Shlesinger, Arkwright & Garvey LLP
Method for manufacturing steel parts by continuous copper-brazing and quench hardening
There is provided a method for manufacturing steel parts for an automotive automatic transmission in which a desired joint portion of each steel part is copper-brazed at a high temperature while chromium in an alloy steel for machine structural use forming the steel part for an automotive automatic transmission is kept in a reducing atmosphere and without removal of carbon, and the part is successively reheated continuously with the copper brazing by utilizing residual heat at the time of copper brazing, by which the temperature of the part is increased to perform quench hardening. In the above-described manufacturing method, the heating treatment for copper brazing of the part and the heating treatment for quenching thereof are connected to each other via an intermediate cooling treatment in which the temperature of the part is decreased to a temperature below the Ar1 point, and these heating treatments are performed in an atmosphere of a neutral gas such as nitrogen gas supplied into a graphite muffle. At this time, the gas atmosphere is reducing and carburizing, and the temperature increase for copper brazing and quench hardening of the part is accomplished continuously and freely without oxidation of chromium or removal of chromium and carbon.
NSK-Warner K.K. Kanto Yakin Kabushiki Kaisha
C C
C21D C21D
inventional inventional
Hiroaki Hideharu Katsutoshi
Yamashita Tsukamoto Yoshizawa