Shu Chang, Wang Jitai, Shu Xuedao, Tian Duanyang
The William States Lee College of Engineering, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
Faculty of Mechanical Engineering and Mechanics, Ningbo University, Ningbo 315211, China.
Materials (Basel). 2019 Apr 29;12(9):1391. doi: 10.3390/ma12091391.
Due to the instable conditions caused by the wear of rollers, macro voids inevitably occur in skew rolling steel balls. Macro voids in rolled balls greatly weakens the mechanical properties, resulting in the scrapping of about 23% of all skew rolling balls. This paper adopts the floating-pressure method (FPM) to eliminate macro voids in rolled steel balls, and mainly focuses on the investigation of the influencing factor void closure in skew-rolled balls. The research contents are listed as follows: Firstly, the mechanical model of FPM eliminating void in rolled steel balls is established, and the theoretical relationship between influencing factors of void closure is obtained. Then, the metal flow behaviors, the stress distribution and the effect of process parameters on void closure are revealed by numerical analysis. Subsequently, based on the uniform design method, the prediction equation of the required temperature and air pressure for compacting various inferior rolled balls with different diameter by FPM is deduced. Finally, the FPM experiment is carried out to verify the results of numerical analysis. The research results provide theoretical guidance for eliminating macro voids in skew-rolled steel balls.
由于轧辊磨损导致条件不稳定，斜轧钢球中不可避免地会出现宏观孔洞。轧制钢球中的宏观孔洞极大地削弱了力学性能，导致约23%的斜轧钢球报废。本文采用浮动压力法（FPM）消除轧制钢球中的宏观孔洞，并主要关注斜轧钢球中空洞闭合影响因素的研究。研究内容如下：首先，建立了浮动压力法消除轧制钢球中孔洞的力学模型，得到了孔洞闭合影响因素之间的理论关系。然后，通过数值分析揭示了金属流动行为、应力分布以及工艺参数对孔洞闭合的影响。随后，基于均匀设计方法，推导了用浮动压力法压实不同直径各种劣质轧制钢球所需温度和气压的预测方程。最后，进行了浮动压力法实验以验证数值分析结果。研究结果为消除斜轧钢球中的宏观孔洞提供了理论指导。
