The Influence of Austempering Heat Treatment Variables on Dimensional Changes of a Ni-Cu Ductile Iron

Dimensional Changes ◽

Microstructure Evaluation ◽

Austempering Temperature

Control and prediction of the dimensional changes (DC) during austempering heat treatment of ductile iron is difficult because many factors influence this behavior. In the present work cylindrical specimens of ductile iron were used to study the effect of austenitizing temperature, austempering time, temperature, and prior microstructure on DC. The results show that DC increases with increasing austenitizing temperature in the range of 850 to 950°C with a fully ausferrite microstructure. Evaluation of different combinations of ferrite and pearlite contents in prior microstructure indicates that a fully ferritic structure has the highest DC. In addition, results show that by lowering austempering temperature from 400 to 250°C, DC increases.

Hardness and Impact Toughness of Niobium Alloyed Austempered Ductile Iron

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.418-420.1768 ◽

2011 ◽

Vol 418-420 ◽

pp. 1768-1771 ◽

Cited By ~ 1

Author(s):

Bulan Abdullah ◽

Siti Khadijah Alias ◽

Ahmed Jaffar ◽

Rashiddy Wong Freddawati ◽

A. Ramli

Keyword(s):

Impact Toughness ◽

Ductile Iron ◽

Treatment Process ◽

Impact Test ◽

Induction Furnace ◽

Hardness Test ◽

Austempering Temperature ◽

The Impact

The effect of different austempering holding times on the hardness and impact toughness of 0.254% niobium alloyed austempered ductile iron was investigated in this study. Molten ductile iron was prepared in an induction furnace with capacity of 60kg. Samples with dimension of 300m x Ø25mm in form of Y block double cylinder was constituted and solidified samples were then machined in accordance to ASTM E23 for impact test specimens. Samples were ground and polished before Rockwell hardness test was conducted. Austempering heat treatment process with austenitizing temperature of 900°C for 1 hour and austempering temperature of 350°C for 1 hour, 2 hours and 3 hour holding times were then carried out. The results from this research indicated that austempering the sample for 1 hour resulted in significant improvement of the impact toughness values but increasing the austempering holding time deficiently reduced the values. On the contrary, the hardness of niobium alloyed austempered ductile iron continues to increase with respect to longer austempering holding times.

Mechanical characterization and optimization of heat treatment parameters of manganese alloyed austempered ductile iron

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.13.1.2019.01.0371 ◽

2019 ◽

Vol 13 (1) ◽

pp. 4356-4367

Author(s):

Ananda Hegde ◽

Sathyashankara Sharma ◽

Ramakrishna Vikas Sadanand

Keyword(s):

Heat Treatment ◽

Tensile Strength ◽

Ductile Iron ◽

Manganese Content ◽

Regression Equations ◽

Cast Irons ◽

Austenitization Temperature ◽

The Family ◽

Austempering Temperature

Austempered Ductile Iron (ADI) belongs to the family of cast irons whose mechanical properties are altered using austempering heat treatment process. The objective of this paper is to study the effects of heat treatment parameters on manganese alloyed ADI. Hence, austenitization temperature, austempering temperature and austempering time are taken as the control variables along with the manganese content in the material. The effects of heat treatment are studied by measuring the ultimate tensile strength and the hardness of the material. The regression equations are developed to relate the various parameters under study. The microstructures of the specimen reveal that retained austenite content increases with increase in manganese and results in decrease in hardness of the material. The statistical analyses indicate that the austempering temperature is the major factor affecting the variation in hardness and tensile strength with 74.5 % of contribution within the range of values whereas, variation in manganese content does not have significant effect on hardness within the investigated composition range in the material.

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

10.20944/preprints201710.0090.v1 ◽

2017 ◽

Author(s):

Nikša Čatipović ◽

Dražen Živković ◽

Zvonimir Dadić ◽

Marin Viceić

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Ductile Iron ◽

Salt Bath ◽

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.

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

International Journal of Research -GRANTHAALAYAH ◽

10.29121/granthaalayah.v8.i6.2020.419 ◽

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 ◽

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 Heat Treatment Parameters on the Toughness of Unalloyed Ausferritic Ductile Iron

Archives of Foundry Engineering ◽

10.1515/afe-2016-0030 ◽

2016 ◽

Vol 16 (2) ◽

pp. 79-84 ◽

Cited By ~ 2

Author(s):

