Abstract: The fatigue performance of the welded steel lining sealing layer in artificial caverns for compressed air energy storage under long-term cyclic loading directly affects structural safety and service life. To elucidate the fatigue performance of Q345R welded steel linings under cyclic loading and identify the dominant influencing factors, the effects of stress amplitude, welding procedure, and steel lining thickness on fatigue behavior are investigated. The macroscale and microscale fracture mechanisms are further analyzed, and the crack resistance of various anticorrosive coatings under cyclic loading is evaluated. Accordingly, Q345R welded steel plate specimens were fabricated from base plates of three thicknesses (18, 22, and 25 mm) using different welding procedures (gas-shielded welding and submerged arc welding; double-sided and single-sided welding) and different anticorrosive coatings (cold-sprayed zinc, graphene zinc, and epoxy coatings). Subsequently, a systematic experimental program was performed, comprising nondestructive testing (magnetic particle and X-ray radiographic testing), fatigue tests (207－345, 207－470, and 207－530 MPa), and microscopic observations (coating microstructural examination and fracture surface analysis using scanning electron microscopy). The results indicate the following: (1) At the same thickness, the strain of welded steel liners exhibits a marked positive correlation with stress amplitude, whereas the welding method and the number of surfaces exert no notable influence on the strain. (2) In uniaxial tensile tests, fracture of the welded specimens occurs in the base metal region, whereas under fatigue loading, although cracks initiate at the fusion line-base metal interface, the final fracture remains in the base metal area. (3) Under fatigue loading, the crack resistance of the anticorrosive coatings decreased in the following order: graphene-zinc composite coating > epoxy coating > cold-sprayed zinc coating. (4) Under the three stress ranges, all fatigue-fractured specimens exhibited axial strains ranging from 11% to 13%, which can be preliminarily considered the critical strain threshold for fatigue failure of this type of welded specimen. (5) This finding indicates that utilizing the plastic capacity of the steel plate to reduce liner thickness for cost savings holds potential in compressed air energy storage engineering. However, the associated theory and design guidelines remain to be refined through more comprehensive laboratory and insitu testing.

Key words: compressed air energy storage, artificial caverns, steel plate lining, fatigue performance, anticorrosion coating, fracture mechanism