1) The document studies obtaining ultra fine grain sizes in plain C-Mn steels with 0.15-0.3% carbon through warm deformation processing.
2) Three new processing routes are developed involving heavy warm deformation at different temperatures followed by cooling or coiling to produce either pearlitic, bainitic ferrite 1, or bainitic ferrite 2 microstructures.
3) Lower deformation/coiling temperatures produce finer ferrite grains but more elongated aspect ratios, while pearlitic/bainitic ferrite grains are smaller and more equiaxed than pro-eutectoid ferrite grains.
Microstructure of Welded Joints of Steels based on the research work done by Dr. R. Narayanasamy, Retd. Professor (HAG), Dept. of Production Engineering, NIT Trichy
Grain refinement, which is obtained by changing the size of grain structure by different techniques, is a preferred method to improve simultaneously the strength and plasticity of metallic materials.
The presentation involves "Principles of Equal-channel Angular Pressing as a processing tool for grain refinement", its applications and advantages in the field of technology and research.
Microstructure of Welded Joints of Steels based on the research work done by Dr. R. Narayanasamy, Retd. Professor (HAG), Dept. of Production Engineering, NIT Trichy
Grain refinement, which is obtained by changing the size of grain structure by different techniques, is a preferred method to improve simultaneously the strength and plasticity of metallic materials.
The presentation involves "Principles of Equal-channel Angular Pressing as a processing tool for grain refinement", its applications and advantages in the field of technology and research.
Imaging of dislocations and twins in TWIP steels using electron channeling contrast imaging under controlled diffraction conditions in a scanning electron microscope
Imaging of dislocations and twins in TWIP steels using electron channeling contrast imaging under controlled diffraction conditions in a scanning electron microscope
Mechanism of Fracture in Friction Stir Processed Aluminium AlloyDr. Amarjeet Singh
Aluminium alloys are used for important
applications in reducing the weight of the component and
structure particularly associated with transport, marine,
and aerospace fields. Grain refinement by scandium (Sc)
addition can eliminate the casting defects and increase the
resistance to hot tearing for high strength aluminium alloys.
FSP for cast aluminium alloys have been focused and it has
great advantages including solid state microstructural
evolution, altering mechanical properties by optimizing
process parameters. These parameters are tool rotational
speeds (720, and 1000 rpm), traverse speeds (80, and 70
mm/min), and axial compressive force at 15 kN, etc. The
mechanical properties had been evaluated on FSPed
aluminium alloy with different microstructural conditions.
Fracture properties of aluminium alloys are very important
for industrial applications. Tensile and fracture toughness
properties were correlated to microstructural and
fractographic features of the aluminium alloys need to
explore their essential failure mechanisms.
Presentation for Jindal steels prepared on 02/01/2021 by
Dr. R. Narayanasamy, Retired Professor, Department of Production Engineering, NIT - Trichy, Tamil Nadu, India. Chief metallurgist, Balaji Super Alloys, Karamadai, Coimbatore - 641104, Tamil Nadu, India.
. One of the methods used to surface hardening of ductile iron is chilled cast iron. Chill as the fast cooling rate in the mold during solidification and chill thickness greatly affects the thickness of the hardness layer. The main material used is ductile iron, and the chill material is SS 304. Casting uses the sand casting method. Before pouring, the chill plate has been inserted onto the surface of the pattern that has been formed in the mold, then the chill plate is preheated at 700OC. Pouring was carried out at a melting temperature of 1400OC, and then cooled with argon and O2 sprays into the mold in solidification conditions at exactly 700OC. The results analyzed were the microstructure, hardness value, and the hardness of the thickness layer. This chill coolant will absorb heat very quickly and the Cr and Ni alloy will diffuse to the specimen surface to stabilize the ferrite and austenite phases in the final solidification. The particles on the hard surface have Ferro carbide M7C3, which is in the form of cementite and martensitic phases so that to categorized as white cast iron structure formed on the surface with an area around 1.5-3mm has a hardness of 61-65HRC. But in the center area is 31-49HRC
Experimental and Microstructural Analysis of TIG and MIG Welding on Dissimila...Abu Sufyan Malik
In the modern era, most of the industries have a high demand of light weight, high strength structures with desired product properties which depend on the joining of dissimilar materials for manufacturing.
