Method for producing quenched and tempered wear-resistant steel plate NM400 with thickness of 30 mm or less by using online waste heat

Abstract

The invention relates to a method for producing a wear-resistant steel plate NM400 which is 30 mm in thickness and is quenched and tempered by using on-line waste heat. The on-line waste heat is used for carrying out on-line quenching on a medium-thickness plate production line by using waste heat after rolling and carrying out tempering by using an off-line heat treatment furnace, the tempering temperature is 450-500 DEG C, and the tempering time is 1.8 Tmin (T is the thickness of the steel plate). According to the method, on-line waste heat quenching is used for replacing the process that the steel plate is heated to an austenite area from the room temperature in an off-line heat treatment furnace and then quenched, and the heat treatment cost for producing the quenched and tempered wear-resistant steel plate is greatly reduced. Through the design of chemical components, the martensite structure is obtained by cooling to below 400 DEG C at the cooling rate of 10-15 DEG C/s. The NM400 steel grade comprises the following chemical components in percentage by mass: 0.22 to 0.26 percent of C, 0.4 to 0.6 percent of Si, 1.3 to 1.55 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.007 percent of S, 0.3 to 0.45 percent of Mo, 0.8 to 0.95 percent of Cr, 0.01 to 0.035 percent of Al, 0.001 to 0.005 percent of B, less than or equal to 0.04 percent of Ti and the balance of Fe and inevitable impurities.

Description

technical field [0001] The invention relates to the technical field of wear-resistant steel production, in particular to a method for producing quenched and tempered wear-resistant steel plates NM400 with a thickness of less than 30 mm by using online waste heat. Background technique [0002] NM400 is a high-strength wear-resistant steel plate with fairly high mechanical strength. Its mechanical properties are 3 to 5 times that of ordinary low-alloy steel plates. production cost. It is mainly used for the processing and manufacturing of wear-resistant and vulnerable parts for mines and various construction machinery. [0003] At present, the production of NM400 steel in the industry generally adopts off-line production, that is, after the steel plate is rolled, quenching and tempering are completed in the heat treatment process. This method requires special quenching equipment, the process is cumbersome, the production cost is high, and the energy consumption is large, whi...

AI Technical Summary

Problems solved by technology

This method requires special quenching equipment, the process is cumbersome, the production cost is high, and the energy consumption is large, which is not conducive to the iron and steel industry to achieve the goal of energy saving and emission reduction.

Moreover, the wear-resistant steel produced by this method also has the problem of poor impact deformation resistance. Therefore, there is an urgent need for a production method that is more environmentally friendly and energy-saving and can maintain the excellent mechanical properties of NM400 wear-resistant steel plates

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