scholarly journals Evaluation of Volume Fraction of Austenite in Austempering Process of Austempered Ductile Iron

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 893 ◽  
Author(s):  
Edward Tyrała ◽  
Marcin Górny ◽  
Magdalena Kawalec ◽  
Anna Muszyńska ◽  
Hugo F. Lopez
Keyword(s):  
Ductile Iron ◽  
Volume Fraction ◽  
Metallic Matrix ◽  
Experimental Tests ◽  
Austempered Ductile Iron ◽  
Magnetic Method ◽  
Quantitative Phase Analysis ◽  
Carbide Phases ◽  
Second Stage ◽  
Third Stage

In the present work, an evaluation of the volume fraction of austenite in austempered ductile iron (ADI) is presented by means of three different methods. Experimental tests were conducted on ADI samples after different austempering conditions and contained different volume fractions of the phase components in the metallic matrix (ferrite plates + austenite). A comparison of the volume fraction of austenite was carried out by metallographic magnetic methods using a variable field, as well as X-ray quantitative phase analysis. The main purpose of this work is to show the effectiveness of the proposed magnetic method for estimating the volume fraction of austenite in ADI cast iron. It is evident that the new method in which variable magnetic fields are used to quantify the phase composition exhibits very high accuracy within the second stage of the austempering transformation, in which the metallic matrix consists of ferrite plates and high-carbon austenite. Finally, this research shows that within the first and third stages the estimation of the volume fraction of the austenite is hampered by errors resulting from the presence of martensite (first stage) and carbide phases (third stage).

Effect of Graphite Inclusions on Mechanical Properties of Austempered Ductile Iron

2005 ◽  
Vol 490-491 ◽  
pp. 73-78
Author(s):  
Florin Serban ◽  
Andrzej Baczmanski ◽  
E. Labbe ◽  
Krzysztof Wierzbanowski ◽  
Alain Lodini
Keyword(s):  
Ductile Iron ◽  
Volume Fraction ◽  
Young Modulus ◽  
The Self ◽  
Austempered Ductile Iron ◽  
Graphite Phase ◽  
Self Consistent ◽  
Chemical Segregation ◽  
Mechanical Tensile ◽  
Bull's Eye

Recently, austempered ductile iron (ADI) has emerged as a new class of ferrous materials and represents a major achievement in cast iron technology [1]. The mechanical strength and impact toughness of nodular iron are provided by the precipitation of the graphite phase as spheroids surrounded by ferrite (bull’s-eye structure) in a continuous pearlite matrix. The quality of ductile iron increases with the number of the graphite spheroids. A high spheroids volume fraction, which is mainly controlled by the inoculation process, limits the chemical segregation during solidification and ensures the structural homogeneity of the component. In this work, a lower value of Young modulus was obtained when the graphite phase was taken into account in the self-consistent modelling. For 12% of graphite the theoretical Young modulus agrees with the measured one (mechanical tensile test). The volume fraction of graphite was confirmed independently by micrographic observation (14%). It can be concluded that the macroscopic behaviour of ADI steel can be modelled by the self-consistent approach in which the austeno-ferritic aggregate is represented by an effective matrix, while instead of the graphite spherical empty spaces are introduced. Using such an approach it was shown that in the elasto-plastic range of deformation, presence of graphite phase caused stress relaxation.

scholarly journals Multi-scale phase analyses of strain-induced martensite in austempered ductile iron (ADI) using neutron diffraction and transmission techniques

2020 ◽  
Vol 56 (8) ◽  
pp. 5296-5306
Author(s):  
Xiaohu Li ◽  
Sergio Soria ◽  
Weimin Gan ◽  
Michael Hofmann ◽  
Michael Schulz ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Pole Figure ◽  
Ductile Iron ◽  
Imaging Techniques ◽  
Austempered Ductile Iron ◽  
Quantitative Phase Analysis ◽  
Strain Induced Martensite ◽  
Phase Quantification ◽  
Pole Figure Data ◽  
Multi Phase

AbstractThe content of strain-induced martensite in austempered ductile iron has been quantitatively determined using three different kinds of neutron methods: (1) high-resolution powder diffraction with subsequent standard Rietveld refinement, (2) phase quantification using pole figure measurements and (3) Bragg edge neutron transmission. The accuracy and scope of applications of these neutron diffraction and imaging techniques for phase quantification have been compared and discussed in detail. Combination of these methods has been confirmed as effective for dealing with problems like peak overlap in multi-phase materials and texture formation after plastic deformation. Further, the results highlight the potential of using single peak pole figure data for quantitative phase analysis with high accuracy.

