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Influence of Firing Temperature on Properties of Gun Propellants



Author(s)

Karim Moulai Boulkadid^1*, Michel Lefebvre¹, Laurence Jeuniea¹ and Alain Dejeaifve²

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DOI:10.17265/1934-7375/2015.06.005

1. Laboratory for Energetic Materials, RMA, Brussels 1000, Belgium 2. PB Clermont SA, Engis 4480, Belgium

Initial firing temperatures play an important role on the combustion rate of propellant. In gun propellants, initial temperature is a key factor for both accuracy and safety. Ideally, the initial temperature of the propellant should not influence the ballistic properties of the round. Nevertheless, constant initial temperature coefficients can not be achieved easily. This work focuses on the influence of the firing temperature on the ballistic properties, the mechanical integrity and the sensitivity to impact of nitrocellulose based propellants. Combustion rates have been determined by closed vessel tests. Ballistic properties have been investigated by firing 5.56 cartridges. The propellants have been conditioned at temperatures ranging from -54 °C to +71 °C before firing. The largest temperature coefficient is observed at high temperatures. The temperature sensitivity of the peak pressure in the combustion chamber can not be fully explained by the results from the closed vessel test. The authors speculated that the mechanical behaviour of the propellant grains at low temperatures influences also the overall ballistic properties of the round. Impact tests with propellants conditioned at low and high temperatures permit to investigate their mechanical strength under extreme temperatures and to better understand the propellant performance during firing. Tests on aged propellants have been conducted as well.

Firing temperature, gun propellant, ageing, ballistic firing, closed vessel tests, impact tests.