Preparation method of martensite matrix 1,100-MPa-grade rare earth Q and P steel

Abstract

The invention relates to a preparation method of martensite matrix 1,100-MPa-grade rare earth Q and P steel. The steel is prepared from 0.15-0.22% of C, 0.60-1.70% of Si, 1.10-2.40% of Mn, 0.1-0.5% ofMo, 0.1-0.5% of Al, 0.05-0.11% of V, 0.01-0.05% of Y, 0.02-0.04% of P, 0.005% or below of S, 0.040-0.0700% of Nb, 0.0060% or below of N, 0.001-0.006% of B and the balance Fe and unavoidable impurities. After batching, the raw materials are smelt by a converter and refined and continuously cast by a vacuum furnace to obtain a cast blank, then trace alloy powder is added into an arc-melting furnace, a secondary cast blank is obtained, and heating and hot rolling are conducted in sequence; cold rolling is conducted after acid pickling; then the blank is heated to a two-phase region for heat preservation; carbon partitioning and tempering are conducted to obtain the final steel. According to the preparation method, through the addition of an appropriate quantity of various beneficial alloy elements, the contents of C, Si, Mn and other elements in traditional steel species are reduced, the weldability and corrosion resistance are improved, crystal grains are refined, produced steel plateshave good comprehensive mechanical properties, and lightweight, energy conservation and emission reduction of vehicles are facilitated.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy and manufacturing, in particular to a method for preparing 1100MPa grade rare earth Q&P steel with a martensitic matrix. Background technique [0002] According to data from the Ministry of Public Security, as of the end of 2017, the number of motor vehicles in the country reached 310 million. In 2017, 33.52 million motor vehicles were newly registered with the public security traffic management department, a record high. The number of automobiles reached 217 million, an increase of 23.04 million or 11.85% compared with 2016. The ratio of automobiles to motor vehicles has continued to increase, from 54.93% to 70.17% in the past five years, and has become the main body of motor vehicles. At the same time, relevant tests have shown that for every 10% reduction in the mass of a car, fuel consumption can be reduced by 6% to 8%, and emissions can be reduced by 4%. [0003] At present, althou...

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Problems solved by technology

[0004] The current Q&P steel production process has the following problems: (1) Most of the existing steel types are fully annealed and then quenched-partitioned, that is, the material will be fully austenitized twice, which will cause a huge amount of energy on the one hand. On the other hand, a lot of time will be wasted in the complete annealing process; (2) In order to reduce the cost, only by adjusting the content of C element, and using Mn and Si elements for simple structure adjustment

However, excessive C element content will seriously affect the welding performance while increasing brittleness; (3) Some high-strength steels only focus on strength or plasticity, and the strength-plastic product is low, which cannot meet the needs of modern automobiles; (4) Heat treatment process Complicated, high production technology requirements, industrialization requires the purchase of expensive new instruments, equipment management and maintenance costs are relatively high

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