Compacted graphite iron a material solution for modern. Sintercast will focus on providing process control technology, knowhow and technical support for the reliable high volume production of compacted graphite iron. In 1949, a now wellknown material called ductile iron was patented. Engine components experience high temperatures during operation, which deteriorates the mechanical properties and induce an acceleration of fatigue damage. Compacted graphite iron a material solution for modern diesel. Pdf mechanical properties of compacted graphite cast iron. Ductile iron and compacted graphite iron castings msds special notice. The high local stresses at the graphite tips also result in the opening of the graphite cavities which is much more severe in the flake graphite cast iron than in the compacted graphite cast iron. Controlling the production of compacted graphite iron. Compacted graphite iron cgi, also known as vermicular graphite iron especially in.
Compacted graphite iron for diesel engine cylinder blocks tupy. Refined control technologies can now allow foundries to meet the ongoing demand for higher performance engines through cgi castings. Compacted graphite iron is usually used as pearlitic matrix for the diesel engine block and ferritic matrix for manifold exhaust. Cgi allows the manufacture of diesel engines with better.
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. Schelleng obtained a patent for the production of compacted. 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. Astm a84211 standard specification for compacted graphite. The complex corallike graphite morphology, together with the rounded edges and irregular bumpy surfaces of the compacted graphite particles, results in stronger adhesion between the graphite and the iron matrix, inhibiting crack initiation and providing superior mechanical properties. Compacted graphite iron has a higher resistance and fracture toughness, with a lower section sensitivity. To bring clarity to this issue, interrupted solidification.
It is indicated that the thermal conductivity of cgi declines with. Pdf production and properties of compacted graphite iron cgi. Computational assessment of thermal conductivity of. Astm a84211 standard specification for compacted graphite iron castings.
Casting process simulation of compacted graphite iron 03. Ductile iron and compacted graphite iron castings msds. Us5337799a method for the production of compacted graphite. The method comprises controlling and correcting the composition of the cast iron melt and securing the necessary amount of structure modifying agent. Compacted graphite cast iron, microstructures, mechanical properties introduction compacted graphite cg cast iron is part of the cast iron family belonging to the fec irregular eutectic system, characterised by an intermediate graphite morphology between the classical. It is indicated that the thermal conductivity of cgi declines with the increase of pearlite. Production experience with compacted graphite iron. Compacted graphite cast iron cgi is also referred as vermicular graphite. It depends on a better castability, machinability and thermal. 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. These materials shall be examined metallographically for the acceptance graphite formation. Compacted graphite iron what is compacted graphite iron. Meanwhile, thermal conductivity of cgi with different pearlite contents was tested through the laser flash method.
These worms shape a similar threedimensional, branched out structure as in grey cast iron. The shape of the graphite particles present in cgi greatly enhance the strength and hardness of the iron. Compacted graphite iron cgi along with lamellar graphite iron and spheroidal graphite iron define the three main classes of cast iron according to morphology. Mechanical properties of compacted graphite cast iron with. The advantages of a fractured split line were discussed, including the design freedom that can be achieved using fracture splitting. Thermal conductivity of thin walled compacted graphite. This describes a range of cast irons where the graphite forms round ended flakes rather than sharp flakes or spheres. This specification deals with compacted graphite iron castings. 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. This article discusses the graphite morphology, chemical composition, mechanical and physical properties, and applications of compacted graphite cg irons. Graphite nucleation in compacted graphite cast iron. Compacted graphite iron metals handbook desk edition, 2nd.
Technical introduction to metallurgical process control. The case metal processing laboratory currently holds a sintercast license, enabling controlled production of compacted graphite iron cgi. Mar 11, 2020 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. A sample of the melt is taken with a sample vessel provided with two thermocouples, one positioned so as to be in the centre of the sample. Compacted graphite iron an overview sciencedirect topics. The chemical composition, section thickness and heat treatment are the main factors controlling the microstructure and consequently the mechanical properties. Journal of the brazilian society of mechanical science and. Compacted graphite iron cgi, also known as vermicular graphite iron gjv, vg, jv or ggv from the german. Dawson 2001 stated that the iron age is just beginning and we have taken this statement for the present paper. Customarily, this has led to the increased use of light alloys and composites. Gray iron, compacted graphite iron, and ductile iron are differentiated by the shape of the graphite particles figure 2.
Computational assessment of thermal conductivity of compacted. Recently the need to save energy and resources has forced designers and constructor to focus on light weight castings. This form of cast iron is being used for the manufacture of brake disks, exhaust manifolds, cylinder heads, as well as diesel engine. Compacted graphite iron cgi has been known since the nineties as a highstrength casting material figure 1. Evans, in metalworking fluids mwfs for cutting and grinding, 2012. 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. 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. Compacted graphite iron cgi provides at least 70% higher tensile strength, double the mechanical fatigue strength, and 30 40% higher elastic modulus stiffness than conventional grey cast iron. The aim of this paper is to compare the machinability of gray cast iron and compacted graphite iron cgi, in terms of tool life and microstructure.
