Development of Novel Cyclic Rotating Bending Process for Control of Microstructure and Grain Refinement of Metal Tubes

点击翻译按钮获取中文摘要

As a novel grain refinement and microstructure control method, a cyclic rotating bending processing (CRB) method for metal tubes is proposed and investigated in the present study. The principle is on the basis of the severe straining mechanism of metal tube by using a continuous scheme with the CRB method such as Ono- type rotating bending fatigue testing method. To verify the validity and confirmation of the method, a new CR B processing apparatus is developed and then experiments with magnesium alloy tube AZ31 were carried out using the developed apparatus. CRB experiments for AZ31 are conducted under constant rotation speed of 20 rpm and under different temperatures from 150 to 350°C. As a result, it is seen that CRB deformation at the lower processing temperature is effective to refine the grain size compared with the case of heat treated ones at any temperature. In addition,tensile properties at room temperature of the magnesium alloy tube, which is subjected to CRB deformation at 200 °C, result in the most enhancements in the strength and ductility.