A consistent casting process can sometimes be a challenge to achieve due to the wide array of initial conditions that can affect the process. Variation in these initial conditions during the casting process can generate an array of unexpected results, which sometimes have a negative effect on the structural integrity of the castings. Cold shuts, shrinkage formation, and hot tears are just a few examples of the defects that can arise.
Throughout the history of the railroad, castings found with these types of defects have plagued the industry. Since castings are considered a leading method for manufacturing metal components, it is important to have a consistent and repeatable process. Without this, defects can drive the quality of the product down and cause castings to fail while in service. Studying the effects of initial condition variance can teach us which parameters can positively or negatively affect the overall casting process. Improvements in a foundry’s process can then be implemented resulting in a more consistent, reliable final product.
Computer simulation software has proven to assist in predicting defects before a single casting has even been poured. As with any simulation, care must be taken when setting up the input parameters. Without careful consideration of the initial conditions, the results may not reflect the actual process. Because of this fact, Strato, Inc. continues researching and sharing its findings regarding the effectiveness of these simulations. This research helps to ensure that a higher quality product with a lower fall-out rate is delivered promptly to the customer.
Specific initial conditions are explored in this paper. Variance in the soundness of the casting process is examined through the use of material density plots. These density plots, which provide a visual indication of internal shrinkage, have been obtained using simulation software. These predictions of shrinkage are then compared to actual castings that were poured using the same initial conditions. Results from the following three case studies present evidence to further the belief that using this software, which allows for a deeper understanding of the thermal and fluid dynamics of the casting process, has a direct impact on both quality, as well as the time it takes to develop a sound process. With the knowledge gained by simulating variance in initial casting conditions, a more robust rigging design and overall casting process can be achieved.
This paper is a continuation of Strato’s investigation into the effects of varying initial conditions with simulation software and comparison with real world results. The first part was presented at the 2012 ASME JRC and can be found within its proceedings. Although some concepts and terms are explained in both papers, it is suggested that part one of this paper be reviewed by those who would like more insight into the framework of this paper.
