Research On Reliability Of Low Temperature Pressure Vessel By Strain Hardening Austenitic Stainless Steel

The container of low temperature liquefied gas is produced by the strain hardening theory.The material could produce a higher allowable stress by strain hardening,which can reduce the calculation thickness of the container and save the production cost.Aiming at the failure and reliability of strain strengthening austenitic stainless steel cryogenic pressure vessels to carry out the research,the main failure modes and mechanism,to control and the actual use and inspection guidance.According to the structure and manufacturing process of low temperature vessel by austenitic stainless steel,strain hardening mechanism and influence factors is studied.Through different strain rate materials under low temperature toughness test,and from the simulation test of strain hardening after different strain rate on the interception of samples,the microstructure of weld and base metal the heat affected zone are studied respectively.The results show that the strain rate in the low temperature impact toughness changes a little less than 10% of materials;and with the increase of deformation,the percentage of martensite content increased gradually,with the deformation induced martensitic transformation theory.The key area of strain hardening process in numerical simulation of stress strain,the rule of the stress and strain changing with the load should be strain hardening process,and the cylinder head over near the junction of residual stress is larger,the maximum deformation position is located in the head at the top of the container.Failure mode analysis of the low temperature pressure vessel of the strengthened austenitic stainless steel and fault tree analysis was studied,the results show that Fatigue failure and the effect of the tank's manufacturing quality are the most on safety.The key points of manufacturing and application are studied.The key contents of the inspection are put forward from two aspects of the supervision and inspection of the vessel manufacturing stage and the periodic inspection.