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Baosteel Technical Research 2024年第3期18卷 33-38页

作者： ZHU Min Research Institute Baoshan Iron&Steel Co.Ltd.Shanghai 201999China

The evolution of microstructure and local properties near the welding interface is essential for the service safety of dissimilar metal welded joints between nickel-based alloy(NA) and low-alloy steel(LA).In this work,NA filler metal was deposited on LA substrate under different heat inputs by tungsten inert gas(TIG) *** characterization and microhardness tests were carried out near the prepared cladding *** and scanning electron microscopes show the lack of evident hardening transition layer along the welding *** the heat input increases,the mean hardness of the deposited layer also increases remarkably due to the rising dilution *** characterization shows a significant composition gradient across the cladding interface,but the diffusion gradient is limited to a small *** high heat input,a planar grain zone is generated along the interface due to the large temperature gradient across the interface region.

关键词： welding interface heat input microstructure microhardness

Influence of heat input on microhardness and microstructure across the welding interface between stainless steel and low alloy steel

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Baosteel Technical Research 2024年第1期18卷 14-21页

作者： ZHU Min Research Institute Baoshan Iron&Steel Co.Ltd.Shanghai201999China

The welding interface is crucial to the service safety of dissimilar metal weld(DMW)joints between stainless steel(SS)and low alloy(LA)*** status of welding interfaces was prepared by cladding SS consumables to LA steel substrates with different heat inputs via tungsten inert gas arc welding(TIG),followed by a series of microstructural characterizations and hardness *** showed that a hardening and transition layer(TL)would be generated along the welding interface,and the width and hardening degree of the TL would increase with the heat ***,heavy load hardness tests showed that highly severe inhomogeneous plastic deformation and the microcrack would be generated in the interfacial region and the welding interface respectively in the highest heat input sample(1.03 kJ/mm).These results indicate that the increase in heat input would deteriorate the bonding performance of DMW *** microstructural observations showed that the higher hardening degree of the highest heat input sample was mainly attributed to the stronger grain boundary,solution,and dislocation strengthening effects.

关键词： welding interface transition layer heat input microstructure hardness

Effect of heat input on the Microstructure and Mechanical Properties of 07MnCrMoVR Weld Joints

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Chinese Journal of Mechanical Engineering 2011年第2期24卷 207-213页

作者： XU Lianghong ZHANG Jun CHEN Yanqing Shougang Research Institute of Technology Beijing 100043 China

As a new type of low cracking suscepbility high strength steel,07MnCrMoVR steel has excellent weldability,with low carbon equivalent and cold cracking susceptibility ***,there are still some problems when this steel is on the outdoor actual welding condition,such as having some extend cold cracking suscepbility and embrittlement of heat affected ***, researching works for the welding of this steel mostly focus on the evaluation the weldability of it,only few works are concentrated in how the heat input affecting the embrittlement of *** goal of this research is to study the effect of heat input on the embrittlement of the heat affected zone so as to get the optimal welding heat input range for *** this paper,38 mm 07MnCrMoVR steel made by Shougang is welded by manual arc welding technology,and the effect of heat input on the microstructure and mechanical properties of weld joints is also investigated by use of optical microscope（OM）,scanning electron microscope（SEM）,mechanical properties testing machines and Viker hardness *** microstructure and fractography observation results and the mechanical properties testing results indicate that the 07MnCrMoVR steel made by Shougang has a wide adaptable range for heat input,and when the heat input is in the range of 15-42 kJ/cm,the toughness of the weld joints is *** the increase of heat input,the impact toughness of weld zone and heat affected zone decrease,whereas the tensile strength of the weld joints does not change at *** microstructure of the weld is acicular ferrite with small amount of proeutectoid ferrite,and with the increase of heat input,the ratio of proeutectoid ferrite and the amount of M-A constituent increase,as well as the grain size and the width of the bainite lath in coarsened grain heat affected zone. Fractography results show that with the increase of heat input,the number of dimples in impact fracture specimens decreases,and the cleavage patterns incre

关键词： 07MnCrMoVR heat input microstructure impact toughness heat affected zone

Effect of heat input on the Microstructure and Properties of Dissimilar Weld Joint Between Incoloy 28 and Superaustenitic Stainless Steel

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Acta Metallurgica Sinica(English Letters) 2014年第2期27卷 259-266页

作者： M.S.Abdel Rahman N.A.Abdel Raheem M.R.El Koussy Department of Metallurgy Faculty of EngineeringCairo University

