Effects Of Heat Treatment Process On The Microstructure And Properties Of High Silicon And High Chromium Cast Iron

High chromium cast iron is a kind of wear resistant material that highly focusedon for its excellent performance; it’s the third generation of white cast iron after thegeneral white cast iron and Ni hard cast iron. It is regarded as the most excellentabrasive resistant materials for its wear resistance better than the alloy steel, andhigher toughness, strength than the general white cast iron, and it also has goodresistance to high temperature and corrosion. It is widely used in the mining industry,construction machinery, wear-resistant material, and so on. It is always used for thelining plate, hammer, grinding ball material.Silicon element is very helpful to improve the properties of high chromium castiron for it can increase its hardenability, and improve the Ms point of the material,reduce the temperature range of eutectic reaction. At present, high silicon and highchromium cast iron is still inadequate about the performance. In order to improve itsperformance, using different heat treatment process, and the results show that: withthe increase of quenching temperature, the macro hardness of high silicon and highchromium cast iron increased first and then decreased, when the temperatureis1000℃high, the material has the highest hardness of49.1HRC, but its antiabrasion performance declined firstly and then increased with the increase ofquenching temperature. During the quenching cooling, the faster of cooling rate is,the higher of the materials’ macro hardness to be. And when the high silicon and highchromium cast iron have different initial quenching temperature, both of theirhardness changing law is almost of the same to the cooling rate. Besides, afterquenching, different tempering temperature and tempering time on the high siliconand high chromium cast iron test, the results show that: when the temperingtemperature is200℃to400℃, the hardness of high silicon and high chromium castiron basically unchanged, and when the tempering temperature is higher than480℃,the hardness of high silicon and high chromium cast iron obviously declined; whenthe tempering temperature is below200℃, the hardness of high silicon and highchromium cast iron almost unchanged when the time of tempering changed, but theanti abrasion performance of the material is increased a little; when the tempering temperature is400℃, with increasing tempering time, the hardness of the material isreduced, but the anti-wear properties increased first and then decreased, and theincreasing of properties is better than the increasing properties that when thetempering temperature is200℃.In addition, the results of different angle wear experiments to the high siliconand high chromium cast iron show that: the wear process is mainly caused by theinteraction of "micro cutting" and frontal impact that by the quartz sand particleseffect on the surface of the material, and high silicon and high chromium cast ironshows a good anti abrasion performance to large impact angle.