低温环境对枪械零件冲击疲劳的影响研究

Study on the influence of low temperature environment on impact fatigue of gun parts

通过对某型号自动步枪进行低温环境和室温环境下的实弹射击实验,探究低温环境对枪械零件冲击疲劳的影响。低温环境下,击锤零件的疲劳寿命显著降低,与材料轴向疲劳性能测试结果不符。通过对失效零件进行宏观和微观观察,排除加工或者材料缺陷的影响。结合微观断口形貌和力学性能测试数据分析,结果表明:冲击疲劳相对于正常轴向疲劳来说,温度降低,疲劳敏感性升高;冲击疲劳寿命与材料强度和塑性韧性有关,低温回火后冲击韧性较低,随回火温度降低,冲击韧性低于冲击疲劳抗力的下限,疲劳寿命降低。对于长期在低温条件下服役的枪械零件,需要提高材料的低温冲击韧性,保证符合设计寿命需求。

In this study,live firing experiments were carried out on a certain type of automatic rifle at low temperature and room temperature.To explore the influence of low temperature environment on impact fatigue of gun parts.At low temperature,the fatigue life of hammer parts decreases significantly,which is not consistent with the test results of axial fatigue properties of materials.Through the macroscopic and microscopic observation of the failed parts.Eliminate the influence of processing or material defects.Combined with the experimental data of micro fracture morphology and mechanical properties,the results show that impact fatigue is more sensitive to temperature effect than normal axial fatigue.When the temperature decreases,the fatigue sensitivity increases.The impact fatigue life is related to the strength and ductility of the material.The impact toughness is lower after tempering at low temperature.With the decrease of temperature,the impact toughness is lower than the lower limit of impact fatigue resistance,which leads to the decrease of fatigue life at low temperature.For the gun parts which have been in service at low temperature for a long time,it is necessary to improve the low temperature impact toughness of the material in order to meet the design life requirements.