A Potential Metallographic Technique for the Investigation of Pipe Bombings

Abstract

This study was conducted in an attempt to develop a metallographic method for the investigation of pipe bombings. Three common pipe materials, ASTM A53 steel, AISI 304L stainless steel, and 6061-T6 aluminum, were shock-loaded using five high explosives and three propellants. The explosives used were ANFO, Composition C4, C6 detasheet, nitroglycerine-based dynamite, and flake TNT. The propellants used were FFFFg black powder, Red Dot smokeless powder, and Turbo Fuel A. The post-blast microstructure, hardness, and, in the case of 304L, transformed martensite content were examined for each test. The damage done to the microstructure was found to increase with increasing detonation velocity of the explosives and increase in pressure generated by the shockmetal interaction. Material hardness and, in the case of 304L, martensite content showed a sharp increase followed by a plateau as the shock pressure and detonation velocity increased.

Forensic Science

“…A highly sensitive screening method based on HPLC-atmosphere pressure ionization-mass spectrometry has been developed for the analysis of 21 nitroaromatic, nitramine and nitrate ester explosives (286). A study was conducted in an attempt to develop a metallographic method for the investigation of pipe bombings (287). A study was undertaken to assign a rough order of magnitude for the amount of explosive residue likely to be available in real-world searches for clandestine explosives (288).…”

The Anatomy of a Pipe Bomb Explosion: Measuring the Mass and Velocity Distributions of Container Fragments

“…This has included microstructure deformation and hardness, to correlate explosive properties with material response. Walsh concludes that as the detonation pressure and velocity increase, microstructure deformation increases as well, to the point of localized recrystallization in some cases (17). At low detonation velocities and pressure, the hardness increased immediately, compared with a plateau at medium velocities and a decrease in hardness with high energy fillers.…”