Device for two-way cooling of rolls of multi-roll mills during laser hardening

Abstract

Development of the automotive industry, electronics, aviation and other modern branches of science and technology has led to the need to produce thin (up to 0.01 mm thick) and the thinnest (up to 0.001 mm) high-quality band from high-alloy steels, non-ferrous and noble metals, obtained on multi-roll cold rolling mills. One of the main requirements for work rolls is a high and uniform hardness of the surface of the barrel after hardening, which should increase the wear resistance of the working layer, reduce the degree of its damage and, thereby, ensure the high quality of the rolled strip. An effective way to improve the quality of rolls with a diameter of up to 20 mm is surface laser hardening. In laser hardening of rolling rolls, a technological scheme was used, according to which the roll made a screw movement at preset speed relative to a fixed laser beam, which led to formation of a continuous screw track (spiral) of the hardened material on the surface of the roll. The minimal rotational frequency, at which uniformity of the active layer is observed, has been experimentally established, while laser hardening of samples with double-sided water jet cooling turned out to be the most effective. The design of a sprayer device for cooling of rolls during laser processing is proposed, which provides a uniform active layer along the entire barrel length and significantly reduces buckling of rolls. The technology for the manufacture of rolls has been developed, which makes it possible to obtain work rolls for multi-roll mills with high operational resistance, and to improve the technical and economic indicators of production of precision band. Tests of the rolls made of Kh9VMFSh steel after laser hardening on the mill 300 showed reduction in wear by 1.5-2.0 times compared to the standard volume-hardened rolls and reduction in roll consumption from 0.22 to 0.11 kg / t.