Study On Safety Characteristics Of Spherical Nitroguanidine And Its Charge

Taking spherical nitroguanidine and its charge as the research object,the mechanical stimulation characteristics and thermal safety characteristics of spherical NQ were studied,and the low vulnerability performance of its charge was verified.The explosion probability and critical mechanical stimulation threshold of spherical NQ were studied by using impact sensitivity and friction sensitivity test devices.The results show that in the impact sensitivity test,the explosion probability of ordinary NQ and spherical NQ is0%,and the critical impact energy is 25 J and 27.5 J respectively;For spherical NQ,when the temperature increases from 25 ℃ to 80 ℃,the critical impact energy decreases from 27.5 J to22.5 J;In the friction sensitivity test,the explosion probability of ordinary NQ and spherical NQ is also 0%,and the critical friction is greater than 360 N.When the temperature rises to80 ℃,the critical friction decreases from more than 360 N to 360 N.It shows that the mechanical sensitivity of spherical NQ does not change significantly with temperature in the test temperature range,and it is very insensitive to mechanical stimulation.The thermal safety characteristics of spherical NQ and its charge were studied by differential scanning calorimeter(DSC),adiabatic calorimeter(ARC),slow cook-off and fast cook-off tests.The DSC heating rate is from 1 K / min to 15 K / min,and the initial decomposition temperature of the sample is increased from 236 ℃ to 254 ℃.The apparent activation energy of the sample reaction is 144.84 k J / mol.There is only one exothermic peak in the exothermic process of spherical NQ measured by ARC.The initial decomposition temperature of the sample is 140.91 ℃ and the end temperature is 246.85 ℃.The apparent activation energy of the sample is 162.67 k J / mol and the critical temperature of thermal explosion is 92.25 ℃.The initial decomposition temperature measured by ARC is lower than that measured by DSC,because there is heat exchange between DSC test system and outside during sample decomposition,while ARC provides an adiabatic environment,and the sample heat will not be lost.The response temperatures of the two slow cook-off are 154.3 ℃ and157.4 ℃ respectively,which is basically consistent with the experimental results of ARC.The response grades of the sample in slow cook-off and fast cook-off are deflagration,indicating that the spherical NQ has a strong response to thermal stimulation.The response characteristics of spherical NQ charge under mechanical stimulation were studied by bullet impact and fragment impact tests.The response grades are combustion and below;The compound stimulation response characteristics of spherical NQ charge were studied through shaped charge jet impact,martyrdom explosion and thermal debris impact tests.The response grades are combustion,non reaction,combustion and below respectively.All of them have passed the ammunition low vulnerability test,which is consistent with the research conclusion of mechanical sensitivity of spherical NQ in chapter 2.It shows that spherical NQ charge is very insensitive to mechanical stimulation and compound stimulation.