Al元素对高碳珠光体钢连续缓慢冷却相变行为的影响

Effect of Al element on slow continuous cooling transformation behavior of high-carbon pearlitic steel

结合试验与热力学、动力学计算,研究了在缓慢冷却条件下Al合金化对C-Si-Cr-Mn系高碳钢珠光体转变行为的影响。结果表明,在锻造后空冷条件下,不添加Al和添加1.5%Al的试验钢室温组织均为珠光体和少量马氏体,与Al-free钢相比,添加1.5%Al的试验钢的珠光体片层间距为130nm,细化了约20nm,维氏硬度HV1降低了约56。结合热力学和动力学计算结果可知,Al元素的添加可以提高试验钢的珠光体转变温度及缩短珠光体转变时间,增大了奥氏体向珠光体转变的自由能,促进珠光体形成的同时也起到细化珠光体片层间距的作用。

By means of experimental research and thermodynamic and kinetic calculations,the effect of Al element on the pearlite transformation behavior of C-Si-Cr-Mn-based high-carbon steel during slow continuous cooling process was investigated. The results show that,after forging and subsequent air-cooling,the room temperature microstructure of the tested steels,i.e. Al-free and Al-bearing ( w (Al)=1.5%),is perlite and a small portion of martensite. Compared with Al-free steel,the tested steel containing 1.5%Al exhibits finer pearlite structure with a lameller spacing of 130 nm refined by about 20 nm,and the Vickers hardness HV 1 is reduced by around 56. According to the results of thermodynamic and kinetic calculations,the addition of Al element is beneficial to increase the pearlite transformation temperature and shorten the pearlite transition time of the tested steel,and the free energy of austenite to pearlite transformation also increases;as a result,the formation of perlite and the refinement of its lamellar spacing are promoted.