Preparation method and application of 700 MPa grade ultra-fine grain high-strength weathering steel

Abstract

The invention relates to a preparation method and application of 700 MPa grade ultra-fine grain high-strength weathering steel. The preparation method includes the steps that a continuous casting blank directly enters an M rack rough rolling unit at a high pulling speed and is subject to M-gate continuous high reduction (50%-60%) rough rolling, austenite grains are greatly refined, after rough rolling is carried out, an intermediate billet is quickly heated by an induction heating furnace to the temperature needed by a finish rolling inlet, and meanwhile a reverse temperature field is formed; and then the blank sequentially passes through a finish rolling unit, a laminar cooling part and a reeling machine, and the microstructure characteristics that the surfaces and core parts are thick and 1 / 4 thickness parts are thin are finally formed. In the production process, finish rolling and rough rolling are both full-endless rolling. By means of the preparation method, an ultra-fine grain high-strength weathering steel strip with the weather fastness equal to that of corten-A can be obtained, the effects of replacing thick parts with thin parts and replacing cold with heat are achieved, and the automotive body weight is small; and meanwhile, the service life of an automotive sheet is prolonged, the production efficiency is improved, the production cost is reduced, energy consumption is reduced, emission is reduced, and resource-saving and environment-friendly production is achieved. The preparation method and application belong to the technical field of metallurgy.

Description

technical field [0001] The invention belongs to the technical field of metallurgy. In particular, it relates to a preparation method and application of a 700MPa ultra-fine-grained high-strength weathering steel. Background technique [0002] Weathering steel is a low-alloy steel made by adding a certain amount of alloy elements to ordinary steel. The main alloy components are Cu, P, Cr, Ni and other elements. It has the characteristics of toughness, plastic extension, forming, welding and cutting, abrasion, high temperature, and fatigue resistance of high-quality steel; its weather resistance is 2 to 8 times that of ordinary carbon steel, and its paintability is 1.5 to 10 times that of ordinary carbon steel. At the same time, it has the characteristics of rust resistance, corrosion resistance and life extension of components, thinning and consumption reduction, labor saving and energy saving. Compared with other lightweight materials such as aluminum alloys and plastics, a...

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Problems solved by technology

[0005] The traditional rolling process has the disadvantages of increased production line length, complex equipment composition, high operation and maintenance costs, and high energy consumption.

And because the production line is too long (above 400m), the temperature at the entrance of fine rolling cannot be accurately controlled, resulting in unstable final product performance

In addition, the surface quality and product specifications of the hot-rolled sheets produced by traditional single-slab rolling or semi-endless rolling cannot meet the requirements of downstream users, and hot-rolled sheets after pickling generally need to undergo subsequent cold-rolling and annealing processes before they can be supplied. , so that the production process is complicated, the production efficiency is reduced, and the production cost is increased.

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