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To reduce the waste of austenitic stainless steels due to their low yield strengths, the strain hardening technology is used to significantly improve their yield strength, in order to increase the elastic loadcarrying capacity of austenitic stainless steel pressure vessels. The basic principle of strain-hardening foraustenitic stainless steel pressure vessels and two common models of strain hardening, including AvestaModel for ambient temperature and Ardeform Model for cryogenic temperature, were briefly introduced.However, it was fully established by experiments, the lack of a necessary theoretical foundation and thesafety concern affect its widespread use. In this study, we investigated the load carrying capacity ofstrain-hardening austenitic stainless steel pressure vessels under hydrostatic pressure, based on the elastic-plastic theory. To understand the effects of strain hardening on material behavior, the plasticinstability loads of around tensile bar specimen were also derived under two different loading paths andvalidated by experiments. The results of theoretical, experimental and finite element analyses illustrated,considering the effect of material strain hardening and structural deformation, at ambient temperature, thestatic load carrying capacity of pressure vessels does not relate to the loading paths. To calculate the plasticinstability pressures, a method was proposed so that the original dimension and original materialparameters prior to strain hardening can be used either by the theoretical formula or finite element analysis.The safety margin of austenitic stainless steel pressure vessels under various strain hardening degrees wasquantitatively analyzed by experiments and finite element method. A 5％ strain as the restrictive conditionof strain hardening design for austenitic stainless steel pressure vessels was suggested.