Method for improving surface quality of large-thickness steel plate produced by roller type quenching furnace

Abstract

The invention provides a method for improving the surface quality of a large-thickness steel plate produced by a roller type quenching furnace, which comprises the following steps: carrying out lower surface mechanical grinding and bilateral cutting treatment on the steel plate before the steel plate enters the furnace, and controlling the bearing weight of a quenching machine roller way to be less than or equal to 2.5 t / m; strictly controlling the atmosphere and pressure in the quenching furnace, and controlling the swinging rhythm of the steel plate in the quenching furnace; the surface of the steel plate is purged before the steel plate enters the quenching machine and after the steel plate exits from the quenching machine, and the high-pressure air flow and pressure are strictly controlled. The steel plate produced through the method is good in surface quality after being quenched and discharged out of a furnace, no iron sheet gathering phenomenon exists, the iron sheet area proportion is smaller than or equal to 5%, and the roller mark area proportion is smaller than or equal to 8%; and the steel plate can be delivered without surface mechanical grinding treatment and shot blasting treatment, so that the cost is saved by 50-70 yuan per ton of steel.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for improving the surface quality of large-thickness steel plates produced by a roller quenching furnace. Background technique [0002] For large-thickness steel plates with strict requirements on mechanical properties, quenching + tempering treatment is required to ensure that the properties of the steel plates meet the standard requirements. The heat treatment furnaces for quenching in iron and steel plants mainly include roller furnaces and supporting quenching machines, trolley furnaces and supporting quenching tanks. Compared with the trolley furnace, the roller furnace has the following advantages: 1) When the roller quenching furnace heat-treats the steel plate, the steel plate is in the swing process, the steel plate is fully heated and the temperature is uniform; 2) The steel plate produced by the roller quenching furnace has a good...

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Problems solved by technology

[0004] When the steel plate is heated in the quenching furnace, part of the iron scale will be produced. If the red hot steel plate with the oxide scale is directly put into the quenching machine for cooling, most of the iron scale will adhere to the surface of the steel plate, which is difficult to remove later; and for the large thickness steel plate, due to the Single weight, when the steel plate is swaying in the quenching furnace, there will be a slipping phenomenon, that is, the steel plate will not sway with the swing of the roller table, and then the lower surface of the steel plate will produce roller printing defects

The above-mentioned iron oxide scale and roll printing defects on the surface of the steel plate will seriously affect the surface quality of the steel plate

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