scholarly journals Experimental assessment of the gray cast iron production by inoculant injection

Author(s):  
G. Reyes-Castellanos ◽  
A. Cruz-Ramírez ◽  
Hugo Gutiérrez-Pérez ◽  
J.E. Rivera-Salinas ◽  
R.G. Sánchez-Alvarado ◽  
...  

An initial assessment of the gray cast irons production by injecting an inoculant with a conveying gas into a molten iron bath was evaluated at a laboratory scale. A numerical simulation was carried out to determine the hydrodynamic behavior between the inoculant particles injected into the molten iron. It was determined that an optimal interaction between the particles with the molten iron occurs at a lance depth of 7 cm and for the particle sizes fine (211 to 297 ?m) and medium (421 to 590 ?m), the residence time was of 0.38 and 0.4 s, respectively. The melting time was calculated at 0.0008 and 0.003 s for the particle sizes fine and medium, respectively. So, after injection, the FeSi of the inoculant melts quickly, releasing the elements of the inoculant which interact with the molten iron and forms oxides and sulfides creating nucleating sites during solidification. The injection technique allows obtaining a type-A graphite distribution for the fine and medium particle sizes. The number of eutectic cells was increased when the inoculant particle size was decreased despite of the low graphitisers elements, and manganese contents used in the gray cast iron manufacturing.

Alloy Digest ◽  
2021 ◽  
Vol 70 (9) ◽  

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.


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 ◽  
...  

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.


2013 ◽  
Vol 800 ◽  
pp. 221-224
Author(s):  
Jun Tao Zhang ◽  
Feng Zhang Ren

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.


2012 ◽  
Vol 490-495 ◽  
pp. 3348-3352
Author(s):  
Li Li Xiao ◽  
Feng Zhang Ren ◽  
Meng Qi Liu ◽  
Yu Fei Wang ◽  
Na Wen Zhang ◽  
...  

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.


2018 ◽  
Vol 925 ◽  
pp. 110-117 ◽  
Author(s):  
Marcos López ◽  
Juan M. Massone ◽  
Roberto Enrique Boeri

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.


2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
A. R. Kiani-Rashid ◽  
M. Mostafapour ◽  
S. K. Kaboli-Mallak ◽  
A. Babakhani

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.


2017 ◽  
Vol 62 (2) ◽  
pp. 1113-1117
Author(s):  
Seung-Yeon Park ◽  
J.H. Kim ◽  
S.J. Seo ◽  
J.S. On ◽  
K.M. Lim

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.


2019 ◽  
Vol 3 (5) ◽  
pp. 21-27
Author(s):  

As the tensile strength of gray cast iron is low, it is tried to increase tensile strength by testing various alloying elements. The most preferred of these alloying elements was the copper element. However, it is known that copper increases both hardness and tensile strength by enhancing perlite ratio in microstructure. On the other hand, when tin (Sn) is used in trace amounts compared to copper, it has similar effects on hardness and tensile strength of cast iron. In this study, adding tin element of 0,03-0,06-0,09-0,12-0,15 % by weight in gray cast iron, its effect on tensile strength was investigated and the appearance of the fracture surfaces was examined. It was compared with two different gray cast irons containing 0.4% copper element and free of alloying elements. According to the tensile strength results, the highest tensile strength was observed to be 195 N / mm2 in the specimen number 6 containing 0,12% Sn. The lowest tensile strength was determined as 157 N / mm2 in the specimen number 1 which did not contain alloying elements. In SEM (Scanning Electron Microscopy) images, it is seen that the samples generally exhibit a brittle rupture behaviour. In some of the specimens with the addition of tin and copper, regional ductile rupture behaviours were observed.


2014 ◽  
Vol 782 ◽  
pp. 269-274 ◽  
Author(s):  
Cinca Ionel Lupinca ◽  
Marian Dumitru Nedeloni ◽  
Dorian Nedelcu

The paper presents the cavitation stand used, the work methodology, the trials realized on specimens of gray cast irons, with flake graphite and spheroidal-graphite, which were tested for cavitation erosion during different periods of time of the cavitation attack. Finally, the conclusions were interpreted on the basis of comparative graphics realized at the macro and microstructures level obtained for these two types of cast iron. Of the two types of gray cast iron, the nodular cast iron presents a better cavitation erosion resistance.


Alloy Digest ◽  
2021 ◽  
Vol 70 (6) ◽  

Abstract ISO 185/JL/300 is a higher-tensile-strength gray cast iron that has a pearlitic matrix; it has a tensile strength of 300–400 MPa (44–58 ksi), when determined on test pieces machined from separately cast, 30 mm (1.2 in.) diameter test bars. It provides 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 casting and heat treating. Filing Code: CI-82. Producer or source: International Organization for Standardization.


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