Structure and mechanical properties of laser-MIG hybrid welded SAF 2507 super duplex stainless steel joints

Joining of super duplex stainless steel (SDSS) is still a challenge, in particular, the need to control the phase balance in the weld metal. In this paper, laser-MIG hybrid welding process was used to join SAF 2507 SDSS plates. The effects of welding parameters on weld appearance, microstructure and phase distribution and mechanical properties were studied systematically. Results showed that the arc/laser hybrid effect was more significant when the arc led the laser with 2 mm distance. It was indicated that arc current mainly affected the weld width while laser power mainly affected weld penetration depth. The composition and microstructure varied a lot at different positions in the weld due to the differences in peak temperature and cooling rate. From top to root, the content of ferrite phase increased and austenite phase decreased. With optimized welding parameters, due to the increase of heat input and the introduction of welding wire, the ferrite/austenite phase balance in the weld metal was obtained. Mechanical property tests showed that the joints exhibited higher tensile strength but lower toughness compared to base metal.

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Influence of Argon-Nitrogen Gas to Balance the Microstructure in the Welding of Super Duplex Stainless Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.836.165 ◽

2016 ◽

Vol 836 ◽

pp. 165-172

Author(s):

Suheni

Keyword(s):

Stainless Steel ◽

Weld Metal ◽

Duplex Stainless Steel ◽

Heat Input ◽

Oil And Gas ◽

Austenite Phase ◽

Super Duplex Stainless Steel ◽

Shielding Gas ◽

Input Variables ◽

Protective Gas

Super duplex stainless steel is steel that has a corrosion resistance and good mechanical strength so that used in industry especially in oil and gas and petrochemical industry. In use in the field is often used for the connection process by welding methods. To produce good welds, it should be noted that the welding procedures and parameters used , especially the heat input. In this study is used the heat input variables shielding gas composition to determine how much influence on the balance of ferrite - austenite phase structure in the weld stainless steels SAF 2507 super duplex with tungsten inert gas welding method (TIG). Heat input varied by applying different welding speed 1,3,4 and 5 mm /sec while the shielding gas is used 100 % argon, 98 % argon + 2 % nitrogen and 95 % argon + 5 % nitrogen. The result showed that at different welding speeds generated depth and width of the weld metal which is different. Likewise the use of protective gas will produce a different ratio wide and deep of weld metal which is different. By using protective gas 95 % argon + 5 % nitrogen squeak - ausenit phase, resulting in weld metal that is relatively balanced than others. On a slow welding in addition to produce a large heat input also produces weld metal hardness at high and affect the growth of the austenite phase. The higher the heat input ( 2,280 kJ / mm ) , the lower the austenite phase in the weld metal.

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Effect of shielding gas combination on microstructure and mechanical properties of MIG welded stainless steel 316

Materials Testing ◽

10.1515/mt-2020-0014 ◽

2021 ◽

Vol 63 (1) ◽

pp. 97-101

Author(s):

İsmail Açar ◽

Behçet Gülenç

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Stainless Steel ◽

Weld Metal ◽

Base Metal ◽

Welding Process ◽

Bending Test ◽

Welding Parameters ◽

Microstructural Properties ◽

Shielding Gas

Abstract The quality of welded joints depends on the most optimal welding parameters and the selection of shielding gas type. The shielding gas was selected for joining stainless steels through gas metal arc welding methods by considering properties such as chemical-metallurgical interaction of shielding gas and the molten weld metal during the welding process, heat transmission capability of the gas and cost. In this study, the effect of different shielding gas combinations on the mechanical and microstructural properties of 316 austenitic stainless steel joined by the metal inert gas (MIG) welding method was investigated. In the welding process, pure argon (100 % Ar), 98.5 % Ar + 1.5 % H2 and 95 % Ar + 5 % H2 were used as shielding gases. Tensile, hardness, and bending tests were conducted to determine mechanical properties of the welded samples. In addition, metallographic examinations were carried out to detect the macrostructural and microstructural properties of weld zones. According to the results obtained from the study, the highest tensile strength was obtained from the joints welded using 100 % Ar shielding gas. When the addition of H2 into the Ar gas increased, the tensile strength of the welded samples decreased. As a result of the tensile test, fractures occurred in the base metal in all welded samples. In all welding parameters, the hardness of the weld metal was lower as compared to the heat affected zone (HAZ) and the base metal. As a result of the bending test, crack and tearing defects were found in the weld zone.

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Optimization of GMAW Welding Parameters in Duplex Stainless Steel Welds Mechanical Properties

Volume 6: Materials and Fabrication, Parts A and B ◽

10.1115/pvp2009-77203 ◽

2009 ◽

Author(s):

Carolina Payares-Asprino ◽

John P. H. Steele

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Duplex Stainless Steel ◽

Gas Metal Arc Welding ◽

Welding Process ◽

Welding Parameters ◽

Metal Arc Welding ◽

Physically Based ◽

Arc Welding Process ◽

Steel Welds

The objective of the current work is to provide sufficient knowledge of the welding industry to allow the optimization of the process so as to achieve best final properties. The welding process is complex with many interacting variables controlling the procedure. In addition, not all of the physics of the process, particularly with regard to the factors which control mechanical properties, are well understood. It is unlikely that a full analytical model can be prepared and physically based numerical techniques will also suffer from a lack of basic understanding. A model for use as an optimization tool will thus have to proceed along different lines. Fortunately, this work has produced a wealth of experimental observations, which can be used for optimization. In this research, several welds were fabricated using Gas Metal Arc Welding process at different welding conditions. The technique of Response Surface Methodology was applied to develop a mathematical model to analyze various effects of GMAW parameters on the and mechanical properties such as yield strength and ultimate tensile strength of Duplex Stainless Steel weldments.

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