Measuring and Improving the Puncture Resistance of Self-Pressurized Containers
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When self-pressurized containers, or aerosols, are accidentally dropped they are susceptible to puncture. The likelihood of puncture depends on the distance of the fall, the nature of the object that the aerosol might strike, the orientation of the impact, and the aerosol’s materials of construction, including microstructure. Due to the flammable nature of the propellants common to aerosols as well as other flammable contents, the accidental puncture of an aerosol has on occasion resulted in significant personal injury and property damage. While the Department of Transportation regulates several aspects of aerosol containers, there are no government regulations concerning puncture resistance. Likewise, there are no standard tests for the puncture resistance of aerosol containers. This article presents two different test methods that can be used to quantify the puncture resistance of aerosol containers. One mode of puncture is not a pure puncture, but rather an impact-induced circumferential puncture or crack. This is due to the anisotropic microstructure of the body material of most 3-piece steel aerosol containers. Experimental testing has shown that the most common type of aerosol container is highly vulnerable to impact-induced impact circumferential puncture. Free falls from a little as 20.32 cm (8 in.) onto wood pyramids are able to induce this type of puncture. This is a hidden and unexpected vulnerability inherent in most 3-piece steel aerosol containers. Experimental tests show that this susceptibility to impact-induced circumferential puncture as well as pure puncture can be greatly reduced, if not eliminated, by using container bodies with more isotropic microstructures.