Improvements in or relating to the surface hardening of hollow ferrous metal articles

摘要

567,172. Hardening metal articles. SHORTER PROCESS CO., Ltd., and SHORTER, A. E. Nov. 1, 1943, No. 18015. [Class 72] A method of imparting a hardened structure to one of the cylindrical surfaces of a hollow cylindrical ferrous metal article, the other cylindrical surface of which has thermally susceptible properties which it is desired to preserve comprises the steps of mounting the article with its longitudinal axis vertical, applying the surface hardening operation to the surface to be hardened and simultaneously directing a stream of cooling liquid against the upper end of the surface with thermally susceptible properties so that a continuous film of liquid flows downwards over the latter surface. In hardening an external surface the work W is supported on a jig 111 secured to a turntable 110 mounted on the bed 109 of a tank 108. The turntable is rotated through a worm drive 106. Cooling liquid is supplied through the hollow column 116 to the distributing member D which consists of a chamber 114 and a cap 119 spaced a short distance from the lip of the chamber. The liquid flows down the wall of the article and drains through holes in the jig. The hardening operation is applied progressively from the lower end upwards by an annular burner 121 with which is associated a quenching unit 122.