轴承钢棒材超快速冷却的试验研究

在特殊钢棒材厂原有连轧生产线上,通过增设超快速冷却系统,对轴承钢棒材高温终轧后进行超快速冷却工业试验.在连轧机组后增设三组超快速冷却系统.通过调节水压、喷嘴孔大小以及开启水箱个数,对GCr15轴承钢棒材进行高温终轧后超快速冷却.结果表明:随着连续冷却速度增加,晶界处二次碳化物中C,Cr含量减小,珠光体球团直径和片层间距减小,显微硬度值增大.棒材断面不同位置的冷却速度均可以达到抑制网状碳化物析出、过冷奥氏体完全发生珠光体转变的冷却速度要求,网状碳化物级别小于2级,达到轴承行业标准.

Commercial Test of Ultra-Fast Cooling for Bearing Steel Bar

Commercial ultra-fast cooling industrialized tests were carried out after high temperature final rolling of the Cr15 bearing steel bar by installing three ultra-fast cooling systems in addition to the original continuous rolling line in a special steel plant. The cooling rate was controlled by readjusting water pressure, nozzle size and the number of turn-on taps of water tanks after high temperature deformation of steel bar. The results showed that the C and Cr contents at the grain boundaries of secondary carbides are reduced with the size of pearlite pellets and the pearlitic lamellar gaps both decreased but the micro-hardness increases along with the continuously increasing cooling rate. Moreover, the cooling rate at anyplace on the cross section of the steel bar is available to restrain the precipitation of network carbides and transform all the overcooled austensites into pearlites. As a result, the class of the network carbides is lower than the grade II that is the professional standard.