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.

scholarly journals Research and Analysis of the Effect of Heat Treatment on Damping Properties of Ductile Iron

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 566-574
Author(s):  
Yu Zhang ◽  
Erjun Guo ◽  
Liping Wang ◽  
Yicheng Feng ◽  
Sicong Zhao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Cast Iron ◽  
Ductile Iron ◽  
Cast Steel ◽  
High Stress ◽  
High Strength ◽  
Spheroidal Graphite ◽  
High Plasticity

Abstract With the continuous development of metal manufacturing technology, high-strength and high-hardness ductile iron materials have excellent comprehensive performance. Many performance indexes are comparable to those of alloy steels, and they have excellent casting properties. Many large-scale parts produced by cast steel are slowly being replaced by this material. Ductile iron is obtained by a spheroidizing treatment and inoculation to obtain spheroidal graphite. The mechanical properties of cast iron have been effectively improved, especially plasticity and toughness, and the strength obtained is higher than that of carbon steel. Ductile iron has the properties of iron and the properties of steel. It is a new type of engineering material with high plasticity, strength, corrosion resistance, and wear-resistance. Because of its excellent performance, it has been successfully used to cast parts with high-stress conditions, high strength, toughness and wear resistance. Due to the small splitting effect of ductile iron on the metal matrix, the stress concentration is effectively eliminated. Therefore, the matrix structure of ductile cast iron is changed by heat treatment, thereby improving its mechanical properties and the damping performance of the material itself. Through a heat treatment process experiment of ductile iron, the related process and technical measures of damping performance in the heat treatment production process are obtained.

Advances in Carbidic Austempered Ductile Iron (CADI) – a wear resistant material

2021 ◽  
Vol 14 ◽  
Author(s):  
Lakshmiprasad Maddi ◽  
Ajay Likhite
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Cast Iron ◽  
Ductile Iron ◽  
Viable Alternative ◽  
Austempered Ductile Iron ◽  
Resistant Material ◽  
Fine Carbide ◽  
Matrix Graphite ◽  
Malleable Cast

Background: Ductile irons provide a more viable alternative for malleable cast iron in areas that do not demand extreme wear resistance. Austempering of ductile irons was a well researched area in the last two decades. Attempts to further improve the wear resistance led to the development of Carbidic austempered ductile iron (CADI), wherein the carbides contribute to wear resistance. Combination of ausferritic matrix, graphite nodules, and carbides (eutectic and alloy) symbolizes the microstructure of CADI. Methods: Two principal approaches adopted by the researchers to change the microstructure are (i) addition of carbide forming elements (ii) heat treatment (s). Results: Both the above methods result in the refinement of graphite nodules, carbide precipitations, along with fine ausferrite. Conclusion: Improvement in hardness, toughness and wear resistance was observed largely as a consequence of fine carbide precipitations and formation of martensite.

scholarly journals Effect of Heat-treatment Parameters of Cast Iron GJS-X350NiMnCu7-3-2 on its Structure and Mechanical Properties

2017 ◽  
Vol 17 (1) ◽  
pp. 121-126 ◽  
Author(s):  
D. Medyński ◽  
A. Janus ◽  
S. Zaborski
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Cast Iron ◽  
High Hardness ◽  
Spheroidal Graphite ◽  
Air Cooling ◽  
Material Hardness ◽  
The Matrix ◽  
Lower Material

Abstract The paper presents influence of soaking parameters (temperature and time) on structure and mechanical properties of spheroidal graphite nickel-manganese-copper cast iron, containing: 7.2% Ni, 2.6% Mn and 2.4% Cu. Raw castings showed austenitic structure and relatively low hardness (150 HBW) guaranteeing their good machinability. Heat treatment consisted in soaking the castings within 400 to 600°C for 2 to 10 hours followed by air-cooling. In most cases, soaking caused changes in structure and, in consequence, an increase of hardness in comparison to raw castings. The highest hardness and tensile strength was obtained after soaking at 550°C for 6 hours. At the same time, decrease of the parameters related to plasticity of cast iron (elongation and impact strength) was observed. This resulted from the fact that, in these conditions, the largest fraction of fine-acicular ferrite with relatively high hardness (490 HV0.1) was created in the matrix. At lower temperatures and after shorter soaking times, hardness and tensile strength were lower because of smaller degree of austenite transformation. At higher temperatures and after longer soaking times, fine-dispersive ferrite was produced. That resulted in slightly lower material hardness.

scholarly journals Effect of Phenomena Accompanying Wear in Dry Corundum Abrasive on the Properties and Microstructure of Austempered Ductile Iron with Different Chemical Composition

