Nemak of Canada Corporation

Windsor, Canada

Nemak of Canada Corporation

Windsor, Canada
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Mackay R.,Nemak of Canada Corporation | Sokolowski J.,University of Windsor
International Journal of Metalcasting | Year: 2010

A significant portion of the literature on new and/ or modified alloy compositions that could serve as a replacement for the traditional 300 series aluminum alloys used for engine components are performed on test castings, which at times have limited complexity, lending themselves to advantageous liquid feeding conditions in the semi-solid state. More specifically the limited complexity of the test casting design may lead to conditions where progressive solidification provides enhanced soundness and limited segregation, which may not repeat in the component casting, made of the same alloy with the same melt treatment strategy. The research contained in this paper will investigate both a directionally chilled wedge test casting and a component engine block (CEB) poured with four development test alloys having the same melt treatment, with the aim to establish similarities and differences encountered in the test results of both casting designs used. The authors will make a recommendation regarding the best approach for successful alloy conversion strategies for production castings. Copyright © 2010 American Foundry Society.


MacKay R.I.,Nemak of Canada Corporation | Cusinato D.,Nemak of Canada Corporation | Sokolowski J.H.,University of Windsor
International Journal of Cast Metals Research | Year: 2010

The research contained herein reviews an alternative Al-Si-Cu alloy that provides the fatigue durability that would be nearly comparable to the 356 or the 319 alloys (having integrated chill), while having comparable or lower associated raw material and processing costs. A total of forty-three V8 engine blocks were produced with an Al-9Si-1Cu alloy, assessed and compared to the production version of the same engine block casting that uses the 319 alloy (Al-7Si-3•5Cu). The casting process used to manufacture the engine blocks was the Cosworth Precision Sand Process. This comparison to the production variant of the V8 engine block includes a detailed microstructure assessment (secondary dendrite arm spacing λ2, secondary phase distribution/type and porosity), room temperature tensile testing, elevated temperature fatigue staircase plots and hardness measurements. The observation found from the aforementioned analysis was that the Al-9Si-1Cu alloy has lower porosity and, as a consequence, was able to show a 40% increase in the elevated temperature fatigue staircase plot when compared to the same plots made from regular production. © 2010 W. S. Maney & Son Ltd.


MacKay R.I.,Nemak of Canada Corporation | Sokolowski J.H.,University of Windsor
International Journal of Cast Metals Research | Year: 2010

Recent metal casting literature has focused on the effect of Al melt practices and alloy chemistry on the formation of dispersed microshrinkage porosity in the cross-section of sand castings. In the present work, an attempt is made to explain observations on the severity of microshrinkage porosity formation in wedge castings of four alloys having different Si and Cu concentrations, with cooling rates ranging from 0.75 down to 0.045°C s -1. The Al-9Si-1Cu alloy provided the lowest level of dispersed microshrinkage along the wedge and the Al-7Si-4Cu alloy had the highest porosity. It is concluded on the basis of interpretative thermal analysis with fraction solid calculation that the requirements for the lowest level of porosity are primary α-Al dendritic mass being low in volume and more permeable, a high volume of Al-Si eutectic phase but within a shorter freezing range, and a low volume fraction of the Cu and Mg containing phases post-Al-Si eutectic reactions. © 2010 W. S. Maney & Son Ltd.


Lombardi A.,Ryerson University | D'Elia F.,Ryerson University | Ravindran C.,Ryerson University | Sediako D.,National Research Council Canada | And 2 more authors.
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2012

