Preparation method and application of 550 MPa-grade ultra-fine grain high-strength weather-resistant steel

Abstract

The invention relates to a preparation method and application of 550 MPa-grade ultra-fine grain high-strength weather-resistant steel and belongs to the technical field of metallurgy. The preparation method comprises the steps that continuous casting blanks directly enter an M rack rough rolling unit under the high pulling speed and are subjected to M-pass continuous heavy reduction (50-60%) rough rolling, and austenite grains are greatly refined; after rough rolling, middle blanks are rapidly heated through an induction heating furnace to the temperature needed for a finish rolling inlet, and meanwhile a reverse temperature field is formed; and then sequentially through a finish rolling set, laminar flow cooling and a reeling machine, finally the organization characteristics that the surface and the core part are coarse, and the portion of the 1 / 4 thickness position is fine are formed. In the production process, finish rolling and rough rolling are both full-headless rolling. An ultra-fine grain high-strength weather-resistant hot-rolling steel belt with the weather resistance being equivalent to corten-A is obtained, and the effects that the thin effect replaces the thick effect and the hot effect replaces the cold effect are achieved; while the weight of a car body is small, the service life of a car plate is prolonged, the production efficiency is improved, and the production cost is reduced; and meanwhile energy consumption is reduced, emission is reduced, and resource-saving and environment-friendly production is achieved.

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 550MPa 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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