2015 ◽  
Vol 60 (1) ◽  
pp. 483-490 ◽  
Author(s):  
D. Myszka ◽  
A. Wieczorek
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Ductile Iron ◽  
Surface Hardening ◽  
The Other ◽  
Austempered Ductile Iron ◽  
High Wear Resistance ◽  
New Materials ◽  
Heat Treated ◽  
Mining Machinery

Abstract The research described in this article is a fragment in the series of published works trying to determine the applicability of new materials for parts of the mining machinery. Tests were performed on two groups of austempered ductile iron - one of which contained 1.5% Ni and 0.5% Mo, while the other contained 1.9% Ni and 0.9% Cu. Each group has been heat treated according to the three different heat treatment variants and then the material was subjected to detailed testing of mechanical properties and abrasion wear resistance, measuring also hardness and magnetic properties, and conducting microstructural examinations. The results indicated that each of the tested materials was senstive to the surface hardening effect, which resulted in high wear resistance. It has been found that high temperature of austempering, i.e. 370°C, favours high wear resistance of ductile iron containing nickel and molybdenum. Low temperature of austempering, i.e. 270°C, develops high wear resistance in ductile iron containing nickel and copper. Both these materials offer completely different mechanical properties and as such can be used for different and specific applications.

Microstructural and Mechanical Properties Changes of Silicon Nitride Based Ceramic Using Post-Sintering Heat Treatment

2012 ◽  
Vol 727-728 ◽  
pp. 1085-1091
Author(s):  
José Vitor C. Souza ◽  
O.M.M. Silva ◽  
E.A. Raymundo ◽  
João Paulo Barros Machado
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Grain Size ◽  
Wear Resistance ◽  
High Hardness ◽  
Gas Pressure ◽  
Low Density ◽  
Nitrogen Gas ◽  
Structural Applications

Si3N4based ceramics are widely researched because of their low density, high hardness, toughness and wear resistance. Post-sintering heat treatments can enhance their properties. Thus, the objective of the present paper was the development of a Si3N4based ceramic, suitable for structural applications, by sintering in nitrogen gas pressure, using AlN, Al2O3, and Y2O3as additives and post-sintering heat treatment. The green bodies were fabricated by uniaxial pressing at 80 MPa with subsequent isostatic pressing at 300 MPa. The samples were sintered at 1900°C for 1 h under N2gas pressure of 0.1 MPa. Post-sintering heat treatment was performed at 1500°C for 48 h under N2gas pressure of 1.0 MPa. From the results, it was observed that after post-sintering heat treatment there was a reduction of α-SiAlON phase and increase of β-Si3N4phase, with consequent changing in grain size, decrease of fracture toughness and increase of the Vickers hardness.

scholarly journals Prediction of Microstructure in ADI Castings

2016 ◽  
Vol 61 (4) ◽  
pp. 2159-2164 ◽  
Author(s):  
E. Guzik ◽  
M. Sokolnicki ◽  
M. Królikowski ◽  
M. Ronduda ◽  
A. Nowak
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Wear Resistance ◽  
Functional Properties ◽  
Ductile Iron ◽  
A Priori ◽  
Salt Bath ◽  
Process Window ◽  
Regression Equations ◽  
Matrix Morphology

Abstract Tests were carried out on samples of low-alloy ductile iron with additions of Ni, Cu and Mo, subjected to austempering heat treatment. The samples were austenitized at 850, 900 and 950 °C, and then austempered at T = 210, 240, 270, 300 and 330 °C. The ausferritizing treatment was carried out in a salt bath for the time τ = 2 - 8 hours. Additionally, tests and studies covered samples subjected to the ausferritizing treatment at 270 °C with the time of holding castings in a bath from 2 to 24 hours. Evaluation covered the results of the ADI microstructure examinations and hardness measurements. The ADI matrix morphology was identified counting the average number of ausferrite plates and measuring their width and spacing. The regression equations HB = f (τ, T) and τ = f (HB, T) were derived to establish the, so-called, “process window”, allowing obtaining a priori the required microstructure of ADI and, consequently, the required mechanical properties, mainly hardness, shaping the functional properties of castings, abrasion wear resistance – in particular.

scholarly journals Ultrafine Ductile and Austempered Ductile Irons by Solidification in Ultrasonic Field

2021 ◽  
Author(s):  
M. Ahmed ◽  
E. Riedel ◽  
M. Kovalko ◽  
A. Volochko ◽  
R. Bähr ◽  
...  
Keyword(s):  
Ductile Iron ◽  
Acoustic Waves ◽  
Iron Alloy ◽  
Austempered Ductile Iron ◽  
Maximum Speed ◽  
Spheroidal Graphite ◽  
Dual Phase ◽  
Nodule Count ◽  
The Matrix ◽  
Sg Iron

