On the Fatigue Strengths of Fillet welded Joints Connecting high Tensile Strength Structural Steels, and of Similar Joints of high Tensile Strength Structural Steel, Connected with Mild Steel

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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Mixed Scheduled Rolling of High Tensile Strength and Mild Steel Using a High-accuracy Profile Model in Hot Strip Finishing Mill

Tetsu-to-Hagane ◽

10.2355/tetsutohagane.100.1499 ◽

2014 ◽

Vol 100 (12) ◽

pp. 1499-1507 ◽

Cited By ~ 1

Author(s):

Suguhiro Fukushima ◽

Yoshiro Washikita ◽

Tamotsu Sasaki ◽

Shigemasa Nakagawa ◽

Yasuhiko Buei ◽

...

Keyword(s):

Tensile Strength ◽

Mild Steel ◽

High Accuracy ◽

High Tensile Strength ◽

Profile Model ◽

Accuracy Profile ◽

Hot Strip ◽

Finishing Mill ◽

Hot Strip Finishing Mill

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Bending Strength of Welded Joints in TMCP Steel Square Tubular Profiles “T” Connexions

International Journal of Engineering & Technology ◽

10.14419/ijet.v5i3.6195 ◽

2016 ◽

Vol 5 (3) ◽

pp. 70

Author(s):

Rafael Luciano Dalcin ◽

Ivan Guerra Machado ◽

Arnaldo Ruben Gonzalez ◽

Cintia Cristiane Petry Mazzaferro

Keyword(s):

Tensile Strength ◽

Welded Joints ◽

Bending Strength ◽

Mechanical Efficiency ◽

Structural Steels ◽

Detailed Data ◽

Welded Structures ◽

Longitudinal Joints ◽

Longitudinal Welds ◽

Loading Axis

The use of DOMEX 700 MCTM steel weldments is still little explored, due to some concern of the validity of the rules imposed by several standards and Codes for this class of steel. This material has low ductility and consequently the relation between tensile strength and yield strength is significantly lower than ordinary structural steels. For this reason, the instability phenomena are more critical than the instability phenomena of ordinary structural steels. Therefore, the aim of this study was to obtain detailed data on the mechanical efficiency of joints welded by GMAW. Six different heat inputs were used on square tubular profiles of TMCP steel. The tubular profiles were placed as a column/beam weldment with transverse and longitudinal welds positioned in relation to the loading axis. Twelve welded structures were instrumented with extensometer and tested in simple bending. Comparing the obtained data, it was verified that longitudinal welded joints presented higher bending strength than transversal welded joints. In the case of longitudinal joints, two weld beads were subjected to bending efforts, and in the case of transverse joints, only one weld bead resisted bending forces.

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