Pampa Ghosh - Academia.edu (original) (raw)

Papers by Pampa Ghosh

Research paper thumbnail of Effect of microstructure on the impact toughness transition temperature of direct-quenched steels

Materials Science and Engineering: A, 2018

A sufficient level of toughness at low temperatures is paramount for the use of structural steels... more A sufficient level of toughness at low temperatures is paramount for the use of structural steels intended for arctic applications. Therefore, it is important for the steel industry to identify the factors that control brittle fracture toughness. In this study, the quantitative effect of microstructure on the impact toughness transition temperature has been investigated with 18 different thermomechanically rolled and direct-quenched low-carbon ultra-high-strength steels with varying martensite and bainite contents. The steels were produced by altering their chemical composition, the finish rolling temperature and the total reduction of the prior austenite grains in the non-recrystallisation temperature regime, i.e. austenite pancaking, and characterised in terms of microstructural constituents, grain size distributions and texture as well as by using Charpy-V impact and tensile testing. It is shown for the first time that the impact toughness transition temperatures T 28J and T 50 closely follow a dynamic reference toughness, defined by yield strength and the size of the coarsest grains in the effective grain size distribution at 80th percentile. Decreasing the area fraction of {100} cleavage planes oriented within 15°of the macroscopic fracture plane by increasing austenite pancaking is also shown to improve T 28J. The best toughness is achieved with the lowest finish rolling temperatures that are nevertheless high enough to avoid the subsequent formation of granular bainite, which weakens both the toughness and strength. The results show that it is perfectly possible to produce untempered ultra-high-strength martensitic and martensitic-bainitic structural steels with adequate low-temperature toughness when the grain size is properly controlled.

Research paper thumbnail of Characterization of tin-plated steel

Frontiers in Materials

Tinplating on steel is a useful industrial process extensively used for food packaging. Cold-roll... more Tinplating on steel is a useful industrial process extensively used for food packaging. Cold-rolled annealed steel coated with tin gives the steel corrosion resistance property and a beautiful luster. Tinplating on steel is a complex process where rolled and annealed steel sheets are cleaned with acid to remove rust, grease, or oil from the surface. Pure tin is electrodeposited on this freshly prepared surface after the electrodeposition of tin on the steel strip; the surface becomes lustrous, the color of pure tin appears, and the finish is called matte. Very often, the flowing heat treatment is just about the tin melting point of 232°C–265°C. After electrodeposition, pure tin deposits on the steel surface; however, a chemical reaction between tin and iron occurs during the brightening treatment. This process results in iron–tin intermetallic formation; their orientation grain structure and orientation of substrate steel all have a synergistic effect on the final properties of tin-...

Research paper thumbnail of Determination of the crystal structure of FeTiP-type precipitates in a few interstitial-free high-strength steels

Scripta Materialia, 2007

ABSTRACT

Research paper thumbnail of Effects of composition and processing parameters on precipitation and texture formation in microalloyed interstitial free high strength (IFHS) steels

Materials Science and Technology, 2009

ABSTRACT

Research paper thumbnail of Effect of Ag nanoparticle addition and ultrasonic treatment on a stable TiO2 nanofluid

Ultrasonics Sonochemistry, 2012

Nanoparticles, when homogeneously dispersed in a base fluid, e.g. water, ethylene glycol etc. are... more Nanoparticles, when homogeneously dispersed in a base fluid, e.g. water, ethylene glycol etc. are commonly known as nanofluids. Nanofluids have gained attention in the scientific community for their enhanced thermal properties. One of the major problems in using nanofluids as a heat transfer medium for commercial applications is that, in most of the closed circuit industrial cooling processes, the cooling fluid has to be replaced after several cycles of cooling operation because of an increased presence of contaminants. If nanofluids were used as a coolant, it would be very hard to separate the nanoparticles from the waste fluid. The present work is aimed at the separation and recycling of nanoparticles from fluid waste by means of quick settling of titanium dioxide nanoparticles using silver nanoparticles along with ultrasonic treatment. It is observed that with increasing silver concentration and time of ultrasonication, the stability of the dispersion decreases. There is a value for both the silver concentration and ultrasonication time above which the settling time decreases drastically.

