Analysis and Research on Common Failure Modes of Internal Combustion Engine Springs

Abstract

In order to improve the service reliability of internal combustion engine springs, the spring steel sample in this paper is an experimental test piece, the material is chromium-silicon (55CrSi, 60CrSiA), chromium-vanadium (50CrVA), etc., using macroscopic observation, scanning electron microscopy fracture analysis, energy spectrum EDS component detection and metallographic inspection and other methods to detect common failure modes such as quenching cracks, folding, pits, corrosion pits, mechanical damage, scratches, inclusions, The results show that the quenching cracks are due to the superposition of thermal stress and microstructure stress during the quenching process. Folding and inclusions are the main sources of stress concentration with defects in the manufacturing process; corrosion is mostly related to the high-temperature service environment. As the origin point of fatigue cracks, the pits on the surface of the spring destroy the continuity of the material and significantly reduce the fatigue strength, causing early fatigue fracture. This paper clarifies the key failure forms and root causes of internal combustion engine springs, and proposes a set of scientific and systematic electron microscopy analysis methods, which cover the analysis and characterization of the micro-composition of the fracture anomaly area, the surface distribution and line distribution of elements, inclusions and other chemical elements of defects, evaluate the influence of parts physical and chemical indicators on the causes of fracture, and provide theoretical support and improvement direction for the reliability optimization of internal combustion engine springs.