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Papers by Mayur Pratap Singh

World Journal of Engineering, 2019

Purpose AA2014 is a copper-based alloy and is typically used for production of complex machined c... more Purpose AA2014 is a copper-based alloy and is typically used for production of complex machined components, given its better machinability. The purpose of this paper was to study the effects of variation in weight percentage of ceramic Al2O3 particulates during electrical discharge machining (EDM) of stir cast AA2014 composites. Scanning electron microscopy (SEM) examination was carried out to study characteristics of EDMed surface of Al2O3/AA2014 composites. Design/methodology/approach The effect of machining parameters on performance measures during sinker EDM of stir cast Al2O3/AA2014 composites was examined by “one factor at a time” (OFAT) method. The stir cast samples were obtained by using three levels of weight percentage of Al2O3 particulates, i.e. 0 Wt.%, 10 Wt.% and 20 Wt.% with density 1.87 g/cc, 2.35 g/cc and 2.98 g/cc respectively. Machining parameters varied were peak current (1-30 amp), discharge voltage (30-100 V), pulse on time (15-300 µs) and pulse off time (15-450...

International Journal of Structural Integrity, 2020

PurposeThe key purpose of conducting this review is to identify the issues that affect the struct... more PurposeThe key purpose of conducting this review is to identify the issues that affect the structural integrity of pipeline structures. Heat affected zone (HAZ) has been identified as the weak zone in pipeline welds which is prone to have immature failuresDesign/methodology/approachIn the present work, literature review is conducted on key issues related to the structural integrity of pipeline steel welds. Mechanical and microstructural transformations that take place during welding have been systematically reviewed in the present review paper.FindingsKey findings of the present review underline the role of brittle microstructure phases, and hard secondary particles present in the matrix are responsible for intergranular and intragranular cracks.Research limitations/implicationsThe research limitations of the present review are new material characterization techniques that are not available in developing countries.Practical implicationsThe practical limitations are new test methodol...

Fatigue & Fracture of Engineering Materials & Structures, 2020

In this paper, microstructure observations and mechanical behaviour of fusion line and offsetting... more In this paper, microstructure observations and mechanical behaviour of fusion line and offsetting positions from fusion line by 1, 2 and 3 mm were analysed. For the welding of X80 pipeline steel plates, different magnitudes of heat inputs such as high heat input (HHI) 25 kJ/cm, medium heat input (MHI) 20 kJ/cm and low heat input (LHI) 15 kJ/cm were employed. Critical values of J-integral (J 0.2) and crack tip opening displacement (CTOD 0.2) for predetermined regions in the X80 weldment were determined as per ASTM-E1820a. M-A constituents of different sizes such as small (1-2 μm), large >2 μm and slender (>4 μm) were observed in the microstructure of subzones of weldments for different heat inputs. Formation of granular bainite, M-A constituents and inclusions of Ti, Si, Mo in the microstructure impaired fracture toughness property. In the X80 weldment, the fusion line (FL) for HHI was found weakest in terms of fracture resistance, which subsequently increases the risk of fracture.

Journal of Thermal Analysis and Calorimetry, 2019

Continuous cooling transformation diagrams were obtained for a simulated coarse-grain heat-affect... more Continuous cooling transformation diagrams were obtained for a simulated coarse-grain heat-affected zone of API X-80 and X-65 steels using Gleeble-3800 thermo-mechanical simulator. Dilatometry results showed that variable cooling rates have significant effect on phase transformation behaviour and microstructure of the steels. For X-80 steel, a mixture of bainite/martensite at fast and medium cooling rates and ferrite/pearlite at slow cooling rates was obtained and confirmed by microhardness measurements between 340 and 240 HV, whereas, for X-65 steel soft phase such as ferrite was nucleated along with bainite at moderate (15-100°C s-1) and pearlite at slow cooling rates (3-10°C s-1). Dilatometry curve comprises inherent noise, and Loess computational filter was used to filter background noise in the curves. Martensite/ bainite and ferrite/pearlite coexisted for most cooling rates, which made it difficult to distinguish transformation kinetics of individual phases. In the first derivative analysis d/dT {(DL/L o)} of dilatometry curves, peaks of individual phases were clearly observed. Peaks of individual phase were separated according to their transformation temperature range, and peak rate temperatures were determined. It was confirmed that the first derivative d/dT {(DL/L o)} analysis described phase transformation behaviour precisely and aided in identification of the transformed phases.