Research paper thumbnail of Comparative study of precipitation behavior and texture formation in cold rolled-batch annealed and cold rolled-continuous annealed interstitial free high strength steels

Scripta Materialia, 2007

ABSTRACT Two interstitial free high strength (IFHS) steels of comparable chemistries but processe... more ABSTRACT Two interstitial free high strength (IFHS) steels of comparable chemistries but processed through batch annealing and continuous annealing routes have been studied. The near absence of FeTiP and presence of a large volume fraction of TiC are considered to be primarily responsible for the sharp {1 1 1} texture in the CA steel.

Research paper thumbnail of Microstructural Evolution and Its Correlation with Gas Metal Arc Welded Dissimilar Advanced High Strength Steels

Journal of Materials Engineering and Performance, 2022

Two dissimilar advanced high strength steels (AHSS)—ferrite-bainite (F-B) and ferrite-martensite ... more Two dissimilar advanced high strength steels (AHSS)—ferrite-bainite (F-B) and ferrite-martensite (F-M) steel grades were joined by gas metal arc welding (GMAW) process. Microstructure of the heat-affected zone (HAZ) after welding was critically reviewed and further correlated with the performance of the welded joint. It was observed that both the steels had softening in the HAZ, particularly in the intercritical HAZ (ICHAZ) although the reasons were found to be different. For the F-B steel grade, the extent of softening was much higher and primarily attributed to the annihilation of the dislocations (which was manifested by presence of internal strain) present in the base matrix. Besides, the volume fraction of the precipitates present in the base steel was also reduced drastically and aided in the softening process. In contrast, the F-M steel inherently contained less internal strain and the softening was predominantly due to the tempering of the martensite islands distributed in the ferrite matrix during the welding process. Thus, to extract the optimum benefits from these modern AHSSs after welding, it is important to have a thorough knowledge about the steel design philosophy (i.e., base metal chemistry and transformed microstructural products).

Research paper thumbnail of Microstructural evaluation of magnetic pulse welded plain carbon steel sheets

Journal of Materials Processing Technology

Abstract Two plain carbon steel plates were joined by magnetic pulse welding process. The optimum... more Abstract Two plain carbon steel plates were joined by magnetic pulse welding process. The optimum condition was found to be 16 kV discharge voltage and 0.8 mm standoff distance for the present set of plates. Three distinct zones of bonding namely; solid state bonding, homogeneous liquid state bonding and liquid state bonding with pores and cracks were observed. Any appreciable changes observed were restricted within 5 μm distance from the weld line. Microstructural as well as crystallographic alterations of the structures were not detected beyond 5 μm.

Research paper thumbnail of Influence of Microstructure and Crystallographic Texture on the Surface Brightness of Industrially Produced Tinplated Steels

Metallurgical and Materials Transactions A

Three distinct layers are present in commercially produced tinplated steels: the top tin layer, t... more Three distinct layers are present in commercially produced tinplated steels: the top tin layer, the middle Fe-Sn alloy layer, and the bottom steel substrate. The brightness of these steels is inversely proportional to the roughness of the top layer. Substrate steels with recrystallized structure, sharper texture, and cleaner matrix result in flatter Fe-Sn interlayer and subsequently smoother top Sn layer. This in turn gives brighter surface finish.

Research paper thumbnail of Effects of Deformation Texture and Microstructure on Recrystallization and Grain Growth in Twip Steels

Proceedings of the 6th International Conference on Recrystallization and Grain Growth (ReX&GG 2016), 2016

The importance of TWinning Induced Plasticity (TWIP) and TRansformation Induced Plasticity (TRIP)... more The importance of TWinning Induced Plasticity (TWIP) and TRansformation Induced Plasticity (TRIP) has increased drastically in the recent past due their potential for automobile applications. These steels have good combination of specific strength and ductility, which could improve the crash resistance or energy absorption capacity in the situations like accidents. Stacking Fault Energy (SFE) is the most important parameter for the design of such steels. In low SFE TWIP steels, Brass (Bs)-type texture typically develops during rolling. Present investigation deals with the role of deformation texture, microstructure and SFE in recrystallization kinetics and grain growth, during processing in medium Mn steels. The SFE of Fe-12Mn-0.5C (wt %) alloy could be altered by the addition of alloying elements, such as Al. Recrystallization experiments have been carried out in cold rolled samples for different annealing times. In order to understand the recrystallization kinetics and grain growth phenomenon, detailed microstructural characterization has been performed by using Electron back-scatter diffraction (EBSD).

