04312685 is referenced by 180 patents and cites 2 patents.

A cam of a camshaft has its surface hardened by rotating the camshaft about its axis while maintaining a TIG torch at a fixed spacing from the surface, and while relatively axially reciprocating the torch and the camshaft so the torch heats the surface along an undulating path. The pitch or crest-to-crest spacing of this path is maintained constant for uniform hardening either by varying the angular rotation rate of the camshaft or by varying the axial reciprocation frequency between the camshaft and torch. The radial spacing of the portion of the surface being heated at a given instant from the axis is measured to control the rotation or reciprocation rate.

Title
Surface hardening of cams of motor-vehicle camshafts
Application Number
6/74300
Publication Number
4312685
Application Date
September 11, 1979
Publication Date
January 26, 1982
Inventor
Volker Riedl
Ingolstadt
DE
Agent
Karl F Ross
Assignee
Audi Nsu Auto Union Aktiengesellschaft
DE
IPC
C21D 9/30
View Original Source