Simple case hardening recipe

[VersabossParticipant @versaboss]

Posted by SillyOldDuffer on 30/03/2023 11:38:47:

… carbon to diffuse into an Iron surface by heating the two in contact at about 2000°C for quite a long time.

Well, that's very interesting. I always thought Iron at 2000°C would have the viscosity of running water. So they had a method to keep the original form after the case hardening?

Regards,
Hans

[FulmenParticipant @fulmen]

2000C is slightly on the hot side of things My notes say 900-950°C, and it has worked very well for me in the past.

One source suggested the following mix: 50% charcoal, 35% coke, 10% barium carbonate, 3% calcium carbonate and 2% sodium carbonate. I've only used straight BBQ charcoal with 10-20% carbonates. As noted earlier the barium is probably not needed for our kind of work, any carbonate will work fine or at least better than none.

[Ady1Participant @ady1]

Dirty engine oil I believe

Make sure you plunge "straight" along the axis

[bernard towersParticipant @bernardtowers37738]

in the 30s and 40s velocette used to do black chrome handlebars which mine were lucky enough to have.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Versaboss on 30/03/2023 18:10:55:

Posted by SillyOldDuffer on 30/03/2023 11:38:47:

… carbon to diffuse into an Iron surface by heating the two in contact at about 2000°C for quite a long time.

Well, that's very interesting. I always thought Iron at 2000°C would have the viscosity of running water. So they had a method to keep the original form after the case hardening?

Regards,
Hans

I plead guilty. No idea where 2000° came from. My book says 900 to 920°C and all I did was copy it. Should have realised it was stupid because I know steel melts at about 1250°C.

Time to take up knitting…

[Author]

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