The replacement of nodular cast iron with 319 type aluminum (Al) alloys in gasoline engine blocks is an example of the shift towards the use of lighter alloys in the automotive industry. However, excessive residual stress along the cylinder bore may lead to bore distortion, significantly reducing engine operating efficiency. In the current study, microstructure, mechanical properties and residual stress were characterized along the cylinder bridge of engine blocks following thermal sand reclamation (TSR), T7 heat treatment, and service testing of the casting. Neutron diffraction was effectively used to quantify the residual stress along both the Al cylinder bridge and the adjacent gray cast iron cylinder liners in the hoop, radial, and axial orientations with respect to the cylinder axis. The results suggest that an increase in cooling rate along the cylinder caused a significant refinement in microstructure at the bottom of the cylinder. In turn, this suggested an increase in alloy strength at the bottom of the cylinder relative to the top. This increased strength at the bottom of the cylinder likely reduced the susceptibility of the cylinder to rapid relief of residual stress at elevated temperature. In contrast, the coarse microstructure at the top of the cylinder likely triggered stress relief at an elevated temperature. © 2012 The Minerals, Metals & Materials Society and ASM International.


Lombardi A.,Ryerson University | Sediako D.,National Research Council Canada | Ravindran C.,Ryerson University | Mackay R.,Nemak of Canada Corporation
SAE International Journal of Materials and Manufacturing | Year: 2014

The development of an optimized heat treatment schedule, with the aim of maximizing strength and relieving tensile residual stress, is important to prevent in-service cylinder distortion in Al alloy engine blocks containing cast-in gray iron liners. However, to effectively optimize the engine block heat treatment schedule, the current solutionizing parameters must be analyzed and compared to the as-cast condition to establish a baseline for residual stress relief. In this study, neutron diffraction was carried out to measure the residual stress along the aluminum cylinder bridge following solution heat treatment. The stresses were measured in the hoop, radial and axial orientations and compared to a previous measured as-cast (TSR) engine block. The results suggest that solution heat treatment using the current production parameters partially relieved tensile residual stress in the Al cylinder bridge, with stress relief being more effective near the bottom of the cylinder. Copyright © 2014 SAE International.


Lombardi A.,Ryerson University | Ravindran C.,Ryerson University | Sediako D.,National Research Council Canada | MacKay R.,Nemak of Canada Corporation
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science | Year: 2014

In recent years, stringent government legislation on vehicle fuel efficiency has pushed the automotive industry to replace steel and cast iron power train components with light weight Al alloys. However, unlike their ferrous-based equivalents, Al-Si alloy engine blocks are prone to permanent dimensional distortion in critical locations such as the cylinder bore regions. Understanding the mechanisms that cause distortion will promote the use of Al alloys over ferrous alloys for power train applications and enable automotive manufacturers to meet emission standards and reduce fuel consumption. In this study, neutron diffraction was used to evaluate residual stress along the Al cylinder bridge and the gray cast iron liners of distorted and undistorted engine blocks. Microstructural analysis was carried out using OM, SEM, and TEM, while mechanical testing was accomplished via ambient and elevated temperature [~453 K (180 °C)] tensile testing. The results suggest that the distorted engine block had high tensile residual stress in the Al cylinder bridge, reaching a maximum of 170 MPa in the hoop direction, which triggered permanent dimensional distortion in the cylinders when exposed to service conditions. In addition, the middle of the cylinder had the highest magnitude of distortion since this region had a combination of high tensile residual stress (hoop stress of 150 MPa) and reduced strength compared with the bottom of the cylinder. © 2014, The Minerals, Metals & Materials Society and ASM International.


Lombardi A.,Ryerson University | Ravindran C.,Ryerson University | MacKay R.,Nemak of Canada Corporation
Journal of Materials Engineering and Performance | Year: 2014

The use of Al engine blocks has increased significantly to improve vehicle fuel efficiency. However, the gray cast iron cylinder liners cause the development of large tensile residual stress along the cylinder bores which necessitates the optimization of mechanical properties in this region to prevent premature engine failure. This study compared the microstructure of T4-treated Al billet castings of varying cooling rate to that of the cylinder region of T4-treated (current production schedule) Al engine blocks. The aim of this study was to develop a cost-effective small scale heat treatment optimization method for engine block production. Comparisons in microstructure between the engine block and the billet castings were carried out using optical and scanning electron microscopy. The results suggest that the microstructure and hardness at the top, middle, and bottom of the cylinder were similar to those of each representative billet casting, indicating that heat treatment resulted in successful replication of the engine block locations. In addition, tensile testing revealed that the YS and UTS increased slightly following T4 treatment for all billet castings, which was also observed at the middle of the engine block cylinder bridge. As such, this method can be an effective forerunner for future heat treatment optimization in Al engine block production. © 2014 ASM International.


