| 摘要 |
PURPOSE: A method is provided to produce high strength hot rolled steel strip having excellent bending performance, fatigue resistance and welding property with 70kg/mm2 of tensile strength. CONSTITUTION: A steel slab is composed of 0.06 to 0.1wt% of carbon, less than 0.3wt% of silicon, 1.4 to 2.0wt% of manganese, less than 0.02wt% of phosphorus, less than 0.05 wt% of sulfur, 0.01 to 0.05wt% of aluminium, 0.05 to 0.15wt% of titanium, 0.02 to 0.04wt% of niobium, less than 50ppm of nitrogen and the remain of Fe and impurities. The slab is hot rolled in a temperature of more than 840°C. Then, the slab is wound in a temperature of 580 to 620°C on a runout table to be a high strength hot rolled steel strip. The steel strip has 70kg/mm2 of tensile strength, excellent bending performance and fatigue resistance.
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