Compacted graphite iron: Cast iron makes a comeback

JOM ◽  
1994 ◽  
Vol 46 (8) ◽  
pp. 44-47 ◽  
Author(s):  
S. Dawson
Keyword(s):  
Cast Iron ◽  
Compacted Graphite Iron ◽  
Compacted Graphite

Microstructural Evolution of Compacted Graphite Iron under Thermo-Mechanical Fatigue Conditions

2011 ◽  
Vol 409 ◽  
pp. 757-762 ◽  
Author(s):  
S. Ghodrat ◽  
M. Janssen ◽  
Roumen H. Petrov ◽  
Leo Kestens ◽  
Jilt Sietsma
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Elevated Temperatures ◽  
Easy Access ◽  
Compacted Graphite Iron ◽  
Microstructural Changes ◽  
Oxide Layers ◽  
Cooling Cycle ◽  
Compacted Graphite ◽  
Mechanical Fatigue

Cast iron components in combustion engines, such as cylinder blocks and heads, are exposed for long periods of time to elevated temperatures and subjected to large numbers of heating and cooling cycles. In complex components, these cycles can lead to localized cracking due to stresses that develop as a result of thermal gradients and thermal mismatch. This phenomenon is known as Thermo-Mechanical Fatigue (TMF). Compacted Graphite Iron (CGI) provides a suitable combination of thermal and mechanical properties to satisfy the performance of engine components. However, TMF conditions cause microstructural changes, accompanied by the formation of oxides at and close to the surface, which together lead to a growth in size of the cast iron. These microstructural changes affect the mechanical properties and accordingly the thermo-mechanical fatigue properties. The aim of this research is to provide insight into the microstructure evolution of CGI, with its complex morphology, under TMF conditions. For this, optical and scanning electron microscopy observations are made after cyclic exposure to air at high temperature, both without and with mechanical loading. It was found that the oxide layers, which develop at elevated temperatures, crack during the cooling cycle of TMF. The cracking results from tensile stresses developing during the cooling cycle. Therefore, paths for easy access of oxygen into the material are formed. Fatigue cracks that develop also show oxidation at their flanks. In order to quantify the oxide layers surrounding the graphite particles, Energy Dispersive X-Ray Analysis (SEM-EDX) and Electron Probe Micro Analysis (EPMA) are used.

scholarly journals Effect of Copper on the Crystallization Process, Microstructure and Selected Properties of CGI

2017 ◽  
Vol 17 (1) ◽  
pp. 51-56 ◽  
Author(s):  
G. Gumienny ◽  
B. Kacprzyk ◽  
J. Gawroński
Keyword(s):  
Cast Iron ◽  
Crystallization Process ◽  
Maximum Temperature ◽  
Compacted Graphite Iron ◽  
Austenite Transformation ◽  
Compacted Graphite ◽  
Eutectic Transformation ◽  
High Propensity ◽  
Eutectic Crystallization ◽  
Effect Of Copper

Abstract The paper presents the results of the research on the effect of copper on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in cast iron was obtained using Inmold process. The study involved the cast iron containing copper at a concentration up to approximately 4%. The effect of copper on the temperature of the eutectic crystallization as well as the temperature of start and finish of the austenite transformation was given. It has been shown that copper increases the maximum temperature of the eutectic transformation approximately by 5°C per 1% Cu, and the temperature of the this transformation finish approximately by 8°C per 1% Cu. This element decreases the temperature of the austenite transformation start approximately by 5°C per 1% Cu, and the finish of this transformation approximately by 6°C per 1% Cu. It was found that in the microstructure of the compacted graphite iron containing about 3.8% Cu, there are still ferrite precipitations near the compacted graphite. The effect of copper on the hardness of cast iron and the pearlite microhardness was given. This stems from the high propensity to direct ferritization of this type of cast iron. It has been shown copper increases the hardness of compacted graphite iron both due to its pearlite forming action as well as because of the increase in the pearlite microhardness (up to approx. 3% Cu). The conducted studies have shown copper increases the hardness of the compacted graphite iron approximately by 35 HB per 1% Cu.

