摘要
手扶电梯的主轴在使用过程中发生断裂,对断轴的化学成分、力学性能、显微组织观察和非金属夹杂物等进行检测,并对焊缝组织及影响区域进行显微组织观察,测量了主轴在轴径变化处的过渡圆角R及焊缝各组织区域的尺寸,并分析了主轴的断裂原因。结果表明:主轴及焊缝断裂处未发现异常组织,并且焊缝硬度符合相关标准要求;该主轴轴径变化处R角的直径小于Φ4 mm以及主轴加工形成的越程槽底部圆角较小是导致主轴断裂的根源。
Shaft of a certain escalator cracked during using,the cause of fracture of the shaft was analyzed by means of chemical composition analysis,mechanical property test,microstructure observation and non-metallic inclusion analysis,and the transition R angle and the size of welding zone were measured. The results show that no abnormal microstructure was observed at the fracture shaft and weld,and the hardness of weld meets the requirements of related standards. The R angle at the position of the change of main axle is less than Φ4 mm,and the incorrect design of the relief groove for grinding during the processing of the shaft,which lead to the shaft crack.
引文
[1]EN ISO 5817:2014,Welding-Fusion-welded joints in steel,nickel,titanium and their alloys(beam welding excluded)-Quality levels for imperfections[S].
[2]ISO 15614-1:2004,Specification and qualification of welding procedures for metallic materials-Welding procedure test-Part 1:Arc and gas welding of steels and arc welding of nickel and nickel alloys[S].
[3]GB/T 4336-2002,碳素钢和中低合金钢火花源原子发射光谱分析方法(常规法)[S].
[4]GB/T 1591-2008,低合金高强度结构钢[S].
[5]GB/T 13298-1991,金属显微组织检验方法[S].
[6]GB/T 6394-2002,金属平均晶粒度测定方法[S].
[7]GB/T 10561-2005,钢中非金属夹杂物显微评定方法[S].
[8]GB/T 2975-1998,钢及钢产品力学性能试验取样位置及试样制备[S].
[9]GB/T 228-2002,金属材料室温拉伸试验方法[S].
[10]BS EN 1043-1:1996,Destructive tests on welds in metallic materials.Hardness testing,Part 1.Hardness test on arc welded joints[S].