| 1. |
- Calmunger, Mattias, et al.
(author)
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Creep and Fatigue Interaction Behavior in Sanicro 25 Heat Resistant Austenitic Stainless Steel
- 2016
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In: Transactions of the Indian Institute of Metals. - : Springer. - 0972-2815 .- 0975-1645. ; 69:2, s. 337-342
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Journal article (peer-reviewed)abstract
- Sanicro 25 is a newly developed advanced high strength heat resistant austenitic stainless steel. The material shows good resistance to steam oxidation and flue gas corrosion, and has higher creep rupture strength than other austenitic stainless steels available today. It is thus an excellent candidate for superheaters and reheaters for advanced ultra-super critical power plants with efficiency higher than 50 %. This paper provides a study on the creep–fatigue interaction behavior of Sanicro 25 at 700 °C. Two strain ranges, 1 and 2 %, and two dwell times, 10 and 30 min, were used. The influences of dwell time on the cyclic deformation behavior and life has been evaluated. Due to stress relaxation the dwell time causes a larger plastic strain range compared to the tests without dwell time. The results also show that the dwell time leads to a shorter fatigue life for the lower strain range, but has no or small effect on the life for the higher strain range. Fracture investigations show that dwell times result in more intergranular cracking. With the use of the electron channeling contrast imaging technique, the influences of dwell time on the cyclic plastic deformation, precipitation behavior, recovery phenomena and local plasticity exhaustion have also been studied.
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| 2. |
- Carlberg, Torbjörn, et al.
(author)
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Surface Segregation and Surface Defect Formation During Aluminum Billet Casting
- 2015
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 68:6, s. 1065-1069
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Journal article (peer-reviewed)abstract
- In this paper the surface zone formation during direct chill casting of aluminum billets, produced by the air slip technology, is discussed. The shell zone depth and compositions have been quantitatively studied, and the surface microstructures of 6060, 6005 and 6082 alloys are compared and coupled to surface appearances. The understanding of the results is based on the exudation of liquid metal through the mushy zone and the fact that the exudate liquid is contained within a surface oxide skin, and the oxide skin movements are coupled to various surface appearances. The major defects that occur during billet castings are different kinds of vertical drags or horizontal bandings, also called lapping. The structures coupled to these defects and theories for their formation are discussed.
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| 3. |
- Deshmukh, A. A., et al.
(author)
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Investigating the Applicability and Limitations of Glass-Forming Criteria Based on Bond Parameters on Thermal Stability in Mg-Based Multicomponent Bulk Metallic Glasses
- 2018
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In: Transactions of the Indian Institute of Metals. - : SPRINGER INDIA. - 0972-2815 .- 0975-1645. ; 71:11, s. 2631-2634
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Journal article (peer-reviewed)abstract
- In this paper, correlation of thermal stability () with the bond parameters such as electronegativity (), atomic radius mismatch (), and valence electron concentration () for Mg-based multicomponent bulk metallic glasses (BMGs) have been evaluated. A statistical approach of regression analysis has been adopted to investigate correlations among these parameters. Available experimental data have been used for the systematic investigation from ternary to multicomponent Mg-based BMGs. In addition, the applicability of the criteria has been assessed for the systems with and without rare earth (RE) elements. We have found that BMG systems containing RE group elements have significant effect on width of supercooled liquid region. Results obtained from our modified empirical equation have been compared with that of earlier models and have shown better correlations.
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| 4. |
- Gupta, R. K., et al.
(author)
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Hot Deformation Studies on beta(0) Stabilized TiAl Alloy Made Through Ingot Metallurgy Route
- 2021
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 74:12, s. 2977-2989
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Journal article (peer-reviewed)abstract
- Hot deformation studies of a newly designed gamma + alpha(2) based TiAl alloy of composition Ti-42Al-6Nb-3Cr-0.1B at.% (nominal) realized through ingot metallurgy route using double vacuum arc remelting were carried out. Hot isothermal compression testing was performed in Gleeble (TM) 3500 at different temperatures ranging from 1123 to 1373 K at 50 K intervals and strain rates of 0.001-1 s(-1). Processing maps were developed using an approach of dynamic material modeling of the flow curves to establish the safe hot working regime. Strain rate sensitivity and Zener-Holloman parameters were calculated and constitutive equation was derived. Microstructural investigation revealed dynamic recrystallization and activation of multiple twin systems as the main softening mechanisms operating at optimum hot working conditions. Safe hot working temperature and strain rate regime for the alloy was found to be in the temperature range of 1323-1373 K and strain rate range of 0.001-0.01 s(-1).
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| 5. |
- Hajiannia, I., et al.
