Determination of the relationship between microstructure and constitutive behaviour of nodular cast iron with a unit cell model

2005 ◽  
Vol 40 (2) ◽  
pp. 107-116 ◽  
Author(s):  
L Collini ◽  
G Nicoletto
Keyword(s):  
Cast Iron ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Cell Model ◽  
Nodular Cast Iron ◽  
Unit Cell ◽  
Constitutive Law ◽  
Cast Irons ◽  
Present Contribution ◽  
The Matrix

Unit cell models have been proposed to predict the constitutive law and failure of ductile materials with complex microstructures, such as ferritic nodular cast iron and particulate metal matrix composites (PMMCs). The present contribution aims to extend this modelling approach to the prediction of the constitutive response of nodular cast iron with a mixed ferritic/pearlitic matrix. The finite element method is used within the framework of continuum mechanics to carry out the calculations. The effect of some microstructural features, such as graphite volume fraction and ferrite-pearlite ratio of the matrix, on the mechanical performance is determined. The computational results are compared to results obtained in a previous experimental activity on nodular cast irons.

scholarly journals Characterising Fatigue Behaviour of Nodular Cast Iron Using Micromechanical Simulations

2019 ◽  
Vol 300 ◽  
pp. 13002
Author(s):  
Mehul Lukhi ◽  
Meinhard Kuna ◽  
Geralf Hütter
Keyword(s):  
Finite Element ◽  
Cast Iron ◽  
Volume Fraction ◽  
Cell Model ◽  
Kinematic Hardening ◽  
Nodular Cast Iron ◽  
Fatigue Behaviour ◽  
Cyclic Stress ◽  
Finite Element Simulations ◽  
Final Failure

Elastic-plastic porous materials experience an increase in the mean void volume fraction when they are subjected to cyclic loading. This behavior is known both from the experiments and simulations in the literature. The authors have first time used this mechanism for the evaluation of the fatigue life in nodular cast iron. In this contribution, the stress-life approach is presented for the characterization of fatigue failure. For this purpose, micromechanical finite-element simulations are carried out using the axisymmetric cell model. The cell model having isotropic/non-linear kinematic hardening behavior is subjected to fully reversed cyclic stress controlled loading. The finite element simulations are carried out cycle by cycle until the final failure of the cell model. The numbers of cycles to failure are extracted from the simulations. The stress-life curves are shown for spherical and elliptical graphite particle cell models. The results of the micromechanical simulations are in qualitative agreement with the typical experimental stress-life curves.

scholarly journals PRELIMINARY STUDY ON EFFECT OF ROD GEOMETRY IN FHPP BETWEEN FE55006 NODULAR CAST IRON AND SAE 8620 STELL

2019 ◽  
Vol 16 (31) ◽  
pp. 642-650
Author(s):  
Douglas MARTINAZZI ◽  
Guilherme V. B LEMOS ◽  
Renan M LANDELL ◽  
Diogo T BUZZATTI ◽  
André BRUSIUS ◽  
...  
Keyword(s):  
Cast Iron ◽  
Base Material ◽  
Nodular Cast Iron ◽  
Lower Surface ◽  
Fusion Welding ◽  
Plastic State ◽  
Cast Irons ◽  
Preliminary Study ◽  
Sae 8620 Steel ◽  
Made In

Nodular cast irons are an excellent alternative in manufacturing process of axels due to their characteristics and good mechanical properties. However, the necessity of joining the axels to the gears and other components, made in carbon steel, is a great challenge. Traditional fusion welding methods applied to dissimilar ferrous materials are not deeply studied. In this context, it is well known that different materials have distinct melting points which can cause difficulty in welding, besides of defects formation from solidification. Therefore, modern joining processes such as Friction Hydro Pillar Processing (FHPP) are a great alternative. In this technology, a consumable rod is rotated against to a base material, generating the heat due to the friction, promoting materials in the plastic state and then producing the weld. Hence, this work presents a preliminary study of FHPP between the FE55006 nodular cast iron and SAE 8620 steel and evaluates the rod geometry influence on microstructure and surface stresses of the welded joints. Two rod geometries were used and two welds were further produced. The results indicated that an increase in the rod contact area promoted a lower surface stress as well as a better welded joint.

scholarly journals Iron-chromium-carbon-vanadium white cast irons: Microstructure and properties

2014 ◽  
Vol 68 (4) ◽  
pp. 413-427 ◽  
Author(s):  
Mirjana Filipovic
Keyword(s):  
Fracture Toughness ◽  
Strain Hardening ◽  
Volume Fraction ◽  
Dynamic Fracture Toughness ◽  
M23c6 Carbide ◽  
Cast Irons ◽  
Repeated Impact ◽  
Secondary Carbides ◽  
The Matrix ◽  
Microstructure Parameters

