Tuesday, September 25, 2018

A Guide to Centrifugal Casting

Centrifugal casting, also known as rotocasting, is a casting process that can create thin-walled cylinders
of metal that are of high quality. It is often used to make stock materials in applications where the
standardization and quality are important. Here are some things to know about centrifugal casting.

What is Centrifugal Casting?

Centrifugal casting is the process of casting metals such as iron, steel, and aluminum alloys into a
rotating mold. In the normal casting process, these metals are poured into a mold that forms them into a
precise shape as they cool. This works well for most applications where the finished product has a solid
metal core. Centrifugal casting works in the opposite way, creating shapes that are hollow inside. This is
done by pouring liquid metal into a mold that is rotating at a high speed. Instead of filling the center of
the mold, the metal moves to the outer walls.

Types of Centrifugal Casting

There are three basic types of centrifugal casting: horizontal, vertical, and vacuum. Horizontal centrifugal
castings rotate on a horizontal axis to create long cylindrical parts using fast speeds. Vertical centrifugal
casting uses dies that rotates on a vertical axis and may use sand or ceramic molds to achieve outer
diameter shaping. In the vacuum centrifugal casting process, the process takes place in a vacuum to
limit the metal’s exposure to oxygen, which could react with some metals.

How Does Centrifugal Casting Work?

The process starts when a molten metal is poured into a mold as it spins around. The centrifugal force
distributes the metal at an intense pressure greater than that of gravity. As the die fills with the molten
metal, the densest metal is forced to the wall of the die while lighter metals stay closer to the core. The
result is a formed metal object that is hollow and generally has a rounded outer shape.

Benefits of Centrifugal Casting

Centrifugal casting creates a high-quality finished product that is known for its controlled metallurgy and
crystal structure. The process can create castings that have rotational symmetry. In traditional casting
applications, it is difficult to create thin-walled cylinders.

Applications for Centrifugal Casting

Due to the high material soundness that results from centrifugal casting, it is an excellent choice for
creating materials that need a consistent and reliable level of quality. Many components used in
manufacturing, industrial, military, and aeronautics applications benefit from centrifugal casting. It can
also be used to make items that will be placed under high pressure such as underground pipes, tubes,
and cylindrical objects with highly dense outer shells.

Atlas Bronze is a leading distributor of bronze, copper, brass, iron, and sintered products in the U.S. If you’re in the market for metal engineered products, including high quality centrifugal castings, contact Atlas Bronze by contacting us or shopping in our online store. We’re happy to answer any questions you may have about our castings and the various applications in which they can be used.

A Guide to Continuous Casting

Also known as strand casting, continuous casting is the process of solidifying molten metal into a
semi-finished billet or slab for rolling in a finishing mill. Before the 1950s, casting required the liquid
metal to be poured into individual molds to create ingots. Continuous casting speeds up and smooths
out the process, reducing the cost of cast metal while raising its quality and standardizing its

Advantages of Continuous Casting

No single casting method is the right choice for all applications. Still, for many applications, continuous
casting has a number of advantages over other casting methods.
Continuous Casting vs Ingot Casting: Ingot casting loses approximately 5 percent of all blocks to
waste due to cracks and deformations that arise during the casting process. Continuous casting
creates solid, uncracked bars and slabs every time.
Continuous Casting vs. Sand Casting: Most metal castings are created through sand casting, and
it remains an excellent option for many projects. However, sand casting carries several risks that are
virtually eliminated by continuous casting, such as shifting molds, non-uniform cooling, and the
possibility of cracks in the mold.
Continuous Casting vs. Extrusion Molding: Extrusion molding is an inexpensive way to churn out
simple parts. However, it uses force to ram one metal into another, and as such, it cannot be used to
create complex shapes. In addition, extrusion raises the risk of cracking in the finished product.

Steps to Continuous Casting

Molten metal is ladled into a casting machine where it is molded, cooled, and stretched into the desired
shape and size. Different machines have their own pros and cons, but the basic steps remain the
1. Tundish: Liquid alloy is ladled into the tundish, which serves as a reservoir and directs the flow of
the metal into the mold.
2. Mold: The tundish directs the liquid alloy into a water-cooled mold, where it partially solidifies and
receives its basic shape. The semi-cooled metal is known as a grid.
3. Strand Guide: When the grid is semi-solid, it is sent through the strand guide, which stretches the
metal to its proper thickness while continuing to cool it.
4. Straightener: When the grid is fully hardened, it is sent through a straightener to receive its final
5. Rolling: The finished material is wound into a roll and stored.

Bending and Straightening Considerations

Throughout the casting process, the metal is bent and straightened over and over again to achieve a
precise shape and size. However, this can cause excess strain that weakens the finished metal.
Therefore, it is critical to find just the right arc to bend the grids depending on the mechanical properties
of the specific metal that is selected. It is also important to choose a multi-point straightening process
that can minimize the effects of the strains caused by bending.

Ready to Start?

Atlas Bronze is a leading U.S. distributor of bronze, copper, brass, iron, and more. Contact us today at 1-800-478-0887 to place an order or learn about our custom products.