scholarly journals Microstructure and Mechanical Characterization of Austempered AISI 1018 Steel

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Muideen Bodude ◽  
Oluwole D Adigun ◽  
Ahmed Ibrahim
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Impact Energy ◽  
Microstructural Analysis ◽  
Salt Bath ◽  
Isothermal Transformation ◽  
Critical Conditions ◽  
Average Value ◽  
Extreme Load ◽  
Bainite Microstructure

AISI 1018 mild steels are widely used for engineering applications in machine components and for structural purposes. These materials suffer mechanical damages especially when used under critical conditions of extreme load. In this study, the effect of austempering heat-treatment on the hardness, tensile strength, impact energy and the microstructure of AISI 1018 steels were evaluated. The steel specimens were subjected to austempering heat-treatment by austenitizing at a temperature of 830°C, maintained at this temperature for a period of 1 hour 30 minutes, before rapidly cooled down in a NaNO3 salt bath maintained at 300°C for isothermal transformation for a further 50 minutes before finally cooled down to room temperature. Microstructural analysis using Scanning Electron Microscope (SEM) shows transformation from ferrite/pearlite to bainite microstructure. The tensile strengths of the specimen increased from 400 MPa to 500 Mpa; hardness increased from an average value of 140Rc to 162Rc; while impact energy increased from 15.6 Joule to 30.6 Joule by the austempering heat-treatment. Keywords—Austempering, hardness, tensile strength, impact energy, microstructure

scholarly journals Effects of Austempering on the Microstructure, Corrosion and Mechanical Properties of AISI 1018 Steel

2021 ◽  
Author(s):  
Oluwole Daniel Adigun ◽  
Muyideen Adebayo Bodude ◽  
Aanuoluwapo Rebecca Adigun ◽  
Babatunde Abiodun Obadele ◽  
Abdullahi Olawale Adebayo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Energy ◽  
Room Temperature ◽  
Low Carbon Steel ◽  
Salt Bath ◽  
Isothermal Transformation ◽  
Low Carbon ◽  
Micro Hardness ◽  
Microstructural Investigation

Abstract In this study, the effects of austempering on the microstructure, mechanical properties (micro hardness, impact energy and tensile strength) and corrosion behaviours of AISI 1018 low carbon steel were evaluated. The steel specimens were subjected to heat treatment by austenitizing at 830°C, maintained in this condition for 90 min before rapid cooling in a NaNO3 salt bath sustained at 300°C for isothermal transformation for additional 50 min and finally allowed to air cool to room temperature. The as-received and the austempered samples were tested for corrosion in both 0.5M aqueous acidic (HCl) and 0. 5M alkaline (NaOH) media. Microstructural investigation using scanning electron microscope (SEM) reveals transformation from ferrite/pearlite phases to bainite over the austempering process. Interestingly, significant improvements of 15.7% to 95.7% in the various mechanical properties (micro hardness, impact energy and tensile strength) and corrosion resistance in both media were observed.

The Influence of Austenisation Temperature and Holding Time on Mechanical Properties, Scale Thickness, and Microstructure in Alloy Steel

2015 ◽  
Vol 776 ◽  
pp. 239-245
Author(s):  
Abdul Aziz ◽  
Maulud Hidayat ◽  
Indah Hardiyanti
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Alloy Steel ◽  
Impact Energy ◽  
Holding Time ◽  
Micro Structure ◽  
Scale Thickness ◽  
Alloy Steels ◽  
Steel Weight

