surface hardness 1

[thejackal3]

Dear all
We are facing a different problem in induction of rock shafts of tractor.we have inductotherm medium frequency induction hardening machine. we required 2.5 mm to 3 mm case depth at 45 hrc in there and surface hardness is 50 hrc after tempering.we are getting proper depth when u cut the section and check but surface hardness is varying alot when we check on splines.our polymer ratio is 5% to water..please advise.
regards.

 

[swall]

What is your method for determining surface hardness?

 

[TVP]

Are you evaluating the surface of the steel shaft before hardening? Is there decarburization present?

 

[FennLane]

Some idea of the shaft material would help along with the basic diameter of the shaft you are hardening.

 

[tbuelna]

What is the size and form of your spline teeth? A spline tooth requiring a 2.5-3mm case depth would likely be extremely large.

Also, I agree with TVP that surface decarb might be an issue.