Flange Bolt Encyclopedia: The Seal Guardians Of Industry

1. What is a Flange Bolt?

A flange bolt is an intelligent fastener with a built-in circular flange at its head. It combines the traditional bolt and washer into one unit. The flange extends like a mushroom cap, reaching 1.5-2 times the diameter of the screw threads. This design increases contact area to protect material surfaces while evenly compressing seals-making it essential for preventing leaks in pipelines, valves, car engines, and more.

2. Four Key Advantages

①Sealing Expert:
Like pressing a sponge evenly with your palm, the flange disperses pressure on sealing gaskets, cutting leak risks by 50%.

②Vibration Warrior:
Serrations or knurling on the flange bite into materials, tripling lifespan in shaky environments.

③Installation Accelerator:
No separate washer needed-reduces installation time by 1/3.

④Durability Defender:
Zinc/stainless steel armor resists oil, salt, and corrosion for over a decade.

3. How It Works: A Three-Act Play

Squeeze:
Tightening the nut flattens the seal like stepping on clay.

Seal:
The flange spreads pressure like an umbrella-filling microscopic gaps.

Lock:
Serrations grip the base material like teeth, fighting vibrations.

4. Simple Type Selection

By Face:
Smooth face (for rubber seals) • Serrated face (for metal gaskets)

By Strength:
Grade 8.8 (everyday use) • Grade 12.9 (cars/wind turbines)

By Material:
Zinc-plated (economical) • Stainless steel (acid-resistant)

5. Four Major Applications

①Oil Pipeline Connections
Serrated flange bolts clamp metal gaskets in deep-sea pipes, holding firm against the weight of 200 elephants (20MPa)-zero leaks.

②Chemical Reactor Seals
Stainless steel flange bolts act like chemical-proof soldiers, protecting PTFE seals from sulfuric acid attacks.

③Wind Turbine Tower Assembly
Oversized flange bolts reinforce 100-meter-high towers like steel skeletons-unshaken by gales for 20+ years.

④Automotive Engine Mounting
Guardian of electric vehicle "hearts":

Knurled flange surface bites into aluminum brackets-no slippage from engine vibrations.

Dacromet coating withstands engine bay heat and grease.

Lasts 2.5× longer than standard bolts-quieter, safer rides.

6. Five-Step Selection Guide

① Check Media

Water/oil → Zinc-plated

Acids/alkalis → Stainless steel (pick 316L for strong acids)

High heat → Heat-resistant alloy

②Assess Pressure