| 摘要 |
PROBLEM TO BE SOLVED: To impart characteristics of high strength and high twist to a wire to be drawn by specifying the reduction of area of a steel wire by respective dies at the time of continuously drawing the steel wire using plural dies. SOLUTION: A high carbon steel element wire is formed into an extremely thin wire with three dies. At this time, when the dies are expressed with A, B, C from the inlet side of the element wire, the reduction of area at the time of passing through the die A is expressed with Ra, the same at the time of passing through the die B is expressed with Rb, the same at the time of passing through the die C is expressed with Rc and the whole reduction of area by three dies is expressed with Rabc, the conditions of Rb/Ra>=2, Rb/Rc>=2, and further Rabc<=40% are specified to be satisfied. Also, a residual stress (compressive stress) in the region from the surface layer to the depth of radius (r)×0.2 of the drawn extremely thin wire is specified to have <=10μsurface roughness Rmax. Moreover, when the steel wire of JIS-SWRS 82 A, 5.5 mmϕis drawn into 1.8 mmϕand drawn into 0.3 mmϕafter patenting by this method, tensile strength of nearly 3680 MPa and a twist value of 29/100 d are shown.
|
