中文摘要：

针对动车组车轮在运用过程中出现的踏面浅表层裂纹,分别通过材料检测和理论计算对裂纹成因及影响因素进行了分析。分析表明,影响踏面浅表层裂纹形成的因素主要有两个方面：一是在轮轨接触应力作用下踏面下2~4mm范围内存在一个应力较大的区域,在该区域内车轮材料对应的强度裕量最小,容易形成材料疲劳,进而萌生疲劳裂纹;二是轮辋材料中靠近踏面表层区域可能存在脆性非金属夹杂物,在该区域较高的应力场条件下,脆性非金属夹杂物即成为萌生裂纹的起源。为防止产生车轮踏面浅表层裂纹,提出两个方面的对策,一是应提高车轮制造过程中钢材冶炼纯净度,控制脆性非金属夹杂物的数量和分布;另一方面对出现踏面浅表层裂纹的车轮及时进行旋修,在裂纹萌生的早期即将其去除,防止裂纹向深处扩展。

英文摘要：

Aiming at the shallow surface crack occurred on tread during the operation process of EMUs wheels,both methods of materials testing and theoretical calculation were used to analyze the reasons and influence factors of the crack.The analysis results show that there are two influence factors of shallow surface crack formed on tread.On one aspect,there is a large stress area 2~4mm below the tread due to the wheel rail contact forces.The wheel material in this area shows the minimum strength margin,which is vulnerable to fatigue,leading to the initiation of fatigue crack.On the other aspect,brittle nonmetallic inclusions may exist at tread surface,which could become the crack initiation under the high stress action in this area.In order to prevent the formation of shallow surface crack at the tire tread,two countermeasures are put forward.One is to improve the steel smelting purity in the manufacturing process of wheels,and control the number and distribution of brittle nonmetallic inclusions.The other is to carry out tread turning in time,and remove the micro-cracks at the early stage of crack initiation to prevent them from expanding into cracks.