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利用高温显微鏡测定了20CrNi钢和40CrNi鋼魏氏組織的长大速率,并研究了奥氏体化溫度,时間和晶粒大小对魏氏組織形成及长大的影响,实驗指出:亚共析鋼中魏氏組織的长大速率在恒溫下与时間无关,但晶核数目随时間增加,魏氏組織侧向长大的激活能Q=31000卡/克分子,这数值和鋼內碳含量无关,說明侧向长大只受碳在奧氏体內扩散的控制,魏氏組織的伸长受碳在典氏体內扩散和过冶度(形核功)的控制,长大速率在一定温度下呈現最大值,长大速率的变化和孕育期相对应,这些都和一般相变的情况相类似。魏氏組織的形成不完全依輟于奥氏体的晶粒大小,而主要依賴于奥氏体的均匀度。
The growth rate of Widmanstatches of 20CrNi steel and 40CrNi steel was measured by high temperature microscope. The effects of austenitizing temperature, time and grain size on the formation and growth of Widmanstall were studied. The results showed that: The growth rate of Wei’s tissue in eutectoid steel was independent of time at constant temperature, but the number of nuclei increased with time. The activation energy of lateral growth of Widmanstatus was Q = 31 000 cal / mol, Carbon content has nothing to do, indicating that lateral growth only by carbon in the diffusion of austenite control, Westend tissue elongation by carbon in the body of the proliferation and overgrowth (nucleation work) control, growth rate At a certain temperature, the maximum value appears, and the change of the growth rate corresponds to that of the gestation period, all of which are similar to the general phase change. The formation of Widmanstatten does not completely depend on the grain size of austenite, but mainly depends on the homogeneity of austenite.