scholarly journals Thermal Behavior of Ti-64 Primary Material in Electron Beam Melting Process

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2853
Author(s):  
Jean-Pierre Bellot ◽  
Julien Jourdan ◽  
Jean-Sébastien Kroll-Rabotin ◽  
Thibault Quatravaux ◽  
Alain Jardy
Keyword(s):  
Electron Beam ◽  
Thermal Behavior ◽  
Electron Beam Melting ◽  
Continuous Process ◽  
Melting Process ◽  
Melting Rate ◽  
Vacuum Arc ◽  
Vacuum Arc Remelting ◽  
Primary Material ◽  
Set Up

The Electron Beam Melting (EBM) process has emerged as either an alternative or a complement to vacuum arc remelting of titanium alloys, since it is capable of enhancing the removal of exogenous inclusions by dissolution or sedimentation. The melting of the primary material is a first step of this continuous process, which has not been studied so far and is investigated experimentally and numerically in the present study. Experiments have been set up in a 100 kW laboratory furnace with the aim of analyzing the effect of melting rate on surface temperature of Ti-64 bars. It was found that melting rate is nearly proportional to the EB power while the overheating temperature remains roughly independent of the melting rate and equal to about 100 °C. The emissivity of molten Ti-64 was found to be 0.22 at an average temperature of about 1760 °C at the tip of the bar. In parallel, a mathematical model of the thermal behavior of the material during melting has been developed. The simulations revealed valuable results about the melting rate, global heat balance and thermal gradient throughout the bar, which agreed with the experimental values to a good extent. The modeling confirms that the overheating temperature of the tip of the material is nearly independent of the melting rate.

scholarly journals Effect of Melting Interruption on Composition and Microstructure of BT22 Ingot in VAR

2020 ◽  
Vol 321 ◽  
pp. 10008
Author(s):  
Zhengli Hua ◽  
Wenzhong Luo ◽  
Tao He ◽  
Qiang Lei ◽  
Longzhou Wang ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Inductively Coupled Plasma ◽  
Melting Process ◽  
Melting Rate ◽  
Vacuum Arc ◽  
Vacuum Arc Remelting ◽  
Electron Probe Micro Analyzer ◽  
Normal Region ◽  
Distribution Of Elements ◽  
Equiaxed Grains

BT22 ingot was remelted by vacuum arc remelting (VAR) furnace with a melting rate of 20kg/min. The power of VA R was interrupted for five minutes when the weight of the remelted ingot is approximately 4000 kg. The melting process was then resumed at the same melting rate after the five minutes interruption. Optical microscopy (OM), inductively coupled plasma-mass spectrometry (ICP-MS) and electron probe micro analyzer (EPMA) were utilized to analyze the microstructure, composition and distribution of elements. No significant microstructural difference was oberved at the remelting interrupted region. The variation of Al, Mo, V, Cr, Fe contents between the melting interruption region and normal region is within 0.23 wt%. The distribution of elements in equiaxed grains of the melting interruption region and the normal regions were compared by EPMA analysis. The contents of Al, V, Fe and Cr increase from the center of equiaxed grains to their grain boundaries. The content of Mo decreases from the center of equiaxed grains to their grain boundaries. The trend of element content in the normal region is similar to that of the melting interrupted region. Key words: BT22; ingot; composition; microstructure

scholarly journals Residual stress investigation on Ti-48Al-2Cr-2Nb samples produced by Electron Beam Melting process

Procedia CIRP ◽  
2021 ◽  
Vol 99 ◽  
pp. 336-341
Author(s):  
Manuela Galati ◽  
Giovanni Rizza ◽  
Alessandro Salmi ◽  
Sara Biamino ◽  
Cristian Ghibaudo ◽  
...  
Keyword(s):  
Residual Stress ◽  
Electron Beam ◽  
Electron Beam Melting ◽  
Melting Process ◽  
Electron Beam Melting Process

Realizing a full volume component by in-situ welding during electron beam melting process

