Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels
Steel is a versatile metal, got a wide range of applications in all the fields of engineering and technology. Generally, low carbon steels are tough and high alloy carbon steels are hard in nature. Certain applications demand both properties in the same steel. Carburization is one such technique tha...
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AIMS Press
2021-11-01
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| Online Access: | https://www.aimspress.com/article/doi/10.3934/matersci.2021051?viewType=HTML |
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| author | Pavan Hiremath Gowrishankar M. C. Manjunath Shettar Sathyashankara Sharma Jayashree P. K. Suhas Kowshik |
| author_facet | Pavan Hiremath Gowrishankar M. C. Manjunath Shettar Sathyashankara Sharma Jayashree P. K. Suhas Kowshik |
| author_sort | Pavan Hiremath |
| collection | DOAJ |
| description | Steel is a versatile metal, got a wide range of applications in all the fields of engineering and technology. Generally, low carbon steels are tough and high alloy carbon steels are hard in nature. Certain applications demand both properties in the same steel. Carburization is one such technique that develops hard and wear resistant surfaces with a soft core. The objective of this work is to study the influence of post carburizing treatment (normalizing) on three grades of steels (EN 3, 20MnCr5, and EN 353). Post carburizing treatments are necessary to overcome the adverse effects of carburization alone. Here carburization was carried out in the propane atmosphere by heating the gas carburizing furnace to 930 ℃ for more than a day. Normalizing was carried out at 870 ℃ for 1 h and cooled in air. Tensile, hardness, Charpy impact tests along with SEM (scanning electron microscopy) and EDAX (energy dispersive X-ray analysis) were conducted to analyze the phase transformation, failure mode analysis in all the samples. Carburized steels displayed the formation of ferrite, pearlite, and sometimes bainite phases in the core and complete coarse pearlite in the case regions, whereas in the post carburized steels, increased amount of ferrite, fine pearlite, and bainite in the core and fine pearlite with traces of bainite in the case region was observed. Normalizing also refines the grain with increased UTS (ultimate tensile strength), hardness, and impact resistance. EN 353 showed higher UTS among the steels with 898 MPa after carburization and 1370 MPa after normalizing treatment. Maximum hardness of 48 HRC was observed in 20MnCr5 and toughness was superior in EN 3 with energy absorbed during test i.e., 8 and 12 J before and after normalizing treatment. Based on the fracture surface analysis, in EN 353 steel, a finer array of dimples with voids and elongated bigger clustered dimples containing ultrafine dimples array are observed in the core and case respectively during carburizing whereas, more density of river pattern and cleavage failure (brittle) are observed in the core and case respectively after post carburizing (normalizing) treatment. There is a reduction in the ductility of the steels after post carburizing treatment. It was observed that normalizing treatment produces superior mechanical properties in the carburized steels by grain refinement and strong microstructures like bainite. Normalizing as post carburizing treatment can be recommended for engineering applications where ductile core and hard surface are of great importance. |
| first_indexed | 2024-12-24T01:23:53Z |
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| spelling | doaj.art-7cf63f878db1483eb041778373a94ca82022-12-21T17:22:34ZengAIMS PressAIMS Materials Science2372-04842021-11-018583685110.3934/matersci.2021051Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steelsPavan Hiremath0Gowrishankar M. C. 1Manjunath Shettar2Sathyashankara Sharma3Jayashree P. K.4Suhas Kowshik5Department of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, IndiaDepartment of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, IndiaDepartment of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, IndiaDepartment of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, IndiaDepartment of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, IndiaDepartment of Mechanical and Manufacturing Engineering, Manipal Institute of Technology, Manipal Academy of Higher Education, Manipal, Karnataka, IndiaSteel is a versatile metal, got a wide range of applications in all the fields of engineering and technology. Generally, low carbon steels are tough and high alloy carbon steels are hard in nature. Certain applications demand both properties in the same steel. Carburization is one such technique that develops hard and wear resistant surfaces with a soft core. The objective of this work is to study the influence of post carburizing treatment (normalizing) on three grades of steels (EN 3, 20MnCr5, and EN 353). Post carburizing treatments are necessary to overcome the adverse effects of carburization alone. Here carburization was carried out in the propane atmosphere by heating the gas carburizing furnace to 930 ℃ for more than a day. Normalizing was carried out at 870 ℃ for 1 h and cooled in air. Tensile, hardness, Charpy impact tests along with SEM (scanning electron microscopy) and EDAX (energy dispersive X-ray analysis) were conducted to analyze the phase transformation, failure mode analysis in all the samples. Carburized steels displayed the formation of ferrite, pearlite, and sometimes bainite phases in the core and complete coarse pearlite in the case regions, whereas in the post carburized steels, increased amount of ferrite, fine pearlite, and bainite in the core and fine pearlite with traces of bainite in the case region was observed. Normalizing also refines the grain with increased UTS (ultimate tensile strength), hardness, and impact resistance. EN 353 showed higher UTS among the steels with 898 MPa after carburization and 1370 MPa after normalizing treatment. Maximum hardness of 48 HRC was observed in 20MnCr5 and toughness was superior in EN 3 with energy absorbed during test i.e., 8 and 12 J before and after normalizing treatment. Based on the fracture surface analysis, in EN 353 steel, a finer array of dimples with voids and elongated bigger clustered dimples containing ultrafine dimples array are observed in the core and case respectively during carburizing whereas, more density of river pattern and cleavage failure (brittle) are observed in the core and case respectively after post carburizing (normalizing) treatment. There is a reduction in the ductility of the steels after post carburizing treatment. It was observed that normalizing treatment produces superior mechanical properties in the carburized steels by grain refinement and strong microstructures like bainite. Normalizing as post carburizing treatment can be recommended for engineering applications where ductile core and hard surface are of great importance.https://www.aimspress.com/article/doi/10.3934/matersci.2021051?viewType=HTMLcarburizationnormalizing treatmentpearliteinterlamellar distancebainite |
| spellingShingle | Pavan Hiremath Gowrishankar M. C. Manjunath Shettar Sathyashankara Sharma Jayashree P. K. Suhas Kowshik Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels AIMS Materials Science carburization normalizing treatment pearlite interlamellar distance bainite |
| title | Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels |
| title_full | Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels |
| title_fullStr | Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels |
| title_full_unstemmed | Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels |
| title_short | Influence of normalizing post carburizing treatment on microstructure, mechanical properties and fracture behavior of low alloy gear steels |
| title_sort | influence of normalizing post carburizing treatment on microstructure mechanical properties and fracture behavior of low alloy gear steels |
| topic | carburization normalizing treatment pearlite interlamellar distance bainite |
| url | https://www.aimspress.com/article/doi/10.3934/matersci.2021051?viewType=HTML |
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