Preparation method of high-reaming property high-tensile steel

Abstract

The invention discloses a preparation method of high-reaming property high-tensile steel, and belongs to the technical field of rolling heat treatment. The preparation method comprises the following steps of using low-alloy high-tensile steel cold-rolled plates as annealing slabs for preparing the high-reaming property high-tensile steel, wherein each cold-rolled plate contains the components in percentage by weight of : 0.05-0.2% of C, 0.10-0.25% of Si, 1.0-1.7% of Mn, P which is lower than or equal to 0.015%, S which is lower than or equal to 0.01%, 0.015-0.05% of AlS, Ca which is lower thanor equal to 0.005%, and the balance being Fe and inevitable impurities; and the thickness of the cold-rolled plates is 0.7-2mm; then according to a model, determining annealing temperature of the cold-rolled plates, and determining an annealing technology in a stepped manner according to the annealing temperature; and according to a heat preservation time model, determining the heat preservationtime, determining heating rate and heat preservation time of the cold-rolled plates in different phases in a heating furnace, perform heating for three times, performing heat preservation for 2-3h, then performing furnace cooling to room temperature at the rate of 0.01 DEG C-0.03 DEG C / s, and completing the annealing course, so as to prepare and obtain the high-reaming property high-tensile steel. Through the adoption of the preparation method disclosed by the invention, high-tensile steels which are high in strength, high in forming property and low in production cost can be prepared.

Description

Technical field: [0001] The invention belongs to the technical field of rolling heat treatment, and in particular relates to a preparation method of high-strength steel with high hole-expanding performance. Background technique: [0002] As the lightweight development of automobiles has become the mainstream of current automobile development, high-strength steel has a wide range of applications in the automobile industry. For body structural parts, it occupies a large part of the steel used in automobiles. Therefore, the forming characteristics and reaming shape design of automobile structural parts can improve the strength and rigidity of steel structural materials, and at the same time, it is convenient for stamping and forming, and is easy to process and produce. [0003] The hole expansion performance of the metal plate is related to many factors such as chemical composition, production process and organizational uniformity. The hole expansion rate of traditional carbon-...

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Problems solved by technology

[0003] The hole expansion performance of the metal plate is related to many factors such as chemical composition, production process and organizational uniformity. The hole expansion rate of traditional carbon-manganese steel and low-alloy high-strength steel 440MPa can reach 50%-70%, but with the shape of the car The design is constantly improving, and the forming of automotive structural parts is becoming more and more complex, so higher requirements are required for the strength and formability of steel plates. At present, in terms of heat treatment, for carbon structural steels on the market, general annealing systems can be used. Good mechanical properties and forming properties, but for some users of high-grade products, the general annealing system cannot meet their higher deep drawing properties, and the comprehensive properties cannot reach the ideal level

[0004] Japanese patent JP2006063394 discloses a preparation method of hot-rolled reaming steel, which is annealed at 640°C after rolling, so that its strength can reach 70% on the basis of greater than 440MPa, and the carbon content is 0.2-0.48%. Due to the carbon content compared with low-carbon steel of the same strength level, its welding performance is poor, and although the hole expansion rate reaches the traditional level, it cannot meet the needs of users who require greater formability

[0005] The high hole expansion rate steel disclosed in Chinese patent CN101353757 adopts low-carbon design, and its mechanical properties and hole expansion performance are all at a good level, but Nb and Ti alloys are added in the composition design, which increases the cost in the production process

At the same time, during the coiling process of the hot-rolled sheet, for carbon-manganese steel, a banded structure will appear in the structure, which will reduce the hole expansion rate.

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