| 摘要 |
A high performance weathering steel having a minimum yield strength of 70-75 ksi and a yield/tensile ratio less than about 0.85 is produced from a steel composition consisting essentially, in weight percent, of about: carbon 0.08-0.12%; manganese 0.80-1.35%; silicon 0.30-0.65%; molybdenum 0.08-0.35%; vanadium 0.06-0.14%; copper 0.20-0.40%; nickel 0.50% max.; chromium 0.30-0.70%; phosphorous 0.010-0.020%; columbium up to about 0.04%, titanium up to 0.02%, sulfur up to 0.01%, iron, balance except for incidental impurities; heating the steel to a hot rolling temperature, rolling the steel to a thickness about 2 to 3 times the final desired thickness, air-cooling the steel to a temperature of about 1800-1850 DEG F. (RCR) or about 1600-1650 DEG F. (CCR), recrystallize control rolling or conventionally control rolling the steel with finish rolling at a temperature of about 1700-1750 DEG F. (RCR) or about 1400-1500 DEG F. (CCR), then water-cooling the steel to about 900-1200 DEG F., especially about 1100 DEG F., then air-cooling the steel to ambient temperature, to produce sections up to at least 2 inches thick and a length of 90 feet or more, without further heat treatment.
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