Bimetallic Composite Casting Mill Liner And Its Performance

Lining board is used for protecting cylinder, avoiding cylinder directly endure impacting and wearing from materiel and grind-ball. It is an easy damaged part. At present, the frequent use of material of lining board is Hadifield steel which has nice ductility, poor abradability and low yield strength. Hadifield steel is easy to deform, which leads to lining board pull-off, and is impossible to match with high hardness, high wearability of grinding ball. High-chromium cast-iron has nice wearability which life span is 2～6 times more than Hadifield steel in dry work condition though it is brittleness. In enduring stated wallop and in work condition of grinding abrasion, it appears fracture failure, showing lack of toughness. Therefore, it is unsafe to make lining board of large-scale ball grinder with high-chromium cast-iron.This paper researches the use of lining board in the world and domestic. For lining board will both have nice ductility and nice wearability, we bring forward to adopt bimetal casting. That is to say that the high quality steel which has nice toughness and the high-chromium cast-iron which has nice wearability will be compounded together by using the method of cast. As the result, the abrasive surface has excellent wearability while the unabrasive surface has excellent plastic nature.The technique of bimetal casting indicate that: upright-casting is better than horizon-casting; the key point of upright-casting is adding a clapboard between the duplex metal; the duplex metal's point of pouring is 30～50℃ higher than general molten iron and molten steel; and in pouring process, it needs to hold the fluid level concordance.In this paper, we research the heat treatment of multiple lining board. Using the equipments of Rockwell hardometer, metallographic microscope, scanning electric mirror, Charpy impact machine tester, MLD-10 dynamic load abrasion tester to research the rigidity, microstructure, abradability and nature of bonding pad.Apply ANSYS to analyze the static of multiple lining board. The resultindicates the area of high-chromium cast-iron has maximum stress, and the possibility of abruption from the area of high-chromium cast-iron and bonding pad is little.The analysis of impact test indicates that: the nature of bonding pad of bimetal casting lining board is better than single high-chromium cast-iron. In the 16 samples, the 7^th has maximum value of impact ductility which is 22J/cm².The analysis of fractograp and metallurgical structure indicates that: according to the mode of abruption in bonding pad, the first is clapboard snapped, the second is snapped on the side of 20steel and the last is snapped on the side of high-chromium cast-iron. The samples of clapboard snapped both have brittle fracture and gliding fracture, the samples of snapped on the side of 20steel have gliding fracture, and the samples of snapped on the side of high-chromium cast-iron have brittle fracture following with gliding fracture.The results of abrasion test indicate that: by 15 species methods of heat treatments, samples under the condition of experiments of 1.2J ballistic work, 30～35kilograms per hour sand-flow, 2 hour wearing-in period, 150 turns per minute impact times, 20～30mu abrasive particle, put to test. The 7th has the best wearability property, only lost 0.0997g.Through the research of material and capability of multiple lining board, we can learn that upright-casting is able to make lining board of large-scale ball grinder, which steel, iron and clapboard form metallurgical bonding, and integrally have nice wearability and excellent toughness. In all samples, the sample quenching at 900°C and tempering at 420℃ will perform satisfactorily.