This work aimed to identify and evaluate the reasons that led to a compression spring to fail. The compression spring was operating in a wagon torpedo, a vehicle that transported pig iron in a liquid state from the blast furnace to the steel mill. For this purpose, optical microscopy (OM), scanning electron microscopy (SEM), quantitative chemical analysis by combustion and x-ray fluorescence, Vickers microhardness test (HV), Rockwell superficial hardness with N scale (HRN), and residual stress analysis by x-ray diffraction were used. The industrial quenching, tempering heat treatment, and shot peening process, were also redone for the spring under analysis, all in order to simulate the treatments that were supposedly done on the original spring. It can be concluded that the process that led to spring fracture was a mechanism of fatigue failure that originated from a defect in the spring surface. Although residual stresses on the spring surface were expected to prevent fatigue failures from surface defects, the hardness in this region of the material was lower than specified due to a decarburizing process.

这项工作旨在确定和评估导致压缩弹簧失效的原因。压缩弹簧在货车鱼雷中运行，该车辆将液态生铁从高炉运送到钢厂。为此，光学显微镜（OM），扫描电子显微镜（SEM），通过燃烧和X射线荧光的定量化学分析，维氏显微硬度测试（HV），N等级的洛氏表面硬度（HRN）以及通过使用X射线衍射。还对分析中的弹簧重新进行了工业淬火，回火热处理和喷丸处理，所有这些都是为了模拟据称在原始弹簧上进行的处理。可以得出结论，导致弹簧断裂的过程是由弹簧表面缺陷引起的疲劳失效机理。尽管预计弹簧表面会产生残余应力，以防止由于表面缺陷造成的疲劳失效，但由于进行脱碳处理，材料在该区域的硬度低于规定值。