Abstract: The practice of suspects using gas explosions to conceal tool marks at crime scenes poses challenges for case investigations, yet research on the retention patterns of cutting tool marks in gas explosion environments remains relatively scarce. This study examines gas rubber hoses cut by household scissors. Using an instantaneous high-temperature experimental platform (heating durations of 200, 400, 600, 800, 1 000 ms) and a full-scale gas explosion experimental platform, combined with digital cameras, stereomicroscopes, and energy dispersive spectrometers, we systematically analyzed and compared the morphological and elemental composition changes on the cut surfaces of the rubber hoses. Results indicate that under instantaneous high-temperature conditions with heating durations below 200 ms, shearing tool marks remain identifiable via stereomicroscopy. When heating exceeds 400 ms, marks become unrecognizable due to severe carbonization and ablation. Comparisons between full-scale explosions and 200 ms instantaneous high-temperature conditions revealed that both scenarios yielded identifiable surface shearing tool marks morphologically. Elemental content differences primarily resulted from varying oxidation environments and thermal intensity. This study provides theoretical foundations and technical support for identifying and analyzing shearing tool marks in gas explosion cases.

Key words: transient heat, rubber tube, shear tool marks, gas explosion site