铁路车轮、轮箍踏面剥离的类型及形成机理

Type and Formation Mechanism of Railway Wheel and Tire Tread Spall

由车轮和轮箍生产厂按产品供货技术条件交货的铁路车轮和轮箍 ,在使用中通常会发现或发生各种不同类型的失效 ,主要反映在磨耗、疲劳裂纹、剥离、掉块、崩块、崩箍等。从目前国内车轮、轮箍运用情况来看 ,踏面剥离现象占了失效的绝大多数 ,从国外的运用现状来看也是如此。车轮、轮箍踏面剥离是一个比较复杂的失效种类 ,导致其剥离的因素很多 ,无论是车轮、轮箍材质本身 ,还是运用工况的变化或机车车辆的结构设计等方面缺陷 ,均有可能导致剥离现象的产生 ,因此 ,正确判别剥离失效的特性 ,找出产生剥离的主要原因 ,对指导现场进行正确的预防 ,保证机车车辆的安全行驶具有重要意义。本文运用失效分析手段 ,根据各种典型剥离现象的宏观和微观形貌特征 ,总结出车轮、轮箍踏面剥离的四种类型 (接触疲劳剥离、局部接触疲劳剥离、制动剥离、局部擦伤剥离 ) ,其中对制动剥离提出了它的两种产生方式 (制动热裂纹和马氏体碎裂 ) ,本文对每种剥离类型均配有实物宏观和微观金相照片加以说明 ,指出了各自的宏观形貌表现特征 ,并对其各自的形成原因进行了机理上的分析和探讨。需要说明的是 ,在实际运用过程中 ,很可能在同一个车轮或轮箍上同时出现文中所提的两种或两种以上的剥离类型 ,这时就需要根据经验和各种失效形?

The railway wheel and tire delivered by the manufacturer should live up to the technical specification but they always have occurred some different kinds of failures, including primarily the tread wear, fatigue crack, tread spall, mass lose and wheel tire separation. The application of wheel and tire show that the wheel spalled tread is the major failure. So is in foreign countries.Wheel and tire spalling is a kind of complicated failures; there are many factors leading to it, such as the defection of the material of wheel and tire, variance of running, or the structure design of locomotive & car. So, it is important to distinguish the properties of spalling failure correctly so as to find the reason and to prevent it, and to ensure the safe running of locomotive and car. According to the characteristics of typical spalling, using the failure analysis method, this paper summarizes four types of wheel and tire treads spalling, and describes two ways of braking spalling generation. This paper explains every kinds of spalling type with the metallurgical phase photos, and puts forward their characteristics, analyzes the formation mechanism. On the same wheel or tire, two or more spalling types mentioned above can occur. In that case, further analysis and decision should be made according to the experience and failure exhibition.