Research paper thumbnail of Local Scale Microstructural Effects from the Deformation and Recrystallization of Non-Oriented Electrical Steels

Metallurgical and Materials Transactions E, 2016

The magnetic properties of non-oriented electrical steels are determined by a combination of seve... more The magnetic properties of non-oriented electrical steels are determined by a combination of several metallurgical variables, including crystal orientation, misorientation (the orientation difference between two crystal orientations), and the amount of residual stress associated with plastic deformation. These variables are influenced by cold rolling and annealing. In order to study these relationships, samples in the semi-processed condition were subjected to an additional cold roll and a subsequent annealing at different temperatures, and then characterized using electron backscatter diffraction and nanoindentation. The process routing for these samples was not intended to be representative of real-world manufacturing; the purpose was to produce a spread in the metallurgical variables being investigated. Although some trends were observed involving orientation and misorientation, when present, deformation observed close to grain boundaries appeared to be the most influential variable on the magnetic properties.

Research paper thumbnail of Effects of Composition and Coiling Temperature on Precipitation and Texture Formation in a Few Interstitial Free High Strength Steels

Research paper thumbnail of Texture in the Design of Advanced Steels

This paper deals with the importance of crystallographic texture as one of the design criteria fo... more This paper deals with the importance of crystallographic texture as one of the design criteria for the development of advanced steels. The importance of texture has been highlighted by considering the cases of three important grades of steel, such as the electrical-, the deep-drawing quality-and the linepipe steels. In each case the evolution of texture as a function of the compositional and processing variables has been evaluated. This has clearly shown that texture is as fundamental as the microstructure in deciding the properties.

Research paper thumbnail of The effect of easy axis misorientation on the low induction hysteresis properties of non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2015

ABSTRACT The coercivity and hysteresis losses of non-oriented electrical steels (NOES) are determ... more ABSTRACT The coercivity and hysteresis losses of non-oriented electrical steels (NOES) are determined by metallurgical parameters evolved during their manufacturing process. Although the links between grain size, inclusion content, orientation and these magnetic properties are well established, the effects of misorientation, especially with respect to the magnetic easy axis, are mostly unexplored. From this work examining NOES samples with “typical” grain size and inclusion distributions, but with texture variations induced by lab processing, the major factors determining the coercivity and hysteresis losses were limited to the magnetocrystalline anisotropy energy (Ea) and EAM, a newly created easy axis misorientation parameter. It is believed that Ea is a measure of the contribution of domain rotation processes, while EAM is a representation of the ability of the sample to nucleate reverse magnetic domains. The utilization of EAM allows for a better understanding of the influence of metallurgical parameters on the magnetic properties, especially for samples with large differences in processing and texture.

Research paper thumbnail of Correlation Between AC Core Loss and Surface Magnetic Barkhausen Noise in Electric Motor Steel

Journal of Nondestructive Evaluation, 2014

Core loss is a significant source of energy loss in electric motor steel laminates. Therefore, th... more Core loss is a significant source of energy loss in electric motor steel laminates. Therefore, there is interest in monitoring the quality and consistency of laminates at various stages of manufacturing. The purpose of this study was to investigate the feasibility of using surface magnetic Barkhausen noise for the evaluation of AC core loss, and further, to examine potential origins of magnetic loss in nonoriented electrical steel. Core loss values were measured by a single sheet tester and Barkhausen noise measurements were performed using pole flux control on eight laminates with various grain size, texture and composition. Magnetocrystalline energy was calculated from X-ray diffraction data to quantify texture. Results demonstrated higher surface Barkhausen emissions for samples with lower core loss. Barkhausen noise analyses were used to examine the interplay among core loss, grain size, magnetocrystalline energy and B-H characteristics. The inverse correlation between core loss and Barkhausen noise emissions was qualitatively explained in terms of the orthogonal vector contribution of microscopic eddy currents to losses associated with bulk currents arising in the sample during magnetization.

