An improved understanding of solidification of compacted graphite iron cgi is necessary to predict shrinkage related casting defects. A process for producing compacted graphite cast iron thin walled shaped castings in a high productivity line is provided which comprises. His point of view, added to those from rizzo 2001, discloses the enormous. This article discusses the chemical composition, castability, mechanical properties at room temperature and elevated temperature, and physical properties of compacted graphite cg cast iron. Cutting developments make application now practical. Compacted graphite cast iron cgi is also referred as vermicular graphite. The change of graphite shape from flakelike in gray iron to compacted in cgi and spheroidal in nodular, or ductile, iron is a function of the amount of magnesium modification. It could be explained by the alternating growth patterns of compacted graphite. Graphite nucleation in compacted graphite cast iron. As shown in figure 3, cgi is stable over a range of approximately 0.
Types of cast iron compacted graphite iron it is formed after adding small amount of mg andor ce to gray cast iron. Astm a84210 standard specification for compacted graphite. Its graphite occurs as blunt flakes that are interconnected within each cell. Nov 21, 2012 compacted graphite iron cgi also known as the vermicular graphite cast iron is an alloy with attractive features that is used in the automotive industry ref 14 for brake discs and brake drums, exhaust manifolds, engine heads, and diesel engine blocks, and is traditionally manufactured from gray cast iron. Waupaca foundry produces various grades of gray, ductile and compacted graphite iron castings. Compacted graphite iron is the material of choice for engine cylinder heads of heavyduty trucks.
The difference in these types of iron is the characteristics of the graphite used in the material. Wear mechanism when machining compacted graphite iron. A395, a536, a476, a874, a897, compacted graphite iron cgi a842 product identification label identifier ductile iron joint restrains. Dawson 2001 stated that the iron age is just beginning and we have taken this statement for the present paper.
Pdf effect of holding time, thickness and heat treatment. Casting process simulation of compacted graphite iron 03025. Compacted graphite cg cast iron is also referred to as vermicular graphite, upgraded, or semiductile cast iron ref 1. Compacted graphite iron cgi, also known as vermicular graphite iron gjv, vg, jv or ggv from the german. Wear mechanism when machining compacted graphite iron e. Compacted graphite iron a material solution for modern diesel engine cylinder blocks and heads he holds a bachelor of engineering metallurgical degree from mcgill university in montreal and master of applied science and doctor of philosophy degrees from the university of toronto. Gray iron, compacted graphite iron, and ductile iron are differentiated by the shape of the graphite particles figure 2. It has inadvertently been produced in the past as a result of insufficient magnesium or cerium levels in molten intended.
C 300 to 375 350 to 425 400 to 475 450 to 525 500 to 575 100. Pdf production and properties of compacted graphite iron cgi. This material was developed around the same time as sg iron ductile cast iron back in the 1940s but it is only recently that designers and engineers have started to full utilise its unique mechanical qualities. At the same time, a lesserknown material called compacted graphite iron cgi was also patented, though it was just considered a curiosity at the time. Pdf machinability of compacted graphite iron cgi and. Compacted graphite iron cgi castings sds scooo042 rev. Sep 04, 2007 this video is of a makino hightorque horizontal machining center plunge and helical finish boring automotive engine blocks made of compacted graphite iron cgi. Us4806157a process for producing compacted graphite iron. This graphite structure and the resulting properties of the iron are intermediate between gray and ductile irons. Ductile iron compacted graphite iron cgi castings sds sc000042 rev 12 page 1 of 6 20 american foundry society meets the requirements of osha standard 29 cfr 1910. The objective of this work was to create cobased coatings compositionally close to stellite 6 on compacted graphite and gray cast iron substrates with a high power laser 2 kw continuous nd. The full sintercast cgi material property database is available to sintercasts customers and has also been used as the basis of the chapter entitled mechanical properties of compacted graphite iron in the recently published afs american foundry society iron castings engineering handbook. Astm a84211a standard specification for compacted graphite. Although compacted graphite iron has been known for more than four decades, the absence of a reliable massproduction technique has resulted in relatively.
The improved mechanical properties of compacted graphite iron relative to conventional gray iron allow for substantial weight reduction in gasoline and diesel engines or substantial increases in horsepower, or an optimal combination of both. The introduction of modern measurement and control technologies has made cgi a viable material for highvolume series production. Rotary cutting tools star su pressure coolant reamers utilize pressurized coolant to force chips ahead of the tool to produce ultrasmooth, ultraprecise holes. The second phase serves as an application of the previously built model to capture the more complex scenario involving machining of cgi at different cutting. Microstructure specifications typically require a nodularity range of 020%. Nevertheless, the complex 3d morphology of compacted graphite cg has hindered significant advances in similar theories for this type of graphite. The material is being used for the manufacture of brake disks, exhaust manifolds, cylinder. Influence of fading on characteristics of thermal analysis. This describes a range of cast irons where the graphite forms round ended flakes rather than sharp flakes or spheres. These individual particles are elongated and randomly oriented, in a similar way as in grey iron, despite being shorter and thicker then these last ones, as well as having rounded edges 6. Compacted graphite iron cgi along with lamellar graphite iron and spheroidal graphite iron define the three main classes of cast iron according to morphology. Compacted graphite iron cgi continues to gain use within the automotive industry.
