The main components of tungsten carbide rolls
Tungsten carbide rolls are prepared by powder metallurgy method using tungsten carbide, cobalt powder, etc. In 1909, with the development of metal processing industry, powder metallurgy technology came into being. Due to the high-speed and high-stress operation of the finishing mill, cast iron rolls and tool steel rolls are replaced by combined tungsten carbide rolls, because they have poor wear resistance, short roll life, frequent maintenance and loading and unloading, affect performance, and are not suitable for finishing rolling production. requirements, while tungsten carbide rolls have long life and high wear resistance.
There are various grades of tungsten carbide roll sets, even if it is the same finishing mill, its structure is different, and the composition of the tungsten carbide rolls corresponding to the rolls of different stands is different. The rolls used in high-speed wire rod mills are mainly tungsten carbide rolls with cobalt as a binder. A few continuous casting and rolling mills also use tungsten carbide rolls with Co-Ni-Cr as binder due to poor water quality, and the cost is also lower. Its metallographic structure is composed of matrix phase WC and binder phase Co. With the increase of WC content, the hardness of carbide roll increases proportionally with the content, while the toughness changes proportionally with the change of binder phase content.
With the high speed of wire finishing, people are constantly exploring ways to improve the hardness and strength of tungsten carbide rolls. This process is mainly to add a small amount of TaC, NbC and Ni, Cr, Mo and other elements to the tungsten carbide roll, and obtain a better quality tungsten carbide roll by hot isostatic pressing, vacuum sintering-low pressure hot isostatic pressing, heat treatment and other methods. .