Method for controlling no soft strip at end part of roller body of large forged steel support roller after quenching

Abstract

The invention discloses a method for controlling no soft strip at an end part of a roller body of a large forged steel support roller after quenching. The method comprises the following steps: (1) the length allowance of the roller body is controlled; (2) in the heating process, the surface temperature uniformity of the roller body is controlled within +-10 degrees; (3) the precooling is performed by 5-15 minutes after heating and before spraying cooling; and (4) a spraying cooling mode of uniformly spraying the surface of the large forged steel support roller by water mist formed by combined action of compressed air and compressed water is adopted; and the spraying covering length is greater than the total length of the roller body by 50-100 mm to guarantee the water mist to cover the whole roller body. In the quenching process of the large forged steel support roller, the large forged steel support roller obtained by the control method is better in roller body surface hardness and uniformity, and is free of soft strips.

Description

technical field [0001] The invention belongs to the technical field of heat treatment of large forged steel support rolls, and in particular relates to a method for controlling the absence of soft bands at the ends of large forged steel support rolls after quenching. Background technique [0002] The body of large forged steel back-up rolls generally adopts overall induction heating or differential temperature heating for surface heating, so that the metal with a certain thickness on the surface of the roll body can be quickly heated to the austenite temperature, while the temperature of the core of the roll body is still below AC1 , so that different structures can be obtained inside and outside the quenched roll body to ensure the hardness of the working layer of the roll body and the strength and toughness of the core of the roll body. [0003] In order to prevent the end of the roll body from falling off due to excessive cooling speed, the two ends of the roll body will ...

AI Technical Summary

Problems solved by technology

[0003] In order to prevent the end of the roll body from falling off due to excessive cooling speed, the two ends of the roll body will be covered during the spray cooling process or the cooling speed here will be reduced by adjusting the water volume and pressure. However, in this way Can produce soft bands at the ends of large forged steel back-up rolls after quenching

[0004] The rolling load of modern strip mills is relatively large, the contact load between the work roll and the back-up roll or between the middle roll and the back-up roll is very uneven, and the presence of soft strips at the end of the roll body will cause the rolling to continue with the rolling. , so that the amount of wear of the soft belt at the side of the back-up roll is greater than that in the normal hardness area, resulting in a local contact pressure peak, causing early damage to the roll surface and roll end at the side of the back-up roll, thereby reducing the service life of the back-up roll

Images