旋转真空过滤机转鼓滤网支撑板开裂失效分析

Analysis on Cracking Failure of Support Plate of Drum Filter Net of a Rotary Vacuum Filter

某旋转真空过滤机滤网支撑板,在使用5a(年)后开始出现零星开裂失效,局部更换后又使用了约2a出现大面积开裂失效。采用宏观观察、化学成分分析、金相检验、扫描电镜分析、能谱分析等方法,对该支撑板开裂失效原因进行了分析。结果表明:支撑板材料中钼、镍元素含量低,使得滤网支撑板的耐腐蚀性能较低,在冷加工过程中产生的形变马氏体进一步影响了材料的耐腐蚀性能;过滤物中含有Br-造成了滤网支撑板的点蚀,在点蚀坑位置处产生应力集中,最终导致滤网支撑板发生了应力腐蚀开裂。

Fragmentary cracking occurred on a rotary vacuum filter support plate after 5 a（annum）service.The plate was used about 2 aby replacing some parts,after that large area cracking failure appearing.The failure reasons were analyzed by means of macroscopic observation,chemical composition analysis, metallographic examination,scanning electron microscope analysis and energy spectrum analysis.The results show that the low content of Mo and Ni in the support plate,which makes the poor corrosion resistance of the filter support plate.The strain-induced martensite produced during cold processing further affects the corrosion resistance.The filters contains Br-,which results in pitting on the filter support plate.Stress concentration was produced at the pitting position,which eventually leads to the stress corrosion cracking of the filter support plate.