scholarly journals Nickel in Compacted Graphite Iron

2017 ◽  
Vol 62 (2) ◽  
pp. 657-662 ◽  
Author(s):  
G. Gumienny ◽  
B. Kurowska ◽  
T. Szymczak ◽  
J. Gawroński
Keyword(s):  
Cast Iron ◽  
Wall Thickness ◽  
Crystallization Process ◽  
Research Work ◽  
Nickel Concentration ◽  
Compacted Graphite Iron ◽  
Iron Matrix ◽  
Compacted Graphite ◽  
Eutectic Crystallization ◽  
The Matrix

AbstractThe paper presents results of the research work concerning effects of nickel concentration on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in the cast iron was obtained with use of the Inmold process. The study has comprised the cast iron containing nickel up to concentration providing obtainment of austenitic microstructure of the matrix. The effect of the nickel on temperature of the eutectic crystallization was specified. It has been presented composition of the cast iron matrix in function of nickel concentration in a casting with wall thickness of 3 mm and 24 mm. Moreover, it has been presented conditions defining the possibility of obtaining an austenitic and martensitic compacted graphite iron. Effect of the nickel on hardness of the cast iron was described.

Machinability of Compacted Graphite Iron in Honing

2008 ◽  
Author(s):  
Yhu-Tin Lin
Keyword(s):  
Energy Efficiency ◽  
Cast Iron ◽  
Mechanical Strength ◽  
Manufacturing Process ◽  
Gray Cast Iron ◽  
Removal Rate ◽  
Compacted Graphite Iron ◽  
Compacted Graphite ◽  
Machining Operations ◽  
Stock Removal

Compacted graphite iron (CGI) has been viewed as the next generation casting material for diesel engines to further the automotive energy efficiency because of its better mechanical strength for lighter engine designs as compared to gray cast iron. The machinability of CGI is analyzed and tested in honing, a standard engine manufacturing process for cylinder bores. Its comparable stock removal rate and tool life to cast iron honing lessen the concern of the machinability problems normally seen in other machining operations on CGI parts.

scholarly journals Investigation of Drilling Machinability of Compacted Graphite Iron under Dry and Minimum Quantity Lubrication (MQL)

Metals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1095 ◽  
Author(s):  
Li ◽  
Wu ◽  
Kuzu ◽  
Zhao ◽  
Hong
Keyword(s):  
Cast Iron ◽  
Wear Mechanism ◽  
Minimum Quantity Lubrication ◽  
Grey Cast Iron ◽  
Compressed Air ◽  
Drilling Process ◽  
Compacted Graphite Iron ◽  
Machine Material ◽  
Compacted Graphite ◽  
Grey Cast

Compacted graphite iron (CGI), which is used as a potential material in the auto industry, is a hard-to-machine material for the different minor elements and for the geometry of graphite with grey cast iron. The machinability of CGI in the drilling process was investigated with a 4-mm diameter fine-grain carbide twist drill under four lubrication conditions, dry (no compressed air), dry (with compressed air), MQL 5 ml/h, and MQL 20 mL/h in this paper. The maximum flank wear, types of wear, and cutting loads were studied for identifying the wear mechanism in drilling of CGI. The tool life in the four experiments of CGI drilling is 639 holes, 2969 holes, 2948 holes, and 2685 holes, respectively. The results showed that the main wear mechanism in drilling of CGI is adhesion and abrasion. Carbon, which originates from the graphite of CGI, can improve the lubrication in the drilling process by comparing with MnS in drilling grey cast iron. The thrust force and torque are more than 1000 N and 150 N*cm after 2700 holes in CGI drilling. Drilling of CGI under dry conditions (with compressed air) and MQL 5 ml/h is feasible.

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