To attain softening by means of in-line heat treatment on the continuous rolling line and obviate the heat treatment over a long time by off-line at the time of manufacture of a martensitic stainless steel wire rod, to provide a method of manufacture of a steel wire formed by applying cold drawing to the above wire rod, so that making them sufficiently exhibit the characteristics of an inexpensive component system.
At the time of hot-rolling a wire rod having a composition containing, by weight, 0.06-0.40% C and 10-16% Cr, intensive working at ≥65% reduction of area is performed at 750-950°C within 10 sec and after that, forced cooling is carried out and then, without cooling down to ≤600°C, isothermal transformation treatment is performed by in-line operation. It is preferable to carry out isothermal transformation treatment under the condition of holding at 700-800°C for 10-40 min and further to carry out forced cooling under the condition of cooling at ≥10°C/sec cooling rate within 5 sec after intensive working. Moreover, the steel wire is obtained by subjecting the wire rod to cold drawing at 10-90% reduction of area and then to annealing at 700-900°C.
MIZUTA YOSHIO
NAKAMURA YOSHITAKA
MORI YUJI
FUKAYA MASUHIRO
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