Curved Washer Bolt Customized Curved Spring DIN137A Black Galvanized Manufacturer

Curved washer bolt is one type of SEMS bolt with DIN137A curved spring washer attached. SEMS screw combines two separate parts into one pre-assembled, low-cost fastener. With washers under the head, SEMS screw is fast, permanent, and easily adaptable to many applications. Ever Hardware provides custom-made fasteners and customizable packaging.

Spring washers are a left-hand helix and allow the thread to be tightened in a right-hand direction only, i.e. a clockwise direction. When a left-hand turning motion is applied, the raised edge bites into the underside of the bolt or nut and the part that it is bolted to, thus resisting turning. Therefore, spring washers are ineffective on left-hand threads and hardened surfaces. Also, they are not to be used in conjunction with a flat washer under the spring washer, as this isolates the spring washer from biting into the component that will resist turning. Where a flat washer is required to span a large hole in a component, a nyloc nut (nylon insert) must be used.

Galvanization, or galvanisation, (or galvanizing as it is most commonly called in that industry), is the process of applying a protective zinc coating to steel or iron, to prevent curved washer bolt rusting. The most common method is hot-dip galvanizing, in which parts are submerged in a bath of molten zinc. Galvanizing protects in three ways:
It forms a coating of zinc which, when intact, prevents corrosive substances from reaching the underlying steel or iron.
The zinc serves as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the remaining zinc.
The zinc protects its base metal by corroding before iron. For better results, the application of chromates over zinc is also seen as an industrial trend.

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