| 1. |
- Andersson, Britt M., et al.
(author)
-
Electrical resistivity and critical temperature of Bi-based high-Tc superconductors to 1 GPa
- 1990
-
In: High Pressure Research, volumes 3 to 5. - London : Gordon and Breach. - 2881247466 ; 3:1-6, s. 120-122
-
Conference paper (peer-reviewed)abstract
- We have measured the electrical resistance R of a sintered, two-phase, high-TC superconductor with the nominal composition BiSrCaCu2Ox, as a function of T and p. We find d(lnR)/dp ≃ -0.06 GPa-1 at 295 K, while dTC/dp is 2.5 K/GPa for the phase with Tc ≃ 76 and 2 K/GPa for that with TC ≃ 106 K.
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| 2. |
- Ashby, M. F., et al.
(author)
-
A first report on diagrams for grain growth in welds
- 1982
-
In: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 30:11, s. 1969-1978
-
Journal article (peer-reviewed)abstract
- Data for carbide dissolution, grain growth and martensite formation in the heat-affected zone of a weld can be assembled into a diagram showing the extent of each, for different weld cycles, and at different points in the zone. The diagrams are based on elementary kinetic models for grain growth and carbide dissolution, integrated over the weld cycle; and on experimental data. The sets of poorly-known kinetic constants which appear in such a treatment are determined by fitting the equations to data from real or simulated welds, at certain fixed points. Diagrams are presented for six steels. As well as summarising much data they allow the effect of change in weld procedure, or of preheat, to be predicted.
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| 3. |
- Ashby, M.F., et al.
(author)
-
A first report on welding diagrams
- 1981
-
Reports (other academic/artistic)abstract
- Data for carbide dissolution and grain growth in the heat affected zone of a weld can be assembled into a diagram showing the extent of each, for different weld cycles, and at different points in the zone. The diagrams are based on elementary kinetic models for grain growth and carbide dissolution, integrated over the weld cycle. The sets of kinetic constants which appear in such a treatment are determined by fitting the equations to data from real or simulated welds, at certain fixed points. Diagrams are presented for six steels. As well as summarizing much data they allow the effect of change in weld procedure, or of preheat, to be predicted.
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| 4. |
- Ashby, M.F., et al.
(author)
-
The transformation hardening of steel surfaces by laser beams-I. Hypo-eutectoid steels
- 1984
-
In: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 32:11, s. 1935-1948
-
Journal article (peer-reviewed)abstract
- Surfaces can be treated with a scanning laser beam to modify their properties. The beam subjects the near-surface to a thermal cycle with an amplitude and shape which depends on the process variables: the beam size, energy, scan rate and on whether the laser is pulse or continuous, and the chemistry and metallurgy of the steel. Approximate solutions to the equations of heat flow are combined with kinetic models to predict the near-surface structure and hardness of plain carbon steels after laser treatment. The results are assembled into diagrams which show immediately the combination of process variables for a desired surface structure and the associated hardness profile
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| 5. |
- Barbaro, F. J., et al.
(author)
-
Formation of acicular ferrite at oxide particles in steels
- 1989
-
In: Materials Science and Technology. - : Informa UK Limited. - 0267-0836 .- 1743-2847. ; 5:11, s. 1057-1068
-
Journal article (peer-reviewed)abstract
- Experimental steels similar in composition to structural grades were prepared from weld metal deposits to study the formation of acicular ferrite under conditions experienced in the heat affected zone for a range of welding processes. The formation of acicular ferrite under these conditions is found to be dependent on the presence of a suitable distribution of oxide inclusions > 0·4 μm in size. The characteristics and proportion of acicular ferrite in the microstructure also depend on the prior austenite grain size and cooling rate. The relationship between these factors is presented in a simplified quantitative model, which is supported by data from limited welding trials. Metallographic observations suggest that acicular ferrite forms in two stages. The first involves the formation of relatively large primary acicular ferrite plates by multiple nucleation at intragranular inclusion sites, and the second involves the formation of many smaller acicular ferrite grains that grow sympathetically from the primary plates.
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| 6. |
- Diederichs, J., et al.
