Abstract: Grinding, polishing, cutting and other machining processes generate high volumes of fine metallic dust. Due to different material and processing methods, the explosion risks of these kinds of industrial dust are uncertain. An improved dust explosion screening test method based on both Hartmann tube and 20 L siwek sphere was worked out and used to test 85 kinds of aluminum and its alloy dust generated in common machining process. XRF was performed to analyze the dust explosibility with different aluminum and iron content. The relationship between oxidation degree and dust explosibility was studied by using TG-DSC. The results show that the dust can be divided into three categories: certainly explosible, possibly explosible, and not explosible, that the explosion risk of dust is affected by particle size, composition, and oxidation among others, that most of the certainly explosible dust samples have more than 40% aluminum content or more than 70% iron content, and most of the possibly explosible dust have more than 40% iron content, and that the explosion risk of aluminum dust is inversely related to the degree of oxidation and dust samples are no longer explosible when the elemental content is less than 5.0%.

Key words: metallic dust, dust explosion, machining, screening test, risk analysis, X ray fluorescence(XRF), thermo gravimetric analysis & differential scanning calorimeter(TG-DSC)