E. Guzik ◽

M. Sokolnicki ◽

A. Nowak

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Cast Iron ◽

Ductile Iron ◽

High Strength ◽

Process Window ◽

Plastic Properties ◽

Alloyed Cast Iron ◽

Nodular Graphite

Abstract Studies were carried out to determine the effect of heat treatment parameters on the plastic properties of unalloyed ausferritic ductile iron, such as the elongation and toughness at ambient temperature and at – 60 °C. The effect of austenitizing temperature (850, 900 and 950°C) and ausferritizing time (5 - 180 min.) at a temperature of 360°C was also discussed. The next step covered investigations of a relationship that is believed to exist between the temperature (270, 300, 330, 360 and 390 °C) and time (5, 10, 30, 60, 90, 120, 150, 180, 240 min.) of the austempering treatment and the mechanical properties of unalloyed ausferritic ductile iron, when the austenitizing temperature is 950°C. The “process window” was calculated for the ADI characterized by high toughness corresponding to the EN-GJS-800-10-RT and EN-GJS-900-8 grades according to EN-PN 1564 and to other high-strength grades included in this standard. Low-alloyed cast iron with the nodular graphite is an excellent starting material for the technological design of all the ausferritic ductile iron grades included in the PN-EN-1624 standard. The examined cast iron is characterized by high mechanical properties stable within the entire range of heat treatment parameters.

Wear volume prediction of AISI H13 die steel using response surface methodology and artificial neural network

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.2.2020.19.0531 ◽

2020 ◽

Vol 14 (2) ◽

pp. 6789-6800

Author(s):

Vishal Jagota ◽

Rajesh Kumar Sharma

Keyword(s):

Neural Network ◽

Heat Treatment ◽

Artificial Neural Network ◽

Response Surface ◽

Sliding Wear ◽

Tempering Temperature ◽

Die Steel ◽

Artificial Neural ◽

Tempering Time

Resistance to wear of hot die steel is dependent on its mechanical properties governed by the microstructure. The required properties for given application of hot die steel can be obtained with control the microstructure by heat treatment parameters. In the present paper impact of different heat treatment parameters like austenitizing temperature, tempering time, tempering temperature is studied using response surface methodology (RSM) and artificial neural network (ANN) to predict sliding wear of H13 hot die steel. After heat treating samples at austenitizing temperature of 1020°C, 1040°C and 1060°C; tempering temperature 540°C, 560°C and 580°C; tempering time 1hour, 2hours and 3hours, experimentation on pin-on-disc tribo-tester is done to measure the sliding wear of H13 die steel. Box-Behnken design is used to develop a regression model and analysis of variance technique is used to verify the adequacy of developed model in case of RSM. Whereas, multi-layer feed-forward backpropagation architecture with input layer, single hidden layer and an output layer is used in ANN. It was found that ANN proves to be a better tool to predict sliding wear with more accuracy. Correlation coefficient R2 of the artificial neural network model is 0.986 compared to R2 of 0.957 for RSM. However, impact of input parameter interactions can only be analysed using response surface method. In addition, sensitivity analysis is done to determine the heat treatment parameter exerting most influence on the wear resistance of H13 hot die steel and it showed that tempering time has maximum influence on wear volume, followed by tempering temperature and austenitizing temperature. The prediction models will help to estimate the variation in die lifetime by finding the amount of wear that will occur during use of hot die steel, if the heat treatment parameters are varied to achieve different properties.

Heat Treatment Evaluation for the Camshafts Production of ADI Low Alloyed with Vanadium

Metals ◽

10.3390/met11071036 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1036

Author(s):

Eduardo Colin García ◽

Alejandro Cruz Ramírez ◽

Guillermo Reyes Castellanos ◽

José Federico Chávez Alcalá ◽

Jaime Téllez Ramírez ◽

...

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Tensile Strength ◽

Ductile Iron ◽

Volume Fraction ◽

Energy Impact ◽

Treatment Conditions ◽

Mold Casting ◽

Grade 3 ◽

Good Agreement

Ductile iron camshafts low alloyed with 0.2 and 0.3 wt % vanadium were produced by one of the largest manufacturers of the ductile iron camshafts in México “ARBOMEX S.A de C.V” by a phenolic urethane no-bake sand mold casting method. During functioning, camshafts are subject to bending and torsional stresses, and the lobe surfaces are highly loaded. Thus, high toughness and wear resistance are essential for this component. In this work, two austempering ductile iron heat treatments were evaluated to increase the mechanical properties of tensile strength, hardness, and toughness of the ductile iron camshaft low alloyed with vanadium. The austempering process was held at 265 and 305 °C and austempering times of 30, 60, 90, and 120 min. The volume fraction of high-carbon austenite was determined for the heat treatment conditions by XRD measurements. The ausferritic matrix was determined in 90 min for both austempering temperatures, having a good agreement with the microstructural and hardness evolution as the austempering time increased. The mechanical properties of tensile strength, hardness, and toughness were evaluated from samples obtained from the camshaft and the standard Keel block. The highest mechanical properties were obtained for the austempering heat treatment of 265 °C for 90 min for the ADI containing 0.3 wt % V. The tensile and yield strength were 1200 and 1051 MPa, respectively, while the hardness and the energy impact values were of 47 HRC and 26 J; these values are in the range expected for an ADI grade 3.