Materials Research Express, 2018

In the present work, phase transformation behavior and structure-property correlation in X-80 ste... more In the present work, phase transformation behavior and structure-property correlation in X-80 steel was analyzed at three distinct austenitizing peak temperatures (1250 °C, 1030 °C and 950 °C). Dilation studies and simulations of Charpy size samples were carried out using Gleeble 3800 thermal simulator. Dilation studies indicated that the dissolution of Nb rich carbides occurred at 1020 °C. During cooling from 1250 °C, mixed microstructure of bainitic ferrite and martensite formed at fast (200 °C s−1 −80 °C s−1) and medium (50 °C s−1–40 °C s−1) cooling rates. For slow cooling rates (20 °C s−1–0.5 °C s−1), ferrite/pearlite microstructure was obtained. For lower peak temperatures 1030 °C and 950 °C, mixed microstructure of bainitic ferrite and martensite was observed for fast cooling rates. Whereas, ferrite/pearlite with small fraction of bainitic ferrite nucleated in the microstructure at medium and slow cooling rates. Highest area fraction of M-A (8%) was observed at medium cooling rates (50 °C s−1–40 °C s−1) for 1250 °C peak temperature. Charpy size samples simulated for a 1250 °C peak temperature, exhibited the minimum notch toughness at 12.5 °C s−1, due to deleterious effect of granular bainite and M-A constituents. Simulated samples at lower peak temperatures 1030 °C and 950 °C exhibited higher notch toughness due to a mixed microstructure of bainitic ferrite and ferrite-pearlite.

Transactions of the Indian Institute of Metals, 2022

In this investigation, numerical analysis of square butt, butt with V-groove and T-weld joint con... more In this investigation, numerical analysis of square butt, butt with V-groove and T-weld joint configurations have been performed to estimate transient temperature distributions and residual stresses. A computational welding simulation based on a prescribed temperature approach was used that works on thermal load input derived from temperature analysis. In the thermal analysis, welding heat source or torch temperature was considered as the prescribed value of temperature, which helps in simulating real welding conditions. The inclusion of filler metal in the numerical analysis replicates the real welding phenomenon, which provides temperature distribution along the true distance of the joints. The maximum temperature was observed at the weld pool area and decreased in parabolic shape toward the base metal. Residual stresses were measured along the selected path (in the mid of plates) that comprises node-to-node variation of stresses in both longitudinal and transverse directions. von Mises and Tresca stress criterion was adopted to show accumulated stresses in the weld joints. It was observed that stresses accumulated in the different configurations of weld joints were below the yield strength 210 MPa of SUS304 steel. Peak values of stresses were observed at weld beads and in the nearby regions.

World Journal of Engineering, 2019

Purpose AA2014 is a copper-based alloy and is typically used for production of complex machined c... more Purpose AA2014 is a copper-based alloy and is typically used for production of complex machined components, given its better machinability. The purpose of this paper was to study the effects of variation in weight percentage of ceramic Al2O3 particulates during electrical discharge machining (EDM) of stir cast AA2014 composites. Scanning electron microscopy (SEM) examination was carried out to study characteristics of EDMed surface of Al2O3/AA2014 composites. Design/methodology/approach The effect of machining parameters on performance measures during sinker EDM of stir cast Al2O3/AA2014 composites was examined by “one factor at a time” (OFAT) method. The stir cast samples were obtained by using three levels of weight percentage of Al2O3 particulates, i.e. 0 Wt.%, 10 Wt.% and 20 Wt.% with density 1.87 g/cc, 2.35 g/cc and 2.98 g/cc respectively. Machining parameters varied were peak current (1-30 amp), discharge voltage (30-100 V), pulse on time (15-300 µs) and pulse off time (15-450...

International Journal of Structural Integrity, 2020

PurposeThe key purpose of conducting this review is to identify the issues that affect the struct... more PurposeThe key purpose of conducting this review is to identify the issues that affect the structural integrity of pipeline structures. Heat affected zone (HAZ) has been identified as the weak zone in pipeline welds which is prone to have immature failuresDesign/methodology/approachIn the present work, literature review is conducted on key issues related to the structural integrity of pipeline steel welds. Mechanical and microstructural transformations that take place during welding have been systematically reviewed in the present review paper.FindingsKey findings of the present review underline the role of brittle microstructure phases, and hard secondary particles present in the matrix are responsible for intergranular and intragranular cracks.Research limitations/implicationsThe research limitations of the present review are new material characterization techniques that are not available in developing countries.Practical implicationsThe practical limitations are new test methodol...

