Surface Modified Screws

To avoid galling of an unlubricated stainless steel connection it is recommended to use special processed fasteners in vacuum environment. We offer vented and non-vented screws in various surface modifications.

Electropolished fasteners feature a reduced surface roughness. Burrs formed during the machining of the thread are reliably removed by the polishing process and the effective surface will be drastically reduced. Thereby, surface desorption and propensity for galling are obviously decreased.

Silver and gold coatings have the purpose to reduce the friction value between the threads. Thus, reproducible preload forces can be reached by using a well-defined torque. The commonly applied platings of the screws prevent galling. The layer of noble metals increases the chemical resistance even in a harsh environment so that the corrosion of the connecting elements is prevented as well.

Fasteners coated with tungsten sulfide WS2 or molybdenum sulfide MoS2 are predestinated for the use in a vacuum environment under high temperatures. The thermal stability in vacuum is at more than 1000 °C (1832 °F) for each. Both compounds are established as wear-reducing solid lubricants in mechanical engineering and construction for many years. They guarantee a vacuum compliant thread lubrication even for repeated use.

Nickel plated fasteners reach excellent corrosion protection due to the superior chemical resistance of nickel. This coating reliably prevents from galling of the stainless steel threads while reducing the friction value at the same time.

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