PURPOSE: To extend an appropriate load-dealing capacity distribution over a whole cross section of a shaft by specifying a surface resilience hardness, a hardness down to a specified penetration depth, a hardening gradient/structure from a surface layer to a shaft core part and a structure ratio and carbon content of the remaining cross section of the material of a drive shaft.
CONSTITUTION: In the drive shaft for a drive linking mechanism for an automobile made of a high-frequency hardening material, an outside hardened layer of the material has ≥90% of a resilience hardness attainable for the material. A perpetration depth of ≥60% of the material thickness is hardened to ≥90% of a surface hardness attainable, and inside high temp. malleable material region from the surface layer to the shaft core is constituted of a martensitic structure having a hardening gradient of ≤50HV/mm and increasing the ratio of a troosite or bainite. Further, the remaining cross section part of the material is improved for an intermediate stage structuring ratio over the shaft core part, and carbon content of the material is about 0.2-0.5%.
Greulich, Dr. Klaus
JEAN WALTERSCHEID GMBH