Titanium nitride (TiN) precipitation in a maraging steel during the vacuum arc remelting (VAR) process - Inclusions characterization and modeling

International Symposium on Liquid Metal Processing & Casting 2015

材料科学;金属工艺学

Descotes, V.^1 ; Bellot, J.-P.^2 ; Perrin-Guérin, V.^1 ; Witzke, S.^1 ; Jardy, A.^2

Aperam Alloys Imphy, Centre de Recherches P. Chevenard, BP 1, Imphy

F-58160, France^1

Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, LabEx Damas, Parc de Saurupt - CS 50840, Nancy

54011, France^2

关键词: Calcium sulfide;    Formation and evolutions;    Micro-segregation;    Orientation relationship;    TEM analysis;    Tin inclusions;    Tin particles;    Vacuum-arc remelting process;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/143/1/012013/pdf
DOI  :  10.1088/1757-899X/143/1/012013

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

Titanium Nitride (TiN) inclusions are commonly observed in a Maraging steel containing Nitrogen and Titanium and remelted in a VAR furnace. They can be easily detected by optical microscopy. A nucleus is observed next to a large number of TiN inclusions. A TEM analysis was carried out on a biphasic nucleus composed of a calcium sulfide (CaS) and a spinel (MgAl2O4), surrounded by a TiN particle. An orientation relationship between these three phases was revealed, which suggests a heterogeneous germination of the TiN particle on the nucleus by epitaxial growth. Based on this observation, on thermodynamic considerations and on previous work, a model has been developed and coupled to a numerical simulation of the VAR process to study the formation and evolution of a TiN distribution in the VAR ingot. Microsegregation is modeled using the lever rule, while the kinetics of precipitation is mainly driven by the supersaturation of the liquid bath. This model highlights the influence of the melt rate on the final size of TiN particles.