钛合金扁形锭冷坩埚电磁约束成形工艺参数研究  

Effects of Process Parameters on the Quality and Structure of Casting Titanium Slab with Uni-Directional Solidification in Cold Crucible

作　　者：王艳丽[1] 丁宏升[1] 毕维生[1] 郭景杰[1] 傅恒志[1] 

机构地区：[1]哈尔滨工业大学金属精密热加工国防科技重点实验室,黑龙江哈尔滨150001

出　　处：《稀有金属材料与工程》2005年第10期1627-1632,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金重大项目(50395102);国家重大基础研究项目(G200067202-2)

摘　　要：在自行研制的多功能冷坩埚电磁约束定向凝固装置上进行了钛合金扁形锭的冷坩埚连续成形实验,考察了不同参数下的成形工艺过程,分析了工艺参数变化对所成形钛合金锭质量的影响程度。结果表明:增大感应线圈匝数和增加加热功率可提高铸锭表面质量,但是提高抽拉速度和降低底料与线圈之间的相对位置会降低表面质量。在所研究的参数中,对铸锭表面质量影响的主次因素为,感应线圈的匝数最大,加热功率次之,抽拉速度再次,最后为底料相对线圈位置。在讨论这些参数的作用原理基础上,提出了可获得良好表面质量的工艺参数,铸造出表面光滑、无裂纹缺陷的钛合金扁形锭。工艺参数对铸锭宏观组织的影响表现在随感应线圈匝数的增多和抽拉速度的减小,铸锭晶粒的数量减少,晶粒偏离轴向程度减小,后续实验表明在截面形状近似为矩形的冷坩埚下可以获得既有良好表面质量又具有定向组织的钛合金扁形铸锭。The experimcnts of coatirtuous casting and directional solidifing titanium ahoy slabs were performed in a multi-functional electromagnetic casting apparatus with rectangular cold crucible. The influences of process parameters were evaluated on the surface qualities and macrostructures of the casting slabs. It is shown that the surface variations of the slabs get to be well with the increasing of the number of coil turns and the input power. While, it seems to be bad with the increase of the withdrawal velocity and the reduce of the relative position of dummy to the induction coils. The limits of influence of process parameters are deduced as that the first one is the induction coil, the second one is the input power, the third one is the withdrawal velocity, and the last one is the dummy position. With the selective optimized parameters, the slabs free from cracks and ripples are obtained under the experimental conditions. It is interpreted that the variations of meniscus volumes has the significant effects on the casting process, which in turn to be the results of surface qualities of cast slabs. With the increasing of the number of induction coil turns and the decreasing of the withdrawal velocities, the numbers of grains reduced and the grains are parallel to the growth direction. The slabs with both good surface quality and uni-directional macrostructure were cast in cold crucible whose cross section is approximately rectangular.

关 键 词：冷坩埚 电磁约束成形 钛合金 定向凝固 

分 类 号：TG249.9[金属学及工艺—铸造]