Engineered Surfaces are created through both topographical modification (changing the surface finish) and special coatings.
Topographical modifications include our ES10, ES20 and ES30 processes. These methods reduce the surface roughness to levels much lower than conventional grinding and honing methods.
The smoother, topographically modified surface creates a higher contact area that results in less micro-welding of asperities (microscopic high spots) as they come in contact with the mating component. Some roughness, in most cases, is actually desirable. If it were possible to create a perfectly smooth surface, it would provide no spaces for lubricant on the component surface.
We will apply the surface to your component at our service centers or work with you where appropriate to supply the complete component incorporating Timken Engineered Surfaces.
Ground Finish
Modified Finish
The Engineered Surfaces created through coatings have a thickness of 1 to 3 microns, and have been engineered to yield good performance under typical loads and speeds. The coatings are applied using Physical Vapor Deposition. This type of process has been used to coat silicon chips and tools, but Timken has tailored the process and developed coating chemistries for metal components.
The coatings create a surface that is up to four times harder than steel, but up to two times more elastic. The coatings have a friction coefficient that is 50% of steel We apply our coatings at temperatures that do not affect the hardness of the substrate material (less than 150C / 300F).
Nano-crystalline metal carbides from 3-10 nm
embedded in an amorphous matrix
We rely on selection matrices to help us choose the appropriate process from the Engineered Surfaces Toolbox. While greatly simplified, the chart demonstrates how we consider the lubrication level (lambda) and contact mode to select the proper type of finish or coating for an application.
In the example shown, with lambda less than 1 (less than full separation of the contact surfaces by the lube), our ES10, ES20 or ES30 processes are indicated for components with rolling, mixed or sliding contact.
Other selection criteria consider fatigue, wear and additional application parameters.
The coating process significantly reduces the friction coefficient of the treated surfaces. The test data shown was recorded under dry (no lubrication) conditions using pin-on-disk testing. The disk was coated, the pin was not. Both pin and disk were hardened 52100 steel.
Friction Coefficient of ES Coatings
Applying the coating to the disc reduced the wear rate of disk by two orders of magnitude without increasing abrasive wear of the uncoated pin.
Wear Resistance of ES Coatings
As one example of the friction reduction achieved with Engineered Surfaces, we tested the effect of ES200 on a brass counterface and found an impressive reduction in component wear.
Effect of ES200 on Brass Counterface Wear
There are limitations to the Engineered Surface processes. They can be applied only to parts within a certain size range and that have the appropriate geometry. Other component modifications such as alternate material selection may provide a more economical solution.
But for the appropriate components and environments, espeically marginal lubrication, Engineered Surfaces may be the right solution.
Timken Engineered Surface technology can increase the power density of components, reduce wear and minimize frictional losses. This creates higher performance with increased component life and system durability, resulting in reduced warranty costs.