1. Integrally cast flanges
2. Quantity flexibility
3. Delivery of non-standard sizes
4. Alloy Flexibility
5. Availability of heavy wall thickness

1. Integrally Cast Flanges
The centrifugal casting process allows some shaping of the outer diameter of the workpiece. As long as the shaping is graduated in a manner to allow the part to be removed from the die, the shape can be cast integrally. This feature was an important factor in the off-road truck manufacturers switching from welded construction to centrifugals. Typically, large heavy walled cylinders are flanged to accommodate the high pressures exhibited on the end seals. Welded construction utilizes seamless tubing or forged tubing (often economical when purchased in quantity) with a forged flange welded on one or both ends. The weld must be full penetration for safety reasons.

This assembly must then subsequently go through post weld heat treatment to achieve acceptable mechanical properties. An integrally cast flange from the centrifugal process will achieve strengths in excess of four times (4X) that of the welded/heat treated equivalent. For this reason alone, manufacturers have readily accepted centrifugal castings for their critical cylinder bodies.

2. Quantity Flexibility
As already mentioned, seamless, DOM or tube mill tubing can be very economical when purchased in large quantities or “mill runs”. Because each centrifugally cast tube is usually an individual furnace heat, single piece or small quantities do not drastically change the price. While large regular runs are easily accommodated, centrifugal castings are particularly suited to smaller, job-specific runs.

3. Delivery of Non-Standard Sizes
The centrifugal casting process lends itself extremely well to non-standard sizes. The dies, while not inexpensive, are manageable both financially and in lead time. The dies shape and size only the outer diameter of the casting while the amount of molten metal poured sizes the inner diameter. When engineers design cylinders for a specific duty, there are many times when standard pipe sizes are not available. The diameters may not be available or the desired wall thickness may not be available. Centrifugal castings are an excellent solution to this dilemma.

4. Alloy Flexibility
This is an outstanding benefit for using centrifugal castings in hydraulic cylinder applications. Through metallurgical control and a quench facility designed specifically for tubular parts, Spuncast is able to achieve extremely good and extremely repeatable mechanical properties from low alloy steels. This makes our tubes usable in many high pressure applications.
It is also possible to pour high strength stainless alloys such as 17-4PH, duplex stainless steels or super duplex stainless steels. We have the metallurgical experience to pour these alloys.

5. Availability of Heavy Wall Thickness
Centrifugal casting facilitates the production of heavy walled cylinders. Wall thicknesses of 30 mm to 65 mm are possible and common. Other methods of manufacturing are either not capable of these dimensions or will be cost prohibitive. Centrifugal casting offers an economical means to meet design requirements.

Summary:
There are numerous processes that are used to produce hydraulic cylinder bodies. Each can be appropriate, economically, in specific situations. The benefits outlined here show that the centrifugal casting process definitely should be considered when designing and purchasing cylinder bodies. Spuncast Sales Engineers are available to help determine if centrifugal casting would be an economical option for a particular hydraulic application.

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