Speaking of SK series lock washers, most partners are familiar with the fastener industry is commonly known as the "lightning pattern" lock washers. But this locking washer is called SK series locking washer why? What is the origin of this name? I believe it touches the blind spot in the knowledge base of the partners. "SK" from the German word "SperrKant" abbreviation, the origin of this series of products is Germany. The German manufacturer named the products with "SK-X" (X stands for M, S, B, L, Z, K) in order to distinguish the product series easily. SK series locking washers are locking washers developed based on the Bahn-Norm, the German railroad standard BN 208 010. SK locking washers with its own tapered design can provide 360° elastic compensation to the fastener connection, effectively compensating for the settling of the connection in the process of tightening torque Effect.
SK-M locking washer is suitable for common head type bolting with strength class less than or equal to 8.8, "M" is the abbreviation of the German word "mittelbreit", meaning medium width, refers to the washer width is moderate. It is an optimized locking washer based on the relevant provisions of the German railroad standard BN 208 010-8.
Material and performance SK-M lock washers are currently available in two materials, respectively, in accordance with the requirements of the standard DIN 17222 spring steel (usually C60, 51CV4, etc.) and austenitic stainless steel A4. spring steel SK-M lock washers hardness range of 420HV-510HV, the rest of the performance requirements refer to DIN 267-26 implementation. Stainless steel SK-M lock washers are not clear standard requirements.
Surface treatment spring steel SK-M lock washers surface coated with non-electrolytic zinc flake coating. Stainless steel SK-M lock washers surface for stainless steel natural color passivation.