Flange bolts are common fasteners in industrial connections. Their heads have a flange face, which can increase the bearing area and improve connection stability. The following introduces three common types: toothed flange bolts, non-toothed flange bolts, and twelve-point flange bolts.
Toothed Flange Bolts
The core feature of toothed flange bolts is that the flange face of the head is distributed with annular or radial tooth-like patterns. The height of the teeth is usually 0.1-0.3mm, which can form a mechanical interlock with the connecting surface. The bolt shank can be designed as full thread or partial thread, and the material is mostly carbon steel or stainless steel.
Its advantages lie in that the teeth can significantly enhance the friction with the connecting surface, with excellent anti-loosening effect in vibrating environments, reducing the risk of loosening by more than 90%; at the same time, the interlocking connection can disperse the load and reduce the probability of flange face deformation.
The application scenarios are concentrated in high-frequency vibrating equipment, such as flange connections of automobile gearboxes, flange fixing of diesel generator cylinder blocks, flange assembly of vibrating screen bodies, etc., especially suitable for working conditions where bolts are prone to loosening due to resonance.
Non-toothed Flange Bolts
Non-toothed flange bolts (also known as smooth-faced flange bolts) are characterized by a smooth and unpatterned flange face on the head. The edge of the flange is mostly rounded. The strength grade of the bolt shank covers Grade 4.8 to Grade 12.9, adapting to different load requirements.
The advantages are that it causes little damage to the connecting surface during installation, which can protect the precision-machined flange surface; the smooth surface is easy to clean, suitable for hygienic environments; and the manufacturing cost is lower than that of the toothed type, with higher cost performance.
Applicable scenarios include stainless steel flange connections of food processing equipment, flange fixing of water purification pipelines, flange assembly of medical device housings, etc., especially suitable for working conditions that require high surface finish of the connecting surface or no strong vibration.
12-point Flange Bolts
12-point flange bolts are characterized by a 12-point (i.e., dodecagonal) design on the head, used with a special twelve-point wrench. The flange face can be toothed or non-toothed, and the bolt shank is usually of full thread structure, facilitating quick installation.
Its advantages are that the twelve-point design enables a larger contact area with the wrench, more uniform torque transmission, and can reduce the risk of head slipping; in narrow spaces, the twelve-point structure allows a smaller operating angle (30° is sufficient for rotation), improving installation efficiency.
Application scenarios are mostly in compact flange connections of aerospace equipment, dense flange fixing of automobile engine cylinder heads, flange assembly in narrow spaces of precision instruments and other occasions with strict requirements on operating space and torque control.
Conclusion
The above are relatively typical flange bolts. In addition, the selection of flange bolts also depends on factors such as head type, thread, performance level, surface treatment, and application scenario. If you currently need flange bolts but are unsure how to choose, please contact us and let us know your usage requirements - we will match the perfect flange bolts according to your needs.