(author)
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Development of Ultrahigh Strength TRIP Steel Containing High Volume Fraction of Martensite and Study of the Microstructure and Tensile Behavior
- 2018
-
In: Transactions of the Indian Institute of Metals. - : Springer. - 0972-2815 .- 0975-1645. ; 71:6, s. 1360-1367
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Journal article (peer-reviewed)abstract
- A new transformation induced plasticity (TRIP) steel containing high volume fraction of martensite was produced by austempering heat treatment cycle. Microstructure and tensile properties of this TRIP steel were investigated and compared to those of a dual phase (DP) steel with high martensite volume fraction. Microstructural analysis showed a mixture of ferrite, bainite, retained austenite and about 25–30 vol% of martensite in the TRIP steel. As a result of the strain induced transformation of retained austenite to martensite, the TRIP steel showed a strength elongation balance of 86% higher than that for the DP steel. In comparison to the commercial TRIP780 steel, the current TRIP steel showed a 15% higher ultimate tensile strength value while maintaining the same level of ductility. TRIP steel also had a larger work hardening exponent than DP steel at all strains.
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| 6. |
- Heidarzadeh, A., et al.
(author)
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Tensile Properties of Friction Stir Welds of AA 7020 Aluminum Alloy
- 2015
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 68:5, s. 757-767
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Journal article (peer-reviewed)abstract
- In this investigation, response surface methodology was used to predict and optimize the tensile properties of friction stir welded AA 7020 aluminum alloy. Tensile properties, microstructural features and fractography of the joints were measured and investigated using tensile test, optical and scanning electron microscopes, respectively. In addition, the influences of friction stir welding parameters on tensile properties of the joints were examined thoroughly. The results revealed that with increasing the heat input, the tensile strength of the joints increased up to a maximum value and then decreased, where the elongation of the joints increased continuously. Moreover, the optimal condition to obtain a maximum of tensile strength was 1,055 rpm, 97 mm/min and 7.4 kN, where as for tensile elongation was 1,320 rpm, 72 mm/min and 7 kN.
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| 7. |
- Jayamani, Jayaraj, et al.
(author)
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Electrochemical Studies and XPS Analysis of the Surface of Zirconium-702 in Concentrated Nitric Acid With and Without Fluoride Ions
- 2018
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 71:3, s. 521-531
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Journal article (peer-reviewed)abstract
- Zirconium exhibited pseudo-passive behavior in fluorinated nitric acid (11.5 M HNO3 + 0.05 M NaF) as the current density measured from the electrochemical studies was several orders higher than the value in fluoride free nitric acid. Impedance studies on zirconium sample exposed in 11.5 M HNO3 for 240 h confirmed the formation of the passive film with high polarization resistance value and the calculated thickness of the film based on the capacitance value was about ~4.5 nm. On the other hand, in fluorinated nitric acid, the charge transfer resistance value associated with the zirconium dissolution process was dominant when compared to that of the film formation. Results of X-ray photoelectron spectroscopic investigations upheld the presence of ZrOF2 and ZrF4 and indicated that the protective oxide layer growth was restricted by the presence of fluoride ions.
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| 8. |
- Jayamani, Jayaraj, et al.
(author)
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Studies on Corrosion of Titanium and Air-Oxidized Titanium in Fluorinated Nitric Acid
- 2019
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 72:7, s. 1917-1926
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Journal article (peer-reviewed)abstract
- Titanium (Ti) is a lustrous transition metal which possesses excellent corrosion resistance in several aggressive environments but is attacked by acidic fluoride media. In this work, the addition of fluoride ion to nitric acid on the corrosion behavior of Ti and air-oxidized Ti was studied. Air oxidation of Ti at 800 °C for 5 h resulted in the formation of an intact rutile TiO2 layer with a thickness of about 35 μm. The corrosion resistance was investigated from the polarization resistance ($$R_{\text{P}}$$RP) values which were obtained from linear polarization and electrochemical impedance spectroscopy (EIS) measurements. A decrease in the $$R_{\text{P}}$$RPvalue of Ti with the addition of fluoride ion in nitric acid was observed, and this indicated the formation of an unstable layer, which resulted in accelerated dissolution. The several order increase in the $$R_{\text{P}}$$RPvalue of air-oxidized Ti in nitric acid containing fluoride ions pointed the improved resistance to corrosion. The diffusivity of species through the air-oxidized TiO2 layer was estimated from the electrochemical equivalent circuit (EEC) analysis of EIS data. Even though the diffusivity increased by several orders with the addition of fluoride ions, air-oxidized Ti provided better protection against nitric acid containing fluoride ions than Ti. The corrosion rates of Ti and air-oxidized Ti in boiling nitric acid containing fluoride ions were also estimated from weight loss experiments. Even in boiling fluorinated nitric acid, air-oxidized Ti provided better corrosion protection, with corrosion rates of about 1000 times less than that of Ti.
