Effect of pearlitic morphology with varying fineness on the cavitation erosion behavior of eutectoid rail steel

The present work discusses the effect of the pearlitic morphology with varying fineness on the cavitation erosion behavior of eutectoid rail steel. Cavitation erosion of three different types of the pearlitic steels (furnace-cooled, air-cooled, and forced-air-cooled) consisting of coarse, fine, and very fine microstructures were tested in 3.5% NaCl solution and compared with that of the as-received pearlitic rail steel. The variation in the mean depth of erosion (MDE) and mean depth erosion rate (MDER) with erosion time was analyzed. Furthermore, the cavitation erosion resistance of the as-received, the air-cooled, and the forced-air-cooled was found to be 1.03, 1.51, and 2.14 times better than the furnace-cooled pearlitic steel, respectively. It was concluded that the cavitation erosion resistance of the pearlitic steel increased with the increase in the fineness of the microstructure.     

拉拔珠光体钢时效过程的内耗研究

由于珠光体钢大变形过程中存在渗碳体分解现象，分解的碳原子偏聚于位错芯处，且部分固溶于铁素体，时效过程中渗碳体析出。通过内耗对473K时效的拉拔珠光体钢研究表明，随着保温时间增加，Snoek峰驰豫强度先增后降，而SK峰驰豫强度不断降低，且峰宽变窄。由该结果可知由于大量碳原子存在于位错处，随着保温时间增加，分解后的碳原子先部分扩散溶入铁素体，随后以碳化物形式析出于位错处。时效过程中碳原子的三种分配方式有效的提高了拉拔珠光体钢的力学性能。