There are four main forms of roll damage: roll body fracture, roll neck fracture, peeling and roll body cracking. Among them, roll peeling is the primary damage form and the main reason for roll damage and even early scrapping.
Roll spalling not only causes difficulties in roll grinding organization, but also greatly increases the direct cost of strip production, and directly threatens the long-term normal and stable operation of the strip rolling production line. Therefore, it is very necessary to explore the causes of roll peeling and find an effective way to extend the service life of rolls.
Precision roll manufacturers summarize the methods of extending the service life of rolls:
The molten steel in the furnace is injected into the mold through the gap between the surface of the roll mandrel and the copper mold wall. The water-cooled copper mold not only solidifies the molten steel to form a composite layer, but also serves as a non-consumable electrode. Electricity is provided in the slag pool to supplement the continuously consumed heat energy. A very thin layer on the surface of the roll mandrel is melted and needs to be filled with composite liquid metal. A composite layer is formed between the roll mandrel and the copper mold. The filling of molten steel can be continuous or step by step according to a preset procedure . The molten steel pushes the slag to the top, and occupies the original position of the slag to fuse with the melted part of the roll mandrel to form a composite layer. In the compounding process, the part after fusion and solidification is pulled out of the copper mold and the next part is continuously poured. The use of ESSL volume technology has produced a new generation of high-speed steel composite rolls. This roll contains a large amount of carbide forming elements, and the service life of the roll is increased several times. It not only resists thermal fatigue, but also resists various corrosions.