The application of steel products have been widely used and various research have been developed to find a good and appropriate quality of steel and can be produced in the country without have to be imported, for example alloy steels. One of the alloy steels that have been constantly developed is Ni-Cr-Mo alloy steel with additional nickel, chromium and molybdenum which can increase hardness, tensile strength, ductility and toughness. The effect during the production process is at the heating process that causes the formation of iron oxide layer (scale) and the loss of steel weight. Therefore, the selection of heat treatment methods and techniques are required to increase the mechanical properties of steel, such as hardness, tensile strength, and toughness, with the scale is about <5% of steel weight. In this research, the heat treatment was carried out at austenisation temperature of 800°, 850°, 900°C and at holding time of 20, 40, 60 minutes, then followed by a rapid cooling (quenching) to improve the mechanical properties of hardness. This research also tested the mechanical properties of steel that consist of hardness test and impact test, and metallographic observation that consist of micro structure observation and scale thickness observation. The micro structure from heat treatment process is martensite, it is due to a rapid cooling (quenching) that rapidly change the austenite phase into martensite. The data showed the highest hardness is 588.35 HVN at 850°C of temperature and 60 minutes of holding time, 8.5 Joules of impact energy, and 91.5 μm of scale thickness. While the lowest hardness is 539.34 HVN at 800°C of temperature, 5 Joules of impact energy, and 47.81 μm of scale thickness.

scholarly journals Impact of Molybdenum on Heat-Treatment and Microstructure of ADI

2018 ◽  
Vol 925 ◽  
pp. 188-195 ◽  
Author(s):  
Julius Alexander Gogolin ◽  
Babette Tonn
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Transition Point ◽  
Outer Part ◽  
Isothermal Transformation ◽  
Mechanical Tests ◽  
High Tensile Strength ◽  
Manufacturing Costs ◽  
Nickel Copper ◽  
Quenching Process

Austempered Ductile Iron (ADI) is characterized by high tensile strength with acceptable ductility. Steel, as a large competitor to ADI, also meets the tensile and yield strength. Nevertheless, the main advantages of ADI compared to steel are the lower density (7.2 g/cm3 to 7.85 7.87 g/cm3) for weight reduction and lower manufacturing costs because of less energy consumption during the production. One of the main problems of producing ADI is the quenching process during heat treatment of thick-walled castings. The inner part of a massive casting – in contrast to the outer part – cools down more slowly, resulting in a heterogeneous microstructure with parts of pearlite and ferrite embedded in austenite before reaching the isothermal transformation temperature. Molybdenum is, besides nickel, copper and manganese, one of the possible alloying elements that postpone the transition point of ferrite and/or pearlite. To investigate the influence of molybdenum in thick-walled castings experiments with different molybdenum contents were performed. In dependence on the molybdenum content, different austenisation and ausferritisation temperatures and times are examined in order to investigate the transformation points, fraction and morphology of different phases. The mechanism of molybdenum in ADI has been investigated by means of dilatometer tests, microstructure analysis and mechanical tests.

scholarly journals Estimation of Austenitizing and Multiple Tempering Temperatures from the Mechanical Properties of AISI 410 using Artificial Neural Network

2018 ◽  
Vol 7 (4.19) ◽  
pp. 778
Author(s):  
Abdul Kareem F. Hassan ◽  
Qahtan A. Jawad
Keyword(s):  
Neural Network ◽  
Mechanical Properties ◽  
Heat Treatment ◽  
Artificial Neural Network ◽  
Tensile Strength ◽  
Regression Analysis ◽  
Impact Energy ◽  
Ann Model ◽  
Artificial Neural ◽  
Quenching And Tempering

This research involved a study of the heat treatment conditions effect on the mechanical properties of martensitic stainless steel type AISI 410. Heat treatment process was hardening of the metal by quenching at different temperature 900°C, 950°C, 1000°C, 1050°C and 1100°C, followed by double tempering at 200°C, 250°C, 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C and 700°C, were evaluated and study of some mechanical properties such as hardness, impact energy and properties of tensile test such as yield and tensile strength is carried out. Multiple outputs Artificial Neural Network model was built with a Matlab package to predict the quenching and tempering temperatures. Also, linear and nonlinear regression analyses (using Data fit package) were used to estimate the mathematical relationship between quenching and tempering temperatures with hardness, impact energy, yield, and tensile strength. A comparison between experimental, regression analysis and ANN model show that the multiple outputs ANN model is more accurate and closer to the experimental results than the regression analysis results. 

