Gas Tungsten Arc Welding Process Research Articles

An investigation of the effect of sensitization on the metallurgical characteristics of dissimilarly welded austenitic-ferritic stainless steel

Purpose The purpose of this study is to examine the effects of sensitization on the metallurgical characteristics of weld joints made up of austenitic stainless steel (AISI 316L) and ferritic stainless steel (AISI 430), using the gas tungsten arc welding (GTAW) process with ER316L filler wires. Design/methodology/approach A non-consumable tungsten electrode with a diameter of 1.6 mm was used during the GTAW procedure. The filler wire, ER316L, was selected based on the recommendation provided in literature. To explore the interconnections among the structure and properties of these weldments, the techniques including scanning electron microscopy and optical analysis have been used. In addition, the sensitization behaviour of the weldments was investigated using the double loop electrochemical potentio-kinetic reactivation (DLEPR) test. Findings Microstructural analyses revealed the occurrences of coarsened grains with equiaxed columnar grains and migrating grain boundaries in the weld zone. The results of the DLEPR test demonstrated that heat affected zone (HAZ) of AISI 430 was more susceptible to sensitization than HAZ of AISI 316L. Microstructure analysis also revealed the precipitation of large amounts of chromium carbide at the grain boundaries region of AISI 430 welded steel, causing more sensitization and, as a result, more failure or breaking at the side of AISI 430 weld in the dissimilar weldment of AISI 316L–AISI 430. Originality/value The present work has been carried out to determine the appropriate welding conditions for joining AISI 316L and AISI 430, as well as the metallurgical properties of the dissimilar weldment formed between AISI 316L and AISI 430. Owing to the difficulties in measuring the performance of these types of dissimilar joints given their unique mechanical and microstructural characteristics, research on the subject is limited.

Impression creep behaviour of different zones of pulsed gas tungsten arc welded Ti-6Al-4V alloy

Ti-6Al-4V alloy has several industrial applications, because of their excellent combination of mechanical and physical properties. However, welding of Ti-6Al-4V alloy is very challenging due to its high reactivity with atmospheric gases at elevated temperatures (as low as 480 °C). In this work, defect-free bead on plate welding has been carried out on 3 mm-thick Ti-6Al-4V sheets with the help of an indigenously developed shielding set-up, using the pulsed gas tungsten arc welding (GTAW) process, and the impression creep responses of different zones of the weld have been investigated using the impression creep method. A detailed microstructural examination has been carried out, because the creep behaviour of each zone is dependent on the microstructure of that region. Base metal revealed a typical fine bi-modal microstructure with an average grain size of 4.2 µm, but there was significant grain coarsening in the heat affected zone (HAZ) and weld zone with an average prior β grain size of 37 µm and 105 µm respectively. Weld zone and HAZ also showed Widmanstätten morphology as fine laths of α inside the prior-β grains. Coarse prior-β grains and Widmanstätten morphology in HAZ and weld zone assisted in reducing grain boundary sliding and impeding dislocation glide, respectively, which led to an improvement in the creep resistance of these zones in comparison to base metal. In the testing range, dislocation creep appeared as the governing creep mechanism, where activation energies ranged from 255 to 312 kJ-mol−1 in different zones of the weldment.

Non-invasive optical characterization and estimation of Zn porosity in gas tungsten arc welding of Fe–Al joints using CR model and OES measurements

In this study, we employed a non-invasive approach based on the collisional radiative (CR) model and optical emission spectroscopy (OES) measurements for the characterization of gas tungsten arc welding (GTAW) discharge and quantification of Zn-induced porosity during the GTAW process of Fe–Al joints. The OES measurements were recorded as a function of weld current, welding speed, and input waveform. The OES measurements revealed significant line emissions from Zn-I in 460–640 nm and Ar-I in 680–800 nm wavelength ranges in all experimental settings. The OES coupled CR model approach for Zn-I line emission enabled the simultaneous determination of both essential discharge parameters i.e. electron temperature and electron density. Further, these predictions were used to estimate the Zn-induced porosity using OES-actinometry on Zn-I emission lines using Ar as actinometer gas. The OES-actinometry results were in good agreement with porosity data derived from an independent approach, i.e. x-ray radiography images. The current study shows that OES-based techniques can provide an efficient route for real-time monitoring of weld quality and estimate porosity during the GTAW process of dissimilar metal joints.

