scholarly journals Influence of the Salt Bath Agitation and Austempering Temperature on the Microstructure of Austempered Ductile Iron

2017 ◽  
Author(s):  
Nikša Čatipović ◽  
Dražen Živković ◽  
Zvonimir Dadić ◽  
Marin Viceić
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Ductile Iron ◽  
Salt Bath ◽  
Austempered Ductile Iron ◽  
Toughness Test ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated ◽  
Final Microstructure ◽  
Austempering Temperature

In this paper the influence of austempering temperature and salt bath agitation on the final microstructure and mechanical properties of the ferritic ductile iron were studied. 17 samples had been subjected to different heat treatment parameters. Different microstructures were recorded upon the completion of the tests. From the obtained micro images, it is obvious that both the austempering temperature and salt bath agitation affect the final microstructure of the austempered ductile iron. Lower austempering temperatures and salt bath agitation produce more ausferrite in the microstructure, hence the harder and tougher phases are present. This was confirmed with hardness and toughness test of the 17 heat-treated samples. Lower austempering temperatures give more ausferrite phase and therefore higher hardness, but hardness decreases with increasing austempering temperatures. Toughness rises with rising austempering temperatures, but drops significantly with temperatures above 395°C because of the final microstructure.

scholarly journals INFLUENCE OF AUSTEMPERING TIME AND AUSTEMPERING TEMPERATURE IN MICROSTRUCTURE AND MECHANICAL PROPERTIES IN AUSTEMPERED DUCTILE IRON

2020 ◽  
Vol 8 (6) ◽  
pp. 51-62
Author(s):  
Giulliana Victória Tissi ◽  
Gláucio Soares Da Fonseca
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Ductile Iron ◽  
Retained Austenite ◽  
Microstructural Analysis ◽  
Austempered Ductile Iron ◽  
Microstructure And Mechanical Properties ◽  
Different Temperatures ◽  
Austempering Temperature ◽  
Microscopic Techniques

Austempered Ductile Iron (ADI) has excellent mechanical properties related to its microstructure ausferrite, and with the cycle of austempering heat treatment, many mechanical properties can be obtained from the same alloy, simply changing the time and temperature. To evaluate the influence of austempering time and temperature on the ADI, analyzed the modifications in the microstructures and mechanical properties of the samples of ductile iron, subjected to austempering heat treatment with austenitizing time and temperature of 910 °C and 90 minutes and during the austempering bath, the samples were submitted to different temperatures, 300, 320, 340, 360 e 380 °C, and for four different times for each temperature, 75, 110, 145 and 180 minutes. For the microstructural analysis, the microscopic techniques were used: optical and scanning electron and mechanical properties were obtained by mechanical testing of hardness and impact. The results show that there is a relationship between austempering temperature with microstructure and mechanical properties. The highest retained austenite and energy absorbed were 25.73% and 130 J, respectively, for the austempered sample at 380 °C and 180 minutes and the highest hardness value was 458 HB for the austempered sample at 300 °C and 75 minutes.  

Effect of Chills on the Microstructure and Mechanical Properties of Carbidic Austempered Ductile Iron

2014 ◽  
Vol 592-594 ◽  
pp. 192-196
Author(s):  
R. Prem Kumar ◽  
S.S. Mohamed Nazirudeen ◽  
J. Anburaj
Keyword(s):  
Mechanical Properties ◽  
Ductile Iron ◽  
Salt Bath ◽  
Optical Microscope ◽  
Austempered Ductile Iron ◽  
The Third ◽  
Microstructure And Mechanical Properties ◽  
Three Samples ◽  
Recent Addition ◽  
Bath Furnace