Tensile Strength Properties of Niobium Alloyed Austempered Ductile Iron on Different Austempering Time

2012 ◽  
Vol 457-458 ◽  
pp. 1155-1158 ◽  
Author(s):  
Bulan Abdullah ◽  
Siti Khadijah Alias ◽  
A. Jaffar ◽  
Abd Amirul Rashid ◽  
M. Haskil ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Ductile Iron ◽  
Salt Bath ◽  
Strength Properties ◽  
Austempered Ductile Iron ◽  
Bath Furnace

This study focused on tensile strength properties inclusive of ultimate tensile strength and elongation values of niobium alloyed ductile iron in as cast and austempered conditions. The tensile specimens were machined according to TS 138 EN 10002-1 standard. Austempering heat treatment was conducted by first undergoing austenitizing process at 900°C before rapidly quenched in salt bath furnace and held at 350°C for 1 hour, 2 hours and 3 hours subsequently. The findings indicated that austempering the samples for 1 hour had resulted in improvement of almost twice of the tensile strength in niobium alloyed ductile iron. Improvement of elongations values were also noted after 1 hour austempering times. Increasing the austempering holding times to 2 hour and 3 hours had resulted in decrement in both tensile strength and elongations values.

scholarly journals Analysis of Tensile Strength, Hardness and Impact Energy of SAE1040 Steel Using Heat Treatment Processes

2020 ◽  
Vol 18 (02) ◽  
pp. 33-37
Author(s):  
Qadir Bakhsh Jamali ◽  
Muswar Ali Farhad Siyal ◽  
Abdul Sattar Jamali ◽  
Muhammad Sharif Jamali ◽  
Arshad Hussain ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Yield Strength ◽  
Young’S Modulus ◽  
Impact Energy ◽  
Breaking Strength ◽  
Young's Modulus ◽  
Medium Carbon Steel ◽  
Treatment Processes

A systematic study was carried out to improve the mechanical properties of medium carbon steel grade SAE 1040 by heat treatment processes. Test specimen were prepared according to ASTM standards. Test specimen were heat treated in Gas furnace at austenitization temperature of 700C to obtain fully austenite structure, soaked for 90 minutes, cooled in air and furnace, and quenched in water separately. Mechanical properties such as hardness, tensile strength, yield strength, breaking strength, Young’s Modulus, elongation and impact energy were investigated in this study. It was observed that water quenching enhances materials’ hardness, tensile strength, yield strength, breaking strength and Young’s Modulus while reducing the elongation and impact energy as compared with untreated specimen. Furnace cooling decreases materials’ hardness, tensile strength, yield strength, breaking strength, Young’s Modulus while increasing the elongation and impact energy as compared with untreated specimen. Air cooling improved the materials’ mechanical properties such as hardness, tensile strength, yield strength, breaking strength, Young’s Modulus, elongation and impact energy as compared with untreated specimen. The results of this study show that the heat treatment technique greatly influences the mechanical properties of medium carbon steel grade SAE 1040.

scholarly journals Effects of Magnesium Variation and Heat Treatment on Mechanical and Micro-Structural Properties of Ductile Cast Iron

2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Abdullahi O Adebayo ◽  
Gabriel L Taiwo ◽  
Akinlabi Oyetunji
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Structural Properties ◽  
Mechanical Test ◽  
Rotary Furnace ◽  
Salt Bath ◽  
Mechanical Tests ◽  
Ductile Cast Iron ◽  
Relative Reduction ◽  
Two Samples

