Right now we're getting surface hardness of 52-56 Rc with no post-tempering and a case depth of .025"-.050" however we are not induction hardening the output splines or helical spline. The hardened zone washes out roughly where the cracks are forming- on the inboard side of the splines at each...
We curently use a 4140 HT at 28-32 Rc, finish machine and cut the gears, then induction harden. In the application there are two failure modes. The first is helical sliding spline wear. We run a mating helical spline "sleeve" made from 80-55-06 ductile that fully encircles the shaft spline...
I have a fluid power transmission shaft made from 4140. The shaft has a 3.75" diameter center section with helical spline and steps down on each end to roughly 2" diameter with bearing supports and straight spline outputs on either end. We currently induction harden only the sealing and...
