Modeling of the Vacuum Arc Remelting Process for Estimation and Control of the Liquid Pool Profile

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Joseph J. Beaman ◽  
Luis Felipe Lopez ◽  
Rodney L. Williamson
Keyword(s):  
Dynamic Control ◽  
Liquid Pool ◽  
Grain Structure ◽  
Vacuum Arc ◽  
Linear Quadratic ◽  
Vacuum Arc Remelting ◽  
Nonlinear Dynamic Equations ◽  
Pool Profile ◽  
Estimation And Control ◽  
Molten Liquid

Vacuum arc remelting (VAR) is an industrial metallurgical process widely used throughout the specialty metals industry to cast large alloy ingots. The final ingot grain structure is strongly influenced by the molten metal pool profile, which in turn depends on the temperature distribution in the ingot. A reduced-order model of the solidifying ingot was developed specifically for dynamic control and estimation of the depth of molten liquid pool atop the ingot in a VAR process. This model accounts only for the thermal aspects of the system ignoring other physical domains such as fluid flow and electromagnetic effects. Spectral methods were used to obtain a set of nonlinear dynamic equations which capture the transient characteristics of liquid pool profile variations around a quasi-steady operating condition. These nonlinear equations are then linearized and further simplified by suppressing fast modes. The resulting system was used to construct a linear-quadratic-gaussian (LQG) controller which was tested in a laboratory-scale furnace showing a good performance. A high-fidelity physics-based model is used in real-time to provide information about the solidifying ingot and potential solidification defects.

scholarly journals Industrial applications of modelling tools to simulate the PAMCHR casting and VAR process for Ti64

2020 ◽  
Vol 321 ◽  
pp. 10011
Author(s):  
Emiliane Doridot ◽  
Stéphane Hans ◽  
Alain Jardy ◽  
Jean-Pierre Bellot
Keyword(s):  
Joint Venture ◽  
Metal Flow ◽  
Sensitivity Study ◽  
Industrial Applications ◽  
Liquid Pool ◽  
Vacuum Arc ◽  
Operating Parameters ◽  
Vacuum Arc Remelting ◽  
Arc Melting ◽  
Ingot Quality

The PAMCHR (Plasma Arc Melting Cold Hearth Refining) process followed by a VAR (Vacuum Arc Remelting) melting is used to recycle Ti64 scrap for aeronautical applications. The produced ingot quality is linked to the quality of charging materials and to numerous operating parameters. Ecotitanium (a company created by UKAD, a joint-venture between Aubert & Duval and UKTMP, ADEME and Crédit Agricole Centre France) launched a program with the Institut Jean Lamour dedicated to the development of specific modelling tools in order to get a better understanding of operating parameters effect on the final ingot quality. A model of the PAMCHR casting was developed and used to describe the heat transfer, liquid metal flow and alloying elements behavior during mixing in the liquid pool followed by segregation during solidification. The effect of PAMCHR electrode composition on the final VAR ingot composition is also studied using the SOLAR VAR model. Model validation by comparison with industrial ingots is presented with some examples of operating parameters sensitivity study.

A Reduced-Order Model for Dynamic Vacuum Arc Remelting Pool Depth Estimation and Control

2011 ◽  
Author(s):  
Luis Felipe Lopez ◽  
Joseph J. Beaman ◽  
Rodney L. Williamson
Keyword(s):  
Depth Estimation ◽  
Liquid Pool ◽  
Reduced Order Model ◽  
Vacuum Arc ◽  
State Variables ◽  
Order Model ◽  
Operating Condition ◽  
Reduced Order ◽  
Vacuum Arc Remelting ◽  
Pool Depth

Vacuum arc remelting (VAR) is an industrial metallurgical process widely used throughout the specialty metals industry to cast large alloy ingots. A reduced-order model of the growing and solidifying ingot was developed specifically for dynamic control and estimation of the depth of molten liquid pool atop the ingot in a VAR process. This model accounts only for the thermal aspects of the system ignoring high-fidelity physics such as fluid flow and electromagnetic effects. Spectral methods were used to obtain a set of nonlinear dynamic equations which capture the transient characteristics of liquid pool shape variations around a quasi-steady operating condition. These nonlinear equations are then linearized about this operating condition and further simplified by suppressing fast modes. The resulting system can be described by only six state variables. The reduced order model compares favorably to pool depth changes predicted by an accurate finite-volume model. A first approach to use this model in the design of a dynamic VAR pool depth estimator and controller is also proposed.

