Prediction of erosion from heat transfer measurements of 40 mm gun tubes

An empirical equation of the wear rate for a 40 mm gun tube is derived as a function of heat input into the gun barrel. The heat input is calculated from the Fourier's law by substituting measured transient bore surface temperatures. Two series of temperature data, one for ammunition A and another for ammunition B were measured at the same atmospheric conditions by using rapid response K-type thermocouples combined with a high-speed recorder. The measured temperature data show quite similar patterns to those of the references, i.e. 7.62 mm rifle and 105 mm gun, but with lower peak surface temperatures than those of references due to the use of an in-wall thermocouple. By fitting calculated heat input and measured wear data for both As and Bs into the suggested equation, an empirical wear equation as a function of heat input is derived. The resultant numerical wear rate from the empirical wear equation shows good agreement with the measured one and also shows similar patterns with respect to that of the reference, i.e. 105 mm cannon tube.