The as-cast microstructure of Fe-Cr-C-V white irons consists of M7C3 and vanadium rich M6C5 carbides in austenitic matrix. Vanadium changed the microstructure parameters of phase present in the structure of these alloys, including volume fraction, size and morphology. The degree of martensitic transformation also depended on the content of vanadium in the alloy. The volume fraction of the carbide phase, carbide size and distribution has an important influence on the wear resistance of Fe-Cr-C-V white irons under low-stress abrasion conditions. However, the dynamic fracture toughness of Fe-Cr-C-V irons is determined mainly by the properties of the matrix. The austenite is more effective in this respect than martensite. Since the austenite in these alloys contained very fine M23C6 carbide particles, higher fracture toughness was attributed to a strengthening of the austenite during fracture. Besides, the secondary carbides which precipitate in the matrix regions also influence the abrasion behaviour. By increasing the matrix strength through a dispersion hardening effect, the fine secondary carbides can increase the mechanical support of the carbides. Deformation and appropriate strain hardening occur in the retained austenite of Fe-Cr-C-V alloys under repeated impact loading. The particles of precipitated M23C6 secondary carbides disturb dislocations movement and contribute to increase the effects of strain hardening in Fe-Cr-C-V white irons.

scholarly journals Structural Investigations of Solidification and Heat Treatments Influence on High Alloyed Cast Irons Grades with Nb-V-Ti Additions

2009 ◽  
Vol 289-292 ◽  
pp. 77-86 ◽  
Author(s):  
Jacqueline Lecomte-Beckers ◽  
Jérôme Tchoufang Tchuindjang
Keyword(s):  
Phase Transformations ◽  
Volume Fraction ◽  
Raw Materials ◽  
Solidification Process ◽  
Heat Treatments ◽  
Hot Strip Mill ◽  
Cast Irons ◽  
Structural Investigations ◽  
Alloyed Cast ◽  
The Matrix

Two High Alloyed Cast Irons (HACI) were studied, both belonging to the Fe-C-Cr-Si-X system where X represented a strong carbide forming element. One of these alloys was obtained after adding Nb, V and Ti to the chemical composition of the other alloy. Raw materials originated from spun cast rolls for hot strip mill were submitted to different heat treatments routes, in order to study the influence of alloying elements on the microstructure. Both HACI grades contained a mixture of martensite and retained austenite matrix in the as-cast conditions and after quenching. Differential Thermal Analysis was carried out on the heat treated samples in order to determine the phase transformations occurring during re-melting and subsequent solidification sequence. Diffusionless transformations leading to various types of martensite were found in the matrix. Bulky NbC carbides precipitating at the beginning of the solidification process strongly influence the nature and the rate of the subsequent diffusional phase transformations, particularly for HACI grade with Nb, V and Ti additions. Quantitative metallography was done to determine graphite, NbC carbides, cementite and matrix volume fraction in HACI studied grades.

Study on the Influences on Microstructure and Properties of High-Strength Grey Cast Iron in Addition to Alloying Elements Nb

2013 ◽  
Vol 800 ◽  
pp. 221-224
Author(s):  
Jun Tao Zhang ◽  
Feng Zhang Ren
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Mechanical Performance ◽  
High Strength ◽  
Optical Microscope ◽  
Gray Cast ◽  
Dynamic Strain ◽  
Cast Irons ◽  
Grey Cast ◽  
The Relationship

The increase of the strength of gray cast iron is mainly depended on alloying. However, with the improvement of strength, its processing performance will always decrease. So three different gray cast irons are studied in this experiment, including adding 0.1% Nb elements, adding 0.2% Nb elements and adding 0.3% Nb elements, to investigate the Nbs effect to the mechanical performance of gray cast iron, we adopt Dynamic Strain Amplifier to measure cutting force to evaluate processing performance, use Optical Microscope and Electron Microscopy observe each samples organization, explains the relationship between Nbs content and the mechanical and processing performance of gray cast iron from micro-level. Finally, we draw the conclusion: when the Nb comes to 0.3 percent, the appearance of E-type graphite and Nb carbide durum granular will greatly decrease its processing performance.

Mechanical performance of textile-reinforced hoses assessed by a truss-based unit cell model

2019 ◽  
Vol 141 ◽  
pp. 47-66
Author(s):  
Roland Traxl ◽  
David Mungenast ◽  
Oliver Schennach ◽  
Roman Lackner
Keyword(s):  
Mechanical Performance ◽  
Cell Model ◽  
Unit Cell ◽  
Unit Cell Model

Direct Diode Laser Surface Melting of Nodular Cast Iron

2015 ◽  
Vol 809-810 ◽  
pp. 423-428 ◽  
Author(s):  
Damian Janicki
Keyword(s):  
Cast Iron ◽  
Diode Laser ◽  
Heat Input ◽  
Volume Fraction ◽  
Residual Austenite ◽  
Nodular Cast Iron ◽  
Surface Melting ◽  
Laser Surface ◽  
Test Method ◽  
Laser Surface Melting