Carbidic Austempered Ductile Iron (CADI) is a recent addition to the Austempered Ductile Iron (ADI) family. The effect of chills on the microstructure and mechanical properties of CADI was investigated after Austempering. Three samples of chromium alloyed CADI, the first sample without chill, the second sample with bottom chill and the third sample with bottom and side chills were produced in order to evaluate the effect of chills on its mechanical properties. The samples were austenised for 2 hours at 925° C and then austempered at 325° C for 2 hours in a salt bath furnace. The microstructural features of the as-cast and the austempered CADI samples were analysed using Optical Microscope and Scanning Electron Microscope (SEM). The mechanical properties of the CADI samples (as-cast and austempered) were evaluated for hardness, impact and wear. By austempering at 325° C for 2 hours a typical microstructure of bainite was produced in all the three samples. Hardness and wear resistance of austempered samples produced using bottom and side chills were considerably higher than the corresponding values in samples produced without using any chill and also by using only bottom chill. This enhanced mechanical property in the bottom and side chill sample is attributed to the presence of bainite, carbides and more of uniform fine graphite nodules.

scholarly journals Machinability and related properties of austempered ductile iron: A review

2018 ◽  
Vol 12 (4) ◽  
pp. 4180-4190
Author(s):  
Ananda Hegde ◽  
Sathyashankara Sharma ◽  
Gowri Shankar M. C
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Ductile Iron ◽  
High Hardness ◽  
Austempered Ductile Iron ◽  
Spheroidal Graphite ◽  
Light Weight ◽  
Sg Iron

When the ductile iron which is also known as Spheroidal Graphite (SG) iron, is subjected to austempering heat treatment, the material is known as austempered ductile iron (ADI). This material has good mechanical properties and has various applications in different fields. This revolutionary material with its excellent combination of strength, ductility, toughness and wear resistance has the potential to replace some of the commonly used conventional materials such as steel, aluminium and other light weight alloys as it offers production advantage as well. One of the problems encountered during manufacturing is machining of ADI parts owing to its high hardness and wear resistance. Many researchers over a period of time have reported the machinability aspects of the ADI. This paper presents a review on the developments made on the machinability aspects of ADI along with other mechanical properties.

Effect of post-heat treatment cooling on microstructure and mechanical properties of selective laser melting manufactured austenitic 316L stainless steel

2020 ◽  
Vol 26 (10) ◽  
pp. 1739-1749
Author(s):  
Saad Waqar ◽  
Jiangwei Liu ◽  
Qidong Sun ◽  
Kai Guo ◽  
Jie Sun
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
316L Stainless Steel ◽  
Laser Melting ◽  
Content Type ◽  
Post Annealing ◽  
Cooling Conditions ◽  
Microstructure And Mechanical Properties ◽  
Heat Treated

Purpose This paper aims to investigate the influence of different post-annealing cooling conditions, i.e. furnace cooling (heat treatment (HT) 1 – slow cooling) and air cooling (HT 2 – fast cooling), on the microstructure and mechanical properties of selective laser melting (SLM) built austenitic 316L stainless steel (SS). Design/methodology/approach Three sets of 316L SS samples were fabricated using a machine standard scanning strategy. Each set consists of three tensile samples and a cubic sample for microstructural investigations. Two sets were subsequently subjected to annealing HT with different cooling conditions, i.e. HT 1 and HT 2, whereas one set was used in the as-built (AB) condition. The standard metallographic techniques of X-ray diffraction, scanning electron microscopy and electron back-scattered diffraction were used to investigate the microstructural variations induced by different cooling conditions. The resultant changes in mechanical properties were also investigated. Findings The phase change of SLM fabricated 316L was observed to be independent of the investigated cooling conditions and all samples consist of austenite phase only. Both HT 1 and HT 2 lead to dissolved characteristic melt pools of SLM. Noticeable increase in grain size of HT 1 and HT 2 samples was also observed. Compared with AB samples, the grain size of HT 1 and HT 2 was increased by 12.5% and 50%, respectively. A decreased hardness and strength, along with an increased ductility was also observed for HT 2 samples compared with HT 1 and AB samples. Originality/value From previous studies, it has been noticed that most investigations on HT of SLM fabricated 316L were mainly focused on the HT temperature or holding time. However, the post-HT cooling rate is also an equally important factor in deciding the microstructure and mechanical properties of heat-treated components. Therefore, this paper investigates the influence of different post-annealing cooling conditions on microstructure and mechanical properties of SLM fabricated 316L components. This study provides a foundation for considering the post-HT cooling rate as an influential parameter that controls the properties of heat-treated SLM components.

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