Research paper thumbnail of Precipitation Behavior and Textural Evolution in Interstitial Free High Strength (IFHS) Steels

Microstructure and Texture in Steels, 2009

Cold rolled and annealed interstitial free high strength (IFHS) steels show various kinds of prec... more Cold rolled and annealed interstitial free high strength (IFHS) steels show various kinds of precipitates. Out of these, FeTiP is the most deleterious, since its formation leads to a loss of strength as well as degradation of the formability of the steel. This effect is much more pronounced in batch annealed IFHS steels than in their continuous annealed counterparts. The

Research paper thumbnail of Precipitation and Texture Formation in Interstitial Free High Strength (IFHS) Steels: A Short Review

Materials Science Forum, 2012

... Ghosh et al 10 have studied the precipitation behavior and texture formation in two IFHS stee... more ... Ghosh et al 10 have studied the precipitation behavior and texture formation in two IFHS steels of almost similar chemistries but processed through different annealing routes; batch annealing (BA) and continuous annealing (CA) (see Table 2). The batch annealed steel shows ...

Research paper thumbnail of Precipitation and texture formation in two cold rolled and batch annealed interstitial-free high strength steels

Scripta Materialia, 2006

ABSTRACT Precipitation and texture formation in two cold rolled and batch-annealed interstitial-f... more ABSTRACT Precipitation and texture formation in two cold rolled and batch-annealed interstitial-free high strength steels have been studied. TiN, Fe(Ti + Nb)P and TiC were the main precipitates observed. A perceptibly higher population of Fe(Ti + Nb)P precipitates in the steel containing a higher amount of P is considered to be primarily responsible for the less intense {1 1 1} texture.

Research paper thumbnail of Effect of crystallographic texture on the bulk magnetic properties of non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2014

Abstract Quantitative physical models for non-oriented electrical steels require precise knowledg... more Abstract Quantitative physical models for non-oriented electrical steels require precise knowledge of chemical and microstructural parameters for the material, with crystallographic texture being one of the most important. Describing the structure–property relationships in these materials is made difficult in that all of the parameters have an effect on magnetic properties. In the present study, a set of non-oriented electrical steel specimens are examined, where chemistry and grain size are kept similar from sample to sample, but texture is varied. A new texture parameter called Magnetic Texture Factor is introduced which is defined as the ratio of the volume fractions of 〈100〉 direction to 〈111〉 direction along magnetization vector. It was found that this Magnetic Texture Factor was a better parameter for identifying trends of magnetic properties with crystallographic texture than the often used Texture Factor , which is described as the ratio of the volume fractions of {100} planes to {111} planes.

Research paper thumbnail of Effect of metallurgical factors on the bulk magnetic properties of non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2014

Research paper thumbnail of Effect of microstructure on the impact toughness transition temperature of direct-quenched steels

Materials Science and Engineering: A, 2018

A sufficient level of toughness at low temperatures is paramount for the use of structural steels... more A sufficient level of toughness at low temperatures is paramount for the use of structural steels intended for arctic applications. Therefore, it is important for the steel industry to identify the factors that control brittle fracture toughness. In this study, the quantitative effect of microstructure on the impact toughness transition temperature has been investigated with 18 different thermomechanically rolled and direct-quenched low-carbon ultra-high-strength steels with varying martensite and bainite contents. The steels were produced by altering their chemical composition, the finish rolling temperature and the total reduction of the prior austenite grains in the non-recrystallisation temperature regime, i.e. austenite pancaking, and characterised in terms of microstructural constituents, grain size distributions and texture as well as by using Charpy-V impact and tensile testing. It is shown for the first time that the impact toughness transition temperatures T 28J and T 50 closely follow a dynamic reference toughness, defined by yield strength and the size of the coarsest grains in the effective grain size distribution at 80th percentile. Decreasing the area fraction of {100} cleavage planes oriented within 15°of the macroscopic fracture plane by increasing austenite pancaking is also shown to improve T 28J. The best toughness is achieved with the lowest finish rolling temperatures that are nevertheless high enough to avoid the subsequent formation of granular bainite, which weakens both the toughness and strength. The results show that it is perfectly possible to produce untempered ultra-high-strength martensitic and martensitic-bainitic structural steels with adequate low-temperature toughness when the grain size is properly controlled.

Research paper thumbnail of Characterization of tin-plated steel

Frontiers in Materials

Tinplating on steel is a useful industrial process extensively used for food packaging. Cold-roll... more Tinplating on steel is a useful industrial process extensively used for food packaging. Cold-rolled annealed steel coated with tin gives the steel corrosion resistance property and a beautiful luster. Tinplating on steel is a complex process where rolled and annealed steel sheets are cleaned with acid to remove rust, grease, or oil from the surface. Pure tin is electrodeposited on this freshly prepared surface after the electrodeposition of tin on the steel strip; the surface becomes lustrous, the color of pure tin appears, and the finish is called matte. Very often, the flowing heat treatment is just about the tin melting point of 232°C–265°C. After electrodeposition, pure tin deposits on the steel surface; however, a chemical reaction between tin and iron occurs during the brightening treatment. This process results in iron–tin intermetallic formation; their orientation grain structure and orientation of substrate steel all have a synergistic effect on the final properties of tin-...