In TIG welding tungsten electrode is placed centrally in the torch. During the inert gas supplied through the annular space between torch and electrode, the filler material was supplied using a separate rod and shielding undertaken by covering the weld zone with a blanket of gases (Argon, Helium) which prevent the exposure of weld metal to oxygen and hydrogen of the air.
In MIG welding, the arc is struck between the work piece and the wire, which act as electrode and filler material, the arc and weld pool were shielded by inert gas. Depending upon the work material, the shielding gas may be argon, helium and carbon dioxide. In this case, the bare metal electrode (consumable electrode) in the form of continuous wire is fed through welding torch with the help of electrical motor and feed rolls.
Mild Steels are the carbon steels which generally contain less than about 0.60-1.4% wt of Carbon. The alloy of Mild Steel with Chromium, Magnesium, Vanadium, tungsten and Molybdenum are used as Knives, Razors, Cutting tool, dies, hacksaw blades and crankshaft. They typically have a yield strength of 430–585MPa (62–85 Ksi), tensile strengths 605-780 MPa (88–113 Ksi), and a ductility of 33–19%EL.
The stainless steels are highly resistant to corrosion in a variety of environments, especially ambient atmosphere. Their predominant alloying element is chromium; a concentration of at least 11 wt% Cr is required. They typically consist a yield strength of 205 MPa (30ksi) to 1650Mpa (240 Ksi), tensile strengths between 380 and 1790 MPa (55 to 260 Ksi), and a ductility of 20 to 40%EL. A wide range of mechanical properties combines with excellent resistance to corrosion making stainless steels very versatile in their applicability. Equipment employed for these steels includes gas turbines, high-temperature steam boilers, heat-treating furnaces, aircraft, missiles, and nuclear power–generating units.
Dr. R. Narayanasamy - Presentation on Formability of Deep Drawing Grade SteelsDr.Ramaswamy Narayanasamy
Presentation on Formability of Deep Drawing Grade Steels & Others For M/s. Jindal Steel Plant by Dr. R. Narayanasamy, Retired Professor (HAG), Department of Production Engineering, NIT - Trichy.
Overview combining ab initio with continuum theoryDierk Raabe
Multi-methodological approaches combining quantum-mechanical and/or atomistic simulations
with continuum methods have become increasingly important when addressing multi-scale phenomena in
computational materials science. A crucial aspect when applying these strategies is to carefully check,
and if possible to control, a variety of intrinsic errors and their propagation through a particular multimethodological
scheme. The first part of our paper critically reviews a few selected sources of errors
frequently occurring in quantum-mechanical approaches to materials science and their multi-scale propagation
when describing properties of multi-component and multi-phase polycrystalline metallic alloys.
Our analysis is illustrated in particular on the determination of i) thermodynamic materials properties at
finite temperatures and ii) integral elastic responses. The second part addresses methodological challenges
emerging at interfaces between electronic structure and/or atomistic modeling on the one side and selected
continuum methods, such as crystal elasticity and crystal plasticity finite element method (CEFEM and
CPFEM), new fast Fourier transforms (FFT) approach, and phase-field modeling, on the other side.
Dislocation and twin substructure evolution during strain hardening of an Fe–22 wt.% Mn–0.6 wt.% C TWIP steel observed by electron channeling contrast imaging
Investigation of the indentation size effect through the measurement of the geometrically necessary dislocations beneath small indents
of different depths using EBSD tomography
High manganese conference korea twip steelDierk Raabe
Lecture about the effects of strain path and crystallographic texture on microstructure in Fe–22 wt.% Mn–0.6 wt.% C TWIP steels using Electron Channeling Contrast Imaging (ECCI) and EBSD
MRS Dec 2010 Steel With Copper Precipitates Dierk Raabe Dierk Raabe
Copper nanoprecipitates in steel studied by atom probe tomography and ab initio based Monte Carlo simulation
Authors: O. Dmitrieva, P.-P. Choi, T. Hickel, N. Tillack,
D. Ponge, J. Neugebauer, D. Raabe
MRS Fall Meeting 2010
3. The reason is The development of industry needs a steel with advanced mechanical properties Grain refinement is the only method to improve both strength and toughness That is because ......
