弛豫工艺对耐候桥梁钢组织及性能的影响

第41卷 第1期 上 海 金 属 Vol.41,No.1

2019年1月 SHANGHAI METALS January ,20191 基金项目:国家重点研发计划(No.2017YFB0304800)作者简介:黄乐庆,男,硕士,助理工程师,E-mail:huangleqing0716@https://www.360docs.net/doc/5718169103.html, 弛豫工艺对耐候桥梁钢组织及性能的影响

黄乐庆1,2 王彦锋1 杨永达1 马长文1 狄国标1 韩承良3

(1.首钢技术研究院宽厚板所,北京100043;2.北京市能源用钢工程技术研究中心,北京 100041;3.秦皇岛首秦金属材料有限公司,河北秦皇岛 066326) ?摘要? 利用金相分析二力学性能测试二电子探针以及周浸加速腐蚀等方法,研究了轧后直接水冷二弛豫30二85及270s 对420MPa 级耐候桥梁钢显微组织二力学性能及耐候性能的影响三结果表明:随着弛豫时间的延长,试验钢板的组织类型由针状铁素体(AF )+粒状贝氏体(GB )逐渐转变为铁素体(F )+贝氏体(B ),并进一步转变为铁素体(F )+珠光体(P );同时,试验钢板的屈服强度的下降速率明显大于抗拉强度的,屈强比由0.88降低至0.62;周浸试验结果表明:在弛豫过程中耐候性元素未发生明显的扩散,因而钢板的腐蚀速率波动不大三

?关键词? 弛豫时间 耐候桥梁钢 组织与性能 耐候性能

Influence of Relaxing Process on Microstructure and Mechanical Properties of Weather-proof Bridge Steel

HUANG Leqing 1,2 WANG Yanfeng 1 YANG Yongda 1 MA Changwen 1 DI Guobiao 1 HAN Chengliang 3

(1.Plate Technology Department ,Shougang Research Institute of Technology ,Beijing 100043,China ;2.Beijing Engineering Research Center of Energy Steel ,Beijing 100041,China ;3.Qinghungdao Shouqin Metal Materials Co.,Ltd.,Qinghungdao Hebei 066326,China ) ?Abstract ? Influence of relaxing process ,namely direct water cooling ,relaxing for 30s ,85s and 270s ,on the microstructure ,mechanical properties and weathering resistance of 420MPa grade weather-proof bridge steel after rolling was researched by means of metallographic analysis ,mechanical property test ,electron probe and cyclic dry-wet accelerated corrosion test.The results showed that with the extension of relaxation time ,the microstructure of the test steel plate was gradually changed from acicular ferrite (AF )plus granular bainite (GB )to ferrite (F )plus bainite (B ),and further transformed to ferrite (F )plus pearlite (P );moreover ,the yield strength dropped faster than the tensile strength ,thus the yielding-to-tensile ratio decreased from 0.88to 0.62.The results of cyclic dry-wet accelerated corrosion test showed that there was no significant diffusion of the weather-proof elements during the relaxing ,so the corrosion rate of the steel plate fluctuated a little.

?Key Words ? relaxation time ,weather-proof bridge steel ,microstructure and property ,weathering resistance 进入21世纪以来,我国公路桥梁二铁路桥梁,尤其是跨江跨海大桥建设都取得了举世瞩目的成

就三但是与发达国家相比,我国耐候桥梁的发展

仍比较缓慢[1-2]三由于耐候桥梁钢在全寿命周期

内较普通桥梁钢+涂装的防腐处理方式具有较好的成本优势,且符合绿色循环发展的理念[3-4],因此国内在建的拉林铁路藏木雅江特大桥以及官厅水库桥,开启了我国耐候铁路桥及公路桥裸装的

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