Metals

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6526 KiB

Open AccessArticle

Investigation of the Weld Properties of Dissimilar S32205 Duplex Stainless Steel with AISI 304 Steel Joints Produced by Arc Stud Welding

by Aziz Barış Başyiğit and Adem Kurt

Metals 2017, 7(3), 77; https://doi.org/10.3390/met7030077 - 1 Mar 2017

Cited by 16 | Viewed by 8641

Abstract

UNS S32205 duplex stainless steel plates with a thickness of 3 mm are arc stud welded by M8 × 40 mm AISI 304 austenitic stainless steel studs with constant stud lifts in order to investigate the effects of welding arc voltages on mechanical [...] Read more.

UNS S32205 duplex stainless steel plates with a thickness of 3 mm are arc stud welded by M8 × 40 mm AISI 304 austenitic stainless steel studs with constant stud lifts in order to investigate the effects of welding arc voltages on mechanical and microstructural behaviors of the joints. As the welding arc voltage increases starting from 140 V, the tensile strength of the weldment also increases but the higher arc values results in more spatters around the weld seam up to 180 V. Conversely, the lower arc voltages causes poor tensile strength values to weldments. Tensile tests proved that all of the samples are split from each other in the welding zone but deformation occurs in duplex plates during the tensile testing of weldments so that the elongation values are not practically notable. The satisfactory tensile strength and bending values are determined by applying 180 volts of welding arc voltage according to ISO 14555 standard. Peak values of micro hardness occurred in weld metal most probably as a consequence of increasing heat input decreasing the delta ferrite ratios. As the arc voltage increases, the width of the heat affected zone increases. Coarsening of delta-ferrite and austenite grains was observed in the weld metal peak temperature zone but it especially becomes visible closer to the duplex side in all samples. The large voids and unwelded zones up to approximately 1 mm by length are observed by macro-structure inspections. Besides visual tests and micro-structural surveys; bending and microhardness tests with radiographic inspection were applied to samples for maintaining the correct welding parameters in obtaining well-qualified weldments of these two distinct groups of stainless steel materials. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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4742 KiB

Open AccessCommunication

Friction Stir Welding of Dissimilar Materials Aluminum AL6061-T6 to Ultra Low Carbon Steel

by Zakaria Boumerzoug and Yazid Helal

Metals 2017, 7(2), 42; https://doi.org/10.3390/met7020042 - 3 Feb 2017

Cited by 24 | Viewed by 7347

Abstract

In this study, the microstructure and strength properties of friction stir welded 6061-T6 aluminum alloy to ultra-low carbon steel have been investigated using different advancing speeds of 100, 200, and 400 mm·min⁻¹ at constant rotation rate. Microstructure observations have been conducted by [...] Read more.

In this study, the microstructure and strength properties of friction stir welded 6061-T6 aluminum alloy to ultra-low carbon steel have been investigated using different advancing speeds of 100, 200, and 400 mm·min⁻¹ at constant rotation rate. Microstructure observations have been conducted by optical and scanning electron microscopy. The joint strength was evaluated on a tensile testing machine. The effect of advancing speed on the shear load of a joint has been found, as well as a relationship between microstructures and mechanical properties. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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6424 KiB

Open AccessArticle

The 2D Finite Element Microstructure Evaluation of V-Shaped Arc Welding of AISI 1045 Steel

by Omer Eyercioglu, Ahmed Samir Anwar, Kursat Gov and Necip Fazil Yilmaz

Metals 2017, 7(2), 41; https://doi.org/10.3390/met7020041 - 3 Feb 2017

Cited by 4 | Viewed by 5406

Abstract

In the present study, V-shaped arc welding of the AISI 1045 steel is modeled by using 2D Finite Element Model (FEM). The temperature distribution, microstructure, grain growth, and the hardness of the heat-affected zone (HAZ) of the welding are simulated. The experimental work [...] Read more.