Abstract This work focuses on studying the effect of welding heat input within the range from 1 to 5 kJ/mm on the microstructure and the corresponding mechanical and corrosion properties of dissimilar joint between superaustenitic stainless steel （UNS S31254） and Incoloy 28 （UNS N08028）. The two materials were butt-welded with ER NiCrMo3. The metallurgical changes associated with welding of SASS and Incoloy 28 were studied using optical microscope, SEM, and EDX. The mechanical and corrosion properties were investigated using tensile test, Vickers hardness test, and pitting and crevice corrosion tests. The weld metal microstructure showed precipitates with needle-like shape at 3 and 5 kJ/mm. Also, the microstructure showed unmixed zone （UMZ） at the fusion line of both SASS and Incoloy 28 sides at all the investigated heat inputs. The Mo microsegregation within UMZ at Incoloy 28 side increased as the heat input increased from 1 to 5 k J/ram but that in SASS increased with increasing heat input from 1 to 3 kJ/mm and then decreased with increasing from 3 to 5 kJ/mm. The ultimate tensile strengths for all specimens at all the investigated heat inputs are acceptable. The average hardness noticeably changed in weld metal as the heat input increased from 1 to 5 kJ/mm. Other zones such as HAZ or UMZ did not demonstrate marked changes in the average hardness. The pitting and crevice corrosion rates of the weld joint were found significant at l and 3 kJ/mm but insignificant at 5 kJ/mm according to ASTM G48.

关键词： Superaustenitic Incoloy 28 Welding heat input Unmixed zone Microsegregation Corrosion

Influences of the Welding heat input and the Repeated Repair Welding on Ti–3Al–2.5V Titanium Alloy

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Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 684-691页

作者： Hui-Jun Yi Yong-Jun Lee Kwang-O Lee School of Mechanical Engineering Pusan National University

The primary purpose of this study was to determine the effects of gas tungsten arc welding heat input on the high-temperature tensile properties, toughness, and microstructural features of titanium alloy Ti-3A1-2.5V. The secondary objective was to examine the effect of the repeated repair welding on the properties of the alloy. It was also found that the mechanical properties progressively decreased with increasing the repair welding cycles, especially in the case of the weldment after the first welding repair. It was observed that the sizes of the acicular and prior β grain boundaries as well as the volume fraction of the acicular phases increased with increasing the welding heat input. In addition, the amount and size of the acicular a1 phases were found to increase with increasing the repair welding cycles.

关键词： Ti-3AI-2.5V Repair welding heat input Tensile properties Microstructure

Effects of aging treatment and heat input on the microstructures and mechanical properties of TIG-welded 6061-T6 alloy joints

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International Journal of Minerals,Metallurgy and Materials 2013年第3期20卷 259-265页

作者： Dong Peng Jun Shen Qin Tang Cui-ping Wu Yan-bing Zhou College of Material Science & Engineering Chongqing University Fabrication Workshop Dongfang Turbine Co. Ltd.

Aging treatment and various heat input conditions and mechanical properties of TIG welded 606I-T6 alloy joints were adopted to investigate the microstructural evolution by microstructural observations, microhardness tests, and tensile tests. With an increase in heat input, the width of the heat-affected zone （HAZ） increases and grains in the fusion zone （FZ） coarsen. Moreover, the hardness of the HAZ decreases, whereas that of the FZ decreases initially and then increases with an increase in heat input. Low heat input results in the low ultimate tensile strength of the welded joints due to the presence of partial penetrations and pores in the welded joints. After a simple artificial aging treatment at 175℃ for 8 h, the microstructure of the welded joints changes slightly. The mechanical properties of the welded joints enhance significantly after the aging process as few precipitates distribute in the welded seam.

关键词： aluminum alloys tungsten inert gas welding heat input aging mechanical properties microstructure

Influence of heat input on Martensite Formation and Impact Property of Ferritic-Austenitic Dissimilar Weld Metals

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Journal of Materials Science & Technology 2012年第4期28卷 343-352页

作者： M. Mukherjee T.K. Pal Welding Technology Centre Metallurgical and Material Engineering Department Jadavpur University

The effect of heat input on martensite formation and impact properties of gas metal arc welded modified ferritic stainless steel （409M） sheets （as received） with thickness of 4 mm was described in detail in this work. The welded joints were prepared under three heat input conditions, i.e. 0.4, 0.5 and 0.6 kJ/mm using two different austenitic filler wires （308L and 316L） and shielding gas composition of Ar ＋ 5% CO2. The welded joints were evaluated by microstructure and charpy impact toughness. The dependence of weld metal microstructure on heat input and filler wires were determined by dilution calculation, Creq/Nieq ratio, stacking fault energy （SFE）, optical microscopy （OM） and transmission electron microscopy （TEM）. It was observed that the microstructure as well as impact property of weld metal was significantly affected by the heat input and filler wire. Weld metals prepared by high heat input exhibited higher amount of martensite laths and toughness compared with those prepared by medium and low heat inputs, which was true for both the filler wires. Furthermore, 308L weld metals in general provided higher amount of martensite laths and toughness than 316L weld metals.

