Volgograd State Technical University (Volgograd, Russia):

Palatkina L. V., Cand. Eng., Ass. Prof., the Chair “Materials Technology”
Zyuban N. A., Dr. Eng., Prof., Head of the Chair “Materials Technology”, e-mail: tecmat@vstu.ru
Grebnev Yu. V., Cand. Eng., Ass. Prof., the Chair “Equipment and Technology of Foundry Production”

“Zheldorservis” Railroad Car Shed (Volgograd, Russia):

Polyakova O. V., Engineer of 2nd category, Lab. of Non-Destruction Testing

The article observes the results of the analysis of defects of a responsible detail of freight cars — a side frame — in the process of their operation. The research was aimed on the zones that were not controlled at delivery tests of a finished product. It was established that 20% of details are operated with dangerous defect (cracks). The main morphological features of cracks are studied and their crystallizing nature is established using fractographic and metalgraphic analysis. It is shown that the initial crack can unite with nearby defects like sinks that promotes its further development and growth. It is concluded that 85% of the cases of removal of side frames from operation during technical maintenance of trains is connected with manufacturing defects located outside the areas of mandatory non-destructive testing. Visual evaluation of the revealed defects (cast cracks) should accompany by visual observance of their genuine dimensions. i.e. by taking into account nearby groups of pores that increase softening effect of the main crack by 20% in average, being its continuation. In order to improve reliability and safety of side frame operation in freight cars, it is required to recommend the producers to expand volume of delivery tests, including observation of all casting zones.

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