scholarly journals The Effect of Cooling Rate on Bainite Phase Formation in Austempered Nickel-Molybdenum Gray Cast Iron

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
A. R. Kiani-Rashid ◽  
M. Mostafapour ◽  
S. K. Kaboli-Mallak ◽  
A. Babakhani
Keyword(s):  
Cast Iron ◽  
Cooling Rate ◽  
Phase Formation ◽  
Cross Sections ◽  
Gray Cast Iron ◽  
Bainitic Ferrite ◽  
Sample Thickness ◽  
Gray Cast ◽  
Cast Irons ◽  
Phase Proportion

Taking into account the importance of the amount of bainite phase on the microstructure of cast irons and its influence on the improvement of mechanical properties, this research selected an alloy of gray cast iron containing Nickel-Molybdenum and conducted the austenitising and austempering processes at 900°C and 400°C for 60 minutes, respectively. The way of bainite phase formation and the effect of sample thickness, that is, cooling rate, were examined by selecting a standard staircase sample. The results indicated that, by increasing the cross sections of samples, the martensite percentage decreases and the phase proportion of bainitic ferrite increases.

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.

Microstructure and Hardness of Gray Cast Iron as a Product of Solidification in Permanent Mold

2020 ◽  
Vol 991 ◽  
pp. 37-43
Author(s):  
Agus Yulianto ◽  
Rudy Soenoko ◽  
Wahyono Suprapto ◽  
As’ad Sonief ◽  
Agung Setyo Darmawan ◽  
...  
Keyword(s):  
Cast Iron ◽  
Cooling Rate ◽  
Induction Furnace ◽  
Gray Cast Iron ◽  
Casting Process ◽  
Melting Process ◽  
Gray Cast ◽  
Outer Side ◽  
Permanent Mold ◽  
Test Results

Molds of metal are widely used in the casting process. The cooling rate in solidification of castings product with metal molds on the outer side and inner side is different. Therefore, sizes and types of phase will be also different. This study aims to investigate the microstructure andhardness of gray cast iron. To realize this research, the gray cast iron melting process was carried out in an induction furnace. Melted gray cast iron was poured into a Ferro Casting Ductile mold that has been through a preheating process at a temperature of 300 o C. The gray cast iron is then tested for composition, microstructure and hardness. The test results show that the part containing morecementite phase will be harder.

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.

Simulation of Cooling Rate of Gray Cast Iron Casting in a Sand Mold and its Experimental Validation

2012 ◽  
Vol 710 ◽  
pp. 208-213 ◽  
Author(s):  
Vinod Kumar ◽  
Amitesh Kumar
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Cast Iron ◽  
Cooling Rate ◽  
Gray Cast Iron ◽  
Sand Mold ◽  
Gray Cast ◽  
Flow Heat ◽  
Dendritic Arm Spacing ◽  
Heat Transfer And Solidification

Estimation of cooling rates of gray cast iron casting in the sand mold and its dependency on design and process parameters is one of the keys for achieving best processing conditions to produce quality castings. The estimation of cooling rate involves modeling of fluid flow, heat transfer and solidification of molten metal inside the mold. Prediction of heat transfer has been carried out from filling of mold but the estimation of cooling rate has been carried out after complete filling of the mold. In the present work fluid flow, heat transfer and solidification of molten metal in a sand mold model has been developed on a Pro-Cast 2008 platform. A stepped bar pattern with different thickness has been fabricated to carry out the experiment. Stepped bar pattern has been selected because gray cast iron castings are thickness sensitive as well as different section of castings have different cooling rate. Cooling rates have been determined experimentally by measuring the Dendritic Arm Spacing (DAS) and Secondary Dendritic Arm Spacing (SDAS) from the microstructure of different steps. Results show that the morphology of graphite, dendritic arm spacing and secondary dendritic arm spacing as well as the interlamellar spacing of eutectic structure depend on the casting thickness. These decreases as the thickness of castings decrease because thinner section of casting has higher rate of cooling than the thicker section. The estimated cooling rate matched well with the experimentally measured cooling rate.

scholarly journals Evolution of the Macrostructure of Gray Cast Iron from Eutectic to Hypereutectic Composition

2018 ◽  
Vol 925 ◽  
pp. 110-117 ◽  
Author(s):  
Marcos López ◽  
Juan M. Massone ◽  
Roberto Enrique Boeri
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Eutectic Reaction ◽  
Liquidus Line ◽  
Nucleating Agent ◽  
Gray Cast ◽  
Carbon Equivalent ◽  
Flake Graphite ◽  
Cast Irons ◽  
Coupled Growth

This work studies the evolution of the macrostructure of gray cast iron as the carbon equivalent (CE) increases from near-eutectic to highly hypereutectic values. The macrostructure of spherical samples of flake graphite irons of CE ranging between 4.24% and 5.23% was revealed by using direct austempering after solidification technique (DAAS). The results were analysed by applying the concept of coupled zone for gray cast irons. The coupled zone is a region in the stable Fe-C-Si diagram in which solidification proceeds as a cooperative growth of both austenite and flake graphite. The coupled zone for gray cast iron is claimed to be asymmetrical as the eutectic reaction is extended towards the prolongation of the austenite liquidus line. All the samples investigated in the present study show the presence of relatively large austenite grains, demonstrating that the number of active nucleation sites of austenite per unit volume is small. The observation of the microstructure shows the presence of several units of coupled growth inside each austenite grain, what proves that many eutectic colonies have grown from the same austenite nucleus, even for highly hypereutectic compositions. Colour etching was employed to reveal the “hidden” dendrites present in the microstructure. The results suggest that proeutectic graphite is not a good nucleating agent for austenite. These results contribute to the understanding of the solidification of hypereutectic gray irons and verify the earlier understanding of the solidification of eutectic gray irons and its extension to hypereutectic compositions.

scholarly journals Fabrication of High-Strength Gray Cast Iron Using Permanent Magnet Scrap

2017 ◽  
Vol 62 (2) ◽  
pp. 1113-1117
Author(s):  
Seung-Yeon Park ◽  
J.H. Kim ◽  
S.J. Seo ◽  
J.S. On ◽  
K.M. Lim
Keyword(s):  
Tensile Strength ◽  
Cast Iron ◽  
Permanent Magnet ◽  
High Performance ◽  
Gray Cast Iron ◽  
High Strength ◽  
Cost Effective ◽  
Gray Cast ◽  
Cast Irons ◽  
Cast Specimen

AbstractIn this study, we have developed the manufacturing technology for high strength gray cast irons by using the spent permanent magnet scraps. The cast specimen inoculated by using a spent magnet scraps showed the excellent tensile strength up to 306MPa. This tensile strength value is 50MPa higher than that of the specimen cast without inoculation, and is similar to that of the specimen inoculated by using the expensive misch-metal. These superior mechanical properties are attributed to complex sulfides created during solidification that promote the formation and growth of Type-A graphite. It is therefore concluded that spent magnets scrap can provide an efficient and cost-effective inoculation agent for the fabrication of high-performance gray cast iron.

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