• Proceedings of the KWS Conference
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• 1997.10a
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• pp.16-18
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• 1997

• Journal of Welding and Joining
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• v.20 no.6
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• pp.24-24
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• 2002

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.54-56
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• 1994

• Proceedings of the KWS Conference
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• 2002.05a
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• pp.83-84
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• 2002

• Journal of Welding and Joining
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• v.20 no.6
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• pp.748-753
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• 2002

• Journal of Welding and Joining
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• v.32 no.2
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• pp.18-21
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• 2014

Cold cracking of weldment is one of the most serious welding problems. A sufficient quantity of diffusible hydrogen, a residual stress, and a sensitive microstructure are the causes of cold cracking. Removal of any one of these factors can be used to prevent cold cracking. Application of flux cored arc welding process is increasing due to high productivity and easiness of welding. In addition, to prevent cold cracking in the HAZ or weldment, preheat temperature and interpass temperature have to be controlled. In this study, the effect of preheat temperature on the levels of diffusible hydrogen in the weld metal deposited using flux cored wire was examined. The levels of preheat temperature of base metal specimen were ambient temperature, 50, 100 and $150^{\circ}C$ respectively. The result showed that the increase of preheat temperature was a linear relationship with reduction of diffusible hydrogen content in weldment.

• Steel and Composite Structures
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• v.6 no.1
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• pp.71-85
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• 2006

This paper presents the results of a series of tests carried out on cold-formed steel rectangular hollow and concrete infilled beam to column connections and frames. A stub column was chosen such that overall buckling does not influence the connection behaviour. The beam chosen was a short-span cantilever with a concentrated load applied at the free end. The beam was connected to the columns along the strong and weak axes of columns and these connections were tested to failure. Twelve experiments were conducted on cold-formed steel direct welded tubular beam to column connections and twelve experiments on connections with concrete infilled column subjected to monotonic loading. In all the experiments conducted, the stiffness of the connection, the ductility characteristics and the moment rotation behaviour were studied. The dominant mode of failure in hollow section connections was chord face yielding and not weld failure. Provision of concrete infill increases the stiffness and the ultimate moment carrying capacity substantially, irrespective of the axis of loading of the column. Weld failure and bearing failure due to transverse compression occurred in connections with concrete infilled columns. Six single-bay two storied frames both with and without concrete infill, and columns loaded along the major and minor axes were tested to failure. Concentrated load was applied at the midspan of first floor beam. The change in behaviour of the frame due to provision of infill in the column and in the entire frame was compared with hollow frames. Failure of the weld at the junction of the beam occurred for frames with infilled columns. Design expressions are suggested for the yielding of the column face in hollow sections and bearing failure in infilled columns which closely predicted the experimental failure loads.

• Journal of Korean Society of Steel Construction
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• v.23 no.4
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• pp.483-491
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• 2011

The fabrication of steel structural members always involves welding process such as flux cored arc welding. Therefore, for the application of structural steels to cold regions, it is a prerequisite to clarify the service temperature of the welded joints in order to ensure the structural integrity of the welded parts. In this study, the Charpy impact test was conducted to evaluate the service temperature of structural steel weld. The Charpy impact test is a commercial quality control test for steels and other alloys used in the construction of metallic structures. The test allows the material properties for service conditions to be determined experimentally in a simple manner with a very low cost. Standard V-notch Charpy specimens were prepared and tested under dynamic loading condition. The service temperatures of the weld metal, HAZ (heat affected zone) and base metal were derived by the absorbed energy and the impact test requirements; thus the applicability of the structural steels to cold regions was discussed in detail.

• Journal of Welding and Joining
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• v.3 no.2
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• pp.27-34
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• 1985

The mechanical properties and bonding mechanism of aluminum, copper and mild steel have been determined in cold pressure welding. The brittle cover layer to be established by scratch-brushing plays an important role in bond strength and has an influence on the threshold of deformation. The cold pressure welding was achieved at 54% of height reduction in A1-A1, 75% in Cu-Cu, 56% in Al-Cu, and 74% in Cu-steel. The height reduction at which the bond strength of weld interface was the same as the tensile strength of base metal should be over 76% in Al-Al, 82% in Cu-Cu, and 78% in Al-Cu.

• Transactions of Materials Processing
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• v.27 no.2
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• pp.81-86
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• 2018

In the cold forming process, it is not easy to fabricate a asymmetric type nut, due to the difficulty in the exact prediction of metal-flow. As we have identified, in that case, it often results in the various forging defects such as burrs, and an incomplete shape, as well as other problems because of this issue. In the current study, we introduce the development of an unparalleled shape Weld Nut by using a forging analysis tool (AFDEX). For the multi-forming machine, the optimized shapes of each intermediate product (step product) could be found by the use of a model for the prediction and analysis of various types, sizes and heights. Chiefly, forging tools were prepared based on the simulation results and an unparalleled shape could be prepared at one time without any burrs, incomplete shape and size.