Abstract
The shuttle body is the most important and complicate part in the sewing machine.It is made from low C steel, carburized, heated in salt bath, water quenched and grinded. As it is much deformed by heat treatments, the removed amounts by grinding are much and its hardness is not uniform as a result. I have tested the induction hardening and obtained the following results ;
(1) The deformation by induction hardening was smaller than that by salt bath heating and as much as that by salt bath surface heating.
(2) The heating condition of shuttle body by induction heating. Inlet power-80∼90 KW, heating time-1.4∼1.5 sec, cycle 50000∼100000. cooling method-water jet.
(3) The wear resistance of shuttle body which was induction hardened heatnig was as good as that by carburizing salt bath heating and water quenching. But the hardness by induction heating or salt bath surface heating was smaller than that by carburizing, salt bath heating and quenching.
(4) The direction of deformations by induction hardening were unifom, but these by salt bath heating or salt bath surface heating was not unifom.
(5) The C content of steel of the shuttle body for induction hardening which gave the best results in heat treatment and machining was than 0.35∼0.40%.
