催化裂化烟机蝶阀阀杆断裂原因分析及改进措施

Analysis and Improvement Measures for the Fracture of Butterfly Valve Stem in Catalytic Cracking Flue Gas Turbine

为了解催化裂化烟机入口高温蝶阀阀杆在运行一段时间后断裂的原因,从结构特点、强度校核、键槽受力分布及其加工工艺等关键影响因素进行综合分析,结果表明:蝶阀阀杆在使用一段时间后断裂的主要原因是阀杆疲劳强度安全系数过小。此外,不合理的键槽加工工艺和键连接方式对阀杆键槽应力集中的影响也是导致阀杆断裂的重要因素。对阀杆进行磨削和渗氮硬化等处理,改变阀杆和阀板轴孔键槽的加工工艺,同时优化键连接结构,可以有效提高阀杆的疲劳强度安全系数并减小阀杆键槽上的应力集中,对于提高传动件尤其是带键传动轴的机械性能和使用寿命等方面具有重要的参考价值。

In order to understand the reasons of the fracture of the stem of the high-temperature butterfly valve at the inlet of the catalytic cracking flue gas turbine after a period of normal operation,a comprehensive analysis was made from the key factors such as the strength check of the stem,the stress distribution of the keyway and the processing technology.The results show that,the main reason for the fracture of butterfly valve stem after a period of operation is that the fatigue strength safety factor of the valve stem is too small;In addition,the influence of unreasonable keyway processing technology and key connection structure on the stress concentration of valve stem keyway is also an important factor leading to valve stem fracture.Without changing the shaft diameter,grinding and nitriding hardening of the valve stem,changing the processing technology of the valve stem keyway,and optimizing the key connection structure can effectively improve the fatigue strength safety factor of the valve stem and reduce the stress concentration on the valve stem keyway,which has great reference value for improving the mechanical performance and service life of the drive parts,especially the keyed drive shaft.