scholarly journals The Microstructure and Mechanical Properties of Multi-Strand, Composite Welding-Wire Welded Joints of High Nitrogen Austenitic Stainless Steel

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2944 ◽  
Author(s):  
Jianguo Li ◽  
Huan Li ◽  
Yu Liang ◽  
Pingli Liu ◽  
Lijun Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Welded Joints ◽  
Heat Input ◽  
Weld Seam ◽  
High Heat ◽  
High Nitrogen ◽  
Welding Wire ◽  
Δ Ferrite ◽  
High Heat Input

A multi-strand composite welding wire was applied to join high nitrogen austenitic stainless steel, and microstructures and mechanical properties were investigated. The electrical signals demonstrate that the welding process using a multi-strand composite welding wire is highly stable. The welded joints are composed of columnar austenite and dendritic ferrite and welded joints obtained under high heat input and cooling rate have a noticeable coarse-grained heat-affected zone and larger columnar austenite in weld seam. Compared with welded joints obtained under the high heat input and cooling rate, welded joints have the higher fractions of deformed grains, high angle grain boundaries, Schmid factor, and lower dislocation density under the low heat input and cooling rate, which indicate a lower tensile strength and higher yield strength. The rotated Goss (GRD) ({110}⟨1 1 ¯ 0⟩) orientation of a thin plate and the cube (C) ({001}⟨100⟩) orientation of a thick plate are obvious after welding, but the S ({123}⟨63 4 ¯ ⟩) orientation at 65° sections of Euler’s space is weak. The δ-ferrite was studied based on the primary ferrite solidification mode. It was observed that low heat input and a high cooling rate results in an increase of δ-ferrite, and a high dislocation density was obtained in grain boundaries of δ-ferrite. M23C6 precipitates due to a low cooling rate and heat input in the weld seam and deteriorates the elongation of welded joints. The engineering Stress–strain curves also show the low elongation and tensile strength of welded joints under low heat input and cooling rate, which is mainly caused by the high fraction of δ-ferrite and the precipitation of M23C6.

scholarly journals Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Multi-Strand Composite Welding Wire Welded Joints of High Nitrogen Austenitic Stainless Steel

2019 ◽  
Author(s):  
jianguo Li ◽  
Huan Li ◽  
Yu Liang ◽  
Pingli Liu ◽  
Lijun Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Welded Joints ◽  
Heat Input ◽  
Weld Seam ◽  
High Heat ◽  
High Nitrogen ◽  
Welding Wire ◽  
Delta Ferrite ◽  
High Heat Input

A multi-strand composite welding wire was applied to join high nitrogen austenitic stainless steel, and microstructures and mechanical properties were investigated. The electrical signals demonstrate that the welding process using a multi-strand composite welding wire is highly stable. The welded joints are composed of columnar austenite and dendritic ferrite and welded joints obtained under high heat input and cooling rate have a noticeable coarse-grained heat-affected zone and larger columnar austenite in weld seam. Compared with welded joints obtained under the high heat input and cooling rate, welded joints have the higher fractions of deformed grains, high angle grain boundaries, Schmid factor and the lower dislocation density under the low heat input and cooling rate, which indicate a lower tensile strength and higher yield strength. The rotated goss (GRD) orientation of a thin plate and the cube (C) orientation of a thick plate are obvious after welding, but the S orientation at 65° sections of Euler’s space is weak. The δ-ferrite was studied based on the primary ferrite solidification mode. It is observed that low heat input and high cooing rate result in the increasing of δ-ferrite and high dislocation density was obtained in grain boundaries of δ-ferrite. M23C6 precipitates due to low cooling rate and heat input in weld seam and deteriorates the elongation of welded joints. The engineering stress-strain curves also show the low elongation and tensile strength of welded joints under low heat input and cooling rate, which is mainly caused by the high fraction of δ-ferrite and the precipitation of M23C6.

