Effect of modified AA4043 filler on partially melted zone cracking of Al-alloy gas tungsten arc welds (original) (raw)
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Effects of Filler Metals on Heat-Affected Zone Cracking in IN-939 Superalloy Gas-Tungsten-Arc Welds
Journal of Materials Engineering and Performance, 2020
Filler metals play an important role in reducing the weld cracking in nickel-based superalloys. In order to improve the welding conditions of IN939 superalloy, a wide range of solid solutions and age-hardenable filler metals were investigated in this study. Five solid solutions (HAYNES 230, IN625, IN617, HAS-TELLOY X, HAYNES 25) and two precipitation-strengthened alloys (IN718, HAYNES C-263) were used as filler metal to weld IN939 superalloy via gas-tungsten-arc welding. Microstructural studies were performed using optical microscopy and field-emission scanning electron microscopy. The results revealed that IN939 alloy is susceptible to liquation cracking in the heat-affected zone. In addition, the primary c¢ particles had grown into ''ogdoadically diced cubes'' of about of 2 lm in side length. The microstructure of the weld pool made with various filler metals was observed to be made up of fine spherical c¢ particles with a diameter of about 0.2 lm. The study of mechanical properties and thermodynamic behavior of the weld showed that the filler metals with lower concentrations of (Al + Ti + Nb + Ta + Mo + W) than the base metal can effectively attenuate the PWHT cracking. We found that optimal IN939 alloy weld performance can be achieved using HAYNES C-263 as filler metal, followed by IN617 and then IN625.
Effect of modified AA4043 filler on corrosion behavior of AA6061 alloy GTA welds
The International Journal of Advanced Manufacturing Technology, 2012
The corrosion behavior of the fusion zone of gas tungsten arc (GTA) welds of AA6061 alloy was studied. Role of gas tungsten arc welding techniques such as continuous current (CC) and pulsed current (PC) and reference filler (AA5356) were studied. Role of different grain refiners such as scandium, zirconium and Tibor in the reference filler was studied. Dynamic polarization testing was used to determine the pitting corrosion resistance of the fusion zone. Optical studies was carried out to find the mechanism of corrosion. The fusion zone of welds made with the 0.5%Sc with AA5356 filler with PC technique shown better corrosion resistance.
Effect of titanium–boron additions on grain refinement of AA 2219 gas tungsten arc welds
Science and Technology of Welding and Joining, 2012
High strength AA2219 aluminum alloys have gathered wide acceptance in aeronautic and aerospace applications mainly due to their excellent mechanical properties, high corrosion resistance and good weldability. However, these alloys have poor as welded joint strength. The loss of strength is due to melting and quick resolidification, which renders all the strengthening precipitates to dissolve. One way of improving strength is through the modification of weld microstructures. The refinement of fusion zone microstructure helps in improving the mechanical properties of weld metal. The present study has investigated the influence of Tibor additions on the structure and mechanical properties of AA2219 gas tungsten arc (GTA) weldments. Full penetration GTA welds were prepared using alternating current (AC). It was observed that grain size was decreased with increasing amounts of Tibor. The observed grain refinement was shown to result in an appreciable increase in fusion zone hardness.
Journal of Manufacturing Science and Engineering, 2014
Welding defects and the reduction of mechanical performances are the foremost problems for fusion welded aluminum alloys joints. The influences of weld defects and post-weld heat treatment (PWHT) on tensile properties of gas tungsten arc (GTA) welded aluminum alloy AA-6061-T651 joints are investigated in this current study. All welded specimens are non-destructively inspected with phased array ultrasonic testing (PAUT) to classify weld defect and measure the projected defects area-ratio (AR). Ultimate tensile strength (UTS) decreased linearly with the increase of the size of weld defect but tensile toughness behaved non-linearly with defect size. Depending on defect size, defective samples' joint efficiency (JE) varied from 35 to 48% of base metal's UTS. Defect-free as-welded (AW) specimens observed to have 53% and 34% JE based on UTS and yield strength (YS) of base metal, respectively. PWHT was applied on defect-free welded specimens to improve tensile properties by precipitation hardening, microstructures refining, and removal of post-weld residual stresses. Solution treatment (at 540 °C) followed by varying levels of artificial age-hardening time was investigated to obtain optimum tensile properties. For GTA welded AA-6061-T651, peak aging time was 5
Science and Technology of Welding and Joining, 2007
Despite its excellent weldability characteristics, AA2219 suffers from poor fusion zone strength under the as welded condition. In the present work, it is attempted to increase the mechanical properties of the as welded fusion zone of this alloy by increasing the weld cooling rates and multipass welding. The cooling rate was increased with the use of high intense heat source, namely electron beam in a pulsed current mode. Multipass gas tungsten arc welding was carried out using direct current straight polarity. These techniques resulted in a significant improvement in fusion zone hardness and tensile properties, which is attributed to reduced copper segregation and natural aging as well as aging caused by heat of multipass welding.
