Experimental study on variations in charpy impact energies of low carbon steel, depending on welding and specimen cutting method

Abstract

This paper presents an experimental study that examines variations of Charpy impact energy of a welded steel plate, depending upon the welding method and the method for obtaining the Charpy specimens. Flux cored arc welding (FCAW) and Gas tungsten arc welding (GTAW) were employed to weld an SA516 Gr. 70 steel plate. The methods of wire cutting and water-jet cutting were adopted to take samples from the welded plate. The samples were machined according to the recommendations of ASTM SEC. II SA370, in order to fit the specimen dimension that the Charpy impact test requires. An X-ray diffraction (XRD) method was used to measure the as-weld residual stress and its redistribution after the samples were cut. The Charpy impact energy of specimens was considerably dependent on the cutting methods and locations in the welded plate where the specimens were taken. The specimens that were cut by water jet followed by FCAW have the greatest resistance-to-fracture (Charpy impact energy). Regardless of which welding method was used, redistributed transverse residual stress becomes compressive when the specimens are prepared using water-jet cutting. Meanwhile, redistributed transverse residual stress becomes tensile when the specimens are prepared using wire cutting.

Effect of Micro-Segregation on Impact Toughness of 2.25Cr-1Mo Steel after Post Weld Heat Treatment

“…The impact test (Zwick Roell-PSW750, Ulm, Germany) was carried out at a temperature of 1 • C. even at similar locations. The impact toughness of the material is affected by many parameters such as microstructure, phases fractions and distributions, test temperature, grain size, impact velocity, specimen shape, and notch position (sampling position of test specimen) [11][12][13][14][15][16][17][18]. In the impact test of the base metal, not many variables affect the tests and they are completely linked to metallurgical aspects.…”

“…In addition to forming incoherent boundaries between the matrix and precipitate by the HCP crystal structure, they form a surrounding Cr-depleted zone due to the high interrelation of Cr and C. Excess Cr-rich precipitates in the prior austenite grain boundaries cause Cr-depleted zone formation around the precipitate, which softens the grain boundaries and becomes vulnerable to stress corrosion cracking when the Cr content decreases [29,30]. It should also be noted that these precipitates may affect the physical properties of the HAZ during welding [11]. stress corrosion cracking when the Cr content decreases [29,30].…”

“…stress corrosion cracking when the Cr content decreases [29,30]. It should also be noted that these precipitates may affect the physical properties of the HAZ during welding [11].…”

Welding Distortion Prediction in 5A06 Aluminum Alloy Complex Structure via Inherent Strain Method

“…A customized experimental facility (in Figure 8) was used to verify the FEM results in this paper. The residual stress measurement was mainly carried out by the hole-drilling method, cutting method, and X-ray diffraction method [26][27][28]. However, nearly all the stress experiments are not economically or conveniently suitable for such large-scale, complex structural components in this investigation.…”

Effect of Micro-Segregation on Impact Toughness of 2.25Cr-1Mo Steel after Post Weld Heat Treatment

“…This phenomenon occasionally occurs in impact specimens taken from the same pipe and even at similar locations. The impact toughness of the material is affected by many parameters, such as microstructure, fraction and distribution of phase, test temperature, grain size, impact velocity, specimen shape, and notch position (sampling position of test specimen) [11][12][13][14][15][16][17][18]. In the impact test of the base metal, it was judged that there were not many variables and only the view from the metallurgy.…”