AbstractIn this research, ultrasonic melt treatment (UST) was used to produce a new ultrafine grade of spheroidal graphite cast iron (SG iron) and austempered ductile iron (ADI) alloys. Ultrasonic treatment was numerically simulated and evaluated based on acoustic wave streaming. The simulation results revealed that the streaming of the acoustic waves propagated as a stream jet in the molten SG iron along the centerline of the ultrasonic source (sonotrode) with a maximum speed of 0.7 m/s and gradually decreased to zero at the bottom of the mold. The metallographic analysis of the newly developed SG iron alloy showed an extremely ultrafine graphite structure. The graphite nodules’ diameter ranging between 6 and 9 µm with total nodule count ranging between 900 to more than 2000 nodules per mm2, this nodule count has never been mentioned in the literature for castings of the same diameter, i.e., 40 mm. In addition, fully ferritic matrix was observed in all UST SG irons. Further austempering heat treatments were performed to produce different austempered ductile iron (ADI) grades with different ausferrite morphologies. The dilatometry studies for the developed ADI alloys showed that the time required for the completion of the ausferrite formation in UST alloys was four times shorter than that required for statically solidified SG irons. SEM micrographs for the ADI alloys showed an extremely fine and short ausferrite structure together with small austenite blocks in the matrix. A dual-phase intercritically austempered ductile iron (IADI) alloy was also produced by applying partial austenitization heat treatment in the intercritical temperature range, where austenite + ferrite + graphite phases coexist. In dual-phase IADI alloy, it was established that introducing free ferrite in the matrix would provide additional refinement for the ausferrite.

Monitoring Phase Transition Kinetics in Austempered Ductile Iron (ADI)

2010 ◽  
Vol 638-642 ◽  
pp. 3394-3399 ◽  
Author(s):  
Leopold Meier ◽  
Peter Schaaf ◽  
S. Cusenza ◽  
D. Höche ◽  
Menachem Bamberger ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Heat Treatment ◽  
Ductile Iron ◽  
Bainitic Ferrite ◽  
High Strength ◽  
Austempered Ductile Iron ◽  
Design Engineers ◽  
Phase Transition Kinetics ◽  
Complementary Techniques

Austempered ductile iron (ADI) is a very attractive material for applications where high strength, good ductility, wear resistance and fatigue strength are required. Thus, it offers design engineers an alternative to steel and aluminium alloys. ADI essentially is a cast ductile iron that undergoes a specially designed austempering heat treatment, which creates a microstructure of high carbon austenite and bainitic ferrite along with graphite nodules. The final proportion of these phases (and thus the mechanical properties) depends on the phase transformation kinetics which is strongly affected by composition, as-cast microstructure and heat treatment parameters (austempering). ADI samples were austempered (heat treated) and the phase transitions were analysed after interrupted austempering. The phase fractions (austenite, ferrite, martensite, etc.) and their relation to bulk properties, like electrical resistivity, magnetic properties and mechanical properties (e.g. strength, hardness), and others were measured using optical and electron microscopy, X-ray and neutron diffraction, Mössbauer spectroscopy, and micro hardness measure¬ment. This combination of complementary techniques allows the correlation of the phase transition kinetics with the resulting properties.

scholarly journals AUSTEMPERING HEAT TREATMENT STUDY OF CAST DUCTILE IRON: ANALYSIS OF MECHANICAL AND MICROSTRUCTURAL PROPERTIES, ACCORDING TO THE A897M STANDARD SPECIFICATIONS FOR AUSTEMPERED DUCTILE IRON CASTINGS

2018 ◽  
Vol 15 (29) ◽  
pp. 64-74
Author(s):  
A. R. M. SCHIFINO ◽  
F. R. SANTANNA ◽  
A. P. TRINDADE
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Cast Iron ◽  
Ductile Iron ◽  
Great Influence ◽  
Metallic Matrix ◽  
Nodular Cast Iron ◽  
Austempered Ductile Iron ◽  
Mechanical Resistance ◽  
Spring Support

The objective of this work was to develop heat treatment parameters of an austempered cast iron alloy ASTM 897 / A 897M - 1400/1100/1, aiming at the production of a truck spring support. The austempered nodular cast iron, known by the acronym ADI - Austempered Ductile Iron - is a class of nodular cast iron that, after austempered thermal treatment, increases significantly its mechanical properties and tenacity (Machado, 2007). Mechanical and metallographic tests demonstrated the great influence that the level of microshrinkage has on the elongation and mechanical resistance of the material. Generally, tensile tests demonstrate high elongation due to minimal presence of microshrinkage and segregations in the metallic matrix of the material, as well as to the presence of austenite with high carbon retained in the ADI matrix. Analyzes were performed to determine if the mechanical properties required by ASTM 897 / A897M were achieved. Within this standard, four degrees can be obtained. The degree of interest in this study was 1400/1100/1, which is the grade requested by the company, so that the truck spring support can be put into service. Tensile, Charpy and optical microscopy tests were carried out.

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