Rolls are important parts of rolling mills in rolling mills. They use the pressure generated by a pair or a set of rolls to roll steel. It mainly bears the effects of dynamic and static loads, wear and temperature changes during rolling.
There are two types of rolls: hot roll and cold roll.
Among the commonly used cold rolls, the materials of work rolls are 9Cr, 9Cr2, 9Crv, 8CrMoV, etc. The cold rolls require surface hardening, and the hardness is HS45~105.
The commonly used materials for hot rolls are 55Mn2, 55Cr, 60CrMnMo, 60SiMnMo, etc. The hot rolls are used in the processing of billets, thick plates, and section steels. It withstands strong rolling force, severe wear and thermal fatigue, and hot rolls work at high temperatures, and allow diameter wear per unit of work, so surface hardness is not required, only high strength and toughness are required. And heat resistance. Hot rolls are only normalized or quenched as a whole, and the surface hardness is required to be HB190~270. Hardness Roll hardness is an indirect physical value, and its height is affected by the internal structure of the roll itself, such as the matrix hardness of the roll material, the type and quantity of carbides in the roll material, the residual stress of the roll, etc.; at the same time, due to the roll Hardness testing commonly used Shore and Leeb hardness testing are rebound hardness testing, which is greatly affected by other factors such as the state of the testing instrument and the psychological factors of the operator. Therefore, whether it is the manufacturing and use department of the roll, it is necessary to equip a dedicated person to be responsible for the hardness testing, pay attention to the selection of the hardness tester, and the comparison with other hardness should be stable. Qualified companies can promote the use of standard rolls for the proofreading of the hardness tester.
Repair method
1. Cold welding repair method: The cold welding machine uses the principle of high-frequency electric spark discharge to perform non-thermal surfacing welding on the metal surface, so it will not deform, anneal, undercut and residual during the process of repairing roller blisters, scratches and other defects. Stress does not change the state of the metal structure. The repair accuracy is high. The thickness of the coating ranges from a few microns to a few millimeters. It can deposit, seal, fill and repair defects such as wear, scratches, pinholes, cracks, defect deformation, hardness reduction, trachoma, damage and other defects in metal workpieces. , It only needs to be polished and polished, and it can also carry out various mechanical processing such as turning, milling, planing and grinding, as well as post-processing such as electroplating.
Shanghai Duomu Industrial Co., Ltd. is a high-tech industry specializing in power supply development. Welding power supply is my key project. The series of welding machines developed have reached or exceeded the international advanced level, and are well recognized by customers and have a wide customer base. And popularity. The products are professionally used for welding precision parts and thin plates, surfacing welding of valves, rolls, picks, etc., welding repair of molds, mechanical shafts, etc., and have been widely used in electronic appliances, coal mining machinery, aerospace and many other fields.