(author)
-
Critical currents in Tl-2122 and Y-124 sinters under high hydrostatic pressure
- 1991
-
In: Superconductor Science and Technology, volume 4, Special Issue 1S. - Bristol : Adam Hilger. - 0750301082 ; , s. S97-S99
-
Conference paper (peer-reviewed)abstract
- Utilizing AC susceptibility measurements the authors have investigated the inter and intragranular properties of selected bulk materials under hydrostatic pressures to 3.5 GPa. A single phase Tl2CaBa2Cu2O8 sample with superconducting transition temperature Tc approximately=107 K shows a clear maximum in Tc(P) at approximately 2.2 GPa coupled with a nearly twofold increase to 3 GPa of the intergranular critical current density JcJ near Tc. The second sample, a YBa2Cu4O8 sinter, shows a large linear increase in Tc with pressure (+5.5 K/GPa) as well as a fivefold increase JcJ to 3 GPa. Applying a critical state model, the authors find that Tc(P) varies as lambda g-2(P), where lambda g is the intragranular (London) penetration depth.
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| 7. |
- Dou, S.X., et al.
(author)
-
Improvement of critical current density in the Bi-Pb-Sr-Ca-Cu-O system through hot isostatic pressing
- 1990
-
In: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 167:5-6, s. 525-528
-
Journal article (peer-reviewed)abstract
- The effects of hot isostatic pressing (HIPing) on densification and the superconducting properties of the Bi-Pb-Sr-Ca-O system were investigated. A relative density up to 95% and a critical current density greater than 1100 A/cm2 at 77 K were achieved through HIPing at 650°C for 2 h under 200 MPa argon. Under these conditions, the product gave a value of Jc four times that without HIPing. To was unaffected by HIPing for samples encapsulated with a combination of glass and silver tubes. However, To was suppressed from 103 K to 86 K for samples encapsulated with stainless steel and silver tubes while Jc increased from 260 A/ cm2 to 1086 A/cm2 during HIPing, indicating that the weak links were significantly improved. A new minor phase, having a composition of Bi/Pb/Sr/Ca/Cu=0.58/2.8/3.0/2.1/1.1, was observed in HIPed samples but its effect on Jc is not clear
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| 8. |
- Dou, S.X., et al.
(author)
-
Microstructure and flux pinning in superconducting Bi-Pb-Sr-Ca-Cu-O wires
- 1990
-
In: Physica. C, Superconductivity. - 0921-4534 .- 1873-2143. ; 172:1-2, s. 63-70
-
Journal article (peer-reviewed)abstract
- The critical current density (Jc) of Ag-clad Bi-Pb-Sr-Ca-Cu-O wire has been measured to be 1.2×104 A/cm2 at 77 K in zero field. The high Jc is attributed to a combination of elimination of the poisoning effect of Ag on superconductivity, grain alignment, and enhancement of flux pinning. Jc-H dependence was significantly improved in the Ag-clad tape, which has a Jc of 1.0×103 A /cm2 at 77 K and 4000 Oe, while the Jc of the sintered pellet drops two orders of magnitude at only 100 Oe. A pronounced anisotropy in Jc under high magnetic field is attributed to the grain alignment. Planar defects, such as heavy stacking faults parallel to the a-b plane in the rolled tape, are considered to be effective pinning centres.
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| 9. |
- Easterling, Kenneth E.
(author)
-
Hot isostatic pressing of metallic and ceramic powders
- 1990
-
In: Modelling of material behavior and design. - Warrendale : Minerals, Metals & Materials Society. - 0873391217 ; , s. 233-244
-
Book chapter (other academic/artistic)abstract
- The process of hot isostatic pressing is modelled in terms of the various mechanisms of densification and sample shrinkage. Using input data of material type, mean powder size, sample size and shape, and the hot isostatic pressing parameters of pressure, temperature, time, etc. a computer program provides output data on time to complete densification, sample shrinkage and mode of densification. It is shown that the program can be used to help optimise the HIP cycle and provide information of sample (tool steel) shrinkage and potential residual stress problems.
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| 10. |
- Easterling, Kenneth E.
(author)
-
Hot isostatic pressing of metallic and ceramic powders
- 1988
-
In: Sintering '87. - London : Elsevier. - 185166291X ; , s. 731-736
-
Conference paper (peer-reviewed)abstract
- The process of hot isostatic pressing is modelled in terms of the various mechanisms of densification and sample shrinkage. Using input data of material type, mean powder size, sample size and shape, as well as the hot isostatic pressing parameters of pressure, temperature, time, etc., a computer program provides output data on time to complete densification, sample shrinkage and mode of densification. It is shown that the program can be used to help optimise the HIP cycle and provide information of sample shrinkage and potential residual stress problems
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| 11. |
- Easterling, Kenneth E.
