Abstract
Grazing impact experiments of various types of stainless steels were performed in explosive atmospheres of hydrogen, acetylene, ethylene or propane with air. Depending on the gas mixture, kinetic energy of the impact, and applied stainless steel, the dominant ignition sources are either separated particles or hot friction surfaces. An influence of chromium content on the ignition probability was not found, although an increase in chromium content results in a reduction of the oxidizability of separated particles. Additionally, the influence of the material properties thermal conductivity, specific heat, density and hardness on the ignition probability of the hydrogen–air mixture was investigated. With increasing thermal conductivity a decreasing rate of ignitions was observed. In contrast, an influence of the physical properties specific heat, density and hardness on the ignitability was not found.