Fatigue & Fracture of Engineering Materials & Structures, 2020

In this paper, microstructure observations and mechanical behaviour of fusion line and offsetting... more In this paper, microstructure observations and mechanical behaviour of fusion line and offsetting positions from fusion line by 1, 2 and 3 mm were analysed. For the welding of X80 pipeline steel plates, different magnitudes of heat inputs such as high heat input (HHI) 25 kJ/cm, medium heat input (MHI) 20 kJ/cm and low heat input (LHI) 15 kJ/cm were employed. Critical values of J-integral (J 0.2) and crack tip opening displacement (CTOD 0.2) for predetermined regions in the X80 weldment were determined as per ASTM-E1820a. M-A constituents of different sizes such as small (1-2 μm), large >2 μm and slender (>4 μm) were observed in the microstructure of subzones of weldments for different heat inputs. Formation of granular bainite, M-A constituents and inclusions of Ti, Si, Mo in the microstructure impaired fracture toughness property. In the X80 weldment, the fusion line (FL) for HHI was found weakest in terms of fracture resistance, which subsequently increases the risk of fracture.

Journal of Thermal Analysis and Calorimetry, 2019

Continuous cooling transformation diagrams were obtained for a simulated coarse-grain heat-affect... more Continuous cooling transformation diagrams were obtained for a simulated coarse-grain heat-affected zone of API X-80 and X-65 steels using Gleeble-3800 thermo-mechanical simulator. Dilatometry results showed that variable cooling rates have significant effect on phase transformation behaviour and microstructure of the steels. For X-80 steel, a mixture of bainite/martensite at fast and medium cooling rates and ferrite/pearlite at slow cooling rates was obtained and confirmed by microhardness measurements between 340 and 240 HV, whereas, for X-65 steel soft phase such as ferrite was nucleated along with bainite at moderate (15-100°C s-1) and pearlite at slow cooling rates (3-10°C s-1). Dilatometry curve comprises inherent noise, and Loess computational filter was used to filter background noise in the curves. Martensite/ bainite and ferrite/pearlite coexisted for most cooling rates, which made it difficult to distinguish transformation kinetics of individual phases. In the first derivative analysis d/dT {(DL/L o)} of dilatometry curves, peaks of individual phases were clearly observed. Peaks of individual phase were separated according to their transformation temperature range, and peak rate temperatures were determined. It was confirmed that the first derivative d/dT {(DL/L o)} analysis described phase transformation behaviour precisely and aided in identification of the transformed phases.

Materials Research Express, 2018

In the present work, phase transformation behavior and structure-property correlation in X-80 ste... more In the present work, phase transformation behavior and structure-property correlation in X-80 steel was analyzed at three distinct austenitizing peak temperatures (1250 °C, 1030 °C and 950 °C). Dilation studies and simulations of Charpy size samples were carried out using Gleeble 3800 thermal simulator. Dilation studies indicated that the dissolution of Nb rich carbides occurred at 1020 °C. During cooling from 1250 °C, mixed microstructure of bainitic ferrite and martensite formed at fast (200 °C s−1 −80 °C s−1) and medium (50 °C s−1–40 °C s−1) cooling rates. For slow cooling rates (20 °C s−1–0.5 °C s−1), ferrite/pearlite microstructure was obtained. For lower peak temperatures 1030 °C and 950 °C, mixed microstructure of bainitic ferrite and martensite was observed for fast cooling rates. Whereas, ferrite/pearlite with small fraction of bainitic ferrite nucleated in the microstructure at medium and slow cooling rates. Highest area fraction of M-A (8%) was observed at medium cooling rates (50 °C s−1–40 °C s−1) for 1250 °C peak temperature. Charpy size samples simulated for a 1250 °C peak temperature, exhibited the minimum notch toughness at 12.5 °C s−1, due to deleterious effect of granular bainite and M-A constituents. Simulated samples at lower peak temperatures 1030 °C and 950 °C exhibited higher notch toughness due to a mixed microstructure of bainitic ferrite and ferrite-pearlite.

Transactions of the Indian Institute of Metals, 2022

In this investigation, numerical analysis of square butt, butt with V-groove and T-weld joint con... more In this investigation, numerical analysis of square butt, butt with V-groove and T-weld joint configurations have been performed to estimate transient temperature distributions and residual stresses. A computational welding simulation based on a prescribed temperature approach was used that works on thermal load input derived from temperature analysis. In the thermal analysis, welding heat source or torch temperature was considered as the prescribed value of temperature, which helps in simulating real welding conditions. The inclusion of filler metal in the numerical analysis replicates the real welding phenomenon, which provides temperature distribution along the true distance of the joints. The maximum temperature was observed at the weld pool area and decreased in parabolic shape toward the base metal. Residual stresses were measured along the selected path (in the mid of plates) that comprises node-to-node variation of stresses in both longitudinal and transverse directions. von Mises and Tresca stress criterion was adopted to show accumulated stresses in the weld joints. It was observed that stresses accumulated in the different configurations of weld joints were below the yield strength 210 MPa of SUS304 steel. Peak values of stresses were observed at weld beads and in the nearby regions.