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对ZA27蜗轮毛坯进行了金属型铸造、挤压铸造和半固态挤压成形试验,研究了在不同工艺条件下,制件的宏观成形性、微观组织形貌和力学性能。结果发现,金属型铸造蜗轮毛坯组织从齿顶到分度圆,均为细密发达的树枝晶;挤压铸件齿顶无树枝状枝晶,齿根的树枝晶晶臂有碎断现象,分度圆枝晶组织破碎圆整痕迹较为明显;半固态挤压件齿顶晶粒组织细化,分布较为均匀,齿根部呈典型的玫瑰状半固态组织形貌,分度圆为细小的等轴晶粒组织。金属型铸造蜗轮齿型成形困难;挤压铸造制备的蜗轮,外观轮廓清晰,齿形饱满;半固态挤压件成形性更加优良。半固态成形件力学性能高于挤压铸造和金属型铸件。
ZA27 worm gear blank was cast, squeeze casting and semi-solid extrusion test to study the macroscopic formability, microstructure and mechanical properties of the workpiece under different process conditions. The results show that the microstructure of the metal cast worm wheel blank from the addendum to the indexing circle are well-dendritic dendrites. There is no dendritic dendrite on the top of the extruded castings, and the dendrite arm of the dedendum is broken. Circular dendritic tissue broken round marks more obvious; semi-solid extrusion tip of the grain refinement at the top, the distribution is more uniform, the root is a typical rose-like semi-solid tissue morphology, subdivision round small equiaxed Granular tissue. Metal casting worm gear tooth forming difficult; squeeze casting worm gear, the appearance of a clear outline, full profile; semi-solid extrusion forming more excellent. The mechanical properties of semi-solid forming parts are higher than those of squeeze casting and metal casting.