Production method of wear-resistant steel plate

Abstract

The invention discloses a production method of a wear-resistant steel plate, and belongs to the field of steel smelting. The steel plate comprises the following chemical components of, in percentage by mass, 0.19%-0.25% of C, 0.9%-1.2% of Si, 0.7%-1.50% of Mn, less than or equal to 0.020% of P, less than or equal to 0.005% of S, 0.070%-0.20% of Ti, 0.0008%-0.0025% of B, 0.15%-0.50% of Ni, and thebalance Fe and inevitable impurities; and the process route comprises the steps of molten iron desulfurization, converter smelting, refining, vacuum treatment, continuous casting, rolling, quenching and tempering. According to the production method of the wear-resistant steel plate, the percentage content of Si is improved by reducing the alloy content in the components of the wear-resistant steel, a small amount of Ni element is added, and a proper oxide smelting process, a proper rolling process, different tempering processes and a flexible production technology are selected, so that different grades of 6-30mm wear-resistant steel with low production cost, good low-temperature impact toughness, high welding efficiency and good plasticity and toughness can be produced.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a production method of a wear-resistant steel plate. Background technique [0002] 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 defects of the wear-resistant steel produced by the existing technology are: after the thin-gauge wear-resistant steel with Cr and Mo composition system is rolled, the bainite phase transformation occurs in the cooling bed and it flutters, which affects the wear-resistant steel plate below 10mm. The key point of production; after the wear-resistant steel plate is flame-cut, a soft spot is formed at the cutting point to form a crack source, and the crack expands under the action of internal stress, causing the steel plate to crack; the tempering of...

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Problems solved by technology

[0003] The defects of the wear-resistant steel produced by the existing technology are: after the thin-gauge wear-resistant steel with Cr and Mo composition system is rolled, the bainite phase transformation occurs in the cooling bed and it flutters, which affects the wear-resistant steel plate below 10mm. The key point of production; after the wear-resistant steel plate is flame-cut, a soft spot is formed at the cutting point to form a crack source, and the crack expands under the action of internal stress, causing the steel plate to crack; the tempering of the wear-resistant steel plate is not sufficient, and the internal stress after long-term storage The steel plate cracks naturally under the action of the wear-resistant steel plate; the weldability of the wear-resistant steel plate is poor; the low-temperature toughness of the wear-resistant steel plate is poor; produce surface cracks

[0004] Chinese patent application number 201110358240.5 "a production method of wear-resistant steel plate" patent technology: wear-resistant steel composition design adopts C-Si-Mn-Nb-Ti composition system, get rid of the addition of Cr and Mo in traditional wear-resistant steel Although the design reduces the production cost, the weldability and low-temperature toughness of the steel plate are poor; the heat treatment adopts the Q-P (quenching-carbon distribution) process, which requires a serial arrangement of the quenching furnace, quenching machine, and tempering furnace. Equipment layout cannot realize its Q-P (Quenching-Carbon Partitioning) process

[0005] Chinese patent application number 202010029293.1 "A method for heat treatment of wear-resistant steel plates above NM500" patent technology: this method adds an offline insulation box to the existing roller hearth heat treatment furnace, and two steel plates with the same thickness Stack into a furnace loading unit. After the tempered steel plates are released from the furnace, put them into an off-line insulation box for stacking and slow cooling. The steel plates enter the insulation box at a temperature above 180°C, slowly cool for more than 48 hours, and leave the insulation box at a steel plate temperature below 80°C. After the slow cooling is completed, the steel plates Lift out the insulation box to complete the tempering process; although this method reduces the internal stress of the wear-resistant steel plate and the cracking tendency of the wear-resistant steel plate, the heat treatment operation is complicated

[0006] Chinese patent application number is 202010029292.7 "A method of improving heat treatment output and quality of large-thickness wear-resistant steel plate" patent technology: this method adds an offline insulation box on the basis of the existing roller hearth heat treatment furnace, and tempers the steel plate After being released from the furnace, put them into an off-line incubator and stack them for slow cooling. The steel plate enters the incubator at a temperature above 200°C, slowly cools for more than 48 hours, and leaves the incubator at a temperature below 80°C. After the slow cooling is completed, the steel plate is lifted out of the incubator to complete the tempering process; This method only solves the problem of eliminating internal stress, and at the same time, the operation is complicated, and it is difficult for general workshops to have a place to implement it.

The disadvantage of this invention is that it inherits the characteristics of the traditional wear-resistant steel, the low tempering temperature and the addition of Cr alloy elements ensure the high hardness of the steel and poor plasticity and toughness; After Cr, Cr not only increases the strength and hardness of the steel plate, but also reduces the impact toughness of the material; the steel plate is cooled after hot rolling, and the plasticity and toughness of the steel plate are also low, which is also an indisputable fact found in the current rolling process research; When the tempering 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 tempered steel are poor; the wear-resistant steel is tempered 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 adding Cr 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

[0008] Extremely cold regions require wear-resistant steel plates to have good low-temperature impact toughness, and the current wear-resistant steel plates cannot meet the requirements for use in extremely cold regions

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