Residual behaviour of welded hollow spherical joints under corrosion and de-rusting

Abstract

This paper presents an experimental study of welded hollow spherical joints (WHSJs) under corrosion and de-rusting conditions. First, two scanning tests (3D scanning and scanning electron microscopy (SEM)) and a weight loss test were conducted on the same batch of steel used to manufacture the joints to investigate the corrosion morphology and development of the WHSJs under the same corrosion conditions. Subsequently, axial compression and tensile tests on eight corroded WHSJ specimens without anticorrosive coating (including two reference specimens for comparison) were conducted, and the relevant mechanical properties, such as the failure mode, load-displacement relationship, initial stiffness, bearing capacity, and strain distribution were studied. The results showed that the corrosion morphology of the WHSJs consisted mainly of uniform corrosion with slight pitting corrosion; the corrosion depth exhibited a lognormal distribution, and the initial axial stiffness, yield load, and ultimate load of the WHSJs were influenced by the corrosion and different de-rusting methods. After 100 days of accelerated corrosion tests (equivalent to 20 years in the corrosive environment of Qingdao), the compressive ultimate load decreased by 8.433%, and the tensile ultimate load decreased by 7.235%. Finally, a practical corrosion evaluation method with the statistical distribution and corrosion damage kinetics was established and validated.