What i did not mention though and this is where this article connects to the previous one is the fact that. The mechanical properties of the eutectic flake graphite cast iron are largely affected by the size and amount of the graphite particles. Two gray cast irons with different graphite morphologies and one cgi were tested. Its graphite occurs as blunt flakes that are interconnected within each cell. Pdf this research work was carried out to produce compacted graphite iron cgi and to study its mechanical and physical. It can be seen that the values of the properties of compacted graphite iron lie. Twodimensional fe models of cgi with different pearlite contents for thermal conductivity analysis were established according to the real metallographic images obtained by proe and ansys. Compacted or vermicular graphite cast irons cgi have been produced since the beginning of spheroidal graphite cast irons in the late 1940s. The compacted graphite form lies between grey iron, where graphite is in flake form, and ductile iron where graphite is in nodular form.
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. The compacted graphite iron graphite particles are formed in a vermicular shape, as shown in figure 1. Compacted graphite iron is present in the form of worms photo right. Presently, the decision of automobile manufacturers to substitute cgi for gray iron engine blocks. No other units of measurement are included in this standard. Compacted graphite iron vermicular cast iron compacted graphite iron cgi is a form of cast iron which is gaining increasing interest and use within the automotive industry. Compacted graphite iron is an emerging cylinder block material having a higher specific strength than conventional gray. Although compacted graphite iron cgi has existed for more than 40 years, its applications have been limited to simple, lowvolume components with wide microstructural tolerances such as flywheels, exhaust manifolds, pump housings and. The acceptable graphite formation in the microstructure of the test coupon or casting lug shall contain 80% minimum type iv graphite. Compacted graphite iron invariably includes some nodular. A method relating to the production of cast iron castings with compacted graphite crystals. 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. 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 r. In order to explore the effect of the microstructural state of cgi on the.
Pdf machinability of compacted graphite iron cgi and. In comparison to the common aluminum alloys, compacted graphite iron provides double the strength and. Effect of holding time, thickness and heat treatment on. Our diverse customer base has also given us experience in a wide range of applications for compacted graphite iron castings, including pumps and valves, forges, foundries and rolling mills, automotive and aerospace, a wide range of oems, quarries and mines, railways and rolling stock, local authorities and artists and sculptors. The demands for improved fuel economy, performance and emissions continue to pose challenges for engine designers and the materials they choose. 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. An important measure for assessing the application of cgi is the machinability levels and through specific studies it was concluded that cgi is much more difficult to machine than.
The relative properties of the three cast irons are summarized in table i. The advantages to nodular graphite cast iron are up to the thermal expansion. Compacted graphite cast iron offers a higher thermal conductivity and a better resistance to thermal shocks. 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. Compacted graphite iron cgi provides a combination of thermal and mechanical properties satisfying the requirements of diesel engine components of cylinder heads. Cgi displays very useful properties for a range of engineering applications with the tensile strength and elastic modulus being considerably higher than grey cast irons 75% and 35%. Astm a842852004 standard specification for compacted. Compacted graphite iron cgi for their petrol and diesel cylinder block and head applications. 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 wormlike or vermicular compactedgraphite shape provides physical properties that mirror the most beneficial properties of grey and ductile irons. Compacted graphite iron, engine cylinder head and vehicle 20121212 abandoned us20140161657a1 en. Comparison of mechanical properties in flake graphite and. Us20140161657a1 compacted graphite iron, engine cylinder. Casting process simulation of compacted graphite iron 03025.
View enhanced pdf access article on wiley online library html view download pdf for offline viewing. Current research efforts are investigating the effect of sulfur additions on the size of the process window leading to vermicular graphite formation. Nevertheless, the complex 3d morphology of compacted graphite cg has hindered significant advances in similar theories for this type of graphite. Cutting developments make application now practical. Effects of titanium addition on microstructure and. This graphite structure and the resulting properties of the iron are intermediate between gray and ductile irons. 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. Cgi became commercially available as dependable methods for its production were developed. Standard specification for compacted graphite iron castings.
This structure is decisive for the better damping behavior and higher elongation of this material. 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. The properties of gray cast iron, compacted graphite iron and ductile iron are compared on tab. In a recent paper discussing cgi uses for engine cylinder blocks and heads, s. Compacted graphite iron case metal processing laboratory. This gives a range of irons that have toughness with good heat transfer and vibration properties. Pdf occurrence and effect of casting skin in compacted. Occurrence and effect of casting skin in compacted graph ite iron article pdf available in international journal of cast metals research 2912 march 2016 with 340 reads how we measure reads.
It compares the selected properties of gray, ductile and cg irons, and lists their property requirements as per astm a 842. Mechanical properties of compacted graphite cast iron with different microstructures article pdf available in international journal of cast metals research 275. 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. Effects of titanium addition on microstructure and mechanical. A compacted graphite iron having composition comprising. Cg irons have strength properties close to those of spheroidal graphite sg irons. Compacted graphite iron is also known as cgi and vermicular graphite iron. The introduction of modern measurement and control technologies has made cgi a viable material for highvolume series production. Study of the machinability of compacted graphite iron for. Compacted graphite cast iron was produced by accident due to the breakdown of process control. This form of cast iron is being used for the manufacture of brake disks, exhaust manifolds, cylinder heads, as well as diesel engine blocks. His point of view, added to those from rizzo 2001, discloses the enormous. Compacted graphite iron metals handbook desk edition. Pdf mechanical properties of compacted graphite cast.