某机枪枪管內膛损伤特征

为了探明某机枪枪管损伤特征，分析其失效机制，开展了寿命射击试验。采用光学显微镜、扫描电子显微镜、内窥镜和量规对枪管内膛表面进行观察和测量。结果表明，从枪尾至枪口Cr层主要损伤方式为由剥落向磨损转变，根据这个特征，寿终枪管沿轴向可分为剥落区、过渡区和磨损区。从剥落区至磨损区，膛线起始损伤从阴线逐渐向阳线转变。剥落区和磨损区的损伤速率均较高，而过渡区的损伤速率相对缓慢。在剥落区，射弹量为全寿命的27%时阴线出现大块Cr层掉落，射弹量为全寿命的55%时Cr层已完全剥落。在磨损区，射弹量为全寿命的7%时阳线导转侧已发生明显磨损，射弹量为全寿命的7%增至14%时内径从12.69 mm升至12.75 mm.

Bore Damage Characteristics of a Machine Gun Barrel

The shooting experiments were conducted to investigate the bore damage characteristics of a machine gun barrel and analyze the failure mechanisms. Optical microscrope, scanning electron microscrope (SEM), endoscrope, and guage are used for observation and measurement of barrel bore. Results show that the main failure mode of Cr layer along the gun barrel transits from spalling to wear. According to this characteristic, the spalling, transitional, and wear zones are identified along the axial direction of gun barrel. From spalling zone to wear zone, the initial damage location of rifling moves from the groove to the land. The damage rates in both spalling and wear zones are relatively higher, and the damage rate in the transitional zone is relatively lower. In the spalling zone, at 27% lifetime, the Cr layer peels off with large pieces; at 55% lifetime, the Cr layer peels totally off. In the wear zone, for only 7% lifetime, obvious wear occurs in the turn guide side of the land; when the lifetime is increased from 7% to 14%, the bore inner diameter is enlarged from 12.69 to 12.75 mm.