Impact Toughness Characteristics of SM570-TMC Steel Joint Using Welding Wire Containing 0.4% Nickel at Different Level of Heat Input

2020 ◽  
Vol 867 ◽  
pp. 117-124
Author(s):  
Herry Oktadinata ◽  
Winarto Winarto ◽  
Dedi Priadi ◽  
Eddy S. Siradj ◽  
Ario S. Baskoro
Keyword(s):  
Impact Toughness ◽  
Heat Input ◽  
High Heat ◽  
Optical Microscope ◽  
Butt Joint ◽  
Welding Wire ◽  
Steel Joint ◽  
Microstructure Observation ◽  
High Heat Input ◽  
The Impact

The study was conducted to evaluate the impact toughness of flux-cored arc welded of SM570-TMC steel joint under different heat inputs, 0.9 kJ/mm (low heat input) and 1.6 kJ/mm (high heat input). Welding wire containing 0.4%Ni was selected on this experiment. Multi-pass welds were performed on SM570-TMC steel plate of 16 mm in thickness with a single V-groove butt joint on flat position (1G). The evaluation consists of observations on microstructure using an optical microscope and SEM-EDS, and mechanical properties including tensile, microhardness Vickers and Charpy V-notch (CVN) impact test at temperatures of 25, 0 and-20 °C. Results showed that the impact toughness of the base metal (BM) was higher than the weld metal (WM) at all test temperatures. Hardness and impact toughness of WM at low heat input was observed higher than when applied a high heat input. The welded samples at low and high heat inputs had high of tensile strength, and the fracture seemly occurs on the BM. Microstructure observation showed that at a high heat input, larger grains and microsegregation were observed. It might affect on decreasing their impact property.

scholarly journals Mechanical Properties and Microstructures of High Heat Input Welded Tandem EGW Joint in EH36-TM Steel

2007 ◽  
Vol 25 (1) ◽  
pp. 57-62 ◽  
Author(s):  
Hong-Chul Jeong ◽  
Young-Hwan Park ◽  
Young-Ho An ◽  
Jong-Bong Lee
Keyword(s):  
Mechanical Properties ◽  
Heat Input ◽  
High Heat ◽  
High Heat Input

scholarly journals Residual Stress, Microstructure and Mechanical Properties in Thick 6005A-T6 Aluminium Alloy Friction Stir Welds

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 803 ◽  
Author(s):  
Xiaolong Liu ◽  
Pu Xie ◽  
Robert Wimpory ◽  
Wenya Li ◽  
Ruilin Lai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Yield Strength ◽  
Residual Stresses ◽  
Heat Input ◽  
Electron Backscatter Diffraction ◽  
Weld Zone ◽  
High Heat ◽  
Friction Stir ◽  
High Heat Input

Plates (37 mm thick) of 6005A-T6 aluminum alloy were butt joined by a single-sided and double-sided friction stir welding (FSW). The 3D residual stresses in the joints were determined using neutron diffraction. The microstructures were characterized by a transmission electron microscope (TEM) and electron backscatter diffraction (EBSD). In the single-sided FSW specimen, there were acceptable mechanical properties with a tensile strength of 74.4% of base metal (BM) and low residual stresses with peak magnitudes of approximately 37.5% yield strength of BM were achieved. The hardness is related to the grain size of the nugget zone (NZ), and in this study, precipitations were dissolved due to the high heat input. In the double-sided FSW specimen, there were good mechanical properties with a tensile strength of 80.8% of BM, but high residual stresses with peak magnitudes of approximately 70% yield strength of BM were obtained. The heat input by the second pass provided an aging environment for the first-pass weld zone where the dissolved phases were precipitated and residual stresses were relaxed.

Research on High Heat Input Welding of the High Strength Electro-Gas Flux-Cored Wire Used for Large Storage Tank

2010 ◽  
Vol 638-642 ◽  
pp. 3699-3703
Author(s):  
Zhao Xia Qu ◽  
Han Qian Zhang
Keyword(s):  
Heat Input ◽  
Storage Tank ◽  
Welding Process ◽  
High Strength ◽  
High Heat ◽  
Welding Wire ◽  
Cored Wire ◽  
Gas Flux ◽  
Oil Storage ◽  
High Heat Input

Baosteel cooperated with the China’s welding consumable company and developed an electro-gas welding wire BH610-EG, which is a flux-cored welding wire and can match the high strength steel B610E. In this paper, the electro-gas welding technological tests are carried out by B610E with the thickness of 21 mm and 40 mm and BH610-EG wire with the diameter of 1.6 mm. And values of the heat input of electro-gas welding experiments are in the range of 80~100kJ/cm. The main conclusions can be obtained as follows: (1) In condition of high heat input, the electro-gas welding process using BH610-EG wire is very stable, the weld surface is good. (2) Various mechanical properties of the welded joints can meet the design requirements of the storage tanks. (3) The new developed electro-gas flux-cored welding wire BH610-EG can match with B610E steel and meet the requirement of high heat input of the crude oil storage tank.

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