弛豫工艺对耐候桥梁钢组织及性能的影响
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摘要
利用金相分析、力学性能测试、电子探针以及周浸加速腐蚀等方法,研究了轧后直接水冷、弛豫30、85及270 s对420 MPa级耐候桥梁钢显微组织、力学性能及耐候性能的影响。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。
Influence of relaxing process,namely direct water cooling,relaxing for 30 s,85 s and 270 s,on the microstructure,mechanical properties and weathering resistance of 420 MPa 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. 88 to 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.
Influence of relaxing process,namely direct water cooling,relaxing for 30 s,85 s and 270 s,on the microstructure,mechanical properties and weathering resistance of 420 MPa 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. 88 to 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.
引文
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[15]夏卿坤,刘志义,林亮华,等.冷轧变形对Al-Zn-Mg-Cu铝合金剥落腐蚀性能的影响[J].材料热处理学报,2012,33(S2):60-64.
[2]刘清友,汪兵,王向东.耐候钢的研究,应用及展望[J].钢结构,2011,26(S1):112-113.
[3]于千.耐候钢发展现状及展望[J].钢铁研究学报,2007,19(11):1-4.
[4]贺君,刘玉擎,陈艾荣.耐候钢在桥梁工程中的应用[C]//2006年钢桥科技论坛全国学术会议.北京,2006.
[5]王飞,施刚,戴国欣,等.屈强比对钢框架抗震性能影响研究进展[J].建筑结构学报,2010,31(1):18-22.
[6]洪君,陈钊.低屈强比高强度结构钢的发展概况[J].鄂钢科技,2011(2):54-58.
[7]吴耀华,岳清瑞,曾滨.建(构)筑物抗震结构对钢材性能要求的研究[J].钢结构,2017,32(1):87-90.
[8]宋国栋.弛豫技术在低屈强比钢板生产中的应用[J].轧钢,2015,32(6):75-77.
[9]焦多田,蔡庆伍,武会宾.轧后冷却制度对X80级抗大变形管线钢组织和屈强比的影响[J].金属学报,2009,45(9):1111-1116.
[10]郑东升,朱伏先,李艳梅,等.空冷弛豫对铌微合金化热轧多相钢组织性能的影响[J].钢铁,2011,46(4):70-75.
[11]方鸿生,徐平光,白秉哲,等.一种新的复相组织:仿晶界型铁素体/粒状贝氏体[J].金属热处理,2000,25(11):1-5.
[12]聂文金,尚成嘉,关海龙,等.铁素体/贝氏体(F/B)双相钢组织调控及其抗变形行为分析[J].金属学报,2012,48(3):298-306.
[13]马鸣图,汪德根,吴宝榕.双相钢中混合物定律的适用性(一)[J].钢铁研究学报,1983,3(1):86-92.
[14]张旭,杨善武,张文华,等.低合金耐候钢在周期性交替条件下的腐蚀行为[J].材料研究学报,2013,27(1):18-24.
[15]夏卿坤,刘志义,林亮华,等.冷轧变形对Al-Zn-Mg-Cu铝合金剥落腐蚀性能的影响[J].材料热处理学报,2012,33(S2):60-64.