Development And Application Properties Of High-performance Q370qE-HPS Bridge Steel

The safety, reliability and durability of the structure of bridges, put forward strictrequirements for bridge steel of high strength, high toughness, low yield ratio, easywelding and other indicators to the direction of the high performance. In order todevelop the Q370qE-HPS steel and its related industrial production technology and thecomprehensive application of performance. Investigation on Q370qE-HPS steel hasbeen carried out by thermal simulation test and industrial application test, which willprovide the basis for the application in the bridge industry.The laboratory simulation test results show that:(1) the design of controlledrolling and controlled cooling process for Q370qE-HPS steel is that the roughingrolling temperature is more than1000°C, the finishing rolling start temperature is lessthan925°C, interval time is less than25s, the finishing temperature is880~820°C;accelerated cooling stage of start cooling temperature is820~760°C, final coolingtemperature is more than600°C which can be adjusted by different thickness and thecooling rate is estimated to be to5°C/s;(2) the Q370qE-HPS steel has a goodhigh-temperature thermal plasticity than that of the conventional normalized Q370qEsteel;(3)the Q370qE-HPS steel has a good hot straightening properties and thetemperature allows not higher than800°C.The industrial application test results show that:(1) the chemical composition andmechanical properties of Q370qE-HPS steel are in accordance with GB/T714-2008standard and the temporary technical conditions of Q370qE-HPS steel and themechanical properties are of reasonable control, good uniformity, excellent lowtemperature toughness and fracture toughness;(2) the mechanical performance oftypical welded joint is in accordance with the TB10212-2009standard and the impactperformance is significantly better than that of normalized Q370qE steel;(3) themacrostructure of continuous casting of Q370qE-HPS steel is low center segregationand the surface quality of steel plate has increased significantly.