材料及滚压方式对等壁厚螺杆钻具定子滚压成形的影响

对外径Φ73 mm,壁厚6.5 mm的等壁厚螺杆钻具定子进行滚压成形试验,使用双因素方差分析法和主效应图定量研究不同坯管材料及滚压方式对等壁厚定子成形质量的影响。采用DEFORM-3D软件模拟滚压成形过程,分析了坯管材料为45钢和42Cr Mo钢时滚压力、轴向力、加工应力和残余应力分布情况。结果表明：滚压方式对定子管导程影响较大,手动滚压后的导程误差均在15%以上,自动滚压后的导程误差均小于5%;坯管材料对定子管壁厚分布影响较大,45钢坯管滚压成形后的定子管壁厚分布较42Cr Mo钢均匀;45钢和42Cr Mo钢坯管滚压时所需的滚压力相差较大,分别在125和140 k N附近波动;轴向力数值基本相同,均在15 k N附近波动;45钢和42Cr Mo钢坯管的最大加工应力分别为580和1200 MPa,残余压应力峰值分别为87.88和104.52 MPa,且均分布在管壁外表面。因此,滚压成形等壁厚螺杆钻具定子时,坯管建议选用加工性能较好的45钢,滚压方式选用自动滚压。

Horizontal continuous casting process under electromagnetic field for preparing AA3003/AA4045 clad composite hollow billets

A modified horizontal continuous casting process under the electromagnetic field was proposed for preparing AA3003/ AA4045 clad composite hollow billets. To investigate the effect of electromagnetic field on this process, a comprehensive three-dimensional model was developed. Two cases with and without electromagnetic field were compared using the simulations. When rotating electromagnetic stirring is applied, the flow pattern of fluid melt is greatly modified; the mushy zone becomes much wider, the temperature profile becomes more uniform, and the solid fraction decreases for both the external and internal alloy melt layers. These modifications are beneficial for the formation of a bimetal interface and fine and uniform grain structure of the clad composite hollow billet. Experiments conducted using the same electrical and casting parameters as the simulations verify that under the electromagnetic field the microstructure of the clad composite hollow billet becomes fine and the diffusion of the elements at the interface is promoted.