Microstructure Evolution during Strain-Induced Transformation of Austenite in an Austempered Ductile Iron (ADI)

2021 ◽  
Vol 1016 ◽  
pp. 1199-1204
Author(s):  
R. Raghavendran ◽  
Anil Meena ◽  
Murugaiyan Amirthalingam
Keyword(s):  
Phase Transformation ◽  
Thermomechanical Treatment ◽  
Ductile Iron ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Thermomechanical Processing ◽  
Base Material ◽  
High Volume ◽  
Austempered Ductile Iron ◽  
Conventional Heat Treatment

Microstructural evolution during the strain-induced phase transformation of austenite in an Austempered ductile iron (ADI) under various thermomechanical processing conditions is studied in the present study. An alloyed ductile iron is taken as the base material, and thermomechanical treatment is carried out on a Gleeble 3800 thermomechanical simulator coupled with dilatometry. The effect of deformation on the austempering process has been studied by microstructure characterization using optical microscopy (OM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The variations in retained austenite volume fraction and its carbon content with respect to different austempering times are analyzed to study the effect of strain-induced transformation of austenite. It has been observed that the thermomechanical treatment significantly influences the phase transformation kinetics during the austempering process. The thermomechanical treatment produced a martensite free ausferritic microstructure for all austempering times with a high volume fraction of carbon enriched retained austenite as compared to the conventional heat treatment.

The Application of Analysis of Variance to Phase Transformation of an Austempered Ductile Iron

2015 ◽  
Vol 1128 ◽  
pp. 338-343
Author(s):  
Flavius Aurelian Sarbu ◽  
Ioan Milosan
Keyword(s):  
Phase Transformation ◽  
Analysis Of Variance ◽  
Ductile Iron ◽  
Repeated Measures ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Austempered Ductile Iron ◽  
The One

The paper presents an example of calculation for the one-way repeated measures applied for the results of an austempered ductile iron. This research has a number of objectives which can be started as follows: 1. to determine of the volume fraction of retained austenite (Vγr); 2. the calculation for the one-way repeated measures applied for the results of the volume fraction of retained austenite (Vγr).

scholarly journals The Role of Bainite in Wear and Friction Behavior of Austempered Ductile Iron

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 767 ◽  
Author(s):  
Fulin Wen ◽  
Jianhua Zhao ◽  
Dengzhi Zheng ◽  
Ke He ◽  
Wei Ye ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Ductile Iron ◽  
Volume Fraction ◽  
Wear Behavior ◽  
Lower Bainite ◽  
Austempered Ductile Iron ◽  
Isothermal Quenching ◽  
Micro Hardness ◽  
Friction Behavior ◽  
Upper Bainite

The austempered ductile iron was austenitized at 900 °C for 1 h and quenched in an isothermal quenching furnace at 380 °C and 280 °C, respectively. This paper aims to investigate the effects of bainite on wear resistance of austempered ductile iron (ADI) at different loads conditions. The micro-structure and phase composition of ADI was characterized and analyzed by metallographic microscope (OM), X-ray diffractometer (XRD) and scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS). The results showed that the volume fraction of retained austenite in ADI is reduced with the increase of austenitizing temperature. Meanwhile, the two kinds of ADI samples showed varied wear resistance when they were worn at different loads conditions. For wearing at a load of 25 N, the wear resistance of ADI mainly depends on matrix micro-hardness. Thus, ADI with lower bainite structure has higher hardness and leads to better wear resistance. When wearing at a load of 100 N, the increase of micro-hardness of upper bainite was significant. As a consequence, upper bainite showed superior friction and wear behavior. It was also found that the form of wear behavior of ADI changed from abrasive wear to fatigue delamination as the wear load increased from 25 N to 100 N according to the observation on worn surface.

scholarly journals The Influence of Rotational Speed on the Wall Thickness and Mechanical Characteristic of Rotomouldable Plastics

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
Nadhim Mejbil Faleh ◽  
Fatima Masood Hani
Keyword(s):  
Tensile Strength ◽  
Compression Ratio ◽  
Rotational Speed ◽  
Rotation Speed ◽  
Experimental Tests ◽  
Moulding Process ◽  
Second Stage ◽  
Geometrical Features ◽  
Third Stage ◽  
Axial System

