Depending upon the application, and specific performance requirements, a RENCOL® Tolerance Ring can be made from a number of different materials. The most widely used are:
The choice of material used depends on what the requirements of the tolerance rings are. Our engineers work with you to pick the base material depending on criteria such as load or torque requirements, size and handling. In some cases, there are specific requirements around NVH or thermal transfer where we will select specialist materials to meet those requirements.
Other materials, such as Inconel® or Hastelloy®, can be used if there are specific needs for things like corrosion resistance or when in conditions with strong chemicals.
There are a number of reasons stainless steel is the long-established material choice for tolerance rings; it is extremely corrosion resistant, is lightweight, has excellent tensile strength yet can be easily formed at cold working, ambient temperatures with good ductility. And, because stainless steel is typically created from about 70% scrap metal, and it can be 100% recycled it’s a more sustainable choice. This blend of characteristics makes stainless steel the ideal choice from both performance and environmental perspectives.
The austenitic stainless steel alloy used to make RENCOL® Tolerance Rings retains high elasticity and high fatigue resistance after forming. United these properties create tolerance rings that can withstand significant plastic deformation under tensile stress without fracturing. Using stainless steel gives us control over: torque performance, retention force and tolerance compensation. Our engineers will gather your requirements during the design phase to develop a custom-made tolerance ring to resolve your challenges.
All RENCOL® carbon steel Tolerance Rings are formed in the material’s (soft) annealed state before it is heat treated. Forming the tolerance ring first makes it possible to add more waves to thicker material and manufacture smaller diameters. The austempering, heat treatment process, hardens the carbon steel material, converting it from its annealed state to a bainite material structure, a material known for its strength and durability, to produce tolerance rings that can withstand higher forces.
Because each RENCOL® Tolerance Ring is custom-made the performance requirements and design space determine the choice between stainless steel and carbon steel for each application. The percentage of carbon content in our carbon steel tolerance rings is 0.65-0.75%, producing a high carbon steel. This delivers tolerance rings that are hard and strong with low ductility.
For systems that act like a slip clutch then it is often necessary to use a lubricant. This can either be in the form or a separate grease, or as a coating that is applied directly to the tolerance ring as it is being manufactured. The lubrication is sometimes needed if there are many slip cycles or if the value of torque you are trying to achieve has a tight tolerance.
Coating on a RENCOL® Tolerance Ring
Interested in finding out more? Contact us to speak to an engineer about how you could use a RENCOL® Tolerance Ring.