Investigation of consequences of violation of technology of manufacture of individ-ual elements of BMP-2 track tape

Abstract

The operation of the BMP-2 infantry fighting vehicle was accompanied by periodic failures of the tracked belts. This is due to the breakage of the fixing bolts of the track pins fastening bracket, and thus the military equipment became stationary. Establishing the causes of the destruction of the bolt fixing the staple of the track fingers of the tracked belt of military equipment was carried out using a complex of instrumental materials science research. In particular, the chemical composition of the material from which the bolts and staples were made was determined by the spectral analysis; the fracture surface of the fixing bolt was investigated by the macroanalysis; the microstructure of the bolts was examined using optical microscopy; the microhardness and density of the bolt material was measured. The bolts were made from steel grades 30XM and 33XC, and not from the recommended steel grade 38XC. The macrostructure of the broken bolt corresponds to the shearing structure. The microstructure showed rolling and heat treatment defects. Density measurement confirmed the presence of heat treatment defects. The imperfection of the applied heat treatment was confirmed by measuring the microhardness. A complex of metallurgical research has established the main cause of the destruction of the bolts. It consists in an unsuccessful design of bolts and brackets, an incorrectly selected steel grade with defects in rolling and heat treatment.