In the present study, V-shaped arc welding of the AISI 1045 steel is modeled by using 2D Finite Element Model (FEM). The temperature distribution, microstructure, grain growth, and the hardness of the heat-affected zone (HAZ) of the welding are simulated. The experimental work is carried out to validate the FE model. The very close agreement between the simulation and experimental results show that the FE model is very effective for predicting the microstructure, the phase transformation, the grain growth and the hardness. The effect of preheat temperature on the martensite formation is analysed, and it is shown that 225 °C preheating completely eliminates the martensite formations for the 12 mm thick plate. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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5040 KiB

Open AccessArticle

The Effect of Diffusion Welding Parameters on the Mechanical Properties of Titanium Alloy and Aluminum Couples

by Enes Akca and Ali Gursel

Metals 2017, 7(1), 22; https://doi.org/10.3390/met7010022 - 11 Jan 2017

Cited by 11 | Viewed by 6522

Abstract

Ti-6Al-4V alloy and commercially pure aluminum, which are commonly used in aerospace, medical, and automotive industries, are bonded by diffusion welding. Different welding parameters (560, 600, and 640 °C—0, 45, and 60 min—under argon shielding) are used in this process to make the [...] Read more.

Ti-6Al-4V alloy and commercially pure aluminum, which are commonly used in aerospace, medical, and automotive industries, are bonded by diffusion welding. Different welding parameters (560, 600, and 640 °C—0, 45, and 60 min—under argon shielding) are used in this process to make the materials more applicable in the industry. Here, the effects of parameters on the strength of joints were studied. The bonded samples were subjected to microhardness and tensile tests in order to determine their interfacial strength. The hardness values were found to decrease with increasing distance from the interface on the titanium side while it remained constant on the aluminum side. Maximum tensile strength was taken from the maximum bonding temperatures of 600 and 640 °C. A morphology examination of the diffusion interfaces was carried out with scanning electron microscopy. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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3217 KiB

Open AccessArticle

Properties of Resistance Spot-Welded TWIP Steels

by Havva Kazdal Zeytin, Hayriye Ertek Emre and Ramazan Kaçar

Metals 2017, 7(1), 14; https://doi.org/10.3390/met7010014 - 11 Jan 2017

Cited by 19 | Viewed by 6805

Abstract

High manganese TWIP (twinning-induced plasticity) steels are particularly attractive for automotive applications because of their exceptional properties of strength combined with an excellent ductility. However, the microstructure and properties of TWIP steels are affected by excessive thermal cycles, such as welding and heat [...] Read more.

High manganese TWIP (twinning-induced plasticity) steels are particularly attractive for automotive applications because of their exceptional properties of strength combined with an excellent ductility. However, the microstructure and properties of TWIP steels are affected by excessive thermal cycles, such as welding and heat treatment. This paper deals with characterization and understanding the effect of welding current and time on the mechanical properties and microstructure of the resistance spot welded TWIP steel. For this purpose, weld nugget diameter was evaluated and the hardness, tensile shear strength of the weldment, and failure mode of samples were also determined. It has been found that the tensile shear strength of the samples increased with increasing welding current and welding time without expulsion, which reduces the strength of the weldment. Tensile shear samples failed by a partial interfacial fracture mode for low-heat input welds. The pullout fractures were observed with a sufficient heat input without expulsion. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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2920 KiB

Open AccessArticle

A Case Study for the Welding of Dissimilar EN AW 6082 and EN AW 5083 Aluminum Alloys by Friction Stir Welding

by Sefika Kasman, Fatih Kahraman, Anıl Emiralioğlu and Haydar Kahraman

Metals 2017, 7(1), 6; https://doi.org/10.3390/met7010006 - 29 Dec 2016

Cited by 11 | Viewed by 5931

Abstract

The aim of this study is to investigate the effect of keeping constant the tool rotational speed to the welding speed ratio (υ ratio) on the mechanical properties of the dissimilar friction stir welding of EN AW6082-T6 and EN AW5083-H111. Two different pins [...] Read more.