关键词： heat input Ferritic-austenitic dissimilar weld Martensite Grain size Toughness

Predicting Tensile Properties of Friction-Stir-Welded 6063 Aluminum with Experimentally Measured Welding heat input

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Acta Metallurgica Sinica(English Letters) 2020年第9期33卷 1235-1242页

作者： Tianbo Zhao Yutaka SSato Hiroyuki Kokawa Kazuhiro Ito Department of Materials Processing Graduate School of EngineeringTohoku University6-6-02 Aramaki-aza-AobaSendai 980-8579Japan Joining and Welding Research Institute Osaka UniversityMihogaoka11-1IbarakiOsaka 567-0047Japan Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China

This work aims to develop a reliable method to predict mechanical properties of friction-stir-welded 6 xxx-series alloys with experimentally measured welding heat input. A calorimetrical method was utilized to experimentally measure the welding heat input in the friction stir welded of aluminum alloy 6063-T5. Good correlations between the input variables, i.e., welding parameters and physical properties of the materials, and the welding heat inputs obtained with experimental measurements were discovered. The welding heat input can be predicted using the empirical equation derived based on these correlations. Moreover, the results suggested that the thermal conductivities of the welded alloys affected the welding heat input significantly. Mechanical properties, including hardness and tensile properties, of friction-stir-welded aluminum alloy 6063 were in good correlation to the heat input obtained with experimental measurement. These correlations were explained by the evolution of the strengthening precipitates during welding. This work proposed a reliable new route to predict these mechanical responses through the estimation of heat input.

关键词： heat input Friction stir welding Calorimetrical Mechanical properties Hardness

Effect of heat input on Microstructure and Toughness of Coarse Grain heat Affected Zone in Nb Microalloyed HSLA Steels

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Journal of Iron and Steel Research International 2009年第5期16卷 73-80页

作者： ZHANG Ying-qiao ZHANG Han-qian LI Jin-fu LIU Wei-ming Department of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200030 China Research Institute for Advanced Structural Steel Research and Development Center Baoshan Iron and Steel Limited Company Shanghai 201900 China

The influence of Nb on microstructure, mechanical property and the transformation kinetics of the coarse grain heat affected zone （CGHAZ） in HSLA steels for different heat inputs, has been investigated. When welded at higher heat inputs （100-60 kJ/cm）, impact toughness values of the steel without Nb are much higher than those of the steel with Nb, and the lowest span is 153 J at 60 kJ/cm. But only a little higher values are observed at lower heat inputs （40-30 kJ/cm）, and the highest span is 68 J at 30 kJ/cm. Dilatation studies indicate that continuous cooling transformation starting temperatures （Ts） of CGHAZ for the steel with Nb are approximately 15-30℃ which are lower than those of the steel without Nb at all heat inputs. For higher heat inputs, Nb in solid solution suppresses ferrite transformation and promotes the formation of granular bainite which has detrimental effect on impact toughness. For lower heat inputs higher Charpy impact energy values in the steel with Nb are associated with the formation of low carbon self-tempered martensite.

关键词： HSLA steel coarse grain heat affected zone heat input Niobium impact toughness

Effect of heat input and postweld heat treatment on microstructure and toughness of heat-resistant steel E911 deposited metal

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China Welding 2011年第1期20卷 64-69页

作者：王红鸿胡锋吴开明 Hubei Province Key Laboratory for Systems Science on Metallurgical Processing Wuhan University of Science and Technology Wuhan 430081

The microstructure of E911 deposited metal was observed and the effect of heat input and postweld heat treatment on microstructure and impact toughness was investigated. The microstructure consists of tempered martensite and residual δ- ferrite. The morphology of tempered martensite is columnar and the residual δ-ferrite is polygonal. With the increase in heat input, the width of columnar martensite grain and the size of residual δ-ferrite increased, whereas the volume fraction of residual δ-ferrite varied slightly. The impact toughness decreased as heat input increased. The result reveals that coarsening columnar martensite grain and δ-ferrite have greater effect on impact toughness than volume fraction of residual δ-ferrite. As the time of postweld heat treatment is exceeded 8h, aggregation of M23 C6occurs in some grain boundaries or lath interfaces. The partial aggregation of M23 C6 results in the decrease in impact toughness.

关键词： microstructure impact toughness heat input postweld heat treatment deposited metal