This study is interested in the main parameter of this technique that uses a cubic container with an internal dimension of 100 mm and a cylindrical container 100 mm in diameter. We implemented the work in the fifth stage: In the first stage, we designed and manufactured the multi-axial system. In the second stage, the specimens were moulded from polyester, PVC, and polyethylene at a rotational speed axis of 5–120 rpm. The results from this stage indicated that the optimal rotational speed of the steady quality in dimensions and properties of the parts are 85, 100 and 115 rpm. The third stage was concerned with the effect of the speed of rotation on the thickness of the wall. The rotational speed of the axes was changed, and the thickness of the moulded walls was measured. The laboratory measurements revealed that the maximum compression ratio with the change of speed is at the speed of 115 rpm. The fourth stage was concerned with the effect of the speed of rotation on the value of tensile strength. The rotational speed of the axes was changed, and the tensile strength of the mould was measured. The tests revealed an improvement in the tensile strength at the speed of 115 rpm compared with the other speeds. The fifth stage utilised a cylindrical mould, which was re-worked in the previous stages, to investigate the effect of the speed of rotation on the thickness of the wall and mechanical specifications. Based on the conducted experimental tests, the influence of the rotational speed, which characterized the moulding process, on selected geometrical features of the mould was studied and analysed theoretically and numerically. The results showed an increase of about 5% in the compression ratio with increased rotation speed within the range of 85 to 115 rpm. There was also an improvement of about 7% in the tensile strength with increased rotational speed from 85 to 115 rpm. These results are due to the increase in the centrifugal force on the wall of the mould during the process. Also, the study was characterized by the production of the composite of polyethylene reinforced by iron screen wire, with improvement in the mechanical properties by about 300% compared to the base material. 

scholarly journals Microstructure and mechanical properties of CuNiMo austempered ductile iron

2004 ◽  
Vol 40 (1) ◽  
pp. 11-19 ◽  
Author(s):  
Olivera Eric ◽  
Marina Jovanovic ◽  
Leposava Sidjanin ◽  
Dragan Rajnovic
Keyword(s):  
Mechanical Properties ◽  
Ductile Iron ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Bainitic Ferrite ◽  
Austempered Ductile Iron ◽  
X Ray Diffraction ◽  
Microstructure And Mechanical Properties ◽  
Cast Ductile Iron

Microstructure and mechanical properties of Cu, Ni and Mo alloyed cast ductile iron have been investigated after austempering. Samples were austenitised at 860oC for 1h and then austempered at 320oC and 400oC in the interval from 0,5 to 5h. The X-ray diffraction technique and the light microscopy were utilized to investigate the bainitic transformation, while tensile and impact tests were performed for characterization of mechanical properties. By austempering at 320oC in the range between 2 and 5h, a microstructure typical for austempered ductile iron was produced, i.e. a mixture of free bainitic ferrite and highly carbon enriched retained austenite. The characteristic of the whole range of austempering at 400oC is the appearance of martensitic structure. The maximum impact energy (133 J) coincides with the maximum value of volume fraction of retained austenite that was obtained after 2,5h of austempering at 320oC. The appearance of martensite during austempering at 400oC is the main cause for much lower tensile properties than at 320oC.

The Microstructure Evolution of Copper and Gold Bonding Wires during Annealing

2007 ◽  
Vol 550 ◽  
pp. 399-404 ◽  
Author(s):  
Jae Hyung Cho ◽  
Anthony D. Rollett ◽  
Kyu Hwan Oh
Keyword(s):  
Volume Fraction ◽  
Electron Backscatter Diffraction ◽  
Second Stage ◽  
The Third ◽  
Subgrain Growth ◽  
Third Stage ◽  
Bonding Wires ◽  
Main Components ◽  
Backscatter Diffraction ◽  
Equiaxed Grains

Copper and gold bonding wires were characterized and compared using electron backscatter diffraction (EBSD). During drawing, <111> and <100> fiber textures are the main components in the wires and shear components are mainly located under the surface. Grain average misorientation (GAM) and scalar orientation spread (SOS) of the <100> component in copper and gold bonding wires are lower than those of the <111> or other orientations. The bonding wires experience three stages of microstructural changes during annealing. The first stage is subgrain growth to keep elongated grain shapes overall and to be varied in aspect ratio with annealing time. The grain sizes of the <111> and <100> components increase during annealing. The volume fraction of the <100> component increases whereas that of the <111> decreases. The second stage is recrystallization, during which equiaxed grains appear and coexist with elongated ones. The third stage is grain growth which eliminates the elongated grains and enlarges equiaxed grains. The <111> and <100> grains compete with each other and the <111> grains grow faster than the <100> grains during the third stage.

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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