Conference Year



flapper valve, reed valve, hermetic, semi-hermetic, compressors, stainless steel, damping, fatigue


Flap-X is a new reed valve steel developed for compressor applications. The development work was undertaken after consistent feedback from customers requiring higher fatigue strength and improved damping properties. The renewed interest in improved valve strip is a direct result of the industry’s latest trends towards energy efficient compressors. Different steel grades were investigated during process development and Flap-X material, which is an optimized version of the well-known compressor steel UHB SS716, showed the most promising results in terms of production feasibility and desired enhancements in alloy design, metallurgy and mechanical properties. Finished valve strip of each candidate material was used to quantify microstructure, tensile strength and fatigue life. Fracture investigations on the fatigue test samples were undertaken to detect any contributing non-metallic inclusions. Vibration damping was measured at temperatures and frequencies corresponding to operating conditions of reed valves in a compressor. Impact fatigue strength was measured in a recently developed test rig. Both fatigue life and damping properties are improved at increased tensile strength in all of the investigations.Â