全国铁路系统普遍采用内燃机车,因此内燃机车运行的安全和可靠性是决定铁路运输安全正点的最关键因素之一。每一台内燃机车中有64只气阀,而气阀的工作条件十分恶劣,经常因为气阀磨损、腐蚀、变形等致使内燃机车柴油机功率降低,影响运输能力,更危险的是排气阀破损,打坏气缸,造成故障,使行车安全受到威胁,如何保证进、排气阀的使用安全是人们十分关注的问题。为了保证气阀在高温工作时有良好的耐磨损性、抗氧化和抗燃气腐蚀能力,气阀盘面采用等离子堆焊,对堆焊的工艺要求是比较严格的,如果堆焊材料成分、性能以及堆焊工艺,机械设备不当,就会造成气阀有夹杂和气孔,金属含量偏析或应力集中也会直接影响气阀的质量性能和使用寿命。如何能预知气阀的质量,将有缺陷的气阀和可能掉块的气阀查出来成了铁路部门 Therefore, the safety and reliability of the operation of diesel locomotives are one of the most crucial factors that determine the punctuality of railway transport safety. Each diesel locomotive has 64 valves, and the working conditions of the valve is very poor, often because of valve wear, corrosion, deformation, etc. resulting in reduced power diesel locomotive, affecting transport capacity, the more dangerous is the exhaust valve damage , Break the cylinder, causing failure, so traffic safety is threatened, how to ensure that the safety of the exhaust valve is a matter of great concern to people. In order to ensure that the valve works well at high temperatures with good wear resistance, anti-oxidation and anti-gas corrosion, gas valve plate surface with plasma surfacing, the welding process requirements are more stringent, if the surfacing material composition, performance As well as surfacing process, improper mechanical equipment, gas valves can cause inclusions and pores, metal segregation or stress concentration will directly affect the quality of the valve performance and service life. How to predict the quality of the valve, the valve will be defective and the valve may be out of the block became the railway department