Further hardening 4140 pre-hardened
Further hardening 4140 pre-hardened
(OP)
I am making a splined engagement dog of about 2 inches in diameter. The stock material I have to use is 4140 pre-hardened to roughly 30 HRc.
The part will be machined then I would like the hardness to be increased to roughly 45 HRc and then finally internal splines will be cut using Wire EDM.
What processes will be required to achieve this increase in hardness?
The part will be machined then I would like the hardness to be increased to roughly 45 HRc and then finally internal splines will be cut using Wire EDM.
What processes will be required to achieve this increase in hardness?





RE: Further hardening 4140 pre-hardened
Do you know what the actual chemistry of your heat is?
Gold is for the mistress - silver for the maid
Copper for the craftsman cunning in his trade.
"Good!" said the Baron, sitting in his hall
But iron - cold iron is the master of them all.
Rudyard Kipling
RE: Further hardening 4140 pre-hardened
The stock is actually 4142 hot rolled heat treated steel from Speedy Metals. Their documetation says it is pre-hardened to 27-32 rockwell C, but that's about all it says.
Is an anneal recommended or required before rehardening/quenching/tempering?
RE: Further hardening 4140 pre-hardened
RE: Further hardening 4140 pre-hardened
Gold is for the mistress - silver for the maid
Copper for the craftsman cunning in his trade.
"Good!" said the Baron, sitting in his hall
But iron - cold iron is the master of them all.
Rudyard Kipling
RE: Further hardening 4140 pre-hardened
John
RE: Further hardening 4140 pre-hardened
The concern I have would be EDM of the internal splines after quench and temper - ensuring that there is not any heat affect above your tempering temperature. Otherwise you should be OK
RE: Further hardening 4140 pre-hardened
What sort of trends can I expect for distortion? Will the part tend to grow or shrink in diameter? By about how much? Is twisting a possibility?
RE: Further hardening 4140 pre-hardened