Formation optimization of downward overlaid Inconel 625 on curved surface of X65 pipeline basing on dynamic behavior of molten pool

In practical engineering, overlaying on curved surfaces with constantly changing gravity components usually leads to various defects. In this study, Inconel 625 was downward overlaid on curved surface by cold metal transfer (CMT) process with varied heat input, and the dynamic behavior of the molten pool was observed by high speed camera. At high heat input (0.422 kJ/mm and 0.372 kJ/mm), the volume of the molten pool continued to expand due to the downward flow of the liquid, ultimately leading to overflow or instability defects. In contrast, low heat input (0.230 kJ/mm) will make the molten pool shrink during overlaying, which was attributed to the continuously weakened gravity, the relative position between the heat source and the molten pool was then changed. A well-formed and defect-free weld overlay was obtained at optimized heat input 0.230–0.280 kJ/mm. Compared with gas tungsten arc welding (GTAW) process, the weld overlay obtained employing CMT process has the largest thickness and the most uniform fusion line, while the content of Fe element was less than 0.5%. It was confirmed that CMT technology has great potential for overlaying on curved surface.

Directed energy deposition of Invar 36 alloy using cold wire pulsed gas tungsten arc welding: Effect of heat input on the microstructure and functional behaviour

Invar alloys exhibit low thermal expansion and are useful in applications requiring dimensional stability when subject to temperature changes. Conventional production of Invar faces certain challenges that can be offset by exploiting additive manufacturing processes. This study employed pulsed gas tungsten arc welding (GTAW) to deposit Invar 36 alloy blocks at five heat inputs (HI) ranging from 200 to 550 J mm−1. The results show that the microstructure comprised of columnar grains and remained in the austenitic phase regardless of the HI. Ductility dip cracking was found to prevail in all the blocks except the block deposited at the lowest HI. The decreased susceptibility to cracking with a reduction in the HI was due to the preservation of the grain boundary area, consequently leading to an improved partitioning of strain among the grain boundaries. On lowering the HI from 550 to 200 J mm−1 the average yield strength, tensile strength and elongation improved by 16%, 23% and 38%, respectively. The HI had a negligible effect on the mean linear coefficient of thermal expansion (CTE) in different temperature ranges as the CTE values were nearly identical between the blocks deposited at 200 and 550 J mm−1. In general, the CTE in the building direction was slightly higher than the travel direction, with a maximum difference between the CTE of the two directions being 15%. In summary, this work demonstrates the application of the cold wire GTAW process as an alternative to conventional/laser based methods for realizing the functional properties of Invar.

Mechanical Properties Of Welding API 5l X-65 Cladded UNS N08825 Material Due To The Effect of Welding Repair

Abstract This study evaluate the mechanical characteristics and microstructure of API 5L X-65-clad UNS N08825 during repair welding. Gas tungsten arc welding (GTAW) and shielded metal arc welding were used in combination to carry out the welding and the repair welding (SMAW). Filler metals ER NiCrMo3 and E NiCrMo3 were used throughout the GTAW and SMAW welding processes. The first specimen served as the primary focus, after which the weld areas of the remaining four specimens were ground, re-beveled, and then re-welded using the same parameters. It performed tensile testing, bending tests, Impact Charpy tests, macro photography tests, and Vickers hardness tests. Repairs weld carried out, the heat-affected zone's hardness in the capping region increased. The findings of the tensile test demonstrate that the tensile strength is not considerably impacted by the welding repair at any particular welding repair location. The biggest decline in the number is caused by the welding repair at PTR 2, which is 0.83 percent. The heat affected area (FL) value decreased by 10.44 percent according to the charpy impact test results. The PTR 1 and PTR 2 areas in the weld metal area had the lowest charpy impact test results, respectively, of 88 J and 258 J.

Importance of shielding and mechanical characterization of GTAW on Ti-6AL-4V alloy sheet

