Shear bolts black oxide

冷镦加工是一种少切削或无切削的压力加工新工艺
金屬。它是一種利用金屬在