Research paper thumbnail of Determination of the crystal structure of FeTiP-type precipitates in a few interstitial-free high-strength steels

Scripta Materialia, 2007

ABSTRACT

Research paper thumbnail of Effects of composition and processing parameters on precipitation and texture formation in microalloyed interstitial free high strength (IFHS) steels

Materials Science and Technology, 2009

ABSTRACT

Research paper thumbnail of Effect of Ag nanoparticle addition and ultrasonic treatment on a stable TiO2 nanofluid

Ultrasonics Sonochemistry, 2012

Nanoparticles, when homogeneously dispersed in a base fluid, e.g. water, ethylene glycol etc. are... more Nanoparticles, when homogeneously dispersed in a base fluid, e.g. water, ethylene glycol etc. are commonly known as nanofluids. Nanofluids have gained attention in the scientific community for their enhanced thermal properties. One of the major problems in using nanofluids as a heat transfer medium for commercial applications is that, in most of the closed circuit industrial cooling processes, the cooling fluid has to be replaced after several cycles of cooling operation because of an increased presence of contaminants. If nanofluids were used as a coolant, it would be very hard to separate the nanoparticles from the waste fluid. The present work is aimed at the separation and recycling of nanoparticles from fluid waste by means of quick settling of titanium dioxide nanoparticles using silver nanoparticles along with ultrasonic treatment. It is observed that with increasing silver concentration and time of ultrasonication, the stability of the dispersion decreases. There is a value for both the silver concentration and ultrasonication time above which the settling time decreases drastically.

Research paper thumbnail of Comparative study of precipitation behavior and texture formation in cold rolled-batch annealed and cold rolled-continuous annealed interstitial free high strength steels

Scripta Materialia, 2007

ABSTRACT Two interstitial free high strength (IFHS) steels of comparable chemistries but processe... more ABSTRACT Two interstitial free high strength (IFHS) steels of comparable chemistries but processed through batch annealing and continuous annealing routes have been studied. The near absence of FeTiP and presence of a large volume fraction of TiC are considered to be primarily responsible for the sharp {1 1 1} texture in the CA steel.

Research paper thumbnail of Microstructural Evolution and Its Correlation with Gas Metal Arc Welded Dissimilar Advanced High Strength Steels

Journal of Materials Engineering and Performance, 2022

Two dissimilar advanced high strength steels (AHSS)—ferrite-bainite (F-B) and ferrite-martensite ... more Two dissimilar advanced high strength steels (AHSS)—ferrite-bainite (F-B) and ferrite-martensite (F-M) steel grades were joined by gas metal arc welding (GMAW) process. Microstructure of the heat-affected zone (HAZ) after welding was critically reviewed and further correlated with the performance of the welded joint. It was observed that both the steels had softening in the HAZ, particularly in the intercritical HAZ (ICHAZ) although the reasons were found to be different. For the F-B steel grade, the extent of softening was much higher and primarily attributed to the annihilation of the dislocations (which was manifested by presence of internal strain) present in the base matrix. Besides, the volume fraction of the precipitates present in the base steel was also reduced drastically and aided in the softening process. In contrast, the F-M steel inherently contained less internal strain and the softening was predominantly due to the tempering of the martensite islands distributed in the ferrite matrix during the welding process. Thus, to extract the optimum benefits from these modern AHSSs after welding, it is important to have a thorough knowledge about the steel design philosophy (i.e., base metal chemistry and transformed microstructural products).

Research paper thumbnail of Microstructural evaluation of magnetic pulse welded plain carbon steel sheets

Journal of Materials Processing Technology

Abstract Two plain carbon steel plates were joined by magnetic pulse welding process. The optimum... more Abstract Two plain carbon steel plates were joined by magnetic pulse welding process. The optimum condition was found to be 16 kV discharge voltage and 0.8 mm standoff distance for the present set of plates. Three distinct zones of bonding namely; solid state bonding, homogeneous liquid state bonding and liquid state bonding with pores and cracks were observed. Any appreciable changes observed were restricted within 5 μm distance from the weld line. Microstructural as well as crystallographic alterations of the structures were not detected beyond 5 μm.