(author)
-
Microstructure and Properties of the Heat Affected Zone
- 1990
-
In: Recent trends in welding science and technology. - Materials Park, Ohio : ASM International. - 0871703726 ; , s. 177-188
-
Conference paper (peer-reviewed)abstract
- review is made of the main areas of current research interest in modelling and predicting the microstructural/property changes occurring in the heat affected zone in fusion welding. The main subject areas considered are single run welds, multi-run welds, and pulsed welding. The key to modelling in all these cases is the establishment of good equations for the weld thermal cycle. Modelling of other phenomena such as precipitate dissolution, grain growth, phase transformation, property changes, etc. are then tractable. Heat flow equations are well established for single run welds, but there are difficulties in defining the complete thermal cycle in multi-run welding. Pulsed welding, on the other hand, offers good possibilities for accurate modelling and, hence, a better degree of microstructural prediction may be possible in this case. Data are shown for T10 steel
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| 12. |
- Easterling, Kenneth E.
(author)
-
Solidification microstructure of fusion welds
- 1984
-
In: Material Science and Engineering. - 0025-5416. ; 65:1, s. 191-198
-
Journal article (peer-reviewed)abstract
- The microstructure developed during weld solidification and the effect of the various welding and materials parameters is discussed. It is shown that weld solidification is in several ways fundamentally different from solidification in conventional casting in that it is a dynamic (moving heat source) process in which the `mould' material (the base metal) has approximately the same composition as that of the solidifying metal. The moving arc also has the effect of continuously varying the solidification conditions, e.g. the temperature gradient and degree of convection, in the melt. The additional modifications to microstructure during cooling of the weld metal are also briefly discussed
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| 13. |
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| 14. |
- Easterling, Kenneth E.
(author)
-
Tomorrow's materials
- 1990. - 2.
-
Book (other academic/artistic)abstract
- Examples of new materials dealt with in this book include aluminium--lithium alloys and fibre polymer composites for aircraft and sports equipment, rolled structural beams made of toughened concrete, new engineering polymers that may soon displace metals, advanced ceramics that promise to revolutionise the machine tool, electrical and automobile engine industries, fibre optical materials, new generations of transistors, and a "warm" superconducting ceramic with applications in computing, medical scanners and levitating trains. The book begins with an introduction to the fundamentals of materials science and continues with a wide range of current and potential applications for structural and lightweight materials, wear and heat resisting materials, optical materials, electronic and magnetic materials, and sporting materials, and winds up with a section on the environmental issue and the role of advanced materials in tomorrow's world
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| 15. |
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| 16. |
- Gibson, L.J., et al.
(author)
-
Structure and mechanics of the iris leaf
- 1988
-
In: Journal of Materials Science. - 0022-2461 .- 1573-4803. ; 23:9, s. 3041-3048
-
Journal article (peer-reviewed)abstract
- The structure of the iris leaf resembles that of a sandwich beam with fibre composite faces separated by a low-density foam core. Such structures have a high specific stiffness because the separation of the faces by the lightweight core increases the moment of inertia of the section with little increase in weight. In this paper we examine the structure of the leaf of the bearded iris and show that its flexural stiffness can be explained in terms of the mechanics of sandwich beams
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| 17. |
- Ion, John C., et al.
(author)
-
A second report on diagrams of microstructure and hardness for heat-affected zones in welds
- 1984
-
In: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 32:11, s. 1949-1962
-
Journal article (peer-reviewed)abstract
- The paper improves and extends kinetic models to include: precipitate coarsening; the use of semi-empirical equations including carbon-equivalence to predict microstructure and hardness; a comparison between the theory and data obtained from different types of real welds; and an alternative, more easily used diagram.
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| 18. |
- Ion, John C., et al.
(author)
-
Computer modelling of weld-implant testing
- 1985
-
In: Materials Science and Technology. - 0267-0836 .- 1743-2847. ; 1:5, s. 405-411
-
Journal article (peer-reviewed)abstract
- A theoretical model is developed for determining the optimum notch position in an implant test used for predicting the susceptibility to hydrogen cracking during welding. Using a microcomputer for processing the equations for weld-bead geometry and heat flow during welding, a microstructural cross-section, with the notch positioned at the center of the grain-growth zone, and an implant testing diagram, showing the notch position and microstructure as a function of welding parameters, can be generated. A single bead-on-plate weld is used to determine the unknown kinetic and geometrical constants in the equations. It is shown that notch position is very sensitive to the type of welding process employed and that implant diagrams thus can be used to position the notch with greater reliability and hence reduce the scatter in the fracture loads measured in this test.
