Everyone know that heat treatment is important to metal machined parts.
We handle a project for automotive parts recently, the part material is 16Mncr5, heat treat requirements on print : tensile strength.800-950Mpa, Surface Hardness 500HV1.
There are at least three ways to meet this heat treatment requirements as below.
1. Hardened parts at 900 C and oil quenched+200C Tempering
2. Carburization
3. Nitridation
Which kind of treat method will you choose for this machined parts ?
Quench+Tempering will get even hardness from surface to core,but the tenacity is not good.the tensile strength will be exceed 950Mpa.
Carburization will be keep core tenacity and harden surface to 500HV1,but the big distortion during carburization process,we should leave balance for machining after heat treatment,and the extra process will increase the cost.
16MnCr5 is a carburize steel,the carbon content is 0.14~0.19%, Nitride this part to 500HV1, with thin hard layer
0.1mm, core hardness 200HV with good tenacity,the tensile strength around 900Mpa. But customer worry about the annealed soft steel core underneath.
Finally,the customer request the steel bar have to be quench and tempered in order for the core hardness.That means do this part from 16MnCr5+QT, and then Nitriding surface,that would be okay.
So it is very very important to understand customer’s requirements clearly when we get the prints from customer.Heat treatment is also important for us–precision machining manufacturer.
