The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Brian Uy - One of the best experts on this subject based on the ideXlab platform.
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behavior of high strength Structural Steel at elevated temperatures
Journal of Structural Engineering-asce, 2006Co-Authors: Ju Chen, Ben Young, Brian UyAbstract:This paper presents the mechanical properties of high strength Structural Steel and mild Structural Steel at elevated temperatures. Mechanical properties of Structural Steel at elevated temperatures are important for fire resistant design of Steel structures. However, current design standards for fire resistance of Steel structures are mainly based on the investigation of hot-rolled carbon Steel with normal strength, such as mild Steel. The performance of high strength Steel at elevated temperatures is unknown. Hence, an experimental program has been carried out to investigate the mechanical properties of both high strength Steel and mild Steel at elevated temperatures. The high strength Steel BISPLATE 80 (approximately equivalent to ASTM A 514, EN 10137-2 Grade S690Q, and JIS G 3128) and the mild Steel XLERPLATE Grade 350 (approximately equivalent to ASTM 573-450) were tested using steady and transient-state test methods. The elastic moduli and yield strengths were obtained at different strain levels, and the ultimate strength and thermal elongation were evaluated at different temperatures. It is shown that the reduction factors of yield strength and elastic modulus of high strength Steel and mild Steel are quite similar for the temperature ranging from 22 to 540°C. The test results were compared with the predictions obtained from the American, Australian, British, and European standards.
Jani Romanoff - One of the best experts on this subject based on the ideXlab platform.
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influence of grain size distribution on the hall petch relationship of welded Structural Steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Pauli Lehto, Heikki Remes, Tapio Saukkonen, Hannu Hanninen, Jani RomanoffAbstract:Abstract The strength of polycrystalline metals increases with a decrease in grain size according to the Hall–Petch relationship. However, heterogeneous microstructures deviate from this relationship depending on the distribution of grain sizes. This paper introduces a rule of mixtures based approach for determining the characteristic length of the microstructure for heterogeneous weld metal. The proposed grain size parameter, the volume-weighted average grain size, is measured experimentally for nine Structural Steel weld metals and two base materials. The weld metals are found to have a large variety of grain size distributions that are noticeably broader than those of the base material due to differences in phase contents. The results show that the volume-weighted average grain size is able to capture the influence of grain size distribution on the strength of welded Structural Steel. Based on the experimental results, a modified Hall–Petch relationship is formulated for the strength prediction of heterogeneous microstructures. The modified relationship is also found to be applicable to data from the literature.
Egidijus Petronis - One of the best experts on this subject based on the ideXlab platform.
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Influence of welding modes on weldability of Structural Steel lap joints in laser welding
Journal of Laser Applications, 2017Co-Authors: Antti Salminen, Saulius Baskutis, Egidijus PetronisAbstract:This study considers the development and analysis of various welding parameters on the weldability of Structural Steel lap joints. The specimens of Structural Steel S355 were welded at different welding speeds, focal point positions, laser powers, and heat inputs. Welding was performed with a 10 kW IPG fiber laser. The predicted conditions for keyhole stability as well as the microstructure of joints, penetration depth, and microhardness distribution on the cross-section of the welded joints are analyzed. The mechanical properties of lap joints in different welding modes are also reported. The results of the hardness measurements show that the hardness level of the fusion zone is up to 1.5 times higher than the base metal hardness. By the analysis of the double welded lap joints, it is revealed that due to preheating during the first weld, second weld has deeper penetration, lower weld hardness, and minimized formation of solidification cracks in the weld. In addition, the importance of the focal point position in the lap joint quality is also reported.This study considers the development and analysis of various welding parameters on the weldability of Structural Steel lap joints. The specimens of Structural Steel S355 were welded at different welding speeds, focal point positions, laser powers, and heat inputs. Welding was performed with a 10 kW IPG fiber laser. The predicted conditions for keyhole stability as well as the microstructure of joints, penetration depth, and microhardness distribution on the cross-section of the welded joints are analyzed. The mechanical properties of lap joints in different welding modes are also reported. The results of the hardness measurements show that the hardness level of the fusion zone is up to 1.5 times higher than the base metal hardness. By the analysis of the double welded lap joints, it is revealed that due to preheating during the first weld, second weld has deeper penetration, lower weld hardness, and minimized formation of solidification cracks in the weld. In addition, the importance of the focal point po...