A nodular cast iron (NCI) has been surface melted using the high power direct diode laser (HPDDL) with a quasi-rectangular laser beam spot and the uniform distribution of power. The effect of a heat input and a shielding gas on the quality of surface melted layers (SMLs) has been investigated. The microstructure of the SMLs has been assessed by optical microscopy, scanning electron microscopy and X-ray diffraction (XRD). Comparative erosion tests between the SMLs and as-received NCI have been performed following the ASTM G 76 standard test method. The HPDD laser surface melting of the NCI enables to produce non-porous layers having a hardness up to 1000 HV. It has been determined that the hardness of SMLs depends on the amount of cementite and residual austenite in the fusion zone. The SMLs produced in an argon atmosphere contain higher volume fraction of austenite, than those produced in nitrogen, and consequently have the lower hardness. With increasing heat input the hardness increases, as the result of more complete dissolution of graphite and the higher amount of cementite. The SMLs exhibited significantly higher erosion resistance than the as-received NCI for erodent impact angle of 3<em>0°, and slightly lower at 90°.</em><em></em>

Epoxy-matrix nanocomposites reinforced by electrospun polymeric nanofibrous layers: PAN, PA-6,6, and hybrid PAN/PA-6,6

2021 ◽  
pp. 095440622110426
Author(s):  
Farzin Asghari Arpatappeh ◽  
Ali Akbar Gharehaghaji ◽  
Hooshang Nosraty
Keyword(s):  
Epoxy Matrix ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Electrospun Nanofiber ◽  
The Matrix ◽  
Low Volume ◽  
Enhanced Properties ◽  
The Impact ◽  
Matrix Nanocomposites ◽  
Advanced Applications

Composite materials with nanofibrous reinforcements are capable of high mechanical performance and enhanced properties despite their low volume fraction of reinforcement. In this study, tensile properties of epoxy-matrix nanocomposites were investigated after reinforcing by hand layup method implementation of randomly oriented electrospun nanofiber layers. The reinforcements were produced from polyacrylonitrile (PAN), Polyamide-6,6 (PA-6,6), and their 50/50 hybrid. The results indicated that PAN enhanced the tensile toughness of the matrix by almost 4 times, increasing both the ductility (an expected 23% due to fiber being more elastic than the matrix) and the ultimate tensile strength (a surprising 35% even though the fibers were less stiff than the matrix). These results indicate significant improvements in the impact properties for advanced applications. The results revealed that PA-6,6 did not show the characteristics of a promising reinforcement whether used solely or added to PAN.

scholarly journals Graphite Morphology's Influence on Shot Peening Results in Cast Irons

2013 ◽  
Vol 768-769 ◽  
pp. 542-549 ◽  
Author(s):  
Matthias Lundberg ◽  
Ru Lin Peng ◽  
Maqsood Ahmad ◽  
Daniel Bäckström ◽  
Taina Vuoristo ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Cast Iron ◽  
Shot Peening ◽  
Electron Backscatter Diffraction ◽  
Plastic Deformation Zone ◽  
Cast Irons ◽  
The Matrix ◽  
Electron Imaging ◽  
Backscatter Diffraction ◽  
Graphite Inclusions

The different shot peening responds of a grey cast iron (GI) with its flake graphite and a compacted cast iron (CGI) with its vermicular graphite was analyzed and compared in this paper. For peening using identical parameters, CGI showed a larger plastic deformation zone with higher subsurface compressive stresses than GI. Electron backscatter diffraction (EBSD) mapping and backscatter electron imaging revealed that plastic deformation of the matrix near graphite inclusions is affected by the size and geometry of the graphite. The different behaviors of graphite are explained by their capability to damp mechanical force but at the same time to cause stress concentration in the matrix. The better shot peening results for CGI may be attributed to a lower damping effect of its graphite inclusions and capability of the matrix for larger plastic deformation.

scholarly journals Structure and Properties of Cast Iron DESIGNATED for Working Layer of Rolls

2015 ◽  
Vol 5 (1) ◽  
pp. 77 ◽  
Author(s):  
K. N. Vdovin ◽  
A. N. Zavalishchin ◽  
D. A. Gorlenko ◽  
N. A. Feoktistov
Keyword(s):  
Cast Iron ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Centrifugal Casting ◽  
Structure And Properties ◽  
Cast Irons ◽  
Metallic Base ◽  
Slow Cooling ◽  
Working Layer ◽  
Secondary Carbides

<p class="1Body">The formation of the structure and properties of cast irons designated for the working layer during solidification and subsequent tempering of Indefinite Chill Double Poured Centrifugal Casting Rolls (ICDP) has been studied.</p><p class="1Body">Graphitization of cast irons designated for the working layer of rolls occurs under isothermal conditions at high temperatures, which vary over the cross section and resulted from casting the roll core. At subsequent slow cooling, secondary carbides precipitate and austenite partially transforms into martensite; the resulting end structure consists of martensite and austenite metallic base (primary austenite dendrites) with 11.4 per cent of retained austenite, 26 per cent of eutectic and secondary carbides, and 2.6 per cent of flake graphite.<em> </em></p><p class="1Body">The amount of retained austenite in the metallic base of the cast structure of cast iron designated for the working layer, heated to 430 °C, decreases<strong> </strong>from 11.4 per cent to 3.2 per cent due to the partial transformation into bainite. The martensite tetragonality decreases due to the carbide precipitation; the existing excess phases grow and the new ones are formed; the total volume fraction of the carbide phase increases to 29.8 per cent and graphite to 3.7 per cent.</p>

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