Induction hardening is becoming an increasingly popular alternative to thermochemical diffusion processes such as carburizing, and as it does so, manufacturers are on a never-ending quest to expand the scope of
what's possible with the technology.
I would like some instructions for setting the degrees and minutes on a Liebherr
or Barber Colman hob. Our machines use a Vernier scale to match the lead angle
of the cutter to the part to form straight teeth. There is a dispute on how to do
this task, and I wanted insight from another professional.
Contact fatigue and bending fatigue are two main failure modes of steel gears, while surface pitting and spalling are two common contact fatigue failures -- caused by alternating subsurface shear stresses from the contact load between two gear mates. And when a gear is in service under cyclic load, concentrated bending stresses exist at the root fillet -- the main driver of bending fatigue failures. Induction hardening is becoming an increasingly popular response to these problems, due to its process consistency, reduced energy consumption, clean environment and improved product quality -- but not without issues of its own (irregular residual stresses and bending fatigue). Thus a new approach is proposed here that flexibly controls the magnitude of residual stress in the regions of root fillet and tooth flank by pre-heating prior to induction hardening. Using an external spur gear made of AISI 4340 as an example, this new concept/process is demonstrated using finite element modeling and DANTE commercial software.