Prediction of element transfer due to flux and optimization of chemical composition and mechanical properties in high-strength low-alloy steel weld
01 May 2015-Vol. 229, Iss: 5, pp 785-801
TL;DR: The transfer of elements C, Si, Mn, P and S from slag into the weld metal or from weld metal into the slag and microhardness has been studied using formulated fluxes.
Abstract: The transfer of elements C, Si, Mn, P and S from slag into the weld metal or from weld metal into the slag and microhardness has been studied using formulated fluxes. The fluxes have been formulate...
Citations
More filters
01 Jul 2002
18 citations
Dissertation•
28 Apr 2017
TL;DR: In this paper, the authors present a table of contents and a list of tables and lists of figures, including the following categories: Table 1 Table 2 Table 3 Table 4 Table 5 Table 6
Abstract: ii TABLE OF CONTENTS iii-vii LIST OF TABLES viii-x LIST OF FIGURES xi-xv CHAPTER
4 citations
Cites background from "Prediction of element transfer due ..."
..., 2013, 2014a, 2014b, 2015 [68-71] tried to explore mixture design methodology for flux design in submerged arc welding process....
[...]
TL;DR: In this article , a gas-slag-metal equilibrium model was proposed to predict the transfer direction of Si between flux and weld metal, as well as Si content in submerged arc welded metal even when no SiO 2 is contained in the initial flux.
Abstract: The slag-metal and gas-slag-metal equilibrium models have been employed via the Calphad technique to predict Si content in submerged arc welded metal. The investigated fluxes possess a wide range of basicity indices at full coverage with acidic, neutral, and basic fluxes. It is revealed that the gas-slag-metal equilibrium model offers better prediction accuracy for Si content than the slag-metal equilibrium model since the flux O potential is underestimated by the slag-metal equilibrium model. Especially, the gas-slag-metal equilibrium model is capable of predicting the transfer direction of Si between flux and weld metal, as well as Si content in submerged arc welded metal even when no SiO 2 is contained in the initial flux. Additionally, the kinetic factors that influence the transfer behavior of Si have been evaluated to interpret the deviation between measured Si content and the value predicted from the equilibrium model. At last, we have proposed the limitations of the equilibrium models, as well as the models to be further developed with respect to improving the prediction accuracy.
4 citations
30 Apr 2022-Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science
TL;DR: In this article , a novel technology has been developed to recycle steel slag as a flux for the submerged arc welding process, and the chemical, mechanical, and metallurgical properties of welds produced using recycled slag have been evaluated and compared with that of fresh flux available in the market.
Abstract: A novel technology has been developed to recycle steel slag as a flux for the submerged arc welding process. The chemical, mechanical, and metallurgical properties of welds produced using recycled slag have been evaluated and compared with that of fresh flux available in the market. The tensile strengths of weld metal prepared with recycled slag and fresh flux are 462.25 MPa and 471.49 MPa, which are comparable. The impact strength of welds produced using recycled slag is 83.66 J which is acceptable in accordance with AWS SFA 5.17 specifications. The welds produced were subjected to non-destructive tests such as radiography and also dye-penetration test apart from visual inspection to ascertain the soundness of welds produced. Metallurgical investigations were carried out, and a favorable microstructure containing acicular ferrite was obtained in welds deposited using recycled slag. Similar trends of microhardness survey have been observed in both the welds produced.
3 citations
References
More filters
30 Jan 2013
TL;DR: In this paper, the effect of flux constituents on tensile strength, percentage elongation, impact strength, diffusible hydrogen content and microstructure of the weld metal was investigated.
Abstract: Fluxes in submerged arc welding of high-strength low-alloy steels are not readily available, flux compositions are not clear and compositions are patented. This study aims at the design, development and optimization of flux for submerged arc welding of high-strength low-alloy steel. Extreme vertices design suggested by McLean and Anderson is used to formulate twenty-one fluxes to study the effect of flux constituents on tensile strength, percentage elongation, impact strength, diffusible hydrogen content and microstructure of the weld metal. Mathematical models for ultimate tensile strength, percentage elongation, impact strength and diffusible hydrogen content for welded specimens versus flux constituents have been developed. From the experiments, it is found that tensile strength and elongation are affected the most with Al2O3 content, whereas CaO and CaF2 contents have significant effect on impact strength. Synergic binary effect of CaO·CaF2, CaO·MgO and Al2O3·CaF2 mixtures is more than other binary mi...
