The distortion deformation during diameter reduction not only changes the primary defects (such as hair-line seams) into screwy form, but also enlarges the primary cracks.

而减径变形中的扭转变形不但使原始缺陷形成螺旋状，同时还进一步扩展了裂纹。

youdao

During the process of reducing, in case of constant diameter reduction, the major elements responsible for tube wall increase are the rolling temperature and the stretch factor, etc.

钢管在减径过程中，减径量一定时，影响其增壁量的主要因素是钢管的轧制温度和张力系数等。

youdao

Decreasing the diameter of nozzle, increasing the concentration of cosolvent or decreasing the pre-expansion temperature could result in the diameter reduction of the microparticles.

减小喷嘴孔径、提高夹带剂浓度或降低预膨胀温度均可使微粒粒径减小。

youdao