Partially Melted Zone in A356 Al-Si Alloy Welds-Effect of Technique and Prior Condition
Pressure die cast A356 Al-Si alloy with strontium modification was fusion welded by the continuous current gas tungsten arc welding (CCGTAW) and pulsed current gas tungsten arc welding(PCGTAW) techniques. Partially melted zone (PMZ) is an important region, as it is the weak link in the weldments. It is significantly affected by the welding techniques used and prior condition of the alloy. In the present work, effect of welding techniques on PMZ of A356 Al-Si alloy was studied. Microstructural changes in PMZ are related to the welding techniques. Susceptibility to liquation was found to be less in the weld made in as cast condition compared to that of artificially aged condition (T6). Resistance to liquation in PMZ was found to be better in as cast condition of the alloy with pulsed current gas tungsten arc welding, when compared to continuous current gas tungsten arc welding technique.
Materials, 2019
Precipitation hardening aluminum alloys are used in many industries due to their excellent mechanical properties, including good weldability. During a welding process, the tensile strength of the joint is critical to appropriately exploit the original properties of the material. The welding processes are still under study, and gas metal arc welding (GMAW) in pulsed metal-transfer configuration is one of the best choices to join these alloys. In this study, the welding of 6061 aluminum alloy by pulsed GMAW was performed under two heat treatment conditions and by using two filler metals, namely: ER 4043 (AlSi5) and ER 4553 (AlMg5Cr). A solubilization heat treatment T4 was used to dissolve the precipitates of β”- phase into the aluminum matrix from the original T6 heat treatment, leading in the formation of β-phase precipitates instead, which contributes to higher mechanical resistance. As a result, the T4 heat treatment improves the quality of the weld joint and increases the tensile ...
2020
The refinement in weld metal grain size and shape results in both improved mechanical properties such as ductility and toughness as well as significant improvement in weldability. In the present study, the influence of scandium additions to the ER5356 fillers on the structure and mechanical properties of tungsten inert gas welded AA5083 and AA5754 weldments were investigated. A modified ER5356 filler rod with small quantity of scandium was prepared using stir casting. Tungsten inert gas welds were prepared using alternating current. The addition of scandium gives good grain refinement, which is mainly caused by Al3SC particles. The observed grain refinement showed substantial increase in the hardness, yield strength and ultimate tensile strength of the fusion zone. The slow diffusion of SC in Al matrix and stability of Al3SC precipitates at elevated temperature were suggested to be responsible for the improved high temperature yield strength of welds is made from SC modified fillers.
Analysis of Welding Characteristics in Aa 5052 Using Gas Tungsten Arc Welding
In this experimental work, aluminium alloy (5052) weldments were made using Gas Tungsten Arc Welding with pulsed current at different frequencies 2Hz,4Hz,6Hz. The selected material as Aluminium plate and electrode is taken into chemical analysis test for checking proper composition of materials. With the successful results it is subjected to made weldment with chosen parameters. Non-destructive tests like radiography, liquid penetrate test were conducted, evaluated and compared with pulsed welding at different frequencies of two different thick materials (2mm and 3mm of 5052 aluminium alloy).The aim of this experimental work is to see the effect of pulsed current on the quality of weldment. The experimental results pertaining to different welding parameters for the above material using pulsed and non-pulsed current GTAW are discussed and compared.
Journal of Materials Processing Technology, 2003
Weld solidification cracking in age-hardenable aluminium alloys is usually minimised by adjusting weld metal composition. One way of reducing cracking susceptibility is to refine the weld metal microstructure, which offers the additional benefit of improving mechanical properties. In the current work, grain refinement was achieved in weld fusion zones of a medium-strength Al-Zn-Mg alloy through inoculation with Ti, Ti + B and Zr. It was found that the grain structure in the refined welds was equiaxed in all three dimensions and that this led to a reduction in hot cracking tendency and to an improvement in hardness and tensile properties, especially ductility.