In order to ensure the ballistic safety of fusible alloy fuze at reliable delay arming, melting point of fusible alloy needs to be calculated based on projectile velocity at safe time and distance. Taking shrapnel KZ...In order to ensure the ballistic safety of fusible alloy fuze at reliable delay arming, melting point of fusible alloy needs to be calculated based on projectile velocity at safe time and distance. Taking shrapnel KZVD fuze of Switzerland oerlikon 2ZLa/353 35 mm double barrel self-propelled antiaircraft artillery as an example, based on the aerodynamics heating theory, the calculation of theory model and simulation of projectile head stagnation point temperature were done in initial stage of sim-plified exterior ballistic from engineering viewpoint when the initial projectile velocity was 1 175 m/s and the error was ±15 m/s. The melting point of fusible alloy in the safe distance was obtained by analyzing the temperature of projectile head stagnation point at corresponding projectile velocity. The simulated results indicate that the melting point of fusible alloy de-rived by theoretical calculation is identical with the result of simulation at the velocity range of 1 160 to 1 190 m/s. So the aero- thermodynamics model can be applied to design the fusible alloy fuze of corresponding melting point based on the requirement of safe distance. This method can be taken as the reference in studying the thermodynamic question of projectile flying at high speed.展开更多
Three different bismuth-lead systems namely, Wood＇s alloy （Bi50Pb25Sn12.5Cd12.5）, Newton＇s alloy （Bi50Pb31.2Sn18.8） and Rose＇s alloy （B50Pb28Sn22）, with one used as fusible alloys were quenched from melt by m...Three different bismuth-lead systems namely, Wood＇s alloy （Bi50Pb25Sn12.5Cd12.5）, Newton＇s alloy （Bi50Pb31.2Sn18.8） and Rose＇s alloy （B50Pb28Sn22）, with one used as fusible alloys were quenched from melt by melt spinning technique. Thermal analysis, structure and mechanical properties of all alloys have been studied and analyzed. From X-ray diffraction analysis, an intermetallic compound phase, designated Pb7Bi3 is detected. The formation of an intermetallic compound phase causes a pronounced increase in the electrical resistivity. The Wood＇s alloy containing-cadmium exhibits mechanical properties superior to both the Newton＇s and Rose＇s alloys. The presence of cadmium in Wood＇s alloy decreases its melting point. Wood＇s alloy has better properties, which make it useful in various applications such as in protection shields for radiotherapy, locking of mechanical devices and welding at low temperature.展开更多
文摘In order to ensure the ballistic safety of fusible alloy fuze at reliable delay arming, melting point of fusible alloy needs to be calculated based on projectile velocity at safe time and distance. Taking shrapnel KZVD fuze of Switzerland oerlikon 2ZLa/353 35 mm double barrel self-propelled antiaircraft artillery as an example, based on the aerodynamics heating theory, the calculation of theory model and simulation of projectile head stagnation point temperature were done in initial stage of sim-plified exterior ballistic from engineering viewpoint when the initial projectile velocity was 1 175 m/s and the error was ±15 m/s. The melting point of fusible alloy in the safe distance was obtained by analyzing the temperature of projectile head stagnation point at corresponding projectile velocity. The simulated results indicate that the melting point of fusible alloy de-rived by theoretical calculation is identical with the result of simulation at the velocity range of 1 160 to 1 190 m/s. So the aero- thermodynamics model can be applied to design the fusible alloy fuze of corresponding melting point based on the requirement of safe distance. This method can be taken as the reference in studying the thermodynamic question of projectile flying at high speed.
文摘Three different bismuth-lead systems namely, Wood＇s alloy （Bi50Pb25Sn12.5Cd12.5）, Newton＇s alloy （Bi50Pb31.2Sn18.8） and Rose＇s alloy （B50Pb28Sn22）, with one used as fusible alloys were quenched from melt by melt spinning technique. Thermal analysis, structure and mechanical properties of all alloys have been studied and analyzed. From X-ray diffraction analysis, an intermetallic compound phase, designated Pb7Bi3 is detected. The formation of an intermetallic compound phase causes a pronounced increase in the electrical resistivity. The Wood＇s alloy containing-cadmium exhibits mechanical properties superior to both the Newton＇s and Rose＇s alloys. The presence of cadmium in Wood＇s alloy decreases its melting point. Wood＇s alloy has better properties, which make it useful in various applications such as in protection shields for radiotherapy, locking of mechanical devices and welding at low temperature.
