scholarly journals Diffusion crushing of graphite in integrated cast iron processing

2021 ◽  
pp. 26-32
Author(s):  
S.I. Gubenko
Keyword(s):  
Cast Iron ◽  
Thermal Cycling ◽  
Metal Matrix ◽  
Structural Changes ◽  
Gray Cast ◽  
Iron Matrix ◽  
Cast Irons ◽  
X Ray ◽  
Explosive Action ◽  
Graphite Inclusions

Purpose. It is necessary to investigate the possibility of crushing graphite inclusions in cast irons. The aim of the work was to study structural changes in graphite under explosive action followed by thermal cycling treatment of gray cast iron. Methods. Gray cast irons were subjected to explosive action (pressure is 90 GPa, the deformation rate is 100 s-1, the time is 10-6...10-7 s). Then the cast irons were subjected to thermal cycling: 950 °C, holding for 20 min, cooling with a furnace; 5 cycles. Metalographic ("Neophot-21"), micro-X-ray spectral ("Nanolab-7"), X-ray diffraction (DRON-2.0) research methods were used. Results. The features of diffusion crushing of graphite in cast irons with different types of metal matrix (ferritic, austenitic) and graphite shape (lamellar, spherical) have been studied. The features of structural changes in the cast iron matrix under explosive action, which determine the conditions for the transformation of graphite during subsequent thermal cycling, are discussed. It is shown that this process of diffusional crushing of graphite can be accompanied by local melting, which leads to the formation of regularly distributed dispersed particles of graphite. Scientific novelty. From the point of view of physical mesomechanics of plastic deformation, the processes of structural changes in the metal matrix of cast irons are considered. It is shown that nonequilibrium defect substructures of the cast iron matrix obtained during the explosion determine the features of diffusion crushing of graphite inclusions during subsequent thermal cycling. The conditions for diffusion crushing of graphite with reflow and in the solid-phase state have been established. Practical significance.  It has been established that the complex processing of “explosive loading + thermal cycling” promotes crushing of coarse graphite inclusions, which is favorable for the mechanical and operational properties of cast irons. The use of the results obtained will make it possible to develop technologies for complex processing with regulated parameters of graphite inclusions, which will lead to an expansion of the field of application of gray cast irons. Keywords: cast iron; shock wave treatment; graphite; thermal cycling; stress relaxation

ISO 185/JL/350

Alloy Digest ◽  
2021 ◽  
Vol 70 (9) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Tensile Strength ◽  
Cast Iron ◽  
Gray Cast Iron ◽  
High Strength ◽  
Heat Treating ◽  
Gray Cast ◽  
Spheroidal Graphite ◽  
Cast Irons ◽  
Test Pieces

Abstract ISO 185/JL/350 is a higher-tensile-strength gray cast iron that has a pearlitic matrix, and a tensile strength of 350–450 MPa (51–65 ksi), when determined on test pieces machined from separately cast, 30 mm (1.2 in.) diameter test bars. It provides a combination of high strength while still maintaining good thermal conductivity compared with other types of cast iron. This grade approaches the maximum tensile strength attainable in gray cast iron. Applications therefore tend to be confined to those where thermal conductivity requirements in service preclude the use of one of the other higher-strength materials such as spheroidal graphite cast irons, which have inferior thermal properties. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on wear resistance as well as casting and heat treating. Filing Code: CI-85. Producer or source: International Organization for Standardization.

scholarly journals Characterization of Graphite Inclusions in Cast Iron by Cathodoluminescence and X-Ray Microanalysis

2013 ◽  
Vol 19 (S2) ◽  
pp. 1110-1111
Author(s):  
S.A. Wight ◽  
J.R. Hitchings
Keyword(s):  
Cast Iron ◽  
X Ray ◽  
Graphite Inclusions

Extended abstract of a paper presented at Microscopy and Microanalysis 2013 in Indianapolis, Indiana, USA, August 4 – August 8, 2013.

Investigation of Grey Cast Iron Microstructure Influence on its Heat Resistance

2018 ◽  
Vol 284 ◽  
pp. 332-337 ◽  
Author(s):  
Konstantin N. Vdovin ◽  
M.V. Shubina ◽  
I.G. Shubin
Keyword(s):  
Cast Iron ◽  
Heat Resistance ◽  
Thermal Cycling ◽  
Grey Cast Iron ◽  
Matrix Composition ◽  
Compact Graphite ◽  
Grey Cast ◽  
Lamellar Graphite ◽  
Materials Used ◽  
Graphite Inclusions

Grey cast iron is one of the most common engineering materials used to make castings which work in thermal cycling. Under thermal cycling conditions, heat resistance is an important operational property of grey cast iron, which depends to the greatest extent on its structure – size and shape of the graphite inclusions, as well as the metal matrix composition. In this paper, the heat resistance of unalloyed grey cast iron with lamellar and compact graphite distributed in perlitic and perlitic-ferritic metal matrices was determined. The tests were carried out at temperatures of 500 – 800 °C. The results of the studies showed an insignificant difference of perlitic and perlitic-ferritic grey cast iron with lamellar graphite heat resistance. The heat resistance of perlitic ferritic grey cast iron with compact graphite is 16 – 48 % higher than the heat resistance of perlitic ferritic grey cast iron with lamellar graphite. Thus, when the shape of the graphite inclusions changed from lamellar to compact, a significant increase in the heat resistance of unalloyed grey cast iron occurred.