In comparison to either grey iron or ductile iron, the entangled compacted graphite clusters interlock themselves into the iron matrix to provide a strong adhesion. In professional circles, this material is called compacted graphite iron cgi. The resulting increase in thermal and mechanical loading has required a change from conventional grey cast iron to compacted graphite iron cgi in order to. The article describes the production of compacted graphite iron castings and the process control that depends on the production volume of components made from compacted graphite iron. As machining is conceptually a controlled fracture process, this stage comprehensively studies and models the initiation and propagation of fracture in compacted graphite iron. To bring clarity to this issue, interrupted solidification. The compacted graphite cast construction allows for a max operating pressure of 3500psi. Sintercast will focus on providing process control technology, knowhow and technical support for the reliable high volume production of compacted graphite iron. University of groningen thick cobased coating on cast. The difference between the three types of graphite is more striking when viewed in the threedimensional deepetch scanning electron micrographs. Compacted graphite iron, which is also known as cgi or vermicular graphite iron, is a form of cast iron in which the shape of the graphite particles is between that of conventional grey iron flakes and ductile iron where the graphite is in spheres. A reliable and consistent production technology for high volume.
Gusseisen mit vermiculargraphit especially in nonenglish speaking countries, is a metal which is gaining popularity in applications that require either greater strength, or lower weight than cast iron. Cast and wrought 4140 type steels, and cast and wrought h steels also will be evaluated. Compacted graphite iron is also known as cgi and vermicular graphite iron. The engine family utilises twin overhead camshafts and multivalves, single or twinturbochargers with an airtoair intercooler, and innovative compacted graphite iron cgi block construction that leads to a low weight of 202 kg 445 lb dry. This is due to its advantages in combining the benefits of gray and ductile cast iron. This project did not address the risk for the formation of lamellar graphite. Technical introduction to metallurgical process control. Compacted graphite iron a material solution for modern. The shape of the graphite particles present in cgi greatly enhance the strength and hardness of the iron. Compacted graphite iron cgi has an important role in manufacturing of new generation engines.
Astm a84210 standard specification for compacted graphite iron castings. During the last several decades, a multitude of theories have attempted to explain the process of graphite nucleation in lamellar lg and spheroidal sg graphite iron castings. Invariably the structure was produced by accident and still is due to the breakdown of process control during. A common process is when elevated temperatures result in microstructure deterioration, such as the decomposition of pearlite into the equilibrium structure of iron and graphite. Pdf the compacted graphite iron cgi represents an example of material with remarkable and unexplored properties, especially in terms of.
The main output files from the simulation concerning cgi are. Shiha a department of mechanical engineering, university of michigan, ann arbor, mi, usa b state key laboratory for manufacturing systems engineering, xi. The mechanical and physical properties of compacted graphite iron cgi have been studied. Sintercast will also develop and promote novel technologies beyond the core cgi market, including tracking and traceability solutions and other precision measurement products that bring enhanced control and profitability to the. Compacted graphite iron cgi, also known as vermicular graphite iron, is a metal which is gaining popularity in applications that require either greater strength, or lower weight than cast iron. Graphite morphologies in cgi are randomly oriented, elongated and interconnected within eutectic cells as in gray iron, but stubby, bluntedged and have rounded ends and. The compacted graphite morphology inhibits crack initiation and growth and is the source of the improved mechanical properties relative to grey iron. Compacted graphite iron is an emerging cylinder block material having a higher specific strength than conventional gray iron, and with improved fatigue strength and acoustic properties relative to aluminum, thereby allowing cast iron blocks of reduced thickness and mass to be constructed tholl 1996. Compacted graphite iron for diesel engine cylinder blocks. Compacted graphite iron provides the best possible compromise between optimum mechanical properties, compared to. Pdf this research work was carried out to produce compacted graphite iron cgi and to study its mechanical and physical properties. Secondary graphitization is graphite formation that occurs by the transformation of metastable metallic carbides following solidification. Introduction among the modern varieties of cast iron, cast iron with compacted graphite occupies a special place of growing interest.