Research paper thumbnail of Influence of Microstructure and Crystallographic Texture on the Surface Brightness of Industrially Produced Tinplated Steels

Metallurgical and Materials Transactions A

Three distinct layers are present in commercially produced tinplated steels: the top tin layer, t... more Three distinct layers are present in commercially produced tinplated steels: the top tin layer, the middle Fe-Sn alloy layer, and the bottom steel substrate. The brightness of these steels is inversely proportional to the roughness of the top layer. Substrate steels with recrystallized structure, sharper texture, and cleaner matrix result in flatter Fe-Sn interlayer and subsequently smoother top Sn layer. This in turn gives brighter surface finish.

Research paper thumbnail of Effects of Deformation Texture and Microstructure on Recrystallization and Grain Growth in Twip Steels

Proceedings of the 6th International Conference on Recrystallization and Grain Growth (ReX&GG 2016), 2016

The importance of TWinning Induced Plasticity (TWIP) and TRansformation Induced Plasticity (TRIP)... more The importance of TWinning Induced Plasticity (TWIP) and TRansformation Induced Plasticity (TRIP) has increased drastically in the recent past due their potential for automobile applications. These steels have good combination of specific strength and ductility, which could improve the crash resistance or energy absorption capacity in the situations like accidents. Stacking Fault Energy (SFE) is the most important parameter for the design of such steels. In low SFE TWIP steels, Brass (Bs)-type texture typically develops during rolling. Present investigation deals with the role of deformation texture, microstructure and SFE in recrystallization kinetics and grain growth, during processing in medium Mn steels. The SFE of Fe-12Mn-0.5C (wt %) alloy could be altered by the addition of alloying elements, such as Al. Recrystallization experiments have been carried out in cold rolled samples for different annealing times. In order to understand the recrystallization kinetics and grain growth phenomenon, detailed microstructural characterization has been performed by using Electron back-scatter diffraction (EBSD).

Research paper thumbnail of Local Scale Microstructural Effects from the Deformation and Recrystallization of Non-Oriented Electrical Steels

Metallurgical and Materials Transactions E, 2016

The magnetic properties of non-oriented electrical steels are determined by a combination of seve... more The magnetic properties of non-oriented electrical steels are determined by a combination of several metallurgical variables, including crystal orientation, misorientation (the orientation difference between two crystal orientations), and the amount of residual stress associated with plastic deformation. These variables are influenced by cold rolling and annealing. In order to study these relationships, samples in the semi-processed condition were subjected to an additional cold roll and a subsequent annealing at different temperatures, and then characterized using electron backscatter diffraction and nanoindentation. The process routing for these samples was not intended to be representative of real-world manufacturing; the purpose was to produce a spread in the metallurgical variables being investigated. Although some trends were observed involving orientation and misorientation, when present, deformation observed close to grain boundaries appeared to be the most influential variable on the magnetic properties.

Research paper thumbnail of Effects of Composition and Coiling Temperature on Precipitation and Texture Formation in a Few Interstitial Free High Strength Steels

Research paper thumbnail of Texture in the Design of Advanced Steels

This paper deals with the importance of crystallographic texture as one of the design criteria fo... more This paper deals with the importance of crystallographic texture as one of the design criteria for the development of advanced steels. The importance of texture has been highlighted by considering the cases of three important grades of steel, such as the electrical-, the deep-drawing quality-and the linepipe steels. In each case the evolution of texture as a function of the compositional and processing variables has been evaluated. This has clearly shown that texture is as fundamental as the microstructure in deciding the properties.

Research paper thumbnail of The effect of easy axis misorientation on the low induction hysteresis properties of non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2015

ABSTRACT The coercivity and hysteresis losses of non-oriented electrical steels (NOES) are determ... more ABSTRACT The coercivity and hysteresis losses of non-oriented electrical steels (NOES) are determined by metallurgical parameters evolved during their manufacturing process. Although the links between grain size, inclusion content, orientation and these magnetic properties are well established, the effects of misorientation, especially with respect to the magnetic easy axis, are mostly unexplored. From this work examining NOES samples with “typical” grain size and inclusion distributions, but with texture variations induced by lab processing, the major factors determining the coercivity and hysteresis losses were limited to the magnetocrystalline anisotropy energy (Ea) and EAM, a newly created easy axis misorientation parameter. It is believed that Ea is a measure of the contribution of domain rotation processes, while EAM is a representation of the ability of the sample to nucleate reverse magnetic domains. The utilization of EAM allows for a better understanding of the influence of metallurgical parameters on the magnetic properties, especially for samples with large differences in processing and texture.

