Ultrahigh-strength strapping steel is used for packing paper,tobacco and compressed cotton and wool. At present,there is only one company that can produce it through lead quenching. In this paper,the feasibility to produce a kind of ultrahigh-strength strapping steel with tensional strength of1 350 MPa and elongation of 12% by environmentally friendly continuous annealing process is investigated. The experiment results of steelmaking,hot rolling,pickling,cold rolling and continuous heat treatment show that the steel with the above-mentioned properties can be obtained by using the newly-designed chemical composition scheme. The microstructures and X-ray diffraction spectrum of the steel show that the steel is strengthened and toughened by martensite and residual austenitic. The effect of continuous heat treatment on microstructure and mechanical properties is also discussed.
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