D-5S高镍奥氏体球墨铸铁抗高温氧化性能研究

High-temperature Oxidation Resistance of D-5S High-nickel Austenitic Nodular Iron

对含34%~37%Ni的D-5S高镍奥氏体球墨铸铁进行了960℃保温2h空冷正火,随后对铸态和正火态球铁试样在650℃、850℃和1050℃氧化12h、24h、36h、48h、60h、72h。检测了试样的增重、微观形貌和氧化物的组成,目的是研究高镍奥氏体球铁的抗高温氧化性能,以及正火处理对其抗高温氧化性能的影响。结果表明:D-5S高镍奥氏体球铁的氧化增重随氧化时间大致按抛物线规律变化;不同温度氧化的试样氧化物的形貌不同,即650℃氧化的试样氧化物呈针状,850℃氧化的试样氧化物呈胞状,而在1050℃氧化的试样氧化物胞状更明显更致密;正火处理能适当改善高镍奥氏体球铁的抗高温氧化性能,但并不改变氧化物形貌。

D-5S high-nickel austenitic nodular iron with 34% to 37%Ni was normalized by being heated to 960℃,held for 2 h and cooled in air,and then the as-cast and as-normalized samples were oxidized at 650℃,850℃,and 1 050℃ for 12 h,24 h,36 h,48 h,60 h,and 72 h,respectively.After this,the samples were tested for weight gain,microscopic appearance and oxide composition,to investigate high-temperature oxidation resistance of high-nickel austenitic nodular iron and the effect of normalizing on its high-temperature oxidation resistance.The results showed that(a) the oxidation weight growth of D-5S high-nickel austenitic nodular iron varied with the oxidation time approximately according to a parabola rule;(b) the samples oxidized at different temperatures offered oxides of different forms,specifically,the oxides were acicular for the sample oxidized at 650℃ and cellular for the sample oxidized at 850℃,and even more obviously and even more densely cellular for the sample oxidized at 1 050℃;and(c) the normalizing permitted improving high-temperature oxidation resistance of highnickel austenitic nodular iron to a certain extent but did not change form of the oxide.