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Heat-affected zone

About: Heat-affected zone is a research topic. Over the lifetime, 18787 publications have been published within this topic receiving 231744 citations.


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TL;DR: In this article, the effects of Mg on the chemical component and size distribution of Ti-bearing inclusions favored grain refinement of the welding induced coarse-grained heat affected zone (CGHAZ), with enhanced impact toughness in Ti-kill-ed steels, which were examined based on experimental observations and thermodynamic calculations.
Abstract: Effects of Mg on the chemical component and size distribution of Ti-bearing inclusions favored grain refinement of the welding induced coarse–grained heat affected zone (CGHAZ), with enhanced impact toughness in Ti-kill-ed steels, which were examined based on experimental observations and thermodynamic calculations. The results in-dicated that the chemical constituents of the inclusions gradually varied from the Ti-O+Ti-Mg-O compound oxide to the Ti-Mg-O+MgO compound oxide and the single-phase MgO, as the Mg content increased from 0.002 3% to 0.006%. A trace addition of Mg (approximately 0.002%) led to the refinement of Ti-bearing inclusions by creating the Ti-Mg-O compound oxide and provided favorable size distribution of the inclusions for acicular ferrite transformation with a high nucleation rate in the CGHAZ, and a high volume fraction of acicular ferrite was obtained in the CGHAZ with enhanced impact toughness. Otherwise, a high content of Mg (approximately 0.006%) produced a single-phase MgO, which was impotent to nucleate an acicular ferrite, and a microstructure comprised of a ferrite side plate and a grain boundary ferrite developed in the CGHAZ. The experimental results were confirmed by thermodynamic calculations.

64 citations

Journal ArticleDOI
TL;DR: In this paper, a 3D simulation of the non-steady state of a porthole die is performed to predict the welding pressure of product by FE simulations and experiments.

64 citations

Journal ArticleDOI
TL;DR: In this article, the authors used spatially resolved X-ray diffraction (SRXRD) to map the α → β → α phase transformation in the heat-affected zone (HAZ) of commercially pure titanium gas tungsten arc welds.
Abstract: Spatially resolved X-ray diffraction (SRXRD) is used to map the α → β → α phase transformation in the heat-affected zone (HAZ) of commercially pure titanium gas tungsten arc welds. In situ SRXRD experiments were conducted using a 180-µm-diameter X-ray beam at the Stanford Synchrotron Radiation Laboratory (SSRL) (Stanford, CA) to probe the phases present in the HAZ of a 1.9 kW weld moving at 1.1 mm/s. Results of sequential linear X-ray diffraction scans made perpendicular to the weld direction were combined to construct a phase transformation map around the liquid weld pool. This map identifies six HAZ microstructural regions between the liquid weld pool and the base metal: (1) α-Ti that is undergoing annealing and recrystallization; (2) completely recrystallized α-Ti; (3) partially transformed α-Ti, where α-Ti and β-Ti coexist; (4) single-phase β-Ti; (5) back-transformed α-Ti; and (6) recrystallized α-Ti plus back-transformed α-Ti. Although the microstructure consisted predominantly of α-Ti, both prior to and after the weld, the crystallographically textured starting material was altered during welding to produce different α-Ti textures within the resulting HAZ. Based on the travel speed of the weld, the α → β transformation was measured to take 1.83 seconds during heating, while the β → α transformation was measured to take 0.91 seconds during cooling. The α → β transformation was characterized to be dominated by long-range diffusional growth on the leading (heating) side of the weld, while the β → α transformation was characterized to be predominantly massive on the trailing (cooling) side of the weld, with a massive growth rate on the order of 100 µm/s.

64 citations

Journal ArticleDOI
TL;DR: In this article, the effects of coarse initial grain size with varying heat inputs on microstructure and mechanical properties of weld metal and heat-affected zone (HAZ) were investigated.
Abstract: In this study, the effects of coarse initial grain size with varying heat inputs on microstructure and mechanical properties of weld metal and heat-affected zone (HAZ) were investigated. In the welding experiments, SAE 1020 steel specimens in hot-rolled and in grain-coarsened conditions were used. The specimens taken from the hot-rolled steel (original) plate were heat treated at 1100°C for 45 min and then cooled in a furnace in order to obtain a coarse initial grain size. The original and grain-coarsened specimens were welded using a submerged arc welding machine with heat inputs of 0.5, 1 and 2 kJ/mm. Following the welding, microstructure, hardness and toughness of weld metals and HAZs were investigated. From the results, we tried to establish a relationship between initial grain size, microstructure, hardness and toughness of weld metals and HAZs. From the results of the toughness tests, it was seen that the weld metals of coarse initial grain sized specimens and original specimens exhibited nearly the same toughness values with the same heat input, whereas different HAZ toughness values were obtained with the same heat input. Maximum toughness of HAZ of the coarse initial grain sized specimen was achieved with a high input, while maximum toughness of original specimen was obtained with a medium heat input. As a result, considering the heat input, it was observed that the coarse initial grain size had a great influence on the microstructure, hardness and toughness of HAZ of a low carbon steel. Thus, taking into consideration the plate thickness, a higher heat input should be used with respect to the maximum toughness of the HAZ in the welding of grain-coarsened low carbon steels.

64 citations

Journal ArticleDOI
TL;DR: In this paper, the results were comparatively evaluated in terms of weld bead formation and microstructural characterisation using various welding techniques, namely, tungsten inert gas (TIG) welding with Ar shielding gas, TIG welding with He gas shielding, CO2 laser welding, and YAG laser welding.
Abstract: Welding of AZ31 Mg alloy was conducted using various welding techniques, namely, tungsten inert gas (TIG) welding with Ar shielding gas, TIG welding with He shielding gas, CO2 laser welding, and YAG laser welding. The results were comparatively evaluated in terms of weld bead formation and microstructural characterisation. It was found that TIG welding with both Ar and He gas shielding produced good welds without major defects. The penetration capacity can be improved using He gas shielding. Owing to their high energy density, CO2 and YAG lasers can produce weld beads having high aspect ratio. Among the four techniques used, the YAG laser produced the finest weld microstructure, whereas TIG with Ar gas shielding produced the coarsest microstructure. Shielding is a key factor controlling the O contents in the welds. The more effective the shielding provided the lower the O content in the weld. Hardness reduction in the weld metals and heat affected zones was observed for all the techniques owing to...

64 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023229
2022548
2021270
2020365
2019389
2018463