Lombardi A.,Ryerson University | Ravindran C.,Ryerson University | MacKay R.,Nemak of Canada Corporation
Journal of Materials Engineering and Performance | Year: 2015

The increased use of Al for automotive applications has resulted from the need to improve vehicle fuel efficiency. Aluminum alloy engine blocks fulfil the need of lightweighting. However, there are many challenges associated with thermo-mechanical mismatch between Al and the gray cast iron cylinder liners, which result in large tensile residual stress along the cylinder bores. This requires improced mechanical properties in this region to prevent premature engine failure. In this study, replicating billet castings were used to simulate the engine block solution heat treatment process and determine the onset of incipient melting. Microstructural changes during heat treatment were assessed with SEM and EDX, while thermal analysis was carried out using differential scanning calorimetry. The results suggest that solution heat treatment at 500 °C was effective in dissolving secondary phase particles, while solutionizing at 515 or 530 °C caused incipient melting of Al2Cu and Al5Mg8Cu2Si6. Incipient melting caused the formation ultra-fine eutectic clusters consisting of Al, Al2Cu, and Al5Mg8Cu2Si6 on quenching. In addition, DSC analysis found that incipient melting initiated at 507 °C for all billets, although the quantity of local melting reduced with microstructural refinement as evidenced by smaller endothermic peaks and energy absorption. The results from this study will assist in improving engine block casting integrity and process efficiency. © 2015, ASM International.


Lombardi A.,Ryerson University | D'Elia F.,Ryerson University | Ravindran C.,Ryerson University | Mackay R.,Nemak of Canada Corporation
Materials Characterization | Year: 2014

In recent years, aluminum alloy gasoline engine blocks have in large part successfully replaced nodular cast iron engine blocks, resulting in improved vehicle fuel efficiency. However, because of the inadequate wear resistance properties of hypoeutectic Al-Si alloys, gray iron cylinder liners are required. These liners cause the development of large tensile residual stress along the cylinder bores and necessitate the maximization of mechanical properties in this region to prevent premature engine failure. The aim of this study was to replicate the engine cylinder bridge microstructure and mechanical properties following TSR treatment (which removes the sand binder to enable easy casting retrieval) using lab scale billet castings of the same alloy composition with varying cooling rates. Comparisons in microstructure between the engine block and the billet castings were carried out using optical and scanning electron microscopy, while mechanical properties were assessed using tensile testing. The results suggest that the microstructure at the top and middle of the engine block cylinder bridge was successfully replicated by the billet castings. However, the microstructure at the bottom of the cylinder was not completely replicated due to variations in secondary phase morphology and distribution. The successful replication of engine block microstructure will enable the future optimization of heat treatment parameters. © 2013 Elsevier Inc.


Byczynski G.,Nemak of Canada Corporation | Mackay R.,Nemak of Canada Corporation
TMS Annual Meeting | Year: 2014

Casting durability may be assessed by several methods. In industrial powertrain castings engineering design is linked to the assessment of casting properties in particular high cycle fatigue performance. In the past porosity has been shown to be the most deleterious microstructural constituent in Al-Si cast alloys. Porosity is nucleated by oxide biflims and evolves during solidification due to segregated hydrogen gas and/or liquid feeding difficulties in the mushy zone during solidification. Porosity and oxide films have been reported to control casting durability as assessed through the fatigue staircase and calculated -3σ plots. The authors will show in this work that grain structure can also play a major role in terms of controlling fatigue life. Specifically the presence of columnar grains in non grain refined casting structures can lead to low and unpredictable fatigue lives. The mechanisms of fatigue failure due to grain structure are reviewed and the use of grain refiner (in-mold process) to improve fatigue performance and counteract undesirable structure are discussed.

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