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| 19. |
- Li, C-H., et al.
(author)
-
A lattice resolution study of the martensitic transformation of small iron particles in a copper matrix
- 1985
-
In: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 33:2, s. 317-328
-
Journal article (peer-reviewed)abstract
- The martensitic transformation of small, fully coherent, gamma iron precipitates in an epsilon copper matrix, brought about by the bombardment of thin foils with argon ions, has been studied using lattice fringe imaging. It is found, in general, that only partial transformation of individual particles occurs, this corresponding to a simple homogeneous shear (a Bain strain). In addition, the transformation is limited to particles located within about two particle diameters of the foil surface. It is established that the mere presence of a Frank (or Shockley) loop in a particle, due to the bombardment, is insufficient to trigger the transformation. The implications of this result are discussed with reference to bulk martensite. In the present case, it is concluded that transformation may simply initiate at sites of local decohesion or microslip at the matrix/particle boundaries brought about by vacancy condensation following ion bombardment, these sites being most effective in the vicinity of free surfaces
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| 20. |
- Li, Wei-Bin, et al.
(author)
-
Cause and effect of non-uniform densification during hot isostatic pressing
- 1992
-
In: Powder Metallurgy. - : Informa UK Limited. - 0032-5899 .- 1743-2901. ; 35:1, s. 47-52
-
Journal article (peer-reviewed)abstract
- Hot isostatic pressing (hipping) is an extremely efficient way of densifying ceramic and high alloy metallic powders, or for healing porosity in castings. However, depending on the parameters of pressure, temperature, rate of heating, and sample size, hipping can result in a non-uniform mode of densification. This mainly occurs when a rapidly heated sample, or a sample of large dimensions, densifies quickly at the surface to produce, if effect, a fully dense, hard shell. It is shown that there can be a number of negative factors resulting from this, including reduced rates of densification, sample sample shape change, non-uniform shrinkage, and the development of residual stresses in the sample. Criteria for predicting whether or not non-uniform densification will occur are presented and evaluated. Steel and Cu are discussed.
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| 21. |
- Li, W.-B, et al.
(author)
-
Influence of particle shape on zener drag
- 1990
-
In: Acta Metallurgica et Materialia. - 0956-7151. ; 38:6, s. 1045-1052
-
Journal article (peer-reviewed)abstract
- Practically all papers concerned with grain refinement based on pinning by particle dispersions have considered spherical particles. This paper avoids this restriction and develops Zener pinning equations for ellipsoidal particles of any shape, orientation and degree of coherency. Theoretical predictions are verified using soap bubble model experiments. It is found that within well defined conditions of particle orientation, disk or needle-shaped particles may offer greater pinning resistance, or Zener drag to migrating boundaries than spherical ones. However, the pinning resistance of non-spherical particles is sensitive to particle orientation. Their use in alloys is best utilised in systems based on mono-orientation dispersions
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| 22. |
- Li, W-B., et al.
(author)
-
Laser transformation hardening of steel : II. Hypereutectoid steels
- 1986
-
In: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 34:8, s. 1533-1343
-
Journal article (peer-reviewed)abstract
- For pt.I see ibid., vol.32, p.1935 (1984). The properties of surfaces can be modified by heat-treatments using a scanning laser beam. In pt.I it was shown that the hardness and the depth of the laser-hardened layer in hypereutectoid steels could be predicted, with reasonable accuracy, from a model which combined an analysis of heat flow with one of the kinetics of pearlite dissolution, carbon redistribution in austenite, and subsequent transformation to martensite. In the present study the model is extended to include the case of hypereutectoid steels. A new approximate solution for carbide dissolution is developed, which allows both the changes in particle size and volume fraction, and in carbon content of the austenite, to be estimated. Reasonable agreement between measured and predicted hardness for a laser treated 1% C steel are obtained. The results are presented as laser processing diagrams which show how the case depth and hardness depend on the process variables
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| 23. |
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| 24. |
- Li, Wen-Bin, et al.
