Induction hardening of C45 and 42CrMo4

[Gerry45]

Some induction hardening trials have been carried out for me using specimins made in C45 steel. In production however, the material I will use will be 42CrMo4. Unfortunately the C45 tests have produced hardening depths that are just a little under specification.

So, what do you think... will the depth of hardening get a little better or worse when I use 42CrMo4 in production?

Someone has suggested that the CEQ is a way to estimate the performance but Im not so sure. I think other things like thermal and electrical conductivity could play a part in the overall result. Any thoughts gentlemen ?

 

[CoryPad]

The electrical resistivity and relative magnetic permeability are the important parameters for determining how the material responds to induction HEATING. However, you then need to quench the material to obtain a hard case, which is controlled by chemical composition and quenching rate. In general, 42CrMo4 has higher hardenability so it should produce an equal or deeper case compared to C45.

Regards,

Cory

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

 

[Gerry45]

Cory,
Thank you for that guidance. Re the hardenability of the two materials, would this be best compared by CEQ or by say a Jominy test (or other ?!) ?

 

[swall]

Use the Jominy curves if you have them and plan on buying material that conforms. Otherwise, calculate the Ideal Diameter (DI) as described in Appendix A of SAE J406.

 

[dbooker630]

Gerry,
I don't know what your depth of hardening specs are, but you may need to consider pretreatment if you want to use the alloy 42CrMo4 and achieve the same case depth.

Pretreatment as in furnace quench & temper or normalize prior to induction hardening. A pretreated microstructure will respond better to induction hardening. Otherwise you could wind up even worse than C45.

If you wanted to use C45, you may want to use a high side chemistry as far as manganese level. Or perhaps consider an elevated manganese steel like 1541 (This is the SAE designation). May also be less expensive than 42CrMo4.

 

[TVP]

Gerry,

To answer your specific question, use Jominy or Ideal Diameter, not Carbon equivalent.

 

[swall]

Gerry45--what kind of parts will you be hardening? What section size?

 

[Gerry45]

Thanks all for your useful comments.
Gerry