The most common and cost effective case materials are stamped from cold rolled carbon steel. The steel is then phosphate coated to aid in the molding process and to help eliminate corrosion during storage. Other case materials include stainless steel, brass and aluminum. These materials are considered special because of their additional cost, and are not typically used. The other option for case material is fully coated or partially coated rubber. Carbon steel cans are usually selected for rubber molded options.
The case geometry controls the positioning and rigidity of the seal lips. Often overlooked, the case type can affect the life of the sealing system. The case forms a static O.D. radial seal and is susceptible to leakage if not properly designed. The table below shows common case geometries and their advantages.