Steel hex bolt with spring washer and large flat washer, trivalent chromate.
The head shape is hexagonal, allowing for tightening with tools such as wrenches and spanners. It can be tightened more securely than screws with a cross hole. Since the washer does not come off the screw, it eliminates the hassle of setting the washer, thereby improving work efficiency. It is also referred to as a Sems screw. It is compliant with EU-RoHS standards.
Inquire About This Product
basic information
Size range: M5-M12
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 that have been heat-treated or contain additives such as chromium and molybdenum are used according to applications such as shape, strength, and corrosion resistance. Trivalent chromate is a surface treatment that serves as an alternative to chromate plating, providing corrosion resistance equal to or greater than traditional chromate treatment without containing harmful hexavalent chromium. Additionally, it can control the decrease in corrosion resistance that occurs during heating, which is a drawback of chromate treatment. In recent years, there has been a growing awareness of environmental measures globally, and many industries, including automotive and semiconductors, are considering alternatives to hexavalent chromium; among these, trivalent chromate is being used as a substitute for chromate plating. On the other hand, compared to chromate treatment, managing the process parameters such as the stirring state of the plating material, immersion time, temperature, and pH can be challenging, which may lead to 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.