The high-speed steel roll is the core component of the rolling mill. The use of the high-speed steel roll involves the selection of the type of rolling mill, the preparation of the high-speed steel roll, and the maintenance, and periodic dressing during the rolling process, and these all affect the productivity of the rolling mill and the product. Factors of quality and production economy, since the rolling process is a continuous process, the operator needs to constantly check the condition of the high-speed steel rolls, so that the produced products meet the user’s requirements for stricter tolerances and surface quality.
In order to keep the product competitive, it is necessary to continuously require the rolling mill operators to reduce production costs, that is, to increase the rolling speed, and the production flexibility of the rolling mill and reduce the consumption of high speed steel rolls. So what should be paid attention to when surfacing high-speed steel rolls?
(1) Before surfacing welding, the fatigue layer or defects on the surface of the high-speed steel roll body, especially the cracks must be completely removed. During surfacing welding, in order to prevent the occurrence of cracks, the high-speed steel roll body must be preheated first. The preheating temperature depends on the high-speed steel roll and surfacing material.
(2) The key link for the success of surfacing welding during welding. To obtain an ideal surfacing layer, certain variable factors must be considered comprehensively, such as welding voltage, welding speed, speed of high-speed steel rolls, heat preservation of high-speed steel rolls, welding current, Welding materials, etc. For some roll cores containing carbon and high alloy elements, in order to prevent cracks in the brittle zone, in addition to certain preheating measures, a low-carbon and low-alloy transition layer is often used for the pre-surfacing transition layer.
(3) Slow cooling and turning of HSS rolls after surfacing, in order to reduce cracks caused by volume stress caused by different cooling rates on the surface and inside, the cooling rate should be controlled, and the high-speed steel rolls after surfacing should be turned and recovered to original size and finish.