The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Li Jianguo - One of the best experts on this subject based on the ideXlab platform.
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Research Progress on Microstructure and Properties of ULCB Weld Metal
Hot Working Technology, 2012Co-Authors: Li JianguoAbstract:The emerged background of ultra-low carbon bainitic(ULCB) Weld Metal and the main factors on the properties of ULCB Weld Metal were introduced.ULCB Weld Metal has good performance,but chemical composition,and the selection of Welding method and differences of protecting atmosphere have great effects on the properties of ULCB Weld Metal.The good performance of ULCB Weld Metal is maximized,Then the size of inclusions should be controlled and the columnar crystal should be eliminated in order to improve the toughness of Weld Metal.
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Study of effect of rare earths on structure and properties of Weld Metal
Ordnance Material Science and Engineering, 2001Co-Authors: Li JianguoAbstract:In this paper,the effect of rare earth elements on the structure and properties of the Weld Metal was studied through adding RE ferrosilicon and rare earths to the coatings of the Welding electrodes.It is shown experimentally that adding appropriate amount of rare earth additions in the coating of Welding electrodes can modify and purify the Weld Metal,improve the structure of the Weld Metal,refine the grains, increase the amount of acicular ferrite,decrease the amount of the M-A component,alter the shape,size and distribution of the non-Metallic inclusions,thereby the notch toughness of the Weld Metal at low temperature can be increased greatly.
A.k. Bhaduri - One of the best experts on this subject based on the ideXlab platform.
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Delta ferrite in the Weld Metal of reduced activation ferritic martensitic steel
Journal of Nuclear Materials, 2014Co-Authors: Shiju Sam, C. R. Das, V. Ramasubbu, Shaju K. Albert, A.k. Bhaduri, T. Jayakumar, E. Rajendra KumarAbstract:Abstract Formation of delta(δ)-ferrite in the Weld Metal, during autogenous bead-on-plate Welding of Reduced Activation Ferritic Martensitic (RAFM) steel using Gas Tungsten Arc Welding (GTAW) process, has been studied. Composition of the alloy is such that delta-ferrite is not expected in the alloy; but examination of the Weld Metal revealed presence of delta-ferrite in the Weld Metal. Volume fraction of delta-ferrite is found to be higher in the Weld interface than in the rest of the fusion zone. Decrease in the volume fraction of delta-ferrite, with an increase in preheat temperature or with an increase in heat input, is observed. Results indicate that the cooling rate experienced during Welding affects the volume fraction of delta-ferrite retained in the Weld Metal and variation in the delta-ferrite content with cooling rate is explained with variation in the time that the Weld Metal spends in various temperature regimes in which delta-ferrite is stable for the alloy during its cooling from the liquid Metal to the ambient temperature. This manuscript will discuss the effect of Welding parameters on formation of delta-ferrite and its retention in the Weld Metal of RAFM steel.
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Improving 410NiMo Weld Metal toughness by PWHT
Journal of Materials Processing Technology, 2011Co-Authors: M. Divya, C. R. Das, V. Ramasubbu, Shaju K. Albert, A.k. BhaduriAbstract:Abstract Highlights of the present study is the importance of choosing suitable temperatures for two stage PWHT to achieve desirable toughness in the Weld Metals produced by ER 410NiMo filler wire. Weld pads prepared using this filler wire was used for extensive Metallurgical characterization of the Weld Metal. Results indicate by choosing appropriate temperatures for the PWHT, it is possible to obtain toughness in the Weld Metal which is comparable to the toughness reported for the base Metal of similar composition. Good toughness of the Weld Metal is attributed to the presence of retained austenite in the Weld Metal. Two stage PWHT that gave excellent toughness for the Weld Metal was employed for repair of cracked shrouds of a steam turbine in a nuclear power plant. The Metallurgical characterization of the mock up Weld pad prepared prior to actual repair confirmed that microstructure and hardness of the Weld Metal are similar to those obtained during the Welding procedure development.
M. Divya - One of the best experts on this subject based on the ideXlab platform.
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Improving 410NiMo Weld Metal toughness by PWHT
Journal of Materials Processing Technology, 2011Co-Authors: M. Divya, C. R. Das, V. Ramasubbu, Shaju K. Albert, A.k. BhaduriAbstract:Abstract Highlights of the present study is the importance of choosing suitable temperatures for two stage PWHT to achieve desirable toughness in the Weld Metals produced by ER 410NiMo filler wire. Weld pads prepared using this filler wire was used for extensive Metallurgical characterization of the Weld Metal. Results indicate by choosing appropriate temperatures for the PWHT, it is possible to obtain toughness in the Weld Metal which is comparable to the toughness reported for the base Metal of similar composition. Good toughness of the Weld Metal is attributed to the presence of retained austenite in the Weld Metal. Two stage PWHT that gave excellent toughness for the Weld Metal was employed for repair of cracked shrouds of a steam turbine in a nuclear power plant. The Metallurgical characterization of the mock up Weld pad prepared prior to actual repair confirmed that microstructure and hardness of the Weld Metal are similar to those obtained during the Welding procedure development.
Matthew J. James - One of the best experts on this subject based on the ideXlab platform.
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Weld Metal Toughness: Sources of Variation
2010 8th International Pipeline Conference Volume 2, 2010Co-Authors: Marie A. Quintana, S. Suresh Babu, Jeff Major, Craig Dallam, Matthew J. JamesAbstract:Many material properties are statistical in nature. If one measures the same property of the same material repeatedly, ideally the result is a normally distributed “bell” curve about a mean value. This ideal case does not necessarily hold true for all mechanical properties of interest in steel Weld Metals. Tensile strength measurements tend to exhibit normal behavior for a given Weld Metal chemical composition deposited using a reasonable consistent Welding procedure, Figure 1a. However, toughness measurements are not nearly as well-behaved or predictable. In a tensile test, assuming a defect free Weld, the strength measurement is based on the bulk response of the material throughout the gage length. In a Charpy V-notch (CVN) impact test, again assuming a defect free Weld, the toughness measurements are controlled largely by the very local response of the material at the point of highest stress where fracture initiates just below the notch. This paper presents a detailed assessment of a C-Mn Weld Metal and explains how CVN toughness can vary from less than 20 ft-lbf to over 200 ft-lbf in the same Weld, often with test specimens located adjacent to one another in the test Weld, Figure 1b. The much localized microstructure features that give rise to this degree of variation are a combined result of chemical composition, Welding procedure, pass sequence, and individual Welder technique. The evidence suggests that retained austenite in coarse grained regions of the as-deposited Weld Metal transform to martensite at the CVN test temperature, effectively creating local brittle zones in the Weld Metal. This example provides basis for examination of a broader range of microstructural discontinuities in steel Weld Metals and their potential influence on toughness measurement.Copyright © 2010 by ASME
Lijin Dong - One of the best experts on this subject based on the ideXlab platform.
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environmentally assisted crack growth in 308l stainless steel Weld Metal in simulated primary water
Corrosion Science, 2017Co-Authors: Lijin Dong, Enhou Han, Qunjia Peng, Lei WangAbstract:Abstract Environmentally assisted crack growth behavior of 308L stainless steel Weld Metal in simulated primary water was investigated. The results showed ultra-low stress corrosion crack growth in the Weld Metal. However, obvious environmental acceleration of fatigue crack growth was observed, which is increased by more aggressive water chemistry and gentle cyclic loading conditions. Further, the environmental fatigue crack growth rate of 308L Weld Metal was lower than that of 304 and 316 stainless steels under the same environmental and loading conditions. This was attributed to the retardation of crack growth by δ ferrite phase.
