| 摘要 |
PURPOSE: To produce a high-carbon low alloy steel wire rod excellent in wire drawability by hot-rolling a steel having a specific composition consisting of C, Si, Mn, Cr, and Fe and then applying specific cooling treatment to the resultant wire rod to reduce the formation of pro-eutectoid cementite. CONSTITUTION: A steel, having a composition consisting of, by weight, 0.80-1.20% C, 0.10-1.00% Si, 0.20-1.20% Mn, 0.80-1.80% Cr, and the balance Fe with inevitable impurities, is hot-rolled. The resultant steel wire rod is cooled rapidly down to 550-700 deg.C at (8 to 20) deg.C/sec cooling rate and then cooled through the temp. region to 400 deg.C at (0.5 to 2) deg.C/sec average cooling rate. By this cooling treatment, the area ratio and size of pro-eutectoid cementite are regulated to <=3% and <=3μm, respectively, and also the formation of martensite is prevented. By this method, the wire rod, having extremely superior wire drawability in the as-hot-rolled state, can be obtained.
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