THREAD FORMING METHOD Russian patent published in 2003 - IPC

FIELD: machine engineering, forming thread in parts operating at sign-variable loads in condition of abrasive wear. SUBSTANCE: method comprises steps of finishing and strengthening the whole profile of thread by means of tools moving along helical line; electrically heating part mounted with possibility of rotation. In order to lower time period of working, to enhance wear resistance and fatigue strength, - before finishing and strengthening thread is formed. Part is electrically heated by means of tools shifted one relative to another along thread in proportion to their quantity. Sliding forced contact of tools is provided; surface layer along perimeter of helical surface of thread is subjected to electric contact heating. It is possible to use tools mounted on common foundation, isolated one from another and designed for forming thread in combination with electrical heating process by surface plastic deformation or by combination type process. EFFECT: enhanced wear resistance and fatigue strength of part, shortened time period of thread forming. 2 cl, 2 dwg