Cutting Performance of Diamond Coated Si3N4 Tool During Turning

2010 ◽  
Vol 660-661 ◽  
pp. 106-111
Author(s):  
José Vitor C. Souza ◽  
Maria do Carmo de Andrade Nono ◽  
João Paulo Barros Machado ◽  
Olivério Moreira Macedo Silva ◽  
F.C.L. Melo ◽  
...  
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Cutting Tools ◽  
Gray Cast ◽  
Depth Of Cut ◽  
Cast Irons ◽  
Hard Materials ◽  
Tool Wear Mechanisms ◽  
Cutting Length ◽  
Machining Operations

Silicon nitride cutting tools have been used successfully for machining hard materials, like: cast irons, nickel based alloys, etc. However these cutting tools with diamond coating present little information on dry turning operations of gray cast iron. In the present work, Si3N4 square inserts was developed, characterized and subsequently coated with diamond for dry machining operations on gray cast iron. All experiments were conducted with replica. It was used a 1500, 3000, 4500 m cutting length, feed rate of 0.33 mm/rev and keeping the depth of cut constant and equal to 1 mm. The results show that wear in the tool tips of the Si3N4 inserts, in all cutting conditions, was caused by both mechanical and chemical processes. To understand the tool wear mechanisms, a morphological analysis of the inserts, after experiments, has been performed by SEM and optical microscopy. Diamond coated PVD inserts showed to be capable to reach large cutting lengths when machining gray cast iron.

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.

Influence of Alloying on the Uniformity of Strength and Structure of Gray Iron

2012 ◽  
Vol 490-495 ◽  
pp. 3348-3352
Author(s):  
Li Li Xiao ◽  
Feng Zhang Ren ◽  
Meng Qi Liu ◽  
Yu Fei Wang ◽  
Na Wen Zhang ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Cast Iron ◽  
Cutting Force ◽  
Gray Cast Iron ◽  
Brinell Hardness ◽  
Pure Copper ◽  
Gray Iron ◽  
Gray Cast ◽  
Micro Hardness ◽  
Cast Irons

Two gray cast irons with equal tensile strength were prepared to investigate the influence of alloying on the machinability of gray iron. After 75SiFe modifying treatment, they were alloyed by the mixture additive containing RE, Cr, Mn, Si and Fe with a certain proportion and pure copper, respectively. The hardness, section sensitivity, structuralhomogenity and machinability were tested in this experiment. The results show that both of the gray irons have the same brinell hardness and the micro-hardness. The section sensitivity of the gray iron alloyed by the mixture additive is smaller than the gray iron alloyed by copper. The main cutting force of the cast iron alloyed by the mixture additive is lower than that of the cast iron alloyed by copper, therefore, the gray cast iron alloyed by the mixture additive has a better machinability than the cast iron alloyed by copper.

Interfacial Characteristics and Wear Resistance of WCp/White-Cast-Iron Composites

2007 ◽  
Vol 26-28 ◽  
pp. 293-296 ◽  
Author(s):  
Guo Shang Zhang ◽  
Yi Min Gao ◽  
Jian Dong Xing ◽  
Shi Zhong Wei ◽  
Xi Liang Zhang
Keyword(s):  
Wear Resistance ◽  
Cast Iron ◽  
White Cast Iron ◽  
Centrifugal Casting ◽  
Casting Process ◽  
Iron Matrix ◽  
High Chromium ◽  
X Ray ◽  
High Chromium Cast Iron ◽  
Wear Tests

To improve the wear resistance of high chromium white cast iron under severe abrasive conditions, a composites layer was designed for wear surface, which were locally reinforced with WC particles. And the local composites were successfully fabricated by optimized centrifugal casting process. Then the interface between WC and iron matrix was analyzed with scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). And three body wear tests were carried out on a self-made rig to investigate the wear resistance of the composites. For comparison, the wear tests of high chromium white cast iron were also carried out under the same conditions. The results show that: There are no defects such as inclusion, crack, gas pore and so on in the obtained composites layer, which with a uniform thickness of 10 mm. WC particles are homogeneously distributed in the composites layer and tightly bonded with the iron matrix. The WC particles are partially dissolved in the iron matrix during centrifugal casting. The elements W, C and Fe react to form new carbides such as Fe3W3C or M23C6, which precipitate around former WC particles during subsequent solidification. So the interface between WC particles and the iron matrix is a strong metallurgical bonding. WC particles in the composites layer can effectively resist cutting by the abrasive, and then protect the matrix. The wear resistance of the composites layer is 7.23 times of that of high chromium cast iron.

Tribological Research of Properties of Heat – Treated Cast Irons with Globular Graphite

2015 ◽  
Vol 818 ◽  
pp. 209-212 ◽  
Author(s):  
Jozef Bronček ◽  
Peter Fabian ◽  
Norbert Radek
Keyword(s):  
Cast Iron ◽  
Metal Matrix ◽  
Mechanical Energy ◽  
Basic Metal ◽  
Cast Irons ◽  
Globular Graphite ◽  
Treated Steel ◽  
Heat Treated ◽  
Properties Of Materials ◽  
Heat Treated Steel

The contribution deals with the evaluation of tribological properties of materials: isothermally heat-treated cast iron ADI, heat-treated cast iron with globular graphite HTDI with sorbitic structure of the basic metal matrix and heat-treated steel C45. The aim of the research is to gain another knowledge for the application of materials in the condition where the loss of mechanical energy and the loss of material caused by parts wear are being appeared.

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.

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