A steel plate with excellent cold bending performance and yield strength greater than 1100mpa and its preparation method

Abstract

The invention relates to a quenched type ultra-high-strength steel plate with yield strength larger than 1100 MPa. The production technology of the quenched type ultra-high-strength steel plate with the yield strength larger than 1100 MPa comprises the steps of smelting, external refining, vacuum degassing, Ca treatment, continuous casting, dehydrogenation treatment on a casting blank, heating, rolling, cooling, warm straightening, quenching and powerful straightening. According to the quenched type ultra-high-strength steel plate with the yield strength larger than 1100 MPa, the ingredients are economical, the technology is simple, the comprehensive mechanical performance of the steel plate is excellent, the yield strength is over 1100 MPa, the tensile strength is over 1200 MPa, and the Charpy impact energy at the minus 40 DEG C is larger than or equal to 30 J; meanwhile, the performances of the steel plate are uniform, the steel plate is flat, and the waviness of the steel plate is smaller than or equal to 5 mm / m; the cold bending forming performance of the whole steel plate is good, d is equal to 3a, and the result of the 180-degree laboratory GB / T232 cold bending test of the steel plate is qualified; b is larger than or equal to 500 mm, r is equal to 3a, and no crack is generated during 90-degree industrial cold bending forming; and therefore, the machining and use requirements on the ultra-high-strength steel plate of the domestic and overseas large machinery industry are met.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy, and specifically relates to an ultra-high-strength steel plate with an excellent yield strength greater than 1100 MPa and a production method thereof. Background technique [0002] Construction machinery refers to the general term for equipment used in mining and various engineering constructions, such as drilling rigs, electric shovels, electric wheel dump trucks, excavators, loaders, bulldozers, various cranes, and coal mine hydraulic supports. In recent years, with the increasing number of common construction machinery projects such as large-scale and super-large mines, nuclear power plants, and dams around the world, in order to ensure the convenience and speed of construction, construction machinery and equipment have further developed towards large-scale. At the same time, in order to prolong life, reduce self-weight, and reduce energy consumption, the demand for ultra-high-strength...

AI Technical Summary

Problems solved by technology

Ultra-high-strength steel with a yield strength of 1100MPa is currently the highest-strength steel in the field of construction machinery in my country, and its toughness at -40°C is difficult to guarantee

(2) Excellent welding performance is difficult to obtain

In order to ensure ultra-high strength, it is necessary to properly add alloying elements in the composition design, and too much alloying elements will inevitably lead to deterioration of welding performance

(3) It is difficult to control the plate shape

In the process of martensitic transformation, a large amount of internal stress will be generated, resulting in waves on the edge and center of the steel plate, which cannot meet the requirements for use.

(4) It is difficult to guarantee the cold bending performance of steel plate

These technologies mainly focus on the solution of steel plate strength and toughness matching and welding performance, and there is no good way to solve application problems such as steel plate shape control and bending performance.

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