锌合金蜗轮的挤压铸造

Squeezing Casting Zinc Alloy Worm Gear

利用自制装备挤压铸造了锌合金蜗轮,通过金相显微镜及万能试验机研究了其显微组织和力学性能。试验选取锌合金(ZA27)蜗轮挤压铸造工艺参数,保温温度为570～630℃,模具预热温度为150～250℃,冲头速度为5～10mm/s,比压为30～100MPa,保压时间为40～120s。结果表明,挤压铸造显著细化了锌合金的晶粒,提高了锌合金蜗轮的力学性能,很好地控制了蜗轮的品质。与金属型重力铸造相比,挤压铸造锌合金(ZA27)蜗轮的抗拉强度提高了28.6%,伸长率提高了139%。

The zinc alloy worm gear was produced by squeezing casting. The microstructure and mechanical properties of the zinc alloy worm gear were investigated by metallurgical microscope and electron universal test machine. The optimized squeezing parameters were presented as follows： holding temperature of570-630 ℃, both mould and pouring system heated to 150-250 ℃, punching velocity of 510 mm/s and pressure of 30100 MPa for 40- 120 s. The results show that the microstructure of the worm gear is obviously refined, and the mechanical properties are increased greatly, meanwhile the quality of zinc alloy worm gear is controlled effectively. Compared with those of permanent mold casting worm gear, tensile strength and elongation of the squeezing casting worm gear are improved by 100MPa and by 139%, respectively.