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| 9. |
- Korojy, Bahman, et al.
(author)
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On solidification of hypereutectic Al-Si alloys
- 2009
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0019-493X .- 0972-2815 .- 0975-1645. ; 62:4-5, s. 361-365
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Journal article (peer-reviewed)abstract
- Precipitation of primary silicon was studied in Al-Si hypereutectic alloys with 15, 18, and 25 wt. % silicon content. The alloys were solidified with different cooling rates from different super heat temperatures. The liquidus and eutectic temperature were evaluated from the cooling curves. The liquidus temperature was found to decrease with cooling rate. The evaluation of microstructure showed that the fraction of primary silicon decreased with increasing the cooling rate and super heat temperature. Furthermore, the morphology of the primary silicon changed as an effect of cooling rate and super heat temperature.
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| 10. |
- Kuthe, Sudhanshu, et al.
(author)
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Computational Platform for Manufacturing Bulk Metallic Glasses Based on GFA Parameters
- 2018
-
In: Transactions of the Indian Institute of Metals. - : SPRINGER INDIA. - 0972-2815 .- 0975-1645. ; 71:11, s. 2731-2734
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Journal article (peer-reviewed)abstract
- Materials that are hard to manufacture with conventional manufacturing routes can be fabricated by incorporating the advanced automation. This has motivated the authors to propose a new computational methodology which could help in quantitative and qualitative manufacturing of bulk metallic glasses (BMGs). The present model was designed to propose the critical cooling rate () based on glass transition temperature (), onset crystallization temperature () and liquidus temperature (). Available correlation between and parameters has been used to validate the modeled values of, and. It was observed that obtained results have shown a close resemblance to experimental values of . It was found that Pd-based BMGs exhibited better correlation fit than other families of BMGs. Authors believed that this investigation will be useful for processing of bulk metallic glasses in coming days.
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| 11. |
- Lacaze, J., et al.
(author)
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Numerical Simulation of Brazing Aluminium Alloys with Al-Si Alloys
- 2018
-
In: Transactions of the Indian Institute of Metals. - : SPRINGER INDIA. - 0972-2815 .- 0975-1645. ; 71:11, s. 2623-2629
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Journal article (peer-reviewed)abstract
- Joining parts using low-melting temperature alloys has long been used for manufacturing complex components such as heat exchangers made of aluminium alloys. Investigations of the process have shown that core/clad interaction during heating and brazing can lead to a significant decrease in the amount of liquid available for joint formation. This study presents a transient one-dimensional model for the process that takes into account the diffusion of silicon and the movement of the core/clad interface, with the model equations being implemented in the finite element software COMSOL Multiphysics;the results are compared to literature experimental data. Silicon profiles in the core are well described, while there appears a significant difference between predicted and experimental values of remaining clads which suggest a strong effect of silicon diffusion and liquid penetration at core grain boundaries.
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| 12. |
- Millman, M.S., et al.
(author)
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Observations on BOS refining
- 2013
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 66, s. 525-534
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Journal article (peer-reviewed)abstract
- Selected IMPHOS (IMproving PHOSphorus refining) heats ([1], [2]: Millman et al. in Proc. Scanmet 3, 2008; and Millman et al. in Ironmak Steelmak 38:499, 2011), have been used to make observations on decarburizing and dephosphorising performance characteristics during BOS refining. If it is assumed that decarburization takes place solely in the slag/metal emulsion then maximum metal residence time in the emulsion is just under 9 sec and at peak decarburisation time, the maximum amount of metal in the emulsion is ∼ 50 % of the total metal content in the converter. To evaluate the effects of changes in slag component chemistry on phosphorus refining it is necessary to account for changes in slag weight, which can change substantially throughout a heat and be significantly different heat-to-heat. Dephosphorising performance depends on the thermodynamic stability of slag phases that are able to take-up phosphorus and the distribution of phosphorus between these thermodynamically stable phases. The application of proprietary thermodynamic models such as MTDATA and FACTSage has helped to clarify such events. The stability of the foamy slag/metal emulsion changes over the period of the blow. Slag height increases with an increase in FeO (tot) wt% and decreases with a decrease in decarburisation rate and the collapse of the foamy slag. © 2013 Indian Institute of Metals.
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| 13. |
- Muhmond, Haji Muhammad, 1984-, et al.