A Nonlinear Reduced Order Model for Estimation and Control of Vacuum Arc Remelting of Metal Alloys

2005 ◽  
Author(s):  
Joseph J. Beaman ◽  
Rodney L. Williamson ◽  
David K. Melgaard ◽  
Jon Hamel
Keyword(s):  
Moving Boundary ◽  
Reduced Order Model ◽  
Vacuum Arc ◽  
State Variables ◽  
Order Model ◽  
Electrode Gap ◽  
Reduced Order ◽  
Vacuum Arc Remelting ◽  
Integral Methods ◽  
Estimation And Control

Vacuum arc remelting (VAR) is an industrial metallurgical process widely used throughout the specialty metals industry to cast large alloy ingots. The VAR process is carried out in a vacuum with the aim of melting a large consumable electrode (.4 m in diameter and 3000 kg in mass and larger) in such a way that that the resulting ingot has improved homogeneity. The VAR control problem consists of adjusting arc current to control electrode melt rate, which also depends on the electrode temperature distribution and adjusting electrode ram speed to control the arc gap between the electrode and the ingot. The process is governed by a 1 dimensional heat conduction partial differential equation with a moving boundary, which leads to an infinite dimensional, nonlinear system. In addition to the process nonlinearity, the inputs and all of the available measurements are corrupted with noise. In order to design a controller and a Kalman based estimator for this process, integral methods are used to derive a set of two coupled nonlinear ordinary differential equations in time, which capture the steady state and transient characteristics of melting in a VAR furnace. The model with the experimentally measured noise is then used to construct an estimator and a controller. The system can be described by two state variables that change in time: thermal boundary layer and melted length or alternatively electrode gap. The reduced order model compares favorably to an accurate finite difference model as well as melting data acquired for Ti-6Al-4V. It will be shown how this model can be used to obtain dynamic closed loop melt rate control while simultaneously controlling electrode gap. This controller and estimator were tested on a laboratory furnace at Timet.

Effect of remelting current on molten pool profile of titanium alloy ingot during vacuum arc remelting process

2011 ◽  
Vol 16 (2) ◽  
pp. 133-136 ◽  
Author(s):  
Zhi-jun Yang ◽  
Hong-chao Kou ◽  
Xiao-hua Zhao ◽  
Jin-shan Li ◽  
Rui Hu ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Molten Pool ◽  
Vacuum Arc ◽  
Vacuum Arc Remelting ◽  
Alloy Ingot ◽  
Pool Profile

UDIMET 700

Alloy Digest ◽  
1987 ◽  
Vol 36 (1) ◽  
Keyword(s):  
Gas Turbines ◽  
Base Alloy ◽  
Heat Treating ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Nickel Base Alloy ◽  
Vacuum Arc Remelting ◽  
Temperature Performance ◽  
Nickel Base

Abstract UDIMET 700 is a wrought nickel-base alloy produced by vacuum-induction melting and further refined by vacuum-arc remelting. It has excellent mechanical properties at high temperatures. Among its applications are blades for aircraft, marine and land-based gas turbines and rotor discs. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-51. Producer or source: Special Metals Corporation. Originally published March 1959, revised January 1987.

UDIMET 90

Alloy Digest ◽  
1972 ◽  
Vol 21 (6) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Base Alloy ◽  
Heat Treating ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Nickel Base Alloy ◽  
Vacuum Arc Remelting ◽  
Temperature Performance ◽  
Nickel Base

Abstract UDIMET 90 is a nickel-base alloy developed for elevated-temperature service. It is produced by vacuum induction melting and vacuum arc remelting techniques to develop optimum properties. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-174. Producer or source: Special Metals Corporation.

LESCALLOY 15-5 VAC-ARC

Alloy Digest ◽  
1991 ◽  
Vol 40 (8) ◽  
Keyword(s):  
Stainless Steel ◽  
Precipitation Hardening ◽  
Martensitic Stainless Steel ◽  
Heat Treating ◽  
Gas Content ◽  
Vacuum Arc ◽  
Steel Company ◽  
Delta Ferrite ◽  
Clean Steel ◽  
Vacuum Arc Remelting

Abstract LESCALLOY 15-5 VAC-ARC is a precipitation hardening martensitic stainless steel with minimal delta ferrite. Vacuum arc remelting in the production of the alloy provides a low gas content, clean steel with optimum transverse properties. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-522. Producer or source: Latrobe Steel Company.

VASCOMAX T-300

Alloy Digest ◽  
1990 ◽  
Vol 39 (12) ◽  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
High Temperature ◽  
Heat Treating ◽  
Vacuum Arc ◽  
Vacuum Induction Melting ◽  
Induction Melting ◽  
Vacuum Arc Remelting ◽  
Temperature Performance

Abstract VASCOMAX T-300 is an 18% nickel maraging steel in which titanium is the primary strengthening agent. It develops a tensile strength of about 300,000 psi with simple heat treatment. The alloy is produced by Vacuum Induction Melting/Vacuum Arc Remelting. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-454. Producer or source: Teledyne Vasco.

ALLVAC Ti-15Mo

Alloy Digest ◽  
2005 ◽  
Vol 54 (7) ◽  
Keyword(s):  
Vacuum Arc ◽  
Unique Combination ◽  
Vacuum Arc Remelting ◽  
Beta Alloy ◽  
Metastable Beta

Abstract Allvac Ti-15Mo is a metastable beta alloy melted in a vacuum arc remelting (VAR) furnace to minimize segregation. The alloy has a unique combination of properties and is used in the medical, chemical, and aerospace industries. This datasheet provides information on composition. Filing Code: TI-136. Producer or source: Allvac, an Allegheny Technologies Company.

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