Steel is the primary mating surface used in wet brakes and clutches and can be used as the primary heat sink or the means to dissipate the energy into the ambient surroundings.

In a “wet” or oil-immersed application, oil molecules are trapped between the steel mating plate and the friction material. The surface roughness of the steel mating plate and the texture of the friction material combine on shear of the oil to deliver a co-efficient of friction of up to 0.15. Surface roughness is therefore critical to the application and has to be compatible with the opposing friction material.

Steel quality and hardness are application dependent but equally important. Usually a material such as CS 70 would be typical with a minimum hardness of Roc C 25. Further processes such as induction hardening and blackodising are used as required.

Steel mating plates also known as counter or opposing plates are used both in dry & wet applications. When used in a dry application the steel mating plate is the reaction surface which when in unison with the friction material has a coefficient of friction up to 0.90 during engagement. When used in a wet application also known as oil immersed the oil molecules get trapped in-between the steel mating plate & the friction material. Once oil immersed the surface roughness of the steel mating plate in unison with the texture of the friction material has a coefficient of friction up to 0.15 during engagement. There are three main factors to consider before mating the steel plates & friction plates that are crucial to each independent application such as the steels quality, hardness & the surface roughness has to be compatible with the opposing friction plates. Processes such as blackodising & induction hardening are used to achieve this. We can supply all kinds of sizes, geometry & spline of steel mating plates. The following are properties that are associated with this type of material:

> High precision of geometry dimensions
> Stable coefficient of friction
> Good non-deformability