A high-strength and high-plastic annealed steel strip for pipe making and its production method

Abstract

The invention discloses a high-strength and high-plasticity annealed steel strip for making pipes and a production method thereof. The chemical composition and mass percentage of the steel strip are: C: 0.06-0.08%, Si≤0.03%, Mn: 0.35 ~0.50%, P≤0.015%, S≤0.005%, Als: 0.020~0.050%, N≤0.0045%, O≤0.0025%, the balance is Fe and unavoidable impurities; the production method includes steelmaking, continuous Casting, heating, hot rolling, cold rolling, annealing and tempering processes. The invention adopts low-carbon and low-manganese composition design, and through reasonable process control, the tensile strength of the obtained steel strip is 370-400MPa, the yield strength is ≥260MPa, and the elongation is A 80mm ≥28.0%, hardness HRB: 60~68, excellent mechanical properties.

Description

Technical field [0001] The present invention belongs to the technical field of metallurgy, in particular to a tube made of high strength and high plasticity and annealing the steel strip production process. Background technique [0002] Parts of the bicycle handlebar, frame, automobile and other applications headrest stay annealed strip pipe manufacturing, the manufacturing process subject to bending, the step up type or the like, thus requiring the steel having a good formability. Since the front forming, the need for polishing the surface of the pipe, if the presence of subcutaneous steel inclusions, warping, ARB and other issues, the surface quality of the product will cause serious adverse effects, leading to the finished product rate decline. Taking into account the specific application of the above product lifecycle, the applied steel material should have a certain strength and hardness. The steel grades used in the conventional method mostly SPCC, Q195, etc., a yield stren...

AI Technical Summary

Problems solved by technology

However, the grades of steel used in the existing methods are mostly SPCC, Q195, etc., the yield strength is lower than 260MPa, the tensile strength is lower than 350MPa, and the elongation is lower than 28%. After the material is processed into a steel pipe, it is prone to problems such as insufficient strength and forming fracture.

At the same time, the conventional production process is adopted in the steel production process, without RH refining treatment, the internal cleanliness of the steel is poor, there are many non-metallic inclusions, and the surface is prone to defects such as warped skin and slag inclusions. , When polishing, a large number of waste times are often caused by surface problems, resulting in a great cost loss

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