Welding and joining Titanium and its alloys are always challenging because getting a contamination-free joint is difficult with arc welding. For this concern, an attempt was made with and without shielding arrangements using the Gas Tungsten Arc Welding (GTAW) process on the Ti-6Al-4V alloy sheet. To study the presence of oxygen and other elements with respect to surface colourization at the weld zone, an Energy-dispersive X-ray spectroscopy (EDX) analysis is carried out. Based on the EDX analysis, post-flow and pre-flow shielding gases are also included in the operation window. Bead on Plate (BoP) trials are performed using the shielding arrangement setup and selected parameters on the thin sheets (2 mm) of Ti-6Al-4V. After examining the BoP trails, defect-free joins in a 2 mm sheet are fabricated using the optimal welding parameters. The microstructure of the joint is captured and compared with the simulation work. Compared to the base metal, coarse and enormous grains are identified at the weld zone. Due to the proper shielding, no cracks appeared in the joint subjected to the three-point bend test. The considerable heat input during the GTAW process resulted in the nucleation of (ά) in FZ, as spotted in the TEM images. The microhardness value at FZ for base metal is 373 HV and 332 HV, respectively. It is confirmed that the suggested shielding setup could prevent contamination in welds resulting in better mechanical properties.

Characterization of Gas Tungsten Arc welded dissimilar joint of AISI2205 and EN10025

In this paper, duplex stainless steel AISI2205 was welded to structural steel EN10025 by Gas Tungsten Arc Welding (GTAW) process using two different filler metals viz., ER2209 and ERNiCr3. The welded joints were free from weld defects. The ultimate tensile strength of the weldments was in the range of 71% to 82 % of the strength of the low-strength constituent (AISI 2205) of the welded assembly. It appears that either of the filler metals could equally be used. The fracture occurred at the heat affected zone (HAZ) of EN10025 in the weldment made using ER2209, while it was within the fusion zone for the weldment made using ERNiCr3. The microhardness in the fusion zones of the weldments fabricated using both the filler metals were lower than that of the base metals.

Metallurgical characterization and high-temperature tensile failure of Inconel 617 alloy welded by GTAW and SMAW—a comparative study

Two types of the weld joint of Inconel 617 alloy were produced using gas tungsten arc welding (GTAW) and shielded metal arc welding (SMAW) processes with ERNiCrCoMo-1 filler metal and ENiCrCoMo-1 electrode, respectively. The weld metal showed the segregation of the principle alloying elements like Mo and Cr along the inter-dendritic spaces, triggering the formation of secondary phases. The microstructure characterization of the interface ensured the high dilution, which could be attributed to the closeness in melting point and chemistry of base and filler metal. Microhardness variation, tensile testing at room and high temperature, and Charpy impact test were conducted to investigate the effect of the Mo segregation in the weld zone and heterogeneity in the microstructure of weldments on the mechanical behavior of both the welded joints. The cross-weld tensile tests were conducted at room temperature and 550°C. The tensile test samples failed from the weld zone for each condition with a tensile strength value close to the base metal, which ensured the applicability of the joint for end service. The tensile strength of GTAW-RT, GTAW-HT, SMAW-RT, and SMAW-HT were measured as 766 ± 22 MPa, 570 ± 5 MPa, 760 ± 7 MPa, and 600 ± 8 MPa, respectively. A non-uniform hardness plot was witnessed with the hardness of the GTAW-weld and SMAW-weld zone of 257 ± 8 HV and 285 ± 5 HV, respectively, in the transverse direction. The impact toughness of the weld zone was 84 ± 2 J and 48 ± 4 J for GTAW and SMAW weld zone. The average impact toughness of the GTAW-weld zone was approximately 42% higher than the value of the SMAW-weld zone. In a nutshell, it can be concluded that the welded joint of Inconel 617 produced using the GTAW process with ERNiCrCoMo-1 filler had the best metallurgical and mechanical properties.

The role of the strengthening phases on the HAZ liquation cracking in a cast Ni-based superalloy used in industrial gas turbines

This work presents the influence of microstructural constituents on liquation crack formation in the cast Ni-based superalloy, René 108. The investigation was divided into three parts: characterisation of the material's microstructure in pre-weld condition, hot ductility studies and analysis of liquation cracking induced by the gas tungsten arc welding process. Using advanced electron microscopy techniques it is shown that the base material in pre-weld condition is characterised by a complex microstructure. The phases identified in René 108 include γ matrix, γ' precipitates, MC and M23C6 carbides, and M5B3 borides. Based on Gleeble testing, it was found that René 108 is characterised by high strength at elevated temperatures with a maximum of 1107 MPa at 975 °C. As a result of constitutional liquation, the superalloy’s strength and ductility were significantly reduced. The nil strength temperature was equal to 1292 °C, while the nil ductility temperature was 1225 °C. The low ductility recovery rate (32.1), ratio of ductility recovery (36.2) and hot cracking factor (Rf = 0.05) values confirmed the low weldability of Renѐ 108. In the heat-affected zone (HAZ) induced by welding, constitutional liquation of mainly γ' precipitates, with a contribution of M23C6 carbides and M5B3 borides, was observed. The thin non-equilibrium liquid film, which formed along high-angle grain boundaries, led to crack initiation and their further propagation during cooling. The eutectic γ–γ' re-solidification products are visible on the crack edges.

