Cr20Ni80电热合金铸锭与电渣锭的对比研究

Comparative Analysis of Ingots of Cr20Ni80 Alloy Before and After Electroslag Remelting

研究了电渣重熔对Cr20Ni80铸锭组织和力学性能的影响。结果表明,电渣重熔后铸锭大头柱状晶区的范围扩大,中心等轴晶区所占比例为半径的1/2左右;小头靠近型壁的细晶粒区范围扩大,柱状晶范围扩大,晶粒出现一定的圆度。扫描电镜分析结果表明,铸锭中夹杂物主要有5类,其中以第3类夹杂物为主要夹杂物;夹杂物在上浮过程中被结晶雨所捕获并沉降到底部。电渣重熔后,锭子的夹杂物面积比减小了48.3%,并且分布更加均匀。其塑性提高了8~9倍,韧性提高了5~6倍。

Effects of electroslag remelting on as-cast microstructure and mechanical properties of Cr20Ni80 ingot were investigated by analyzing comparatively cross section＇s macrostructure,inclusions,mechanical properties of ingots before and after ESR.The results reveal that the range of columnar crystal zone in big end,and small end as well as fine grain zone at small end is extended after ESR.The columnar crystal zone is one half of the radius in the big end and the crystal grain exhibits a certain degree of roundness in the small end after ESR.SEM analysis shows that there exist 5types of inclusions in the ingot and absence of new inclusion after ESR.By analyzing the amount and size of inclusions in the ingot before remelting,it is found that the main mechanism for inclusion segregation in the bottom of the ingot is the capturing of large inclusions by showering crystallites during floatation.Area ratio of inclusions in the ingot is decreased by 48.3% with more uniform distribution of inclusion,where plasticity is improved bu 8~9times,and toughness is increased by 5~6times after ESR.