| 摘要 |
In a high strength steel with tensile strength of at most 80 kg/mm2 from treating steel slab by hot rolling, quenching, and tempering, the method is characterized by, its compositions of at most 0.04 wt.% Al, 0.005-0.3 wt.% Ti, 0.0005-0.003 wt.% B, at most 0.06 wt.% N and balance Fe, heating it to temperatures of 950-1050 deg.C and 1st quenching it, heating it again to temperatures of 850-930 deg.C and 2nd quenching it, and finally tempering it in conventional method. In this method, manufacuring cost can be lowered by addition of boron to low alloy steel and quenching property also promoted.
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