Effect of thickness on mechanical properties of modified 9Cr 1Mo steel welds made by narrow gap hot wire gas tungsten arc welding process

Hot wire Gas Tungsten Arc Welding (GTAW) process is selected for fabrication of thick section modified 9Cr 1Mo steel components of Steam Generators (SGs) for 500MWe Prototype Fast Breeder Reactor (PFBR) at Kalpakkam, India. During the welding procedure qualification for fabrication of SGs, the 30 mm and 62 mm thick modified 9Cr 1Mo steel welds were subjected to chemical analysis, visual examination, liquid penetrant examination, radiography examination, micro-hardness tests, longitudinal and transverse tensile tests (at ambient temperature and 525 °C), bend tests, drop weight tests and impact tests (at 0 °C and +18 °C). Literature reveals both positive and negative view on the welding of thick section steel components. Limited information is available in open literature on the effect of thickness on material properties of modified 9Cr 1Mo steel welds made by hot wire GTAW method. In view of the above, authors attempted to systematically investigate the influence of thickness on mechanical properties of modified 9Cr 1Mo steel welds made by hot wire GTAW process. In this paper, the chemical compositions, hardness, tensile strength, bending strength and impact properties of 30 mm and 62 mm thick welds produced by narrow gap hot wire GTAW process are characterized and compared. It is found that the mechanical properties of 30 mm and 62 mm thick welds are comparable except the impact properties at 0 °C. The impact strength at 0 °C for 62 mm thick weld was found inferior in comparison with 30 mm thick weld.

Sensitivity Analysis of Gas Tungsten Arc Welding Process Variables for Angular Distortion in Chromium Manganese Stainless Steel Using Design Thinking Approach

An approach to problem solving that is solution-based is provided by the design methodology known as Design Thinking (DT). To address complicated problems, the five stages of design thinking can be applied. This research article focuses on using the DT method, which includes empathising, defining, and coming up with ideas, to produce high-quality weld joints. The selection of welding process parameters plays a vital role in determining the quality of weld. The weld should be free from weld defects to ensure good performance. One of the major defects that affect the weld quality is angular distortion. During welding the rapid heating and cooling of the work piece results in uneven expansion and contraction in all directions. This results in the work piece getting distorted. It becomes imperative to predict distortion in the work piece so that it can be reduced by providing initial angular distortion in the negative direction. Through empathy, it has been found that the welding process parameters such as welding current (I), welding gun angle (θ), shielding gas flow rate (Q), plate length (L), and welding speed (V), significantly contribute to angular distortion of the weld joint. From the ideation process the following suggestions were arrived to predict angular distortion and identify the factor that has significant effect on angular distortion. A statistical prediction model was developed correlating the welding process parameters with angular distortion. Central Composite Rotatable Design with five factor and five levels was used to develop mathematical models. The experiments were conducted on Chromium Manganese Stainless Steel Grade AISI 202 in GTAW process. Optimization of process parameters was done using Simulated Annealing algorithm. From the sensitivity analysis it was found that the lower values of welding current, welding gun angle and higher values of welding speed, shielding gas flow rate and plate length resulted in minimum angular distortion.

Investigation of mechanical, microstructure, and corrosion properties of duplex stainless steel joint for natural gas processing facilities

Duplex stainless steel is an exotic material known for its excellent corrosion resistance and mechanical properties due to the presence of a two-phase structure that is quite balanced between ferrite and austenite, making it one of the top choices for the oil and gas industry. In this paper, we will discuss the process and investigation of the welding results of the A/SA 790 UNS 31803 duplex pipe joint which is connected using the gas tungsten arc welding (GTAW) process for gas purification process applications. The welding process and qualification is based on the ASME BPVC Sec code. IX was then tested to obtain information on the characteristics of the mechanical properties, microstructure, and corrosion resistance of the resulting joints. Heat input in the welding process is a crucial factor that determines the equilibrium of the ferrite and austenite phases which then correlates with the mechanical properties and corrosion resistance of the joint. Based on the microstructural analysis, there was a decrease in the ferrite phase in the weld metal, but it was still within the required limits. Furthermore, the results of the mechanical properties test showed that the tensile strength of the joint was greater than the tensile strength of the base metal and no open discontinuity was observed in the bending test. The corrosion test showed no signs of pitting corrosion with a weight loss value of 1.7 g/m2.

