SAE 4140 thermal treatment
SAE 4140 thermal treatment
(OP)
Hi
I need to trea SAE 4140 thermally by induction and need to know what thermal procedure to use (forging, tempering, normalizing, hardening, etc) to reach three different properties:
1) HB 426 , tensile strengh 1531 MPa
2) HB 283 , tensile 931 MPa
3) HB 216 , tensile 689 MPa
thancks
I need to trea SAE 4140 thermally by induction and need to know what thermal procedure to use (forging, tempering, normalizing, hardening, etc) to reach three different properties:
1) HB 426 , tensile strengh 1531 MPa
2) HB 283 , tensile 931 MPa
3) HB 216 , tensile 689 MPa
thancks





RE: SAE 4140 thermal treatment
1.) You won´t reach 1531 N/mm^2 at any condition
2.) yield point or break point - what You are looking for
3.) mechanical property is also a function of diameter or dimension - what dimensions do You want to use
4.) Have a look to DIN 17200
If 1470 N/mm^2 are needed take 18CrNi8 (1.5920 - maximum number is 1470 N/mm^2 for diameter lower than 11 mm) instead of 42CrMo4 using a case hardening process.
Andreas
RE: SAE 4140 thermal treatment
Can you clarify what you intend to do with the induction heating procedure? Do you want to the 4140 steel to have the tensile strength/hardness values you listed BEFORE or AFTER the induction heating procedure? If it is BEFORE, then you can obtain 4140 steel bar at the various hardness levels from a steel bar vendor. The lowest hardness can be obtained by using a hot-rolled bar which is subsequently cold-drawn. Normalizing will produce a hardness of ~ 300 HB, annealing will produce a hardness of ~ 200 HB.
In order to attain HB 283 or 426, you will need to obtain the steel bar in the Quenched & Tempered condition. The tempering temperature is varied to produce the 2 different strength levels.
Andreas,
4140 or 42CrMo4 CAN be produced with a strength level of > 1500 N/mm2, but it must be Quenched & Tempered, not just hot-rolled/cold-drawn or normalized. Also, DIN 17200 has been superceded by DIN EN 10083.