铁路机车用轮箍超探透声不良分析

Analysis of Poor Soundtransparent Tyres for Locomotive

一炉铁路机车用轮箍J307(U)的部分在超声波检测时草状波严重、底波损失大,解剖取样做金相检验,发现超探透声不良区域的实际晶粒度达1级甚至更粗。对该炉轮箍的生产过程调查发现,该炉轮箍晶粒粗大为热处理过程异常所致。对超探透声性能不合格的轮箍进行重新热处理后,绝大部通过了超声波检测,且金相检验正常。在此基础上,对轮箍超探透声检测方法和等温后吊出轮箍的热处理工艺提出了改进意见。

A heat of J307（U） tyres showed serious grass-like waves and more loss of bottom wave in ultrasonic testing.Macroscopic examination of dissected sample showed that actual grain size of poor soundtranspatent areas reached grade 1 or even coarser.Investigation of the production process found that the coarse grain of those tyres had been caused by abnormal heat treatment process.After re-heat-treatment,most of the defective tyres passed UT and showed normal metallurgical structure.Based on this case,improvement advices are given on soundtransparent testing method and heat treatment technics for tyres out of isothermy.