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Influence of welding modes on weldability of Structural Steel lap joints in laser welding
Journal of Laser Applications, 2017Co-Authors: Antti Salminen, Saulius Baskutis, Egidijus PetronisAbstract:This study considers the development and analysis of various welding parameters on the weldability of Structural Steel lap joints. The specimens of Structural Steel S355 were welded at different welding speeds, focal point positions, laser powers, and heat inputs. Welding was performed with a 10 kW IPG fiber laser. The predicted conditions for keyhole stability as well as the microstructure of joints, penetration depth, and microhardness distribution on the cross-section of the welded joints are analyzed. The mechanical properties of lap joints in different welding modes are also reported. The results of the hardness measurements show that the hardness level of the fusion zone is up to 1.5 times higher than the base metal hardness. By the analysis of the double welded lap joints, it is revealed that due to preheating during the first weld, second weld has deeper penetration, lower weld hardness, and minimized formation of solidification cracks in the weld. In addition, the importance of the focal point po...
Ju Chen - One of the best experts on this subject based on the ideXlab platform.
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behavior of high strength Structural Steel at elevated temperatures
Journal of Structural Engineering-asce, 2006Co-Authors: Ju Chen, Ben Young, Brian UyAbstract:This paper presents the mechanical properties of high strength Structural Steel and mild Structural Steel at elevated temperatures. Mechanical properties of Structural Steel at elevated temperatures are important for fire resistant design of Steel structures. However, current design standards for fire resistance of Steel structures are mainly based on the investigation of hot-rolled carbon Steel with normal strength, such as mild Steel. The performance of high strength Steel at elevated temperatures is unknown. Hence, an experimental program has been carried out to investigate the mechanical properties of both high strength Steel and mild Steel at elevated temperatures. The high strength Steel BISPLATE 80 (approximately equivalent to ASTM A 514, EN 10137-2 Grade S690Q, and JIS G 3128) and the mild Steel XLERPLATE Grade 350 (approximately equivalent to ASTM 573-450) were tested using steady and transient-state test methods. The elastic moduli and yield strengths were obtained at different strain levels, and the ultimate strength and thermal elongation were evaluated at different temperatures. It is shown that the reduction factors of yield strength and elastic modulus of high strength Steel and mild Steel are quite similar for the temperature ranging from 22 to 540°C. The test results were compared with the predictions obtained from the American, Australian, British, and European standards.
Pauli Lehto - One of the best experts on this subject based on the ideXlab platform.
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influence of grain size distribution on the hall petch relationship of welded Structural Steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: Pauli Lehto, Heikki Remes, Tapio Saukkonen, Hannu Hanninen, Jani RomanoffAbstract:Abstract The strength of polycrystalline metals increases with a decrease in grain size according to the Hall–Petch relationship. However, heterogeneous microstructures deviate from this relationship depending on the distribution of grain sizes. This paper introduces a rule of mixtures based approach for determining the characteristic length of the microstructure for heterogeneous weld metal. The proposed grain size parameter, the volume-weighted average grain size, is measured experimentally for nine Structural Steel weld metals and two base materials. The weld metals are found to have a large variety of grain size distributions that are noticeably broader than those of the base material due to differences in phase contents. The results show that the volume-weighted average grain size is able to capture the influence of grain size distribution on the strength of welded Structural Steel. Based on the experimental results, a modified Hall–Petch relationship is formulated for the strength prediction of heterogeneous microstructures. The modified relationship is also found to be applicable to data from the literature.
