Mg含量对21-4N气阀钢凝固组织细化作用的研究  

Effect of Mg Content on Solidification Structure Refinement of 21-4N Gas Valve Steel

作　　者：刘贝贝[1,2,3] 孙晗 徐翔宇 涂玉国 赵衡 付建勋[1,2,3] LIU Beibei;SUN Han;XU Xiangyu;TU Yuguo;ZHAO Heng;FU Jianxun(Center for Advanced Solidification Technology(CAST),Shanghai University,Shanghai 200444,China;State Key Laboratory of Advanced Special Steel,Shanghai University,Shanghai 200444,China;Shanghai University New Materials(Taizhou)Research Institute,Taizhou Jiangsu 225500,China;Jiangsu Shenyuan Group Co.,Ltd.,Xinghua Jiangsu 225700,China)

机构地区：[1]上海大学先进凝固技术中心,上海200444 [2]上海大学省部共建高品质特殊钢冶金与制备国家重点实验室,上海200444 [3]上海大学新材料(泰州)研究院,江苏泰州225500 [4]江苏申源集团有限公司,江苏兴化225700

出　　处：《上海金属》2022年第1期67-73,共7页Shanghai Metals

基　　金：国家自然科学基金(No.51874195,No.52074179)。

摘　　要：为了探究Mg对5Cr21Mn9Ni4N(21-4N)气阀钢组织细化的影响规律,在实验室开展了镁改质气阀钢的高温熔炼试验,冶炼了不同镁含量的钢锭。结果表明:镁含量为0、12、16、34、58和60μg/g的试样的一次枝晶臂平均长度分别为1324.1、941.9、836.0、849.6、1439.1和1294.7μm;二次枝晶臂平均间距分别为145.5、114.6、105.1、130.2、148.7和180.7μm,枝晶间距呈先减小后增大的趋势,当镁含量为16μg/g时,21-4N气阀钢的枝晶间距最小,细化效果最显著;钢中Al_(2)O_(3)、MgAl_(2)O_(4)、MgO夹杂与γ-Fe相之间的晶格错配度分别为7.36%、4.00%、16.98%,MgAl_(2)O_(4)相比Al_(2)O_(3)和MgO更利于γ-Fe相形核;当镁含量为16μg/g时,钢液中出现细小弥散的MgAl_(2)O_(4),与γ-Fe相之间具有更低的晶格错配度,可作为γ-Fe相稳定的形核质点,使组织细化;当镁含量大于16μg/g时,钢液中出现MgO,与γ-Fe相之间的晶格错配度增大,导致非均匀形核能力下降,组织粗化。In order to investigate the influence of Mg on the microstructure refinement of 5Cr21Mn9Ni4N(21-4N)gas valve steel,the trial high temperature smelting of Mg-modified of gas valve steel were carried out in the laboratory,and ingots with different Mg contents were smelted.The results showed that for the samples with Mg contents of 0,12,16,34,58 and 60μg/g,their average size of primary dendrite arm length were 1324.1,941.9,836.0,849.6,1439.1 and 1294.7μm,and the average size of secondary dendrite arms spacing were 145.5,114.6,105.1,130.2,148.7 and 180.7μm,respectively,the dendrite spacing decreased at first and then increased.When the Mg content was 16μg/g,the dendrite arm spacing of 21-4N gas valve steel was the smallest and the refinement effect was the best.The lattice disregistries between Al_(2)O_(3),MgAl_(2)O_(4),MgO inclusions andγ-Fe phase were 7.36%,4.00%,16.98%,respectively,and MgAl_(2)O_(4)was more conducive to nucleation ofγ-Fe than Al_(2)O_(3)and MgO.When the Mg content was 16μg/g,fine dispersed MgAl_(2)O_(4)formed in the molten steel,and had a lower lattice disregistry withγ-Fe,could act as the stable nuclci-formation particle ofγ-Fe,so the microstructure became finer.However,when the Mg content was greater than 16μg/g,MgO appeared in the steel,and had a higher lattice disregistry withγ-Fe,resulting in the decrease in heterogeneous nucleation ability,so the microstructure was coarsened.

关 键 词：21-4N气阀钢 镁 组织细化 二次枝晶间距 

分 类 号：TG244[金属学及工艺—铸造] TG113