Graphite low friction coatings for fasteners, nuts and bolts? The answer is yes. And for a number of reasons.
Begin with installation. Did you know most applied torque goes into overcoming friction? That is right. In the absence of lubrication, clamping pressures can be lost, measurably. Not to mention the difficulty in installation. Or the potential damaging torque applied. All of which can initiate issues such as loosening, galling or early wear, or something catastrophic, like bolt shearing.
Is it the fault of the fastener? Not necessarily. So, the next time you consider changing to a more expensive fastener grade, consider lubrication instead. Friction will be lower, as will be torsional stress.
Dry film lubricants like graphite can play a significant role when vibrations are strong, dynamic loads are high. Without, friction will be higher, failure imminent.Lag screws for wood
Consider microscopic movement under these “oscillating” conditions. More than tangential movement, surfaces can lose contact in each cycle. The result can be a devastating, hammering effect, impact fatigue. Though all these effects can be reduced with carbon graphite.
Similar to molybdenum disulfide (MoS2) and tungsten disulfide (WS2), the structure of carbon graphite is also one of a layered lattice, a hexagonal form with strong covalent bonds. In a normal air atmosphere condition, where metal fasteners are similar material, lubrication can be exceptional. (When nut and bolt are dissimilar metal, an electrical potential exists; consequently, MoS2 or WS2 are better suited. Since graphite can be associated with stimulating galvanic corrosion.)
So, next time you experience failure of your fasteners. First, check for lubrication. And the next time you design with nuts and bolts, do not forget the lubrication. Benefits are many using graphite low friction coatings.
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