Selecting the Appropriate Filler Metal to Join HSLA-100 Steel by Gas Tungsten Arc Welding Process

Selecting the Appropriate Filler Metal to Join HSLA-100 Steel by Gas Tungsten Arc Welding Process

Simultaneous optimization of weld bead geometry and weld strength during gas tungsten arc welding of Inconel 825 strips using desirability function coupled with grey relational analysis (DF-GRA)

Inconel 825 is a prominent Ni-Fe-Cr based superalloy finds application in aerospace, defense, automotive, nuclear, marine industries. This article investigates ‘weld strength’ and ‘weld bead characteristics’ of Inconel 825 weld specimens welded using the gas tungsten arc welding (GTAW) process. The welding speed (V), welding current (I), gas flow rate (GFR) and arc length (N) are considered as GTAW parameter and their effect has been examined on the weld characteristics. Welding speed and welding current has been identified as the most influential factor on process characteristics. Increased heat input from increased welding current and decreased welding speed initially improves weldment penetration (P) and ultimate tensile strength (UTS). However, at the highest heat input condition, the formation of root cracks is observed, resulting in nominal weld strength deterioration. To obtain a favorable parameters setting that satisfies both the criterion simultaneously i.e. maximizing weld strength for optimum weld bead geometry, a hybrid optimization approach employing desirability function coupled with grey relational analysis (DF-GRA) is proposed. Satisfying all the objectives simultaneously, the approach provides an optimum weld parameters setting of (I 3−V 1−GFR 2−N 1:120 A−180 mm min−1−9 l/min−2 mm) resulting an improvement of 4.15% in penetration (P), 5.12% in front width (W), 19.74% in reinforcement (R), 1.29% in ultimate tensile strength (UTS), and 2.9% in percentage elongation (%E) on validation. Upon comparison, the algorithm outperforms the optimization results of both DF and GRA approach suggesting its robust nature. Overall, the DF-GRA hybrid approach is found simple and effective that includes the ignored robustness of the desirability approach.

Development of nickel alloy based hardfacing procedure for fast breeder test reactor control rod sheath using conventional gas tungsten arc welding process and metal cored alloy grade ERC Ni Cr – B

Fast Breeder Nuclear Reactors (FBR) will play a vital role to fulfill the power scarcity of developing India. The main products of the reactor assembly are manufactured using austenitic stainless steel - nuclear grades of AISI 316L. This material has excellent resistance to corrosion, better creep strength at higher temperature, and resistance to impact. Few reactor components are designed to perform rotation and translation movement for operation and control of reactor power. The relative motion between the components may lead to wear. Also, there is a possibility of self welding of these components due to high temperature and presence under a hot sodium working environment. Control rod sheath houses the control rod in a nuclear reactor which is used for raising or lowering the reactor output power. During operation of a nuclear reactor the control rod will move in and out. Due to this movement the control rod sheath will experience wear and tear. To reduce the wear and self welding problems throughout the operating period of the reactor, the components are designed with a layer of hard faced metal. Nickel based hard facing alloy is widely used for hard face coating in the nuclear reactor components. Since, it has high wear resistance under elevated temperature in the nuclear reactor. The process is done using Gas Tungsten Arc Welding (GTAW) by using the metal cored filler wire of grade ERC Ni Cr-B. Efforts have been put through this project for developing GTAW hard facing procedure and to observe the micro structure including micro hardness, macro hardness on coating as well as fusion zone and base metal.

Features detection of Al alloy porosity during GTAW process based on arc spectrum and improved porosity-focus decision tree

As one of the common internal defects in the aluminum welding process, porosity defect is still challenging for real-time control due to the complexity and diversity of the welding process. Arc spectrum contains large amount of welding process information and is effective for the detection of internal defects. This paper proposed a real-time porosity defect detection method for aluminum alloy in gas tungsten arc welding (GTAW) based on the improved gradient boosting decision tree and arc spectrum. The line and continuum spectrum are separated, and the arc blackbody radiation energy and electron temperature are extracted based on the new spectral separation algorithm. Considering the long-tail distribution characteristic of the training samples, a porosity-focus loss function and a parallel training structure were proposed. More targeted line spectrum features were extracted. The defect recall rate increased by 8.6 %, and the area under the receiver operating characteristic curve (AUC) increased by 5 %, without affecting the detection accuracy and response speed. The confidence level of the prediction results was improved. The model shows better robustness through testing experiments in the face of complex welding conditions and is of great importance to the internal quality monitoring of GTAW.

