Failure analysis of screw shaft in screw compressor

A commonly used device for producing compressed air in refineries is the screw compressor. This kind of compressor has been widely used in several applications, such as the electric power, chemical and energy industries, mainly due to its high efficiency and safety [1-6]. Basically, a screw compressor consists of two rotors in a common casting [7]. The rotors are typically made of carbon steel, and the compressor casting is typically made of cast iron [8]. However, it is important to note that during in-service time, the screw shaft, as a critical component of the rotor, is always subjected to high rotational velocity and aggressive environments. To date, several factors have been shown to lead to screw shaft failure. Shahrivar et al. [8] investigated the failure of screw This paper analyses the root causes of screw shaft failure in screw compressors. The failure mechanism was studied by visual inspection, macro-and microfractography, chemical characterization, and mechanical property analysis. The results reveal that the main reason for the failure was multisource fatigue due to the lack of surface quenching at the fracture position of the shaft root. To prevent similar failures, better control of surface quenching is strongly recommended.