TITLE:
Analysis of Structural State of 60/40 Brass Cartridge Case (BCC) after Being Exposed to High Pressure and Temperature of Firing
AUTHORS:
Abdalla Saif Eldin Mohammed
KEYWORDS:
Structural State, Brass Cartridge Case (BCC), Deficiency of Zinc, Reloading
JOURNAL NAME:
Open Journal of Applied Sciences,
Vol.9 No.9,
September
24,
2019
ABSTRACT: This research presents an experimental and analytical study of the
structural state of the 60/40 brass cartridge case, (BCC) after being fired.
The oral section of the BCC has the function of confining the gases of firing
by expanding against the chamber and sealing
the gases. Firing conditions, namely, high pressure and temperature, 3000 bar and
2727°C, respectively, affect performance properties of the (BCC). These are
confining and crack strengths. Experimental study was done on the oral section to address these effects on the structural
and mechanical properties of this brass. This alloy is a 60% copper (Cu) and 40% zinc (Zn) alloy and has a two-phase structure, alpha, (α) and beta, (β). Using “before and after” comparison approach; performance properties were tested in cartridge cases prepared before and after firing. These properties are hardness, tensile strength, micro-structural and chemical composition.
Comparing the tests’ results, after
firing demonstrated considerable degrading in performance properties, micro-structural disorder
and a remarkable deficiency in the zinc element in the brass structure. This
deficiency affects the percentage of beta phase in the alloy which governs the strength of the brass. According to the required properties before firing,
it was found that after
firing, the
brass cartridge case is not qualified for reloading.