弹簧断裂失效分析

Failure Analysis on Cracked Springs

材料为Ⅱa的弹簧在装配时发生了断裂,故障率达到了27%。针对此境况,对Ⅱa材料的断裂弹簧故障件进行了断口、显微组织及能谱分析,并结合弹簧的制造工序,对断裂的形成原因进行了综合分析。在弹簧的断口和裂纹处均发现镉元素的存在,根据产生镉脆的三个条件可知,弹簧的裂纹是在除氢工序过程中产生的。结果表明,弹簧成批断裂的主要原因是在弹簧的制造过程中产生了镉脆裂纹,该裂纹降低了弹簧的承载能力,使得弹簧在装配中发生过载断裂。

20 percent of the springs made of the material of IIa fractured during the process of assembly.In this paper, the fracture surfaces of the springs were observed.The microstructure of the fracture was investigated,and energy spectrum analysis was carded out.Then based on the manufacturing procedure of the springs,fracture cause was analyzed.Cadmium was found on the fracture surfaces and cracks of the springs.According to the three necessary conditions for the creation of cadmium brittleness,it can be concluded that cadmium brittleness cracks came into being during the process of removing hydrogen.It is shown that the main cause of the fracture was that cadmium brittleness cracks were created in the process of manufacturing the springs.These cracks made the bearing capacity of the springs decline and led to overload fracture in the process of assembly.