变电设施用钢与7系铝合金的盐雾腐蚀及力学性能衰减研究  

Study on Salt Spray Corrosion and Decay of Mechanical Properties of Steels for Substation Facilities and 7xxx Aluminum Alloy

作　　者：樊磊 李波 张有佳[2] 黄朝文[3] 石维[3] 李伟[3] FAN Lei;LI Bo;ZHANG Youjia;HUANG Chaowen;SHI Wei;LI Wei(Electric Power Research Institute of Guizhou Power Grid Co.,Ltd.,Guiyang 550000,China;School of Civil Engineering and Architecture,Northeast Electric Power University,Jilin 132000,China;School of Materials and Metallurgy,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州电网有限责任公司电力科学研究院,贵州贵阳550000 [2]东北电力大学建筑工程学院,吉林吉林132000 [3]贵州大学材料与冶金学院,贵州贵阳550025

出　　处：《材料保护》2023年第10期130-138,共9页Materials Protection

基　　金：南方电网科技攻关项目(0666002020030101CL00001)资助。

摘　　要：在海洋及化工厂附近等强腐蚀环境中,钢材的腐蚀一直是严重缩短电力设施服役寿命的关键问题之一。为了解决这一问题,提出利用高强度7xxx系铝合金替代输变电设备用钢的构想,采用室内加速模拟试验,以5%NaCl盐雾腐蚀环境模拟海洋大气环境,结合拉伸试验和微观组织观察对比分析了变电设施用Q345钢和7075铝合金2种材料在不同腐蚀时间(7,21,42 d)后的力学性能衰减和表面腐蚀形貌变化规律,再利用腐蚀失重法、计算机模拟方法等,对比研究了2种材料在相同的腐蚀环境和载荷下的力学性能。结果表明,在5%NaCl盐雾腐蚀环境中,随盐雾腐蚀时间的延长,2种材料均出现了力学性能衰减的趋势,而且Q345钢的最高抗拉强度衰减率(24.58%)是7075铝合金的(3.00%)8倍。2种材料的腐蚀速率均呈先增后减的趋势,Q345钢的平均腐蚀速率[0.030 g/(m^(2)·d)]是7075铝合金[0.002 g/(m^(2)·d)]的15倍左右。相同腐蚀周期时,Q345钢的腐蚀坑比7075铝合金的尺寸更大更深,导致在相同的外载荷下Q345钢中由腐蚀坑引起的应力集中程度显著高于7075铝合金。因此,理论上可用7075铝合金代替Q345钢作为电力设施构件基体材料。The corrosion failure of steel is one of the key problems to shorten the service life of power facilities in some strong corrosive environments,such as marine and chemical plants.To address this problem,the proposition of substituting steel in power transmission and transformation equipment with high-strength 7xxx series aluminum alloys was introduced.Accelerated indoor simulation tests were conducted,using a 5%NaCl salt spray corrosion environment to emulate marine atmospheric conditions.A comparative analysis was performed on the mechanical property degradation and change law of surface corrosion morphology of Q345 steel for substation facilities and 7075 aluminum alloy after varying corrosion durations(7,21,42 d)by integrating tensile tests and microscopic structural observations.Further,employing corrosion weight loss methods and computer simulation techniques,the mechanical properties of the two materials under identical corrosion conditions and loads were comparatively studied.Results indicated that the mechanical properties of both materials tended to decline with the extension of salt spray corrosion time under 5%NaCl salt spray corrosion environment,moreover,the highest tensile strength attenuation rate of Q345 steel(24.58%)was 8 times that of 7075 aluminum alloy(3.00%).Both materials displayed a corrosion rate trend that initially increased and then decreased,with the average corrosion rate of Q345 steel[0.03 g/(m^(2)·d)]being approximately 15 times that of the 7075 aluminum alloy[0.002 g/(m^(2)·d)].At the same corrosion cycle,the corrosion pits in Q345 steel were larger and deeper than those in the 7075 aluminum alloy,resulting in a significantly higher degree of stress concentration caused by corrosion pits in Q345 steel under the same external load compared to 7075 aluminum alloy.Consequently,in theory,7075 aluminum alloy could replace Q345 steel as the base material for power facility components.

关 键 词：Q345钢 7XXX系铝合金 盐雾腐蚀 力学性能 

分 类 号：TG178[金属学及工艺—金属表面处理]