Iron + small screw with spring washer, trivalent chromate black color.
A washer is incorporated into the screw. Since the washer does not come off the screw, it saves the effort of setting the washer and can improve work efficiency. It is also referred to as a Sems screw.
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basic information
Size range: M2-M5
Price information
Delivery times vary depending on the quantity. Same-day shipping is possible at the earliest. Please feel free to contact us.
Delivery Time
※Delivery times vary depending on the quantity. Same-day shipping is possible at the earliest. Please feel free to contact us.
Applications/Examples of results
Steel is widely used as a material for screws due to its easy availability, strength, and toughness. Based on carbon steel, which primarily consists of iron (Fe) and carbon (C), alloy steels with added elements such as chromium and molybdenum are used, depending on the application, with considerations for shape, strength, and corrosion resistance, often through heat treatment. Trivalent chromate is a surface treatment that serves as an alternative to chromate plating, providing corrosion resistance equal to or greater than traditional chromate treatments without containing harmful hexavalent chromium. Additionally, it can control the decrease in corrosion resistance that occurs during heating, a drawback of chromate treatment. In recent years, there has been a growing global awareness of environmental measures, leading many industries, including automotive and semiconductors, to consider alternatives to hexavalent chromium, with trivalent chromate being used as a substitute for chromate plating. However, compared to chromate treatment, managing the process parameters such as the agitation state of the plating material, immersion time, temperature, and pH can be challenging, which may result in inconsistencies in appearance and color. Furthermore, in general chromate treatments, the color may change as corrosion begins.
Company information
Wilco sells various fastening components, including screws, as well as professional tools. Please feel free to contact us regarding custom products, custom processing, and the issuance of various certificates and documents related to other products.