304不锈钢热浸镀铝工艺及镀层的耐冲蚀性能
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摘要
为提高304不锈钢在实际工况中应用时的耐腐蚀性能,采用熔剂法对304不锈钢热浸镀铝,并对镀铝层进行扩散退火处理,通过厚度测试,形貌观察及成分分析优选了热浸镀工艺及扩散退火工艺,并采用冲刷腐蚀试验研究了最佳工艺制备的镀层的冲蚀性能。结果表明:304不锈钢热浸镀Al-3.0%Si-0.5%RE,在740℃左右浸镀15min时,镀层厚度为100μm左右;在820℃扩渗4 h,获得了较好的扩渗层,其厚度约为115μm;冲蚀时间达到120 h时,经最佳条件热浸镀铝+扩散退火处理后镀层的冲蚀失重速率最小,为0.092 g/(h·m2),未热浸镀铝及扩散退火处理的304钢原始试样的冲蚀失重速度相对较快,其冲蚀腐蚀速率为0.121 g/(h·m~2),约为热浸镀铝试样的1.32倍。
Hot dip aluminizing of 304 stainless steel was carried out by flux method,which was then followed by diffusion annealing. Through thickness measurement,morphology observation and composition analysis,the hot dip galvanizing technology and diffusion annealing process were optimized. The erosion corrosion resistance of the specimens in 3. 5% NaCl aqueous solution was studied by erosion corrosion method.Results showed that the average thickness of Al-3.0%Si-0.5%RE hot-dip coating on 304 stainless steel was about 100 μm at 740 ℃ for 15 min,and at 820 ℃ for 4 h the diffusion layer was better and its average thickness was 115 μm. Moreover,the erosion time reached 120 h,the weight loss rate of 304 steel by hot dip aluminizing and diffusion annealing was the slowest,which was 0.092 g/( h·m~2). The weight loss rate of non-hot-dipped aluminum sample was relatively fast [0.121 g/( h·m~2) ],which was 1.32 times that of the hot-dip aluminizing sample.
Hot dip aluminizing of 304 stainless steel was carried out by flux method,which was then followed by diffusion annealing. Through thickness measurement,morphology observation and composition analysis,the hot dip galvanizing technology and diffusion annealing process were optimized. The erosion corrosion resistance of the specimens in 3. 5% NaCl aqueous solution was studied by erosion corrosion method.Results showed that the average thickness of Al-3.0%Si-0.5%RE hot-dip coating on 304 stainless steel was about 100 μm at 740 ℃ for 15 min,and at 820 ℃ for 4 h the diffusion layer was better and its average thickness was 115 μm. Moreover,the erosion time reached 120 h,the weight loss rate of 304 steel by hot dip aluminizing and diffusion annealing was the slowest,which was 0.092 g/( h·m~2). The weight loss rate of non-hot-dipped aluminum sample was relatively fast [0.121 g/( h·m~2) ],which was 1.32 times that of the hot-dip aluminizing sample.
引文
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[3]AWAN G H,HASAN F U.The morphology of coating/substrate interface in hot-dip-aluminized steels[J].Materials Science and Engineering,2008,472:157-165.
[4]WANG C J,CHEN S M.The high-temperature oxidation behavior of hot-dipping Al-Si coating on low carbon steel[J].Surface and Coatings Technology,2006,200:6 601-6 605.
[5]赵红利,胡毅,胡明志,等.不锈钢表面热镀铝试验研究[J].焊接技术,2016,45(7):54-57.
[6]钱卫江,顾文桂.Si对热浸镀Al界面化合物层生长的限制作用[J].金属学报,1994,30(9):403-406.
[7]林建强,刘建华.形变20钢热浸镀铝的镀层组织分析[J].热加工工艺,1999(3):20-21.
[8]李慧莉,李国喜,郑毅然,等.热浸镀铝钢的镀层结构分析[J].材料与冶金学报,2004,3(1):51-53.