The effects of magnesium variation and austempering heat treatment on mechanical and microstructural properties of ductile iron produced using the rotary furnace were investigated. Varied quantity of magnesium-ferrosilicon in the range of 0.03 % to 0.06 % were used as nodulirizer to treat 4 kg mass of molten metal per ladle by sandwich process and poured into sand mould.  Mechanical test (tensile, hardness, fatigue, impact and wear) and micro-structural examinations were carried out on the four samples produced. Samples C and D of 0.056% and 0.061% magnesium showed an improvement in their micro-structural properties due to the presence of more graphite nodules. Hence, they were observed to have exhibited better tensile strength of 598.07MPa and 609.03MPa. The fatigue strength also increased to 501.91MPa and 509.27MPa respectively. These two samples were further subjected to austempering heat treatment by heating to 850ºC for austenitization and soaked for homogenization for one hour at the temperature before quickly transferred into a salt bath of 50 % NaNO3 : 50 % NaCl maintained at 3600C and quenched for transformation for 1 hour before finally air cooled. Mechanical tests and micro-structural examinations were thereafter carried out. Sample C had an outstanding increase in tensile strength, from 598.07MPa to 891.22MPa, while specimen D increased from 609.03MPa to 898.76MPa. The results of abrasion test indicated that samples C and D had abrasion resistance increase from 2.20×10¹¹m² and 2.39×10¹¹m² to 2.35×10¹¹m² and 2.68×10¹¹ m² respectively after austempering. There were also relative increase in fatigue resistance and impact toughness for the two samples but with relative reduction in hardness from 47.7 to 44.2 and 50.3 to 47.4.

The Effect of Intermediate Annealing Condition on Recrystallization Behavior in Continuous Cast Al-Mn Alloy

2014 ◽  
Vol 794-796 ◽  
pp. 1251-1256
Author(s):  
Kenta Suzuki ◽  
Tomohiro Sasaki ◽  
Toshiya Anami
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Tensile Strength ◽  
Rapid Heating ◽  
Salt Bath ◽  
Grain Structure ◽  
Annealing Condition ◽  
Recrystallization Behavior ◽  
Intermediate Annealing ◽  
Continuous Cast

Favorable features such as finer particles and supersaturated solid solution are characterized in continuous casting. In this study, difference of recrystallization behavior was mainly evaluated on two intermediate annealing conditions in continuous cast Al-Mn alloy. One annealing condition was air furnace annealing which corresponds to batch type annealing and is conventionally used to anneal aluminum alloys. Another one was salt bath annealing which simulates CAL type annealing, which is characterized by shorter holding time with rapid heating and cooling. With consideration for application to fin stock in heat exchanger, heat treatment simulating brazing at 600°C was carried out on cold rolled sheets after respective intermediate annealing. After the brazing heat treatment, superior tensile strength and coarser grain structure were attractively obtained with the salt bath intermediate annealed fin. This tensile strength was correlated with much finer particles and more solid solution confirmed after the salt bath intermediate annealing. The coarser grain structure would be brought by changing in recovery and recrystallization behavior during brazing heat treatment.

The Effects of Ni Content and Intermediate Annealing Condition on Recrystallization of Al-Fe-Ni-Si Alloy Fin Stocks

2016 ◽  
Vol 877 ◽  
pp. 166-171
Author(s):  
Kenta Suzuki ◽  
Daisuke Shimosaka ◽  
Tomohiro Sasaki ◽  
Yasuyuki Owada ◽  
Shuhei Kuroiwa ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Heat Exchangers ◽  
Microstructural Analysis ◽  
Salt Bath ◽  
Grain Structure ◽  
Recrystallization Behavior ◽  
Intermediate Annealing ◽  
Annealing Conditions ◽  
Ni Content ◽  
Low Density Area

The effects of Ni content and intermediate annealing conditions on recrystallization behavior during brazing heat treatment of Al–Fe–Ni–Si alloys fin stocks of automotive heat exchangers were studied by means of microstructural analysis. Following brazing heat treatment, coarsening of recrystallized grain structure was observed in both 0.5% Ni and 1.0% Ni fin stocks, which were intermediately annealed in a salt bath. This coarsening was particularly marked in 1.0% Ni fin stocks. The results of the microstructural observations indicated that fine dispersoids were heterogeneously dispersed in 1.0% Ni fin stocks that were annealed at 550°C for 10 s in a salt bath. It was proposed that the preferential recovery and recrystallization during the brazing heat treatment in the low density area of the fine dispersoids contributed to the larger recrystallized gain structure. The coarse recrystallized grains obtained by controlling the salt bath annealing conditions are expected to contribute in improving the properties of Al–Fe–Ni–Si alloy fin stocks of automotive heat exchangers.

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