4140 Surface Hardness
4140 Surface Hardness
(OP)
Hello,
I am trying to harden a 4140 bar to RC 52-55. Is there a reason why the surface hardness on this bar would be so low (RC 10) compared to the hardness at a depth of .050 in where the hardness reaches 52?
Any help will be appreciated.
Thanks!
I am trying to harden a 4140 bar to RC 52-55. Is there a reason why the surface hardness on this bar would be so low (RC 10) compared to the hardness at a depth of .050 in where the hardness reaches 52?
Any help will be appreciated.
Thanks!





RE: 4140 Surface Hardness
RE: 4140 Surface Hardness
Another possibility is the furnace atmosphere, if there was one at all.
RE: 4140 Surface Hardness
We heat it up to 1600 and quenched it in water and it did not even crack or anything which you would expect for 4140. This was part of a project I'm working on.
dbooker630, what do you mean how much was on the incoming product?
RE: 4140 Surface Hardness
4140 can be water quenched without cracking; it might crack, but depending on variables, it may not. If you meet 52 HRC, you have enough carbon to crack if conditions are right.
Get a micorsturcture analysys done and you will see if decarb is the problem.
rp
RE: 4140 Surface Hardness
RE: 4140 Surface Hardness
Thank you!