Studies on weld metal characteristics and their influence on tensile and fatigue properties of pulsed-current GMA welded AlZnMg alloy

The fatigue properties of a low strength weld metal in a dissimilar welding joint in high cycle and very high cycle regimes were investigated by fully reversed axial tests in air at room temperature and 370°C. A clear duplex S-N curve existed as a result of the transition of fatigue failure mode from surface-induced failure to internal-induced failure at 370°C, while the S-N curve was continuously decreased at room temperature. A new model was successfully proposed to predict fatigue life, and interpret the crack initiation modes transition from surface inclusion to interior inclusion. It was concluded that cracks were initiated by competition among non-metallic inclusions, welding pores and discontinuous microstructures in high cycle regime. While in the very high cycle regime, non-metallic inclusions were the dominant crack initiation mechanism which depended on stress level, inclusion size as well as inclusion depth.

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Influence of Pulsed Current Welding on the Microstructure and Porosity Content of Al-Zn-Mg Alloy Weldment / Einfluß des Schweißens mit pulsierender Stromstärke auf das Gefüge und die Porösität von Schweißungen an einer Al-Zn-Mg-Legierung

Practical Metallography ◽

10.1515/pm-1990-271204 ◽

1990 ◽

Vol 27 (12) ◽

pp. 613-626

Author(s):

P. K. Gosh ◽

S. R. Gupta ◽

P. C. Gupta ◽

R. Rathi

Keyword(s):

Mg Alloy ◽

Pulsed Current

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Aging characteristics of the weld metal in the commercial Al-Zn-Mg alloy

Journal of Japan Institute of Light Metals ◽

10.2464/jilm.24.9 ◽

1974 ◽

Vol 24 (1) ◽

pp. 9-16 ◽

Cited By ~ 1

Author(s):

Masao KIKUGHI ◽

Masao MIZUNO

Keyword(s):

Weld Metal ◽

Mg Alloy

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Microstructures and Mechanical Properties of Welded Joints of Several High Tensile Strength Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.224 ◽

2018 ◽

Vol 941 ◽

pp. 224-229

Author(s):

Takahiro Izumi ◽

Tatsuya Kobayashi ◽

Ikuo Shohji ◽

Hiroaki Miyanaga

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Weld Metal ◽

Welded Joints ◽

Welded Joint ◽

Steel Plates ◽

Fatigue Properties ◽

High Tensile Strength ◽

The Matrix ◽

Microstructures And Mechanical Properties

Microstructures and mechanical properties of lap fillet welded joints of several high and ultra-high tensile strength steel by arc welding were investigated. Steel plates having tensile strength of 400 (SPH400W), 590 (SPC590Y, SPC590R), 980 (SPC980Y) and 1500 MPa (SAC1500HP) class with 2 mm thickness were prepared. Four types of joints were formed by MAG welding; SPH400W/SPH400W, SPC590Y/SPC590Y, SPC980Y/SPC980Y and SAC1500HP/SPC590R. In joints with SPC590Y, SPC980Y and SAC1500HP steel which matrixes are martensitic microstructures, the HAZ softens due to transformation of martensite into ferrite with precipitating cementite. By using high and ultra-high tensile strength steel, the weld metal is strengthened due to dilution of the matrix into the weld metal and thus tensile shear strength of the welded joint increases. In the fatigue test, similar S-N diagrams were obtained in the all welded joints investigated. It seems that the effect of stress concentration due to the shape of the welded joint on fatigue properties is larger than that of the strength of the matrix.

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