(author)
-
The effect of non-uniform densification during hot isostatic pressing
- 1992
-
In: Hot isostatic pressing. - : Elsevier. - 185166744X ; , s. 23-28
-
Conference paper (peer-reviewed)abstract
- Hot isostatic pressing (HIPing) is an extremely efficient way of densifying ceramic and metallic powders, or for healing porosity in castings. However, depending on the parameters of pressure, temperature, heating rate and sample size, can result in a non-uniform mode of densification. This mainly occurs when a rapidly heated sample, or a sample of large size, densifies quickly at the surface to produce in effect a fully dense, hard shell. It is shown that there can be a number of negative factors resulting from this, including reduced rates of densification, decrease of effective pressure, sample shape change, non-uniform shrinkage and the development of residual stresses in the sample etc. The materials mentioned are copper, steel, and Al sub 2 O sub 3
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| 25. |
- Liu, H.K., et al.
(author)
-
Cu valence states in superconducting BiPbSrCaCuO system
- 1990
-
In: Journal of Solid State Chemistry. - 0022-4596 .- 1095-726X. ; 87:2, s. 289-297
-
Journal article (peer-reviewed)abstract
- The oxidation states of Bi, Pb, and Cu in the BiPbSrCaCuO (BPSCCO) system have been determined by a combination of volumetric measurement technique and iodometric titration. It was found that, in contrast to previous reports, the concentration of the Cu3+ ions decreased with increasing Pb content, and Cu3+ ions were absent in samples of Bi1.6Pb0.4Sr1.6Ca2Cu3O9.8, while a Tc at 108 K and a Jc of greater than 12,000 A/cm2 at 77 K were observed. The 110 K phase in BPSCCO was stabilized and showed a high tolerance to change in oxygen partial pressure during sintering. In Pb-doped materials, Bi appears to be trivalent while Pb was determined to be mixed-valence Pb4+ Pb2+. It is suggested that superconductivity in BPSCCO may result from a dynamic transfer of holes from Bi PbO layers toward CuO2 planes
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| 26. |
- Loberg, Bengt, et al.
(author)
-
Metallographical study of hot isostatically pressed copper encapsulation of nuclear fuel elements
- 1986
-
In: Scientific basis for nuclear waste management IX. - Pittsburgh, Pa : Materials Research Society. - 0931837154 ; , s. 453-459
-
Conference paper (peer-reviewed)abstract
- Light optical and electron microscopy have been used to study both laboratory-scale and full-scale hot isostatically pressed (HIPed) copper as employed for encapsulation of spent nuclear fuel elements. This work includes the development of computing models for predicting the optimal conditions for HIPing copper and other possible encapsulation materials such as lead and alumina. Mechanical testing of HIPed samples has also been carried out. The current method of using hydrogen to reduce oxides at powder surfaces prior to HIPing is questioned on the basis that metallography reveals definite signs of hydrogen embrittlement. An alternative method of reduction is to use CO/CO//2 mixtures instead of hydrogen, and it is suggested that this approach could be strongly advantageous in future
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| 27. |
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| 28. |
- Navara, Eric, et al.
(author)
-
Austenite formation in manganese-partitioning dual-phase steel
- 1986
-
In: Materials Science and Technology. - : Informa UK Limited. - 0267-0836 .- 1743-2847. ; 2:12, s. 1196-1201
-
Journal article (peer-reviewed)abstract
- Manganese-containing ferritic-pearlitic steels have been studied after intercritical annealing for various times at temperatures of 700 and 725 degree C, during which austenite formation occurred at ferrite grain boundaries. Light and electron optical microscopy, and scanning transmission electron microanalysis and microdiffraction were employed for the study, in which both microstructural development and manganese redistribution were examined in detail. It was observed that the formation of austenite is associated initially with a migration of ferrite grain boundaries. It is proposed that this boundary migration is induced by manganese diffusion along the boundaries, and that this in turn provides the mechanism for rapidly transporting manganese to the growing austenite. On this basis, we find that austenite formation in these steels is associated with manganese-rich migrated ferrite boundaries, and is not dependent on the presence of cementite particles for nucleation
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| 29. |
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| 30. |
- Navara, Eric, et al.
(author)
-
The effect of alloying additions on the inclusion-matrix bond in oxide dispersion hardened alloys
- 1974
-
In: IV. Medzinárodná Konferencia o Práskovej Metalurgii, Československá Socialistická Republika 1974, [Vysoké Tatry, 1 - 3.X]. - : Slovenska Vedeckotechnicka Spolocnost; Kosice. ; , s. 265-280
-
Conference paper (peer-reviewed)abstract
- The factors contributing to strength and ductility of a series of Fe-Al2O3 dispersion hardened alloys are investigated. It is found that the bonding strength between the phases is of particular importance in alloys produced by powder metallurgy techniques, and this aspect of the problem is studied in detail using electron microscopy. The nature of bonding strength is then discussed and a model of diffuse interface postulated in order to account for improvements in the work of adhesion, caused by alloying the matrix with interface active elements. The diffuse-interface bond increases the strain required for the onset of void formation, and in extreme cases fracture occurs within the particles
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| 31. |
- Porter, D.A., et al.