39 citations
"Prediction of element transfer due ..." refers methods in this paper
...Design of experiment (DOE) technique mentioned here was also used previously by Jindal et al.19 with same limits of flux constituents and same design table17 to determine mechanical properties and H2 content....
[...]
...The effect of flux constituents on mechanical properties has been studied and mathematical models have been developed in the earlier work done by the authors using same DOE and same design table.(19) The prediction equations for these mechanical properties are given in Appendix 2....
[...]
...Mechanical properties, ultimate tensile strength and impact strength values have been used from the previous work done by Jindal et al.(19) given in Appendix 2....
[...]
...Mechanical properties, ultimate tensile strength and impact strength values have been used from the previous work done by Jindal et al.19 given in Appendix 2....
[...]
...The optimum welding parameters were selected on the basis of trial runs and performing optimization experiments using response surface methodology (RSM) technique by varying the following parameters: welding current range of 349–651 A, arc voltage range of 24–32 V and weld speed range of 17–33 m/h keeping nozzle-to-tip distance constant at 25 mm with formulated flux number 11 (BI = 1.1) in separate work by Jindal et al.24 Compositions of the flux have significant effect on chemical and mechanical properties of the welds, but the effect of flux constituents on weld bead geometry has not been reported in the earlier literature....
[...]
01 Mar 1990
Abstract: The effects of CaF2, CaO and FeO additions on weld metal chemistry were evaluated for the manganese — silicate flux system. Comparisons were made between AISI 4340 steel and lowcarbon steel welds to understand the weld metal chemistry. The results show that the elemental transfer from the slag to the weld metal and vice versa cannot be consistently explained using thermodynamic data; e.g., the carbon/oxygen partition is apparently controlled by a CO reaction in the 1010 steel welds, but the AISI 1020 and 4340 steel welds show constant carbon contents despite increasing oxygen levels. In addition, data are reported as a resource for future analytical and comparative purposes. Introduction Submerged arc welding of high integrity can be achieved through proper selection of the wire and flux combination for the specific base metal and welding parameters. Small amounts of alloying elements such as nickel, chromium and molybdenum are added to steels to increase strength, hardness or toughness, as is the case with AISI 4340 steel. Generally, welding low-alloy steels requires more careful control of procedures and selection of consumables than welding the carbon steels. Moreover, the oxygen potential of the flux influences the loss or gain of alloying elements during welding, the weld-deposit oxygen content, and the type, size and distribution of oxide inclusions in the solidified weld metal. The effective application of the submerged arc welding process for joining high-strength, low-alloy steels depends heavily upon understanding the behavior of the flux. Understanding the elemental P. A. BURCK and D. L. OLSON are with the Center for Welding and joining Research, Colorado School of Mines, Golden, Colo. J £ INDACOCHEA is with the University of Illinois at Chicago, Chicago, III. transfer mechanisms between the flux and the weld metal can be attained by studying the influence of each chemical additive on the flux behavior. To determine the many slag/weld metal chemical reactions occurring simultaneously during welding, a state of thermodynamic equilibrium has been assumed to be attained. The basis for this assumption is that the high temperatures and high surface-to-volume ratio associated with the welding process counteract the short time available for a reaction to be completed (Ref. 1). Chai and Eagar (Ref. 2) reported that the very short times and the large thermal gradients involved in the process prevent overall slag-metal equilibrium from being reached. They also reported that an understanding of kinetics, in combination with the thermodynamic limits of the process, would be necessary to determine the final weld metal composition. Blander and Olson (Ref. 3) also discussed the influence of kinetics, the role of interfacial reaction, and the degree to which equilibrium is approached. This paper is a part of the systematic investigation undertaken by the Colorado School of Mines (Refs. 3-7) to better understand the behavior of different flux additions to the manganese-silicate and lime-silicate flux systems. The influence of FeO, CaO and CaF2 additions to a manganese-silicate flux on AISI 4340 steel weld metal chemistry is reported here. In addiKEY W O R D S Welding Flux Effects Flux Additions 4340 Steel Weld Metal Weld Composition Submerged Arc Fluxes 1020 Steel Weld Metal Ca2/CaO/FeO Addition Mn-Silicate Fluxes SAW Flux Systems tion, a comparison of the effects of CaF2 and FeO additions to a manganese-silicate flux on welds on AIS11020 and 4340 steels was made in an effort to understand the effect of alloying elements on weld metal chemistry. The results presented in this paper should be a useful database for future analytical