Fe-C-Si-Mn合金中的网状组织及其强化效应

水轮机叶片用Fe-C-Si-Mn合金铸钢热处理后存在网状组织.金相及透射电镜分析表明,退火后的网状组织是层片间距极小的珠光体,正火后的网状组织是马氏体或贝氏体.实验结果并结合理论分析证明,这种网状组织的形成源于枝晶间碳及锰原子的偏聚,较高的热处理加热温度或较长的保温时间将导致网格尺寸的增大并最终消失.这种网状组织对合金强度有一定影响,网格尺寸越小,强化效应越大.

Network Structure and Its Strengthening for Fe-C-Si-Mn Alloys

Fe - C - Si - Mn alloys are used as blades in hydroelectric generators contained network structures after some heat treatments. It is found by metalograph and TEM analysis that annealed network structure is pearlite with very fine slice while the normalized is martensite or bainite. Experimental results together with theoretical analysis prove that the network structures are resulted from segregations of carbon and manganese atoms in the interdendritic areas, higher heat treatment temperature or longer soaking time can enlarge the grid size and finally eliminate the network structure. The network structure has some effects on the strength, and the smaller the grid size, the higher the strength.