2018 ◽  
Vol 22 ◽  
pp. 375-380 ◽  
Author(s):  
Pan Wang ◽  
Mui Ling Sharon Nai ◽  
Wai Jack Sin ◽  
Shenglu Lu ◽  
Baicheng Zhang ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Beam Melting ◽  
Melting Process ◽  
Electron Beam Melting Process ◽  
Full Volume

scholarly journals Beta Fleck formation in Titanium Alloys

2020 ◽  
Vol 321 ◽  
pp. 10001
Author(s):  
K. Kelkar ◽  
A Mitchell
Keyword(s):  
Titanium Alloys ◽  
Formation Mechanism ◽  
Defect Formation ◽  
Melting Rate ◽  
Vacuum Arc ◽  
Formation Mechanisms ◽  
Alloy Development ◽  
Vacuum Arc Remelting ◽  
Freckle Formation ◽  
Nickel Base

Beta fleck is a troublesome segregation defect in many titanium alloys. It has previously been investigated by several authors and appears to have two formation mechanisms, one similar to that of “freckle” in steels and nickel-base alloys, the other arising in the “crystal rain” effect seen in conventional steel ingots. The freckle defect has been extensively studied and several theories developed to account for its formation in both remelted ingots and directional castings. In this work we compare the findings of investigations into the nickel-base freckle formation mechanism to similar conditions in the vacuum arc remelting of titanium alloys. We find that there are strong similarities between the beta fleck formation conditions and the parameters related to the Rayleigh Number criterion for freckle formation. In particular, the dendritic solidification parameters and the density dependence on segregation coefficients both fit well with the conditions proposed to characterise freckle formation. The second formation mechanism arises in the columnar to equiax transition in solidification. The condition for the avoidance of the defect in the two cases is the shown to be the same, namely the use of a very low VAR melting rate, but that it is unlikely to be 100% successful in preventing defect formation. We propose that the techniques presently in use for alloy development in the superalloy field through optimising the composition for minimum sensitivity to freckle formation should be applied to the formulation of future titanium alloys; also that attention should be paid to developing the PAM process to provide suitable solidification conditions for defect absence in a final ingot.

Achieving the maximum melting rate for various vacuum arc remelting schemes

2010 ◽  
Vol 2010 (12) ◽  
pp. 1114-1116
Author(s):  
A. V. Filimonov ◽  
O. Kh. Fatkullin
Keyword(s):  
Melting Rate ◽  
Vacuum Arc ◽  
Vacuum Arc Remelting

Refining Tungsten Purification by Electron Beam Melting Based on the Thermal Equilibrium Calculation and Tungsten Loss Control

2015 ◽  
Vol 34 (6) ◽  
Author(s):  
Luping Long ◽  
Wensheng Liu ◽  
Yunzhu Ma ◽  
Ye Liu ◽  
Shuhua Liu
Keyword(s):  
Electron Beam ◽  
Melting Temperature ◽  
Process Parameters ◽  
Thermal Equilibrium ◽  
Electron Beam Melting ◽  
Melting Rate ◽  
Optimum Process ◽  
Equilibrium Calculation ◽  
Evaporation Loss ◽  
Loss Control

AbstractElectron beam melting (EBM) technology has been considered as one of the key steps for preparing high purity tungsten, and reasonable setting of process parameters is the premise. In this paper, the optimum process parameters obtained from thermal equilibrium calculation and evaporation loss control of tungsten are presented. Effective power is closely related to melting temperature, and the required power for maintaining the superheating melt linearly increases with the increase of melt superheat temperature. The evaporation loss behavior of tungsten is significantly influenced by melting rate and melting temperature. Analysis of experiments show that the best results are realized at melting rate of 1.82 g/s, melting temperature of 4200 K, and the corresponding melting power of 130 kW, in which the main impurity elements in tungsten, such as As, Cd, Mg and Sn, present high removal ratio of 90%, 95%, 85.7% and 90%, respectively.

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