(author)
-
The mechanism of deformation of pearlite
- 1979
-
In: Mechanisms of deformation and fracture. - Oxford : Pergamon Press. - 0080242588 ; , s. 87-96
-
Conference paper (peer-reviewed)
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| 32. |
- Roberts, W., et al.
(author)
-
An in situ sem study of void development around inclusions in steel during plastic deformation
- 1976
-
In: Acta Metallurgica. - : Elsevier BV. - 0001-6160. ; 24:8, s. 745-758
-
Journal article (peer-reviewed)abstract
- Void development around ellipsoidal inclusions (mainly MnS) in steel has been investigated by means of in situ SEM tensile tests using specimens such that the tensile axis is the short-transverse direction in rolled plate. By simultaneous video recording of the microscope image and a load-elongation curve, the nucleation and growth of cavities has been monitored quantitatively. Careful investigation reveals that the behaviour at a free surface as regards cavitation is rather accelerated in comparison to that observed internally; this can be reconciled with a modified interfacial stress distribution around those hard particles in a plastically deformed matrix which lie at or near the specimen surface. In addition, some observations pertaining to the coalescence of cavities as a prerequisite to terminal ductile separation, are described and considered.
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| 33. |
- Strid, J., et al.
(author)
-
Microstructure and plasticity of An Al-Al6Fe directionally solidified eutectic alloy
- 1985
-
In: Materials Science and Technology. - : Informa UK Limited. - 0267-0836 .- 1743-2847. ; 1:2, s. 161-166
-
Journal article (peer-reviewed)abstract
- The microstructure and plasticity of a directionally solidified Al-Al//6Fe eutectic alloy was investigated using quantitative STEM-EDX microanalysis, in situ tensile testing in STEM/SEM, and light/electron optical studies of microstructure before and following drawing and extrusion to wire. It is found that in spite of the brittle nature of the aligned Al//6Fe rods, the alloy as a whole is relatively ductile and can even be drawn or extruded to wire. In the deformed condition the Al//6Fe rods are broken up and the fragmens distributed uniformly throughout the aluminum matrix. The tensile strength and ductility of these drawn wires are good, 400 MN m** minus **2 and 83% area reduction, respectively. Microanalysis studies show that the iron content of the aluminum matrix following solidification is 0. 04 at. %, corresponding to an undercooling of approx. 3 K below the eutectic temperature. The iron content of the matrix can be reduced further by precipitation treatments.
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| 34. |
- Vishnu, P. Ravi, et al.
(author)
-
Heat flow model for pulsed welding
- 1991
-
In: Materials Science and Technology. - : Informa UK Limited. - 0267-0836 .- 1743-2847. ; 7:7, s. 649-659
-
Journal article (peer-reviewed)abstract
- An analytical model of the heat flow during pulsed welding is constructed by first developing a solution for the temperature distribution due to an instantaneous, stationary, Gaussian heat source. This solution is first extended to treat the case of a moving heat source for a single pulse and then extended to treat the case of pulsed welding by summing the temperature changes due to a series of pulses. Test gas tungsten arc welds in mild steel are used to confirm the validity of the model.
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| 35. |
- Vishnu, Ravi P., et al.
(author)
-
Investigation into the promise of using pulsed GTAW [TIG welding] as a "temperbead technique"
- 1991
-
In: Symposium on Joining of Materials for 2000 AD. - Tiruchirapalli : Indian Institute of Welding. ; , s. 723-728
-
Conference paper (peer-reviewed)abstract
- The use of pulsed TIG welding as an in situ repair welding process was investigated. Experiments were conducted on quenched and tempered steels (yield strength of 700 MPa) which were pulse TIG welded, using two sets of welding parameters, to produce bead on plate welds. The microstructure and hardness distributions of the produced welds were examined. The martensitic start (Ms) temperature was determined using simulations. The results were used to determine the optimum welding parameters for producing desirable microstructures within the weld. The use of pulsed TIG welding as an alternative to other temperbead repair processes is outlined
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