As for super high intensity cold forging construction method of the fit part which designates the super high intensity cold

摘要

PROBLEM TO BE SOLVED: To provide a method for cold-forging a fitting part having ultra-high strength used as a material of an austenite-300 series.;SOLUTION: The method for cold-forging the fitting part having ultra-high strength used as the material of the austenite-300 series, is contained with in order, a raw material preparing step, a head-part forming step, a bottom part forming step and a screw thread forming step. In this raw material preparing step, non-working material of the austenite-300 series is prepared and to the non-working material, firstly, the cold-forging is applied and outer diameter of this non-working material is shrunk by ≥15% to form a bar body, and this bar body outer diameter after forming is the same size as the outer diameter needed at the time of working, and then, the strength of this bar body is increased at least at ≥1/2 of the value in the original non-working material. This bar body is further forged through the head part forming step, the bottom part forming step and the screw thread forming step, but as for the forming step, the cold-forging method is used in all. The fitting part has the high strength and high corrosion-resistant characteristic and can be formed at the low cost and the screwing in a material is achieved and the safety of using after screwing is provided.;COPYRIGHT: (C)2009,JPO&INPIT