Shear bolts black oxide

冷間圧造加工は、切削の少ない、あるいは切削を必要としない新しい圧造加工のひとつである。
金属。の作用による金属の塑性変形を利用した加工法である。
外力を受け、金型の助けを借りて、金属の体積を再分配し、移動させる。
必要な部品やブランクを製造します。冷間圧造工程は、標準的な
ボルト、ネジ、ナット、リベット、ピンなどの留め具。

A Shear Bolt with Black Oxide coating is a specialized fastener designed to fail under excessive torque or load, thereby protecting more critical components in a mechanical system. Here’s a detailed description:

1.素材と構造

• Typically made from medium-carbon steel or alloy steel for strength.

• Heat-treated to achieve a precise shear strength.

2. Black Oxide Coating

• Process: The bolt undergoes a chemical conversion coating (black oxide) that creates a magnetite (Fe₃O₄) layer on the surface.

• Appearance: Matte black finish.

• Benefits:

  • 耐食性： Improved rust protection compared to bare steel (though not as robust as zinc plating).

  • Reduced Friction: Smoother surface aids in torque consistency.

  • Aesthetic & Low Reflectivity: Useful in applications where glare or visibility must be minimized.

3. Shear Bolt Design Features

• Precision Shear Point: Engineered to break at a specific torque threshold.

• Head Styles: Hex, socket, or specialty heads (depending on application).

• Threads: May be fully or partially threaded, with tight tolerances.

4. Common Applications

• Agricultural Machinery (e.g., tractor PTO shafts).

• Snowblowers & Rotary Cutters (protects drivelines).

• Industrial Gearboxes & Conveyors.

• Aerospace & Automotive Safety Systems.

5. Advantages of Black Oxide Shear Bolts

• Controlled Failure: Sacrificial protection for expensive equipment.

• Cost-Effective: Black oxide is cheaper than many other coatings.

• Dimensional Stability: Coating adds minimal thickness, ensuring fit in tight tolerances.

6. Limitations

• Moderate Corrosion Resistance: Not ideal for highly corrosive environments (e.g., marine applications) unless supplemented with oil or wax.

• Shear Strength Variability: Proper torque calibration is critical.

Alternatives

• Shear Pins (unthreaded, easier to replace).

• Zinc-Plated or Stainless Steel Shear Bolts (for harsher environments).