碳镍含量对耐铝液腐蚀低合金灰铸铁组织和性能的影响
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摘要
热电偶保护套管是保证热电偶在高温熔体中正常工作的关键部件。在目前实际应用的热电偶保护套管低合金灰铸铁成分基础上,设计了少碳组、含镍组来研究碳和镍对低合金灰铸铁组织、力学性能及耐铝液腐蚀性的影响。结果表明:低合金灰铸铁在减少碳含量后,珠光体、碳化物数量增加,石墨、铁素体和共晶团含量减少,力学性能提高,耐铝液腐蚀性降低;添加镍后,珠光体、共晶团及石墨组织含量增加,碳化物数量变化不大,力学性能变化不明显,而耐铝液腐蚀性提高;在铝液对低合金灰铸铁的腐蚀过程中,基体和铝液间形成由FeAl_3相和Fe_2Al_5相组成的合金层。
The thermocouple protective sleeve is a vital component during the thermocouple immersing in hot temperature melt. In the present work the possibility of improving the corrosion resistance of low alloy gray cast iron to molten aluminum was explored through reducing carbon content or adding a small amount of nickel in the gray iron, and the microstructure, mechanical properties and corrosion resistance of the low alloy gray cast irons used as thermocouple protective sleeve were studied. The results showed that when carbon content in grey iron was reduced, the number of carbides and pearlite content increased, graphite and eutectic cells count as well as ferrite content decreased, and the mechanical properties and the corrosion resistance to molten aluminum were improved; when a small amount of nickel was added in gray iron, pearlite content with eutectic cells and graphite count increased, but the number of carbides and mechanical properties had not obvious change,, the corrosion resistance to molten aluminum was improved. A alloy layer mainly consisting of Fe_2Al_5 and FeAl_3 was formed between the substrate and aluminum liquid in the corrosion process of low alloy gray cast iron in molten aluminum.
The thermocouple protective sleeve is a vital component during the thermocouple immersing in hot temperature melt. In the present work the possibility of improving the corrosion resistance of low alloy gray cast iron to molten aluminum was explored through reducing carbon content or adding a small amount of nickel in the gray iron, and the microstructure, mechanical properties and corrosion resistance of the low alloy gray cast irons used as thermocouple protective sleeve were studied. The results showed that when carbon content in grey iron was reduced, the number of carbides and pearlite content increased, graphite and eutectic cells count as well as ferrite content decreased, and the mechanical properties and the corrosion resistance to molten aluminum were improved; when a small amount of nickel was added in gray iron, pearlite content with eutectic cells and graphite count increased, but the number of carbides and mechanical properties had not obvious change,, the corrosion resistance to molten aluminum was improved. A alloy layer mainly consisting of Fe_2Al_5 and FeAl_3 was formed between the substrate and aluminum liquid in the corrosion process of low alloy gray cast iron in molten aluminum.
引文
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[3]王金洪.硅、铬、铜对铝液测温用铸铁保护管耐铝液侵蚀性能的影响[J].铸造,2001,50(7):384-387.
[4]罗洪峰.金属的铝液熔蚀-磨损及新型合金铸铁研究[D].广州:华南理工大学,2014.
[5]Adedayo A V.Characterization of graphite flakes in grey iron microstructure[J].Arabian Journal for Science&Engineering,2012,37(6):1645-1652.
[6]陆文华,李隆盛,黄良余.铸造合金及其熔炼[M].北京:机械工业出版社,2002.
[7]尤三三.镍对低温高韧性球墨铸铁组织及性能的影响[D].郑州:郑州大学,2010.
[8]张宁,郑洪亮,陈凯,等.灰铸铁凝固数值模拟的形核率模型建立[J].铸造,2010,59(2):165-168.
[9]杨威.铸铁共晶团[J].物理测试,1985(4):33-35.
[10]Elwazri A M,Wanjara P,Yue S.The effect of microstructural characteristics of pearlite on the mechanical properties of hypereutectoid steel[J].Materials Science and Engineering A,2005,404(1-2):91-98.
[11]Hsu C H,Chen M L,Hu C J.Microstructure and mechanical properties of 4%cobalt and nickel alloyed ductile irons[J].Materials Science and Engineering A,2007,444(1-2):339-346.
[12]李炯辉.金属材料金相图谱[M].北京:机械工业出版社,2006:66.
[13]翟景超.灰铸铁中磷共晶的金相显示及消除[C]//中国机械工程学会铸造分会铸件质量控制及检测技术委员会第十一届学术年会暨天津市第十届铸造学术年会论文集:工程技术专辑,2016:201-204.