Reasearch On Corrosion Resistance And Rust Stability Of Uncoating Weathering Bridge Steel

This thesis had studied the difference of corrosion resistance between uncoating weathering steel new researches and carbon steel by analyzing accelerated corrosion tests and outdoor rust layer accelerating test.The stability of the rust layer of weathering steel also be studied in this paper.Weather resistant steel were designed to withstand atmospheric corrosion index(I index)greater than 6.5,and compared with plain carbon steel,studied corrosion resistance of the weathering steel.And the outdoor stability test of rust layer of weathering steel and carbon steel after blasting,the rust layer accelerated stable morphology was studied by the metallographic section,micro morphology,rust layer structure and electrochemical characteristics,to explore the formation process of rust layer,and to evaluate the weathering steel on the stability of rust layer.The first cycle of weathering steel and carbon steel cycle corrosion test in the laboratory,corrosion resistance test respectively simulated marine atmosphere environment,industrial environment,test conditions reference TB/T 2375-1993 and ISO 11130-2010(GB/T 19746-2005).Compared corrosion experiment after weightlessness,macro morphology and phase composition of the rust layer material etc.Under the experimental conditions,the corrosion resistance of weathering steel is about 2 times that of plain carbon steel,which shows that the design of weathering steel has good resistance to atmospheric corrosion.Accelerated stability test of rust layer outdoor on the weathering steel and plain carbon steel specimens after sandblasting was conduct,and compared rust layer of weathering steel with rust of plain carbon steel.Discover that the rust layer thickness of weathering steel and plain carbon steel is close before steady,and cracks exist in both of weathering steel rust layer and plain carbon steel layer,electrochemical characteristics are close.But with the thickness of weathering steel rust layer increasing,get to stable gradually,more dense,crack healing,electrochemical activity reducing.There is no obvious inner and outer rust layer after sandblasting,no falling off.The rust layer is getting stable after 12 weeks of accelerating and growing,and the thickness is about 30μm.Experimental tests have demonstrated that,the corrosion resistance of weathering steel have good performance,rust layer have good stability,no obvious cracks,and it can be used without coating.