(author)
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An Investigation on the Effect of S and Al on the AusteniteGrowth Morphology in Gray Cast Iron, Using Thermal Analysisand Etching Technique
- 2013
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In: Transactions of the Indian Institute of Metals. - : Springer London. - 0019-493X .- 0972-2815 .- 0975-1645. ; 66:2, s. 185-192
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Journal article (peer-reviewed)abstract
- The austenite nucleation and growth morphology was investigated through experiments by inoculation with pure Al in a controlled environment using DTA furnace and H.F furnace. The austenite volume fraction and the dendrite growth orientations were affected by the addition of Al to the melt. Thermal analyses were performed to study the effect of sulfur content on austenite volume fraction and growth morphology using DSC. The possibility of austenite nucleation by MnS particles was analyzed. Different sulfur contents in the alloys were resulting in change in the latent heat of solidification and the rate of austenite formation. Austenite volume fraction was measured with four methods, colour etching, DSC thermal analysis, lever rule, and using LH calculated by Thermo-Calc data base, and a comparison was made among them.
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| 14. |
- Nick, Arash Safavi, et al.
(author)
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On the Relationship Between Inclusions and Pores, Part I : Precipitation
- 2012
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 65:6, s. 791-794
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Journal article (peer-reviewed)abstract
- Formation mechanism and clustering of TiN-Al2O3 inclusions precipitated during solidification of austenitic stainless steel is analyzed in this paper. Steel sample are taken from a continuously cast bloom. Clustering of inclusions was examined with a hypothesis that inclusions gather inside the pores. Precipitation of the inclusions occurs through segregation in the residual melt in the interdendritic area. Size and mean distance of the inclusion particles are calculated with mass balance. Impact fracture test in cryogenic temperature reveals clusters of inclusions inside pores on the fracture surface. Size and distribution of the inclusions are examined using light optical microscopy and scanning electron microscopy. Inclusion's composition is investigated with energy dispersive X-ray spectroscopy analysis. Differential thermal analysis and differential scanning calorimetry Tests determined the transformation temperatures. Results of the experiments are in good agreement with theoretical analysis.
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| 15. |
- Ranganathan, Sathees, et al.
(author)
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Influence of melt temperature on Rapid solidification of Al-Y and Al-Si alloy system
- 2009
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0019-493X .- 0972-2815 .- 0975-1645. ; 62:4-5, s. 515-519
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Journal article (peer-reviewed)abstract
- Solidification behavior of Al-Y and Al-Si were investigated for different melt temperatures. Levitation casting technique was used to achieve a cooling rate of around similar to 2000K/s during the experiment. Light optical microscopy (LOM) and Scanning electron microscopy (SEM) were used to analyze the samples. An energy dispersive system (EDS) analysis of SEM was performed on the samples to identify the phases. Plate like structure of Al8Y3 primary phase was observed at low melt temperature with small percentage of peritectic transformation of Al8Y3 and liquid melt into Al9Y2. A pre-dentritic star like crystal of Al3Y was observed in a fine eutectic matrix at very high melt temperature. Amount and number of primary Si crystals formed in a unit area during the solidification increases as the melt temperature increases. It is believed the melt temperature affects the solidification pattern by changing chemical short range order.
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| 16. |
- Sandström, Rolf
(author)
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Fundamental Models for Creep Properties of Steels and Copper
- 2016
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In: Transactions of the Indian Institute of Metals. - : Springer. - 0972-2815 .- 0975-1645. ; 69:2, s. 197-202
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Journal article (peer-reviewed)abstract
- New fundamental creep models have been developed based on physical mechanisms. They involve no adjustable (fitting) parameters. This is a good basis for long term extrapolation, which is needed in advanced fossil fired power plants and third and fourth generation nuclear plants. It is demonstrated that the models give sufficiently precise predictions that the results can be applied technically. In the paper, results for austenitic stainless steels and copper are presented. The development of the microstructure is followed during creep. The work hardening and recovery of the dislocation structure are considered as well as the role of the substructure. Nucleation, growth and coarsening of precipitates are taken into account. The influence of substitutional and interstitial elements in solid solution is covered. Nucleation and growth of creep cavities are considered. Properties that have been accurately described include creep rupture strength and creep elongation. The influence of brittle rupture on the creep strength by taking cavitation into account has been analysed.
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| 17. |
- Seetharaman, Seshadri, et al.
