Blickle cast iron wheels are made from robust gray cast iron with a hardness of 180 to 220 HB. They are extremely wear-resistant and provide very little rolling and swivel resistance. Cast iron wheels are self-lubricating due to the graphite which they contain. However, they should always be sufficiently lubricated using the grease nipple, particularly when using the plain bore version. Due to the relatively high level of floor pressure, care must be taken when using this wheel series on sensitive surfaces. The silver coating on the wheels can change color at high temperatures, but this does not affect the corrosion protection provided by the coating. Standard cast iron wheels are designed for use in temperatures of up to 248 °F. A heat-resistant version with a plain bore is available for use in higher temperatures of up to 1 112 °F. These are typically used for applications which require a high level of heat resistance and in powder-coating facilities due to their resistance to oil and chipping.