Tips for Choosing Casters and Wheels for High Temperature Applications
When designing an industrial caster for applications with higher temperatures (most casters are designed to function in an environment that does not exceed 150 degrees F), many different aspects of the caster must be taken into account. Applications involving increased temperatures can have many effects on an industrial caster’s performance, such as reduced operating life, increased maintenance, or premature failure. Different examples of industrial caster applications involving higher temperature include the use in autoclaves, bakeries, curing ovens, etc. This article will discuss the use of different materials used in the manufacture of industrial casters at elevated temperatures.
For applications below 180° F, caster wheels with polyurethane tires can still be considered but depending on the application load and speed, there is an increased risk of tire flat spotting and premature failure. When using polyurethane tires at temperature nearing 180° F the application must be properly evaluated.
Most nylon wheels can withstand up to 250° F, with some types being able to withstand intermittent temperatures up to 400° F. Nylon wheels are usually considered when ergonomics is a concern because the wheels roll with minimal force applied.
For applications in temperatures up to 600° F, wheels shoold be made out of either cast iron or steel. These materials also improve ergonomics and have high load capacities, but they can increase wear on the floor surface. As temperatures begin to rise past 600° F, the load rating of the caster will be reduced as the steel/cast iron loses strength. Figure 1 from Engineeringtoolbox.com‘s article “Temperature and Strength of Metals” shows how the strength of certain metals changes as temperature increases.
For applications at elevated temperatures, the type of lubrication used must also be evaluated. If the caster application temperatures exceed the lubrication’s rating then the effectiveness of the lubrication will be compromised. This can lead to increased friction in the wheel bearings as well as the swivel section bearings. This increased friction increases wear and reduces the life of the bearing components, which reduces the life of the industrial caster. When designing the caster for the application, the proper lubrication can be selected for the temperature ranges. These lubricants range from specialized greases to dry film and graphite lubricants.
The bearings in the wheels and swivel section are also important aspects to consider when designing an industrial caster for a high temperature application. Besides changing out the lubricant, different bearing materials, such as ceramics, can be used. For example, most standard ball bearings, roller bearings and tapered bearings are rated for applications at or below 300° F. A bronze sleeve inserted in the wheel bore and acting as a bearing can operate in temperatures ranging from 600°-700° F. The challenge with this approach is that the bronze bearing will decrease roll-ability of the caster by at least 50%.
While wheel material and lubrication may be two large factors in determining the success of an industrial caster in elevated temperature applications, other factors must be considered as well such as the material the caster is manufactured out of and the bearing elements. If these factors are taken into account when designing a caster for high temperature applications, the probability for success is greatly increased.
Caster Concepts can help you design the proper caster configuration for your high temperature application. The engineering staff has extensive knowledge to assist you in specifying the correct caster for your specific application. The upfront due diligence to find the right caster will provide long term returns due to low maintenance and prolonged life cycle.