热变形中铬半钢碳化物的等温球化行为的研究

Investigation on Isothermal Spheroidizing of Carbides in Hot Deformed Medium Chromium Cast Semi-steel

对中铬半钢经高温形变后所获得的碳化物在等温球化过程中的球化行为进行了研究。分析认为 ,碳化物是以大粒子吞食小粒子和短条状碳化物分断及棒端溶解自身球化的方式进行球化长大的 ,特点是碳化物尺寸逐渐增大 ,数目逐渐减少 ,当等温球化温度为 6 5 0℃时 ,其长大速度符合经验公式 :Vr=1 2 2 74× 10 -3(0 32 3 +0 0 0 6 2t) 2 (μm/min)

The spheroidizing behaviors of carbides formed from deformation at high temperature in medium chromium cast semi steel had been studied during isothermal spheroidizing process.The results showed that the carbides grown under the way that the bigger carbide particles merged the smaller ones or short bar like carbide separated and the bar ends resolved to spheroidize itself.The carbide size increased as its number decreased gradually,when the isothermal spheroidizing temperature is at 650℃,the growth speed of spherical carbide could be expressed by the experimental equation:V r=1 2274×10 -3 (0 323+0 0062t) 2( μm /min)