Research paper thumbnail of Correlation Between AC Core Loss and Surface Magnetic Barkhausen Noise in Electric Motor Steel

Journal of Nondestructive Evaluation, 2014

Core loss is a significant source of energy loss in electric motor steel laminates. Therefore, th... more Core loss is a significant source of energy loss in electric motor steel laminates. Therefore, there is interest in monitoring the quality and consistency of laminates at various stages of manufacturing. The purpose of this study was to investigate the feasibility of using surface magnetic Barkhausen noise for the evaluation of AC core loss, and further, to examine potential origins of magnetic loss in nonoriented electrical steel. Core loss values were measured by a single sheet tester and Barkhausen noise measurements were performed using pole flux control on eight laminates with various grain size, texture and composition. Magnetocrystalline energy was calculated from X-ray diffraction data to quantify texture. Results demonstrated higher surface Barkhausen emissions for samples with lower core loss. Barkhausen noise analyses were used to examine the interplay among core loss, grain size, magnetocrystalline energy and B-H characteristics. The inverse correlation between core loss and Barkhausen noise emissions was qualitatively explained in terms of the orthogonal vector contribution of microscopic eddy currents to losses associated with bulk currents arising in the sample during magnetization.

Research paper thumbnail of Precipitation Behavior and Textural Evolution in Interstitial Free High Strength (IFHS) Steels

Microstructure and Texture in Steels, 2009

Cold rolled and annealed interstitial free high strength (IFHS) steels show various kinds of prec... more Cold rolled and annealed interstitial free high strength (IFHS) steels show various kinds of precipitates. Out of these, FeTiP is the most deleterious, since its formation leads to a loss of strength as well as degradation of the formability of the steel. This effect is much more pronounced in batch annealed IFHS steels than in their continuous annealed counterparts. The

Research paper thumbnail of Precipitation and Texture Formation in Interstitial Free High Strength (IFHS) Steels: A Short Review

Materials Science Forum, 2012

... Ghosh et al 10 have studied the precipitation behavior and texture formation in two IFHS stee... more ... Ghosh et al 10 have studied the precipitation behavior and texture formation in two IFHS steels of almost similar chemistries but processed through different annealing routes; batch annealing (BA) and continuous annealing (CA) (see Table 2). The batch annealed steel shows ...

Research paper thumbnail of Precipitation and texture formation in two cold rolled and batch annealed interstitial-free high strength steels

Scripta Materialia, 2006

ABSTRACT Precipitation and texture formation in two cold rolled and batch-annealed interstitial-f... more ABSTRACT Precipitation and texture formation in two cold rolled and batch-annealed interstitial-free high strength steels have been studied. TiN, Fe(Ti + Nb)P and TiC were the main precipitates observed. A perceptibly higher population of Fe(Ti + Nb)P precipitates in the steel containing a higher amount of P is considered to be primarily responsible for the less intense {1 1 1} texture.

Research paper thumbnail of Effect of crystallographic texture on the bulk magnetic properties of non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2014

Abstract Quantitative physical models for non-oriented electrical steels require precise knowledg... more Abstract Quantitative physical models for non-oriented electrical steels require precise knowledge of chemical and microstructural parameters for the material, with crystallographic texture being one of the most important. Describing the structure–property relationships in these materials is made difficult in that all of the parameters have an effect on magnetic properties. In the present study, a set of non-oriented electrical steel specimens are examined, where chemistry and grain size are kept similar from sample to sample, but texture is varied. A new texture parameter called Magnetic Texture Factor is introduced which is defined as the ratio of the volume fractions of 〈100〉 direction to 〈111〉 direction along magnetization vector. It was found that this Magnetic Texture Factor was a better parameter for identifying trends of magnetic properties with crystallographic texture than the often used Texture Factor , which is described as the ratio of the volume fractions of {100} planes to {111} planes.

Research paper thumbnail of Effect of metallurgical factors on the bulk magnetic properties of non-oriented electrical steels

Journal of Magnetism and Magnetic Materials, 2014