Evolution of nonmetallic inclusions in 80-t 9CrMoCoB large-scale ingots during electroslag remelting process  

作　　者：Shengchao Duan Min Joo Lee Yao Su Wangzhong Mu Dong Soo Kim Joo Hyun Park 

机构地区：[1]School of Mechanical and Materials Engineering,North China University of Technology,Beijing 100144,China [2]Department of Materials Science and Chemical Engineering,Hanyang University,Ansan 15588,Rep.of Korea [3]Department of Materials Science and Engineering,KTH Royal Institute of Technology,Brinellvägen 23,Stockholm 10044,Sweden [4]Department of Engineering Science and Mathematics,Division of Materials Science,LuleåUniversity of Technology,97187 Luleå,Sweden [5]Casting&Forging Business Unit,Nuclear Business Group,Doosan Enerbility,Changwon 51711,Rep.of Korea

出　　处：《International Journal of Minerals,Metallurgy and Materials》2024年第7期1525-1539,共15页矿物冶金与材料学报（英文版）

基　　金：the Korea Evaluation Institute of Industrial Technology(KEIT,No.20009956);the Korea Institute for Advancement of Technology(KIAT,No.P0023676,HRD Program for Industrial Innovation);funded by the Ministry of Trade,Industry and Energy(MOTIE),Korea;the Swedish Foundation for International Cooperation in Research and Higher Education(STINT)for supporting the collaboration between KTH(Sweden)and Hanyang University(Korea)。

摘　　要：In combination with theoretical calculations,experiments were conducted to investigate the evolution behavior of nonmetallic inclusions(NMIs)during the manufacture of large-scale heat-resistant steel ingots using 9CrMoCoB heat-resistant steel and CaF_(2)–CaO–Al_(2)O_(3)–SiO_(2)–B_(2)O_(3)electroslag remelting(ESR)-type slag in an 80-t industrial ESR furnace.The main types of NMI in the consumable electrode comprised pure alumina,a multiphase oxide consisting of an Al_(2)O_(3)core and liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO shell,and M_(23)C_(6)carbides with an MnS core.The Al_(2)O_(3)and MnS inclusions had higher precipitation temperatures than the M_(23)C_(6)-type carbide under equilibrium and nonequilibrium solidification processes.Therefore,inclusions can act as nucleation sites for carbide layer precipitation.The ESR process completely removed the liquid CaO–Al_(2)O_(3)–SiO_(2)–MnO oxide and MnS inclusion with a carbide shell,and only the Al_(2)O_(3)inclusions and Al_(2)O_(3)core with a carbide shell occupied the remelted ingot.The M_(23)C_(6)-type carbides in steel were determined as Cr_(23)C_(6)based on the analysis of transmission electron microscopy results.The substitution of Cr with W,Fe,or/and Mo in the Cr_(23)C_(6)lattice caused slight changes in the lattice parameter of the Cr_(23)C_(6)carbide.Therefore,Cr_(21.34)Fe_(1.66)C_(6),(Cr_(19)W_(4)C_(6),Cr_(18.4)Mo_(4.6)C_(6),and Cr_(16)Fe_(5)Mo_(2)C_(6)can match the fraction pattern of Cr_(23)C_(6)carbide.The Al_(2)O_(3)inclusions in the remelted ingot formed due to the reduction of CaO,SiO_(2),and MnO components in the liquid inclusion.The increased Al content in liquid steel or the higher supersaturation degree of Al_(2)O_(3)precipitation in the remelted ingot than that in the electrode can be attributed to the evaporation of CaF_(2)and the increase in CaO content in the ESR-type slag.

关 键 词：nonmetallic inclusion heat-resistant steel electroslag remelting M_(23)C_(6) carbide MnS inclusion supersaturation degree 

分 类 号：TF142[冶金工程—冶金物理化学]