公路护栏钢Q345的表面镀锌与性能  

Surface galvanizing and properties of highway guardrail steel Q345

作　　者：王贵珍[1] 周玲珑 马卫华 Wang Guizhen;Zhou Linglong;Ma Weihua(College of Architectural Engineering,Chongqing Vocational Institute ofEngineering,Chongqing 402260,China;College of Materials Science and Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆工程职业技术学院建筑工程学院,重庆402260 [2]重庆大学材料科学与工程学院,重庆400044

出　　处：《金属热处理》2019年第10期177-181,共5页Heat Treatment of Metals

基　　金：国家自然科学基金(51471142);国家“十二五”规划科技支撑(2014BAJ14B03-2)

摘　　要：采用热浸镀法在公路护栏钢Q345表面制备了10种不同组分的低Al镀锌层,采用光学显微镜、扫描电镜、显微硬度计和盐雾腐蚀试验箱等手段,研究了Al、Mg和Si元素对表面镀层显微组织、硬度和耐腐蚀性能的影响。结果表明,Zn-0.6Al-xMg(x=0、1.2)、Zn-1.8Al-1.2Mg和Zn-1.8Al-1.2Mg-0.26Si镀层的物相组成都为Zn、Al、MgZn2和Fe2Al5相;增加Al含量或者Mg含量有助于镀层晶粒细化和组织均匀化,且Si元素的添加有助于进一步细化镀层晶粒;当Mg<1.2%时,Al含量更高的B系列镀层的硬度会高于相同Al含量的A系列镀层,而Mg>1.2%时,B4镀层硬度略低于A4镀层;添加Si的C1和C2镀层的硬度高于A系列和B系列镀层。全浸腐蚀与中性盐雾腐蚀试验结果相吻合,即镀层耐腐蚀性能从高至低顺序为:C1>C2>A4>B4>B3>A3>B2>A2>B1>A1,添加0.13Si的C1镀层具有较高的硬度以及最佳耐腐蚀性能。10 kinds of low Al galvanized coatings with different components were prepared on the surface of highway guardrail steel Q345 by hot dipping.The effects of Al,Mg and Si on the microstructure,hardness and corrosion resistance of the coatings were studied by means of metallographic microscope,scanning electron microscopy,microhardness tester and salt spray corrosion test box.The results show that the phase compositions of Zn-0.6 Al-xMg(x=0,1.2),Zn-1.8 Al-1.2 Mg and Zn-1.8 Al-1.2 Mg-0.26 Si coatings are all Zn,Al,MgZn2 and Fe2Al5 phases.Increasing Al or Mg content helps to refine the grain size and to homogenize the structure of the coatings,and the addition of Si element helps to further refine the grain size of the coatings.When Mg is less than 1.2%,the hardness of B series coatings with higher Al content is higher than that of the same Al content.The hardness of B4 coating is slightly lower than that of A4 coating when Mg>1.2%,and that of C1 and C2 coating with Si is higher than that of A and B coatings.The results of full immersion corrosion and neutral salt spray corrosion test are consistent,that is,the order of corrosion resistance from high to low is C1>C2>A4>B4>B3>A3>B2>A2>B1>A1,the C1 coating with 0.13 Si addition has higher hardness and the best corrosion resistance.

关 键 词：低Al镀锌层 显微组织 硬度 中性盐雾腐蚀 全浸腐蚀 

分 类 号：TG174.44[金属学及工艺—金属表面处理]