The aim of this study is to investigate the effect of keeping constant the tool rotational speed to the welding speed ratio (υ ratio) on the mechanical properties of the dissimilar friction stir welding of EN AW6082-T6 and EN AW5083-H111. Two different pins shaped as triangular and pentagonal were associated with the constant υ ratio. From the tensile test results, it was found that the υ ratio does not create an evident change in the weld joint strength. The small cavity- and tunnel-type defects were observed at the nugget zone and located on the advancing side of the pin. These defects caused a decrease in the strength and elongation of the weld joint. The most important inference obtained from the experimental results is that if the υ ratio is kept constant, the weld joint strength for each weld does not correspond to a constant value. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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2223 KiB

Open AccessArticle

Structural and Corrosion Study of Uncoated and Zn-Cu Coated Magnesium-Based Alloy

by Mehmet Yakup Hacıibrahimoğlu, Metin Bedir and Abdulcabbar Yavuz

Metals 2016, 6(12), 322; https://doi.org/10.3390/met6120322 - 19 Dec 2016

Cited by 8 | Viewed by 5522

Abstract

Zn-Cu alloy was deposited onto AZ63 substrate, and the corrosion behaviour of resulting modified electrodes was investigated in 3 wt % NaCl solution in comparison with uncoated AZ63. Electrochemical, structural, and morphological study of the coating is presented. SEM images reveal that the [...] Read more.

Zn-Cu alloy was deposited onto AZ63 substrate, and the corrosion behaviour of resulting modified electrodes was investigated in 3 wt % NaCl solution in comparison with uncoated AZ63. Electrochemical, structural, and morphological study of the coating is presented. SEM images reveal that the surface morphology of the films is uniformly small spherical grain distributions. The XRD patterns illustrate polycrystalline structure and the formation of peaks corresponding to hexagonal close-packed ε-phase of Zn-Cu with various crystallographic orientations. Cyclic voltammetry was used to determine the potential ranges where the various redox processes occur. Linear sweep voltammetry results illustrate that longer exposure of uncoated AZ63 in NaCl solution produces a greater corrosion potential shift because of the formation of an oxide layer that did not prevent the progression of corrosion attack. The corrosion resistivity of Zn-Cu coated AZ63 is approximately two orders of magnitude greater than that of uncoated AZ63. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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2891 KiB

Open AccessArticle

Resistance Spot Weldability of Galvanize Coated and Uncoated TRIP Steels

by Hayriye Ertek Emre and Ramazan Kaçar

Metals 2016, 6(12), 299; https://doi.org/10.3390/met6120299 - 28 Nov 2016

Cited by 30 | Viewed by 5461

Abstract

In this study, the resistance spot weldabilty of zinc galvanize-coated and uncoated TRIP800 steels was investigated in detail. Depending on the welding parameters such as welding current and welding time, the effects of zinc coating on the weld nugget geometry, the tensile shear [...] Read more.

In this study, the resistance spot weldabilty of zinc galvanize-coated and uncoated TRIP800 steels was investigated in detail. Depending on the welding parameters such as welding current and welding time, the effects of zinc coating on the weld nugget geometry, the tensile shear strength, the failure modes, the hardness, and the microstructure of the resistance spot-welded sample were studied, and the results are compared with that of uncoated weldment. The coating on the surface of the TRIP steel causes a decrease in the weld nugget size and tensile shear strength of the weldment, and it changes to failure mode of the test sample from pullout to interfacial or partial interfacial fracture. As compared with the uncoated sample, the galvanized TRIP800 steel weldment has required a larger critical nugget size for achieving the desired pullout fracture mode and acceptable tensile shear strength. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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3368 KiB

Open AccessArticle

Effect of Different Current Values on Microstructure and Mechanical Properties of Microalloyed Steels Joined by the Submerged Arc Welding Method

by Hasan Karabulut, Mustafa Türkmen, Mehmet Akif Erden and Süleyman Gündüz

Metals 2016, 6(11), 281; https://doi.org/10.3390/met6110281 - 16 Nov 2016

Cited by 5 | Viewed by 4251

Abstract

In this study, microalloyed steels were joined by using the submerged arc welding method at different welding currents of 350 A, 400 A and 450 A. The effects of selected welding parameters on the microstructure and mechanical properties of welded materials were investigated. [...] Read more.

In this study, microalloyed steels were joined by using the submerged arc welding method at different welding currents of 350 A, 400 A and 450 A. The effects of selected welding parameters on the microstructure and mechanical properties of welded materials were investigated. Tensile tests and microhardness measurements were performed. Microstructural changes have been identified in the welding zone. The results showed an increase in hardness and tensile strength depending on the current intensity. The heat affected zone was observed much wider with the increase in welding current. Full article

(This article belongs to the Special Issue Selected Papers from ICWET16)

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