叠片式连轴节腐蚀失效分析

Analysis of corrosion failure of laminate coupling

通过对连轴节叠片和销轴表面形貌观察以及电子探针、红外光谱对腐蚀产物的分析可知,腐蚀介质主要来自于润滑油中的Cl-和烟气中的SO2、SO3等。AISI301不锈钢叠片为缝隙腐蚀和应力腐蚀开裂,而42CrMo低合金钢销轴则是电偶腐蚀。不锈钢叠片电位高作阴极,销轴电位低作阳极,形成牺牲阳极型阴极保护。由于叠片总表面积远大于销轴,虽然销轴被牺牲而腐蚀,但是叠片被保护效果不良。针对上述腐蚀失效原因提出改进措施即避免使用含有氯组分的润滑油以及叠片与销轴采用相同材料,避免电偶腐蚀。

Surface morphology of laminates and dowels were observed, and corrosion products were analyzed by the probe and the infrared spectroscopy. It was found out that corrosion was mainly caused by Cl- from the lubrication oil and SO2 and SO3 from the smoke. The laminates of AISI301 stainless steel were attacked by crevice corrosion and stress corrosion cracking （SCC）, while the dowels of 42CrMo low ＇alloy steel were attacked by galvanic corrosion. Although the laminates and dowels were respectively the cathode and anode of an electrolytic cell, the laminates were not effectively protected, because the total surface area of the laminates was far larger than that of the dowels. According to the above corrosion mechanism, two improvement measures were proposed ： （ 1 ） chlorine-containing lubrication oil should not be used; （2） same material should be used for laminates and dowels.