modeling and comparisons. Materials and Procedure Single pass, bead-on-plate welds were made using the submerged arc welding process on AIS11010,1020 and 4340 steel base plates. The dimensions of the plates were 73 X 203 X 13 mm (2.9 X 8 X 0.5 in.). The welding wires used were AWS Type E70S-3 for welds produced on AISI 1010 and 1020 steels, and Type EM12K for AISI 4340 steel welds. Compositions of the base plates and welding wires are given in Table 1. The submerged arc welding process was performed using direct current, electrode positive. The welding parameters were maintained constant at 30 V, a travel speed of 8 mm/s (19 in./min), and the wire speed was varied to give 500 A. All welds were made with a heat input of 1.9 kj /mm (48 kj/in.). Three different flux systems were used in this investigation: Si02"MnO-FeO, Si02" MnO-CaO and Si02-MnO-CaF2. The fluxes were prepared using reagent grade chemical powders. The flux compositions were reported as wt-% MnO because M n 0 2 decomposes to form MnO during the melting operation used to produce the fused flux. The iron ion in the fused flux was determined to be in the Fe + state and is reported as wt-% FeO (Ref. 10). The reagent-grade powders were weighed and mixed prior to induction melting. The powders were then placed in a graphite crucible for the melting operation. All fluxes were brought to 1773 K. The crucible was then removed from the furnace and the flux poured onto a stainless steel plate to solidify. After cooling, the fused fluxes were crushed and sized. Fluxes sized 14 to 100 mesh were used for WELDING RESEARCH SUPPLEMENT 1115-s
39 citations
"Prediction of element transfer due ..." refers background in this paper
...Burck et al.14 evaluated the effects of CaF2, CaO and FeO additions on weld metal chemistry on steel plates....
[...]
...Burck et al.(14) evaluated the effects of CaF2, CaO and FeO additions on weld metal chemistry on steel plates....
[...]
Journal Article•
TL;DR: In this paper, the general compositional and microstructural characteristics of high strength steels (HSS) weld metals, including nonmetallic inclusions, were experimentally characterized using different welding processes and commercially available welding consumables with nominal strengths ranging from 490 to 840 MPa (70 to 120 ksi).
Abstract: The use of high-strength steels (HSS) provides several potential advantages. However, the progress in steel technology continually demands new developments in welding processes and consumables to produce weld metals with mechanical properties equivalent to the base metal. To achieve this, however, a better understanding of chemistry- and microstructure-property relationships in HSS weld metals is needed. In this study, the general compositional and microstructural characteristics of HSS weld metals, including nonmetallic inclusions, were experimentally characterized. The weld metals were deposited using different welding processes and commercially available welding consumables with nominal strengths ranging from 490 to 840 MPa (70 to 120 ksi).
34 citations
TL;DR: In this article, a prediction model for low carbon steel weld metal acicular ferrite microstructure as a function of flux ingredients such as CaO, MgO, CaF 2 and Al 2 O 3 was developed for submerged arc welding carried out at fixed welding parameters.
Abstract: The prediction model has been developed for low carbon steel weld metal acicular ferrite microstructure as a function of flux ingredients such as CaO, MgO, CaF 2 and Al 2 O 3 in submerged arc welding carried out at fixed welding parameters. The results of quantitative measurements of acicular ferrite (AF) on eighteen no. of weld metal samples were utilised for developing the prediction model. Among the flux ingredients, CaO appears to be most important as an individual as well as interaction with other ingredients in controlling the amount of acicular ferrite content in the weld metal. Furthermore, formation of acicular ferrite is also related to the weld bead geometry which is influenced by flux ingredients. The prediction equation for acicular ferrite has been checked for adequacy by performing separate experiments on welding using randomly designed flux. The'isoresponse curves were developed to show the level of acicular ferrite content at different percentage of flux ingredients.
33 citations
"Prediction of element transfer due ..." refers background in this paper
...Kanjilal et al.13 studied the change in element transfer (D) for the elements O2, Mn, Si, S and C in terms of flux ingredients....
[...]
...So positive and negative values of regression coefficient bij define synergistic and anti-synergistic effects of the binary mixtures, respectively.(9)...
[...]
...Kanjilal et al.(9) in their work tried to develop mathematical model to find AF in terms of flux constituents for SAW of C–Mn steel....
[...]
...Kanjilal et al.9 in their work tried to develop mathematical model to find AF in terms of flux constituents for SAW of C–Mn steel....
[...]
...CaO combines with sulfur of weld metal forming CaS and releasing O2 as per reaction mentioned in equation (17), thereby lowering sulfur content from weld metal contrary to previous results by Kanjilal et al.13 and in agreement with the results by Chai and Eager10 CaO+S!...
[...]