Lightweight and high strength and ductility automotive steel using silicon instead of aluminum and preparation method of the steel

Abstract

The invention relates to lightweight and high strength and ductility automotive steel using silicon instead of aluminum. An alloy comprises, by weight percentage, 0.1-0.4 wt% of C, 3.5-5.5 wt% of Si,4.0-6.0 wt% of Mn, 0.5-1.0 wt% of Ni, 0.01-0.1 wt% of Ti and the balance Fe. The invention further relates to a preparation method of the lightweight and high strength and ductility automotive steel using silicon instead of aluminum. The preparation method includes the alloy component weighing and taking, smelting, casting and hot rolling procedure. The lightweight and high strength and ductilityautomotive steel using silicon instead of aluminum and the preparation method of the steel are provided. The material has excellent mechanical performance, and is low in production cost and simple inprocess, a series of problems caused by lightweight aluminum are compensated very well, and great application prospects are achieved.

Description

technical field [0001] The invention belongs to the technical field of metal material processing, and relates to a nano-structure microstructure, which uses an alloy system in which silicon is substituted for aluminum to prepare the light-weight, high-strength and tough automobile steel. Background technique [0002] Iron and steel materials are widely used in national defense industry, construction, machinery, shipbuilding, automobiles, home appliances and other industries, and are the material basis for social and economic development; under the current situation, the production of iron and steel materials is facing enormous pressure from energy, resources and the environment; With the development of modern industrial technology and the transformation and upgrading of the national economy, the rapid development of high-rise buildings, long-span bridges, light energy-saving vehicles, advanced rail transit equipment, large-scale marine engineering equipment, high-tech ships, ...

AI Technical Summary

Problems solved by technology

[0003] At present, high-strength and tough automotive steel has been developed to the third generation. Typical products such as Q&P steel, medium manganese steel, low-density steel, super bainitic steel, etc.; the future development of automotive steel is oriented towards high strength, toughness and light weight Therefore, there are many studies on the combination of low-density steel and medium-manganese steel, but there are also many problems. The following lists several typical domestic invention patents for discussion, and clarifies the characteristics and advantages of the invention patent; Chinese invention patent CN201810362095. X introduces a high-strength and tough steel for automobiles with a strength-plastic product greater than 45GPa·% and its preparation method. Medium carbon, medium manganese and a certain amount of aluminum are used as the main alloy system to reduce the density. Cold rolling and annealing make the tensile strength exceed 1000MPa, and the strong-plastic product is greater than 45GPa·%, but the medium carbon and higher alloy system used in this invention is not suitable for structural parts that undertake welding and forming, and A higher content of Al will seriously reduce the stiffness of the material, which is also inappropriate for automotive load-carrying parts. Therefore, it is necessary to redesign from the perspective of alloy system design to meet today's and future lightweight high-strength automotive steels; Chinese invention patent CN201810507557 .2 Introduced a 1200MPa high-strength high-plasticity low-density steel plate and its manufacturing method, which uses high-carbon, high-manganese, and high-aluminum alloy systems, with a tensile strength of more than 1200MPa and an elongation of more than 30%, although the patent introduced The performance of the steel grade is very good, but there are also problems reflected in the above CN201810362095.X patent. First, the weldability and formability are worse. Difficult, in addition, the content of this alloy is too high, the cost is significantly increased, and it is not suitable for the development of current and future automotive steel. Chinese invention patent CN201310733931.8 introduces a 1400MPa-level low yield ratio high elongation cold-rolled ultra-high-strength automobile The preparation method of steel adopts a low-carbon and low-alloy system, and a steel plate with a tensile strength greater than 1400MPa and an elongation greater than or equal to 8% can be obtained by a simple preparation process, but its designed microstructure is based on a conventional martensitic lath structure Mainly, the highest tensile strength is about 1500MPa, which cannot meet the requirements of replacing hot-formed steel. In the future, safer anti-collision structural parts need higher strength to support. Therefore, based on the above-mentioned light weight and martensitic strengthening Correlation analysis, embodies the deficiency that current design and research meet the development of steel for automobiles in the future, and this is also what the present invention will overcome

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