The compacted graphite iron graphite particles are formed in a vermicular shape, as shown in figure 1. The material compacted graphite iron cgi puts high demands on machining. Castability, product design, and production of compacted. Gray iron is the most widely cast metal and is easier to cast and less costly to produce than other types of cast iron because it neither requires special alloy additions necessary to produce ductile iron or compacted graphite iron nor does it require annealing heat treatment of the rough castings as is necessary to produce malleable iron. Compacted graphite iron a material solution for modern diesel engine cylinder blocks and heads dr steve dawson sintercast, sweden op19 the demands for improved fuel economy, performance and emissions continue to pose challenges for engine designers and the materials they choose. This gives a range of irons that have toughness with good heat transfer and vibration properties. Materials may be used asis or alloyed to provide microstructures with different life and stabilities at elevated temperatures. The 1st in our series of technical introduction articles focuses on the growing use of compacted graphite iron cgi. Compacted graphite iron cylinder blocks and heads have become a vital part in todays modern diesel engine production, essential for manufacturers wishing to maintain a competitive edge. Configuration aluminum block and head 60degree v6, compacted graphite iron aluminum block, aluminum head manufacturing location cleveland engine plant lima engine plant intake manifold composite shellwelded with runner pack composite shellwelded with runner pack exhaust manifold threeport integrated into aluminum head integrated into. Compacted graphite iron what is compacted graphite iron. Foundry production similar to ductile iron, compacted graphite iron is produced by adding magnesium to a desulfurized base iron. Compacted graphite iron cast iron with vermicular graphite is commonly named as such due to its wormlike graphite structure wormshaped vermicular, latin. Platt, quaker chemical corporation, metalworking division laboratory scope.
As a stronger material that can absorb more power, cgi offers the improved performance and fuel economy to meet new emissions standards and the. Compacted graphite iron a material solution for modern diesel. Effects of chip morphology on too life in highthroughput. Technical introduction to metallurgical process control for. Astm a84211a standard specification for compacted graphite iron castings. Compacted graphite cast irons russell ductile casting. Compacted graphite iron cgi is a form of cast iron which has elongated graphite particles mixed with spherical graphite particles present within the alloy, as opposed to the graphite flakes present in typical cast iron. The change in graphite morphology from the flake graphite fg in the base iron to the cg in the final iron is achieved by liquid treatment with different. Cgi became commercially available as dependable methods for its production were developed. Dec 17, 2015 new richmond, bridgnorth and stockholm, 17 december 2015 engineered propulsion systems eps has uniquely leveraged the strength and stiffness of compacted graphite iron cgi, together with a. Compacted graphite iron is a highstrength material which enables a thinwalled, cast iron construction.
Theory of crystallization, compacted graphite iron, ausferrite, dta method 1. While it is known that cgi provides at least 70% higher tensile strength, 35% higher elastic modulus and 80% higher fatigue limits than conventional grey cast iron, the objective of this paper was to determine how the properties change with varying nodularity graphite shape and pearlite content. Engineered propulsion systems leverages cgi for diesel. The effect of compacted graphite iron microstructure. Compacted vermicular graphite irons cgi have been produced since the inception of spheroidal graphite nodular or ductile irons in the late 1940s. The compacted graphite grows with characteristics of flakes in some extent, but also has rounded edges. You will be redirected to the full text document in the repository in a few seconds, if not click here. Schulz 1 institute of production management, technology and machine tools ptw university of technology, darmstadt, germany abstract the industrial application of compacted graphite iron in the automotive industry is taking a rather long time due to its uneconomic machinability, because of a significant decrease. Metallography and microstructures of cast iron janina m. Effects of titanium addition on microstructure and mechanical. Interchangeable with the very popular va and vg series hydraulic valve available in individual components or we can build you a custom engineered and tested valve assembly 100% factory tested. Effect of graphite nodularity on mechanical properties of. In 1949, a now wellknown material called ductile iron was patented.
The relationships between the relevant laser cladding parameters. Proposal of characterization procedure of metalgraphite. Compacted graphite iron an overview sciencedirect topics. The wormlike compacted graphite shape provides physical properties that mirror the most. A number in parentheses indicates the year of last reapproval. Platt, quaker chemical corporation, metalworking division laboratory to the differences in the material properties and machinability of these two metals. Gray iron is called that because when it is fractured, its surface appears a dull gray color. Horizontal cnc machining of compacted graphite iron cgi. Better strength of cgi, as compared to flake graphite iron fgi, allows cgi engine to perform at. Pearlite content can be chosen to suit the application. Compacted graphite iron cgi cubic boron nitride cbn 1 introduction compacted graphite iron cgi, belonging to the family of cast irons, has emerged as a candidate material to substitute gray cast iron ci in engine block applications for diesel engines because of superior mechanical properties, and.
Al, ti, mg and s, have the decisive importance for crystallization of compacted graphite and its share in casting structure. In a recent paper discussing cgi uses for engine cylinder blocks and heads, s. A study of compacted graphite iron production in a laboratory environment was conducted by. Metallurgical process control for compacted graphite irons general introduction compacted vermicular graphite irons cgi have been produced since the inception of spheroidal graphite nodular or ductile irons in the late 1940s. The test results are in good agreement with those in the reference 9. However, the same mechanical properties of compacted graphite iron cgi. The data files were store in ascii format by using commercial. The choice of cutting tool can dictate how effective shops are able to machine this challenging material.
The relative properties of the three cast irons are summarized in table i. Production experience with compacted graphite iron. Metallurgical process control for compacted graphite irons. Jan 01, 2008 challenges in cutting cgi compacted graphite iron is increasingly used for diesel and racing engine components. Casting process simulation of compacted graphite iron 03. Spheroidal graphite is not only found in ductile iron sgi but usually also in cgi, but its characteristics and role in this material is less understood. The mechanical and physical properties of compacted graphite iron.
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