Preparation method of hot-rolled acid-washing high-strength steel for automobile carriage

Abstract

The invention relates to a preparation method of hot-rolled acid-washing high-strength steel for an automobile carriage. The hot-rolled acid-washing high-strength steel comprises the following major ingredients in percentage by weight: 0.07 percent to 0.1 percent of C, at most 0.05 percent of Si, 1.5 percent to 1.9 percent of Mn, at most 0.015 percent of P, at most 0.01 percent of S, at most 0.005 percent of N, 0.1 percent to 0.2 percent of Mo, 0.04 percent to 0.06 percent of Nb, 0.15 percent to 0.2 percent of Ti, 0.02 percent to 0.04 percent of Al, 0.001 percent to 0.004 percent of B, 0.002 percent to 0.01 percent of Ca and the balance of Fe and inevitable impurities, Ti / B is greater than or equal to 35, and the carbon equivalent Ceq is smaller than or equal to 0.45 percent. The preparation method has the advantages that the ingredients are simple, the production process is simple, the tempering or hardening and tempering treatment is not needed after hot rolling, the surface qualityis good, the obdurability, the welding performance and the cold forming performance are excellent, and the cost is low.

Description

technical field [0001] The invention belongs to the field of metal materials, in particular to the technical fields of iron and steel smelting and controlled rolling and controlled cooling. Specifically, it is a hot-rolled pickled high-strength steel for automobile body with a tensile strength greater than 1200 MPa and a preparation method thereof. Background technique [0002] Hot-rolled high-strength steel is one of the steel materials with the widest application and the largest consumption in strip products. It is mainly used in containers, excavation machinery, shovel transportation machinery, engineering lifting machinery, mining machinery, forklifts and industrial vehicles, concrete machinery, etc. . With the development of high-parameterization, large-scale and lightweight construction machinery, the requirements for strength, toughness, cold formability and weldability of construction machinery component materials are more prominent, thus promoting the development a...

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Problems solved by technology

[0006] The Chinese patent application with the publication number CN 101899630A discloses a quenched and tempered steel plate for engineering machinery with a yield strength of 900MPa and its production method. The controlled cooling and controlled rolling + quenching and tempering process is adopted to produce a tensile strength of about 1000MPa and a yield strength of 900MPa. Left and right steel plates, but precious metal elements such as Ni and Cr are added to the steel, and quenching and tempering treatment is adopted, the production cycle is long and the production cost is high;

[0007] The Chinese patent application with the publication number CN 102337458A discloses steel for construction machinery with a tensile strength ≥ 1100 MPa and its production method. After the final rolling, the steel plate is heat-treated to produce steel for construction machinery with a tensile After rolling, it needs to be tempered, so the production process and cost are increased. In addition, it contains a high Si content and cannot be used as a hot-rolled pickling plate.

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