一、前言 C_(50)敞车是我国主型通用敞车之一,过去长时间里,铁路货运总量约三分之一是由它完成的。近年来,随着新型车辆的增加,车种比例有所变化,但C_(50)敞车总数仍占全部敞车的二分之一。 C_(50)敞车自1952年设计投产以来,曾多次改变设计,截至1961年,仅主导设计厂就进行了13次。七十年代初,使用我国自轧560工钢和日本进口的H512型钢,又设计制造了一批新的C_(50)敞车。现在,总计约8万辆中的3万辆是1959年后设计生产的450工钢中梁车。这些车在运用过程中不时出现中梁下盖板焊缝开裂及中梁折损,曾造成过重大行车事故。1971年 I. Introduction C_ (50) gondola is one of the main gondola cars in China. In the past a long time, about one third of the total railway freight traffic was completed by it. In recent years, with the increase of new vehicles, the proportion of vehicles has changed, but the total number of G_ (50) gondola cars still accounts for one half of the total. C_ (50) gondola has changed its design many times since it was put into operation in 1952. As of 1961, it has conducted 13 times only in the leading design factory. In the early 1970s, a new batch of C_ (50) gondola was also designed and manufactured using H512 steel imported from China’s self-rolling 560 steel and Japan. Now, a total of 30,000 out of 80,000 vehicles is a 450-girder midship beam designed and manufactured after 1959. Occasionally, heavy traffic accidents have been caused in these vehicles during the course of their operation due to cracked welds in the underside beams and the collapse of the mid-beams. 1971