Marine Structural Steel AH32 Corrosion Fatigue Research And Durability Design

Ocean engineering structures due to its service environment,must be subjected to cyclic loading and corrosive environment at the same time,the corrosion fatigue problem has become the main factors influencing the service life of marine structural steel.So it is necessary to research corrosion fatigue characteristics and durability design.Taking AH32 steel as the research object of corrosion fatigue test,according to the corrosion test,axial tensile test and fatigue test data,respectively obtain its corrosion resistance,mechanical properties and fatigue performance.On the basis of fatigue test,the testing machine to be modified,designed the corrosion environment box and circulating device,prepared corrosion fatigue test conditions.The corrosion fatigue and pre-corrosion fatigue tests have been carried out at the same time,get the corrosion fatigue damage effect is superior to precorrosion fatigue,more than fatigue test.And according to the principle of thermodynamics,SEM topography of fracture formation and destruction mechanism has carried on the qualitative analysis.Based on the damage mechanics theory,two kinds of corrosion fatigue damage model is proposed.The first is based on the corrosion damage and pre-corrosion fatigue damage cumulative model,the second is based on the stress corrosion damage and fatigue damage nonlinear cumulative model.Through design experiment,respectively,to determine the stress corrosion damage parameter,the fatigue damage parameter,so as to establish corrosion fatigue damage evolution rule,used for corrosion fatigue life prediction.Combined with marine structural steel AH32 corrosion fatigue characteristics,in order to enhance its resistance to corrosion fatigue performance,improve life for the purpose,design a set of surface treatment,the technology of prolong life of arc spraying metal coating.And the two kinds of galvanized and chrome plating is prepared specimens,respectively after the corrosion fatigue test and pre-corrosion fatigue test,according to the results of galvanized,chrome plating specimen,compared with the bare steel specimen,its life got a certain level of ascension,in corrosion fatigue tests,the life of the ascending ratio can respectively reach 14.6% and 22%,to achieve the effect of the prolong life.Taking into account the cost and effect of Zinc and chrome,at the same time the most reasonable,can choose the dacromet coating,achieve the goal of significantly increase the durability of marine structural steel.