Casting Education

 

Casting

Gray or ductile iron metal is heated and poured into a pattern (mold) thus producing intricate shapes.


EGI business unit, Ellwood Engineered Castings, pours both ductile and gray iron. Gray iron is a hard brittle material with excellent damping characteristics and good machinability. This is due to graphite flakes which precipitate into the iron during solidification. Gray iron has found its way into a variety of applications over the years including most of EEC’s Ingot Molds. A great thermal conductor with great wear resistance, gray iron is the engineering alloy to suit your needs.

Ductile Iron is a unique engineering alloy that is similar to gray iron except that it is not brittle. The material is able to flex and has more fatigue resistance than gray iron. These properties are a result of creating graphite nodules instead of graphite flakes during solidification. Ductile iron boasts more strength and flexibility than gray iron while also featuring impact resistance and consequently finds its way into a variety of applications in the automotive, piping, mining, and milling industries. With a wide range of properties, ductile iron can meet your toughest needs.

The process of casting:

Engineering

The first step of our process is for our engineering team to produce a 3D model from a two dimensional drawing. Sophisticated software, such as Solid works, Procast and Magmasoft are used for this purpose. SolidWorks creates both drawings and 3D models and is vital to pattern-makers in ensuring that drawing and model dimensions match exactly. Solid Works also helps in the creation of mold setup procedures. Magmasoft and Procast are responsible for ensuring optimum iron flow gets to the casting and to make sure the casting solidifies properly, thus eliminating casting defects.

Pattern

After Engineering creates the 3D model, a physical pattern is necessary for subsequent production steps. Some patterns are made in-house, but the bulk of patterns utilized are sourced from outside shops. EEC does perform pattern repair, maintenance, and alteration on-site, as well as constructing custom blocks for truck, rail, and container shipments. Sourced patterns are made from wood, laminate, and foam, with wood patterns being the most durable of the three. Foam patterns, although less expensive, can only be used a limited number of times. The EEC pattern shop is equipped with a HAAS CNC routing machine. This programmable logic controlled machine reduces the possibility for human error and aids in producing the highest quality patterns.

Molding

The next step of our process is to take the pattern and place an outer shell, also known as a flask, around it. One of our many sand dispensers will release sand to fill the void between the pattern and the flask. After the sand sets, the pattern is removed and the void is filled with iron to make the desired casting. Cores are often placed within the mold to attain further intricacies that are unable to be achieved via the pattern.

Setting

On our engineered castings side of the house, we simply take the two flasks and flip one on top of another. The bottom mold is called the drag and the top is the cope. We will flip the cope onto the drag and put weights on the top so that the iron does not run out of the mold while pouring. In our ingot side of the house setting involves bringing the outer wall of the mold (cheek) together with the inside core of the mold. The core is then tied down to the flask so the core does not float during pouring. The flask is brought down and clamped together to the Core and the void that is left is the casting cavity.

Melting

EEC has Three 55 ton induction furnaces with the capacity to melt 10,000 tons per month. We melt pig iron and scrap iron into a bath. We then add different alloys to meet the specs of our customers. Once we test the chemistries and are at a proper temperature we tap the furnace into a transport ladle or torpedo car which will transfer the iron to the Teeming Bay.

Pouring

When the Iron arrives from the melt shop in the torpedo and or ladle it must be checked for temperature. We pour our iron at a consistent temperature so we eliminate defects. Once the temperature is right we will add inoculants to the iron. The pouring ladle then hovers over top of the mold and the pouring handle is pulled and the iron comes flowing from the bottom of the ladle into the pouring basin of the mold. We bottom pour all of the molds to get the highest quality castings possible.

Finishing

The final processing step is to clean the mold and prepare it for delivery to the customer. In this step, all of the excess iron, including gates and risers (which are used throughout the previous processes to ensure adequate iron flow and control shrinkage) are removed. Planers are also used to machine the top and bottom of the mold to meet customer specifications.