Twin induced plastic steel with high elongation percentage and high hole expansion rate and manufacture method thereof

Abstract

The invention provided twin induced plastic steel with a high elongation percentage and a high hole expansion rate and a manufacture method thereof, the steel consists of 0.30 to 0.70 % of carbon, less than or equal to 1.0 % of silicon, 10 to 20% of manganese, less than or equal to 1.0 % of aluminum, 0.005 to 0.20% of polonium, 0.005 to 0.30% of Ra, 0.004 to 0.05% of nitrogen, less than or equal to 0.2% of niobium, less than or equal to 0.3 % of vanadium, less than or equal to 1 of copper and the balance of Fe. The method comprises the following steps of: (1) smelting: smelting by a vacuum furnace, allowing the molten steel to stand for 3-5 min, casting at a casting temperature of 1450-1550 DEG C; (2) hot rolling: heating the casting blank at a temperature of 1150 to 1200 DEG C, with a heating rate of 10-15 DEG C/min, performing heat preservation for 20 to 40 minutes, rolling at an initial rolling temperature of 1150-850 DEG C, stopping rolling at a finishing rolling temperature of 900-600 DEG C, rapidly cooling to room temperature at a rate of more than or equal to 20 DEG C /second after rolling; (3) cold rolling: performing cold rolling with a reduction ratio of the hot rolled plate being 40%-80% ; (4) heat treatment: performing heat treatment at a temperature of 600 to 1000 DEG C, rapidly cooling to room temperature at a rate of more than or equal to 20 DEG C /second after heat preservation for 3 to 10 minutes. The steel of the invention has low cost, a simple method, good quality of the product surface, an excellent processing property and an integrated mechanical property.

Description

technical field [0001] The invention belongs to the technical field of metal materials, and in particular relates to a twinning induced plastic steel produced by hot rolling, cold rolling and heat treatment. Background technique [0002] The development of the modern automobile industry in the direction of energy saving, consumption reduction, environmental protection and safety has made the development of high-strength and ultra-high-strength steels and the realization of automobile lightweight become the focus of research and development. Ultra-high-strength steel plates for car body frame members, reinforcement members, and crashworthy energy-absorbing members play an important role in reducing the weight of the car body. However, the increase in strength often leads to the deterioration of formability, so the plasticity and formability of automotive steel are also put forward higher requirements. In the development of high-strength and high-ductility steels for automobi...

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