Causes of failure of grinding balls with diameter 110 mm produced traditionally by forging, quenching and low-temperature tempering are considered. The chemical composition of the steel of the balls is studied using an energy dispersive spectrometer. The phase composition is studied with the help of a diffractometer. The fracture morphology, the structure, the type and the mechanism of fracture of the balls are studied using scanning electron and optical microscopes. The Rockwell hardness is measured. The content of retained austenite in the structure is calculated. The fracture is shown to be caused by inhomogeneity and large grain size of the austenite before quenching, by transformation of retained austenite into martensite during service, and by presence of slag inclusions. Practical recommendations are given for preventing cracking of balls during operation.

分析了传统锻造、淬火和低温回火生产的直径110mm磨球失效的原因。使用能量色散光谱仪研究钢球的化学成分。在衍射仪的帮助下研究相组成。采用扫描电镜和光学显微镜研究了钢球的断口形貌、结构、断口类型和断口机理。测量洛氏硬度。计算组织中残留奥氏体的含量。断裂是由淬火前奥氏体的不均匀性和大晶粒尺寸、使用期间残余奥氏体转变为马氏体以及夹渣的存在引起的。