8. To determine the relationship between micro-structure and mechanical properties of UF grained steel
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10. The effect of microstructure on strength Ferrite Grain Size, µm 20 10 5 2 1 0.5 800 700 600 500 400 300 0.15C-0.3Si-1.5Mn Steel ferrite+ cementite ferrite + pearlite Yeild Strengh, MPa +>300MPa Conventional Grain Size Ultrafine Grain Size 104 106 108 1010 Number of Grains in 1 mm3 K. Nagai
11. The PonyMILL processing route Conventional Hot Mill Line Coiler Run out table Coil Handling Coil Transfer PonyMILL Single High Reduction Stand Un-Coiler Re-Coiler
16. Experimental routes hot deformation (conventional hot strip mill) =0.3, =10s-1 holding compression 2min =4×0.4, =10s-1 air cooling simulated final coiling A3 5~12℃/s 50℃/s PF BS heavy warm deformation (PonyMILL) Pearlite route BainiterouteⅠ Bainiteroute Ⅱ
17. Optimum austenite deformation temperature Optimization of deformation temperature in austenite region (WUMSI) Water quenched microstructure after deformation at 860℃ of 0.15%C steel Tg=Ae3+100℃ for 3 min air Tde compression =0.3, =10s-1 water
18. Selection of cooling rate to get desired initial microstructure (F+P or B) Experiment schedule (deformation dilatometry) Changes in microstructure and hardness of experimental steels with different cooling rates Tg =Ae3+100℃ for 3 min air compression Ar3 cooling 64...2℃/s M+B+F F+P +B +M UTS, F+P+B F+P
19. DCCT diagram of the steels DCCT diagram (ferrite + pearlite region) of 0.15%C, 0.2%C and 0.3%Csteel DCCT diagram of 2CMsteel BR II PR BR I
20. Starting temperature of heavy deformation Effect of heavy deformation temperature on flow curves and temperature increase in 0.3%C steel 500℃de 600℃de 700℃de 730℃de
21. The effect of heavy deformation temperature on microstructure 5000C-coiling 5500C-coiling 6000C-coiling 7000C-coiling 5500C 6000C 6400C 7000C bainite route I ND bainite route II
22. (a) grain size: 3.50µm (b) grain size: 1.25µm The effect of heavy deformation temperature on the microstructure in 0.3%C steel 7000C 85-95% are high angle boundaries 5000C
26. Microstructure evolution during compression in PR short pearlitic fragments pearlitic ferrite compression compression pearlitic ferrite pro-eutectoid ferrite with subgrains pearlitic cementite lamella pro-eutectoid ferrite new ferrite grains 1m 1m 2m
27. SEM micrographs of 0.3%C steel after bainite routeⅠ Substructure in large grains subgrains large grain Heavy deformation at 500℃ and subsequent simulated coiling at 700℃
29. * deformation temperature (PR and BR II) or simulated coiling temperature (BR I) Micro-hardness for different routes
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31. Three new process routes for heavywarmdeformation have been designed and employed to obtain UFG steel
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34. L. Storojeva, D. Ponge, D. Raabe, R. Kaspar: Z. Metallkunde 95 (2004) 1108-1114, On the influence of heavy warm reduction on the microstructure and mechanical properties of a medium carbon ferritic-pearlitic steel
35. R. Song, D. Ponge, D. Raabe, R. Kaspar: Acta Mater. 53 (2004) 845858, Microstructure and crystallographic texture of an ultrafine grained C-Mn steel and their evolution during warm deformation and annealing
36. R. Song, D. Ponge, D. Raabe: ScriptaMaterialia 52 (2005) 1075-1080, Improvement of the work hardening rate of ultrafine grained steels through second phase particles
37. R. Song, D. Ponge, D. Raabe: ISIJ International 45 (2005) 1721-1726, Influence of Mn Content on the Microstructure and Mechanical Properties of Ultrafine Grained C-Mn Steels
38. R. Song, D. Ponge, D. Raabe: Acta Mater. 53 (2005) 4881-4892, Mechanical properties of an ultrafine grained CMn steel processed by warm deformation and annealing
39. R. Song, D. Ponge, D. Raabe, J.G. Speer, D.K. Matlock: Mater. Sc. Engin. A 441 , 2006) 1–17, Overview of processing, microstructure and mechanical properties of ultrafine grained bcc steels