Influence of Plate Thickness on Very Low Cycle Fatigue Properties of Butt Welded Joints Containing Weld Defects. Study on Acceptable Size of Defects in Girth Welds of Gas Pipelines. 2nd Report.

The multiaxial fatigue critical plane method can be used to evaluate the extremely-low-cycle fatigue (ELCF) damage of beam-to-column welded joints in steel frameworks subjected to strong seismic activity. In this paper, fatigue damage models using structural detail parameters are studied. Firstly, the fatigue properties obtained from experiments are adopted to assess ELCF life for steel frameworks. In these experiments, two types of welded specimens, namely, plate butt weld (PB) and cruciform load-carrying groove weld (CLG), are designed according to the structural details of steel beam and box column joints, in which both structural details and welded factors are taken into account. Secondly, experiments are performed on three full-scale steel welded beam-to-column joints to determine the contribution of stress and/or strain to damage parameters. Finally, we introduce a modification of the most popular fatigue damage model of Fatemi and Socie (FS), modified by us in a previous study, for damage evaluation, and compare this with Shang and Wang (SW) in order to examine the applicability of the fatigue properties of PB and CLG. This study shows that the modified FS model using the fatigue properties of CLG can predict the crack initiation life and evaluate the damage of beam-to-column welded joints, and can be subsequently used for further investigation of the damage evolution law.

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Fatigue Properties of Welded Joints of High-Carbon Steels

Materials Science Forum ◽

10.4028/www.scientific.net/msf.537-538.47 ◽

2007 ◽

Vol 537-538 ◽

pp. 47-54 ◽

Cited By ~ 1

Author(s):

Attila Magasdi ◽

János Dobránszky ◽

F. Tusz ◽

János Ginsztler

Keyword(s):

Fatigue Fracture ◽

Heat Affected Zone ◽

Welded Joints ◽

Cyclic Load ◽

Low Cycle Fatigue ◽

Carbon Steels ◽

Fatigue Properties ◽

Welding Parameters ◽

Cycle Fatigue ◽

Very High

The typical tool steels of the wood-cutting industry are the unalloyed and chromium and nickel containing, low-alloyed eutectoid steels. These materials, in tempered condition have a very high, 1200-1400 MPa tensile strength. One of the major failure forms of these tools is the fatigue fracture of the tool. The high pretension and the cyclic load, caused by the cutting and the bending of the tool, easily can cause high-cycle fatigue fracture, especially at the welded area and at the heat affected zone. Thus, one of the most critical part in the manufacturing process of the bandsaw blade is the welding. We have examined the fatigue properties of three types of joints: conventional and cold wire TIG welding, MIG welding, and resistance-butt welded joints. The structure at the weld and at the heat affected zone could highly affect the life-span of the tool. Therefore the welding parameters (preheat, post welding heat treatment (PWHT), shield gas, backing gas), affecting the microstructure of the weld, also have serious affects on the fatigue properties. The influence of welding parameters on the fatigue properties were examined by low-cycle fatigue test.

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