(author)
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Retainment, Recovery and Recycling : A Swedish Success Story of ECO-Steelmaking
- 2013
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0972-2815 .- 0975-1645. ; 66:5-6, s. 567-575
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Journal article (peer-reviewed)abstract
- With a view to optimize the environmental aspects of steelmaking, the Swedish Steel Producers Association took the initiative to start a national project on ECO-steelmaking with financial support from Swedish Foundation for Strategic Environmental Research. The Division of Materials Process Science at the Royal Institute of Technology has an important part of the project, viz. "Retention, Recovery and Recycling", with emphasis on the retention of metal values in the steel bath without loss to the slag or gas phases, to recover the metal values that are lost to the slag phase by the development of new or optimized process concepts and aim at a total recycling of the metal values as well as the slag components within or outside the steel sector. The present paper describes the optimization of existing process concepts as well as evolving newer concepts to meet the above project goals. The use of CO2-O-2-Ar gas mixtures for the decarburization of high-alloyed steels, development of a low cost precursor for the addition of molybdenum to steel in EAF, direct alloying in EAF are some of the concepts initiated in the present work. Successful recovery of iron and manganese values by oxidation of the slag and separation of the magnetite or manganese ferrate by electromagnetic separation formed part of the recovery part. As part of the project, a salt extraction process was developed by which the metal values in slags could be extracted into a chloride phase followed by electrolysis in fused chloride medium. This method was found to be successful in the recovery of metal values from slags. This process could be extended to the recovery of a variety of metal values from a variety of secondary sources. The salient features of the process designs and the results are presented in this paper.
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| 18. |
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| 19. |
- Vijh, G., et al.
(author)
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Solid freeform fabrication of aluminum alloy components : Numerical simulations
- 2009
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0019-493X .- 0972-2815 .- 0975-1645. ; 62:4-5, s. 291-294
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Journal article (peer-reviewed)abstract
- A heat transfer model has been developed to simulate the evolution of temperature during semi-solid metal (SSM) solid freeform fabrication (SFF) process. The governing equations were solved numerically using finite difference method. Deposition of simple cubic components of A356 (Al-7%Si-0.45%Mg) aluminum alloy have been simulated. The effect of process parameters such as deposition pattern, deposition velocity, slurry cross-section and slurry temperature on the transient temperature distribution in these components have been studied. Out of the three deposition patterns studied, i.e. rotating, alternating and unidirectional, the alternating pattern enabled depositing larger interfacefree components. Increasing the slurry flow rate resulted in the deposition of larger interface-free components
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| 20. |
- Åberg, J., et al.
(author)
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Heat-flux measurements of industrial on-site continuous copper casting and their use as boundary conditions for numerical simulations
- 2009
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0019-493X .- 0972-2815 .- 0975-1645. ; 62:4-5, s. 443-446
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Journal article (peer-reviewed)abstract
- An embedded sensor, designed for rapid and accurate response times and using wireless data transmission, has been developed for the on-site measurement of temperatures in industrial continuous casting moulds. The sensor has been used to measure the temperature at several points in the mould during production in a Southwire copper casting process. The measured data has been used to calculate the temperature gradient in the mould to estimate the heat flux through it; this is then used as a boundary condition for numerical simulations of solidification. For these, we employ a method that tracks the solidification front explicitly; this has an advantage over fixed-grid methods in simulations for materials having a short solidification interval, since the release of latent heat at the solidification front can be resolved without resorting to a very fine mesh. The special considerations required for setting the initial condition for the numerical scheme and the time taken for the superheated melt to form a solid shell are also discussed.
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| 21. |
- Åberg, Lena Magnusson, et al.
(author)
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Heat of Solidification in Refractory Metals Studied by Drop-Tube Experiments
- 2009
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In: Transactions of the Indian Institute of Metals. - : Springer Science and Business Media LLC. - 0019-493X .- 0972-2815 .- 0975-1645. ; 62:4-5, s. 269-273
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Journal article (other academic/artistic)abstract
- A number of pure refractory metals have been investigated by drop-tube experiments. The cooling curves have been registered and theoretically analysed. A model for analysing the heat of fusion has been developed. It was found that the heat of fusion was approximately 50% of the tabulated value.
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| 22. |
- Åberg, Jonas, et al.
(author)
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An On-site Industrial Experimental Heat Flux Study during Solidification of Pure Copper in the Southwire Process
- 2007
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In: T INDIAN I METALS. - 0972-2815. ; 60:2-3, s. 191-196
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Journal article (peer-reviewed)abstract
- To study the production of pure copper and copper alloys in the Southwire process the temperature in the mould has been measured on-site in the production process in a number of positions. To increase the accuracy and robustness of measurements a new type of thermocouple based temperature sensor has been developed and tested. The test system includes wireless transmission of measured data from the moving mould. The results from the measurements are then used to calculate the energy transfer rate from the solidifying shell as a function of time. An initial in-situ measurement campaign has been performed and the results are very promising.
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