Patent ID: 6048416
Filing Date: 2000-04-11
Classification: C21D,C22C,Y10T

Abstract:
A process for forming a drawn wire, comprising drawing a wire of steel, said steel comprising iron and the following components in percent by weight:0.005%.ltoreq.carbon.ltoreq.0.050%0.005%.ltoreq.nitrogen.ltoreq.0.050%,0.1%.ltoreq.silicon.ltoreq.2.0%,0.1%.ltoreq.manganese.ltoreq.5%,5%.ltoreq.nickel.ltoreq.12%,10%.ltoreq.chromium.ltoreq.20%,0.01%.ltoreq.copper.ltoreq.4%,0.01%.ltoreq.molybdenum.ltoreq.3%0.0001%.ltoreq.sulfur.ltoreq.0.030%,0.005%.ltoreq.phosphorus.ltoreq.0.10%,and impurities inherent to manufacture having a content of less than 0.5% for each individual impurity element and a content of less than 1% in total, the steel composition satisfying the following relationship:JM=551-462.times.(C %+N %)-9.2.times.Si %-20.times.Mn %-13.7.times.Cr %-29.times.(Ni %+Cu %)-18.5.times.Mo %, with-55.ltoreq.JM.ltoreq.-30,the wire being subjected to:pre-drawing to a cumulative deformation ratio .epsilon. of larger than 2 and smaller than 4, to obtain a wire of diameter of between 2 mm and 0.7 mm,an intermediate annealing treatment at above 700.degree. C., permitting reconstitution of a mainly austenitic, soft-annealed structure,optional conditioning before final reduction,final drawing to a cumulative deformation ratio .epsilon. of smaller than 4.5 and larger than 3, to obtain a drawn wire of diameter of between 0.1 mm and 0.4 mm.the wire being maintained at a temperature below 600.degree. C. between pre-drawing and final drawing operations, without annealing between the drawing operations.