Increasing the Corrosion Resistance in the UNS S32750 Super Duplex Steel Welded Joints through Hybrid GTAW-Laser Welding and Nitrogen.

The development of techniques to improve the welding of super duplex steels is necessary in order to ensure that the phase balance and properties of the material are not affected during this process. Hybrid arc-laser welding is a perfect combination of the advantages of both processes, producing deeper weld beads with more balanced phases than the pulsed laser process. Here, the objective was to improve the corrosion resistance of UNS S32750 weld beads by increasing the volumetric austenite percentage in the fusion zone (FZ) with a hybrid process of GTAW (gas tungsten arc welding) and pulsed laser Nd-YAG (neodymium-doped yttrium aluminum garnet). Welds were performed in bead on plate conditions with fixed laser parameters and a varying heat input introduced through the GTAW process. Additionally, welds within a nitrogen atmosphere were performed. After base metal characterization, an analysis of the FZ and heat affected zone were performed with optical microscopy, scanning electron microscopy and critical pitting tests (CPT). The synergy between the thermal input provided by the hybrid process and austenite-promoting characteristic of nitrogen led to a balanced volumetric austenite/ferrite fraction. Consequently, the results obtained in CPT tests were better than conventional welding processes, such as laser or GTAW solely.

Evaluation of microstructure and mechanical behavior of Aluminum 2024 and Stainless steel 304 GTAW joints

This study aims to evaluate the microstructure and mechanical behavior of aluminum 2024 and stainless steel 304 dissimilar joints. The gas tungsten arc welding (GTAW) process has been employed to weld base metals by inserting copper-nickel-based (Cu-10%Ni) filler metal. The effects of GTAW parameters such as welding current, welding speed, and gas flow on microstructure and tensile strength have been analyzed through the Taguchi method. Results revealed that tensile strength is primarily influenced by welding current, followed by speed and gas flow rate. The excellent joint strength of 138 MPa has been achieved by using Cu-10%Ni filler metal. The optimal combination of parameters, i.e., welding current of level 2 (80 A), welding speed of level 1 (100 mm/min), and gas flow rate of level 3 (10 l/min), has been obtained through SN ratio optimization. Microstructure and EDS analysis depicted that the weld zone of a high-strength joint contained fine dendrites and CuAl and NiAl solid solutions, while the weld zone of a low-strength joint featured coarse dendrites and brittle FeAl phases.

Effect of AC signal ratio on the formation, microstructure and mechanical properties of welded joint of AZ31B Mg alloy during the AC/DC mix GTAW

In this work, AZ31B magnesium alloy is welded using an AC/DC mixed gas tungsten arc welding (MIX-GTAW) process. The effect of the AC ratio on the microstructure and mechanical properties of AZ31B magnesium alloy MIX-TIG welded joints was investigated. The AC ratio range tested was 0 %–100 %. The surfaces of the welds formed at different AC ratios all had fish-scale patterns. The larger the AC ratio is, the denser is the resulting fish-scale pattern on the weld surface. When the AC ratio is 10 %–20 %, the density of the fish-scale pattern is uniform, and the welding seam is more beautiful. Changing the AC ratio parameter does not have an obvious impact on the weld cross-section. With an increase in AC ratio, the average grain size of the fusion zone (FZ) decreases. When the AC ratio exceeds 50 %, the average grain size tends to be stable. The width of the heat-affected zone (HAZ) increases as the AC ratio is increased. The width of the HAZ increase from 250.94 μm at DC (0 %) to 345.90 μm at AC (100 %). It can be found from the X-ray diffraction (XRD) pattern that the second phase particles are β-Mg17Al12. When the AC ratio increase, β-Mg17Al12 content increases, the α-Mg content decreases and the hardness of the FZ decreases. Tensile strength increased first and then decreased with an increase in AC ratio and showed the highest values at an AC ratio of 60 %. The tensile strength decreased from 217.9 MPa to 172.4 MPa as AC ratio increased from 60 % to 100 %.