Method for producing wear-resisting steel plate

Abstract

The invention relates to a method for producing a wear-resisting steel plate. Steel comprises the following chemical ingredients in percentage by mass: 0.15 to 0.20 percent of C, 0.4 to 0.7 percent of Si, 0.7 to 1.50 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, 0.020 to 0.10 percent of Ti, 0.0005 to 0.0020 percent of B, 0.010 to 0.020 percent of Nb and the balance of Fe and inevitable impurities. A production process for the steel comprises the following steps of: desulfurizing by molten iron, smelting by a converter, refining, casting continuously, rolling and performing quenching-carbon partition (Q-P) treatment. In the ingredients of the wear-resisting steel, a C-Si-Mn-Nb-Ti ingredient system and the Nb and Ti micro alloy treatment are adopted, the hardenability of the steel is improved by adding B, an appropriate heat treatment process is adopted to ensure that the steel plate has high plasticity and toughness, and the impact energy of the steel plate is improved by over one time; and the heat treatment is performed by a Q-P process, lath martensite and lath retained austenite (between 5 and 10 percent) are formed and 50 to100 nanometers of carbide complex tissue is precipitated, so that the tissue is fine and uniform, and the tenacity of the steel plate is high.

Description

Technical field [0001] The invention belongs to iron and steel smelting technology, in particular to a production method of a wear-resistant steel plate. Background technique [0002] As an important class of steel materials, high-strength wear-resistant steel plates are widely used in mining machinery, vehicles, ships, bridges and other industries. With the rapid development of the economy, the demand for high-strength wear-resistant plates is growing rapidly. [0003] The existing wear-resistant steel process routes are generally divided into three types: hot rolling + quenching + tempering; controlled rolling + controlled cooling after rolling + tempering or controlled rolling + normalizing + tempering; controlled rolling + water curtain controlled cooling + tempering . The defects of the prior art are: the structure of the wear-resistant steel plate is tempered martensite or bainite, the structure is coarse, and the properties of the steel plate are uneven; Fire resis...

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Problems solved by technology

The defects of the prior art are: the structure of the wear-resistant steel plate is tempered martensite or bainite, the structure is coarse, and the properties of the steel plate are uneven; Fire resistance, improve the hardenability of the steel plate to meet the high strength and high hardness performance of the steel plate, but the production cost is high; after flame cutting, a soft spot is generated at the cutting place to form a crack source, and the crack expands under the action of external force, causing the steel plate to crack. Quality objections are often formed; plasticity and toughness are poor, and it is not easy to be cold-formed; after adding a large amount of alloy elements, the welding performance of the steel plate is poor; the alloy content is high, and the continuous casting billet is prone to surface cracks, and the continuous casting billet needs to be stacked and cooled slowly after it comes off the production line , it must be cleaned with temperature, increasing the difficulty of production, and the cleaning operation environment is poor

The disadvantage of this invention is that it inherits the characteristics of traditional wear-resistant steel, low tempering temperature and the addition of Cr alloy elements, high hardness of steel and poor plasticity and toughness; (quenching + tempering) after adding Cr to the steel plate , Cr not only improves the strength and hardness of the steel plate, but also reduces the impact toughness of the material; the plasticity and toughness of the steel plate are also low after accelerated cooling after hot rolling, which is also an indisputable fact found in the current rolling process research; When the fire temperature is 430°C, ε carbides will be precipitated in the martensite. In order to hinder the precipitation of carbides, there must be enough Si. The Si in the steel is low, and the plasticity and toughness of the steel after tempering are poor; the tempering temperature of wear-resistant steel is Cr at 430°C 23 C 6 and Cr 7 C 3 The transformation to M2C has not been completed, and the performance of the steel plate is not uniform, resulting in a large number of steel plates with inconsistent properties; after Cr is added to the steel, the continuous casting slab is prone to cracks, and the slab needs to be cleaned with temperature, and the cleaning operation conditions are poor; the surface quality of the casting slab Unstable, unable to realize direct loading and heating of hot billets, which is not conducive to energy saving and emission reduction

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