| 摘要 |
PURPOSE:To produce a titled drawn wire having an excellent twist value and fatigue characteristic by rolling a steel contg. a specific ratio each of C, Si and Mn to a wire then cooling the wire to have specific composite structure and subjecting the wire to light working at a specific reduction of area in the mid-way of cold drawing. CONSTITUTION:The steel contg., by weight %, <=0.4% C, <=2% Si and <=2.5% Mn is rolled to the wire. The wire is then reheated and cooled according to need to have the composite structure uniformly dispersed with the low-temp. transformation forming phase consisting of martensite or bainite which may partly contain residual austenite or the mixed structure composed thereof in a 10-95% volumetric fraction range in the ferrite phase. The low-temp. transformation forming phase is mainly the needle-like structure and has preferably about <=0.005 volumetric fraction of content of C(weight %)/low-temp. transformation forming phase in the steel. The wire is then subjected to light working at <=10% reduction of area in the mid-way or after cold drawing in the stage of subjecting the wire to cold drawing. The high-strength high-ductility drawn wire which the ductility deteriorated by drawing is restored is thus obtd. |
