高耐候性低屈强比Q500qENH厚板桥梁钢开发研究

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Abstract： To develop Q5o0qENH bridge steel heavy plates meeting the requirements of high weather resistance and low yield ratio， this study conducted trial production using a production process combining“low-carbo and high-alloy composition + cooling process + tempering heat treatment”，with the steel plate thickness being 60 mm.Through tensile， impact，and welding tests，by employing scanning electron microscopy and metallographic microscopy，the mechanical properties and microstructureofthesteel plates after heattreatment were systematically analyzed.Theresults show that the microstructure of the tempered stel plates is mainly composed of bainite and acicular ferrite，and the fracturemorphology presents ductile fracture.Inadition，the transverseand longitudinal tensilepropertiesand low-temperature impact properties ofthe steel platesarebetter than the standardrequirements， with the ductile-brittle transition temperature ranging from -50°C to -60∘C ，exhibiting low yield ratio， high weatherresistance，and excelent low-temperature impact toughness.Meanwhile，the steel plates show excellent welding performance，and the mechanical properties ofeach region of the welded joints meet the technical standards.

Keywords： weather resistant bridge steel; low yield to strength ratio; Q5ooqENH steel; weldability

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随着我国基础设施建设的持续深化，桥梁工程正向大跨度、重载化，以及高原、沿海等复杂环境方向快速发展。（剩余6215字）