304 - Stainless Steel - Serrated - Hexagon flange bolt (94)

316 - Stainless Steel - Serrated - Hexagon flange bolt (31)

What is a Serrated Flange Bolt?

A hexagon flange bolt is a one-piece fastener that combines a hex head and a washer-like flange. Specifically, our bolts come with a serrated bearing face. When tightened, these angled teeth embed themselves slightly into the workpiece. This creates a ratchet-like effect: the bolt can be tightened easily, but the teeth dig in to resist the reverse motion, preventing the bolt from backing out. This self-locking feature makes them superior to standard bolts for machinery and vehicles.

Material Selection Guide: 304 vs 316

Choosing the right grade of stainless steel is crucial for the longevity of your project. We offer two main categories: Stainless Steel 304 (A2): This is the most popular grade for general-purpose use. It offers excellent resistance to atmospheric corrosion, rain, and freshwater. It is widely used in automotive trim, solar racking, and interior architecture. If your application is not exposed to salt water or aggressive chemicals, SS304 is the cost-effective choice. Stainless Steel 316 (A4): Often called "marine grade," SS316 contains molybdenum, which drastically improves its corrosion resistance. It is specifically designed to withstand chlorides, sea water, and industrial pollution. If your flange bolts will be used on boats, chemical plants, or coastal construction, SS316 is required to prevent pitting and rust.

Quality Assurance

Fastener Core ensures that our stainless steel materials meet international standards. We can provide an EN 10204 3.1 Material Certificate upon request to verify the chemical composition. Please note that third-party inspection services are available for an additional fee.

Industrial Applications

Serrated hex flange bolts are versatile components used across various sectors:
  • Automotive: Exhaust manifolds, engine brackets, and gearbox assemblies where vibration is constant.
  • Solar Energy: Securing solar panel frames and racking systems (speed of installation and locking security).
  • Electronics: Mounting components inside server racks and enclosures.
  • Conveyor Systems: Moving parts in factories that require vibration-proof connections.

Frequently Asked Questions

Do I need to use a washer with your flange bolts?

No, you should not use a washer. The integrated flange acts as the washer to distribute the load. Adding a separate flat washer or spring washer underneath the flange would cover the serrations, rendering the locking feature useless and potentially weakening the joint.

Why are my stainless steel bolts slightly magnetic?

This is a very common question. While raw stainless steel (304/316) is non-magnetic, the manufacturing process (cold heading and thread rolling) changes the microstructure slightly, creating a small amount of magnetism. This is perfectly normal for cold-formed fasteners and does not mean the material is of lower quality or not stainless.

Can serrated flange bolts damage the surface?

Yes, by design. The serrations are meant to bite into the surface to lock the bolt. Therefore, they are not recommended for applications where the surface finish (paint or polish) under the bolt head must remain pristine. In such decorative cases, a standard bolt with a nylon washer might be preferred, but for structural holding power, serrated is best.