, 5140, etc. would work. Something will have to change with the material composition in order to gain any improvement similar to a through hardened 4140 at 30 HRC.

 

[kenre]

Ive used 709M, a modified 4140, meant to have properties equal to or above 4140, but machines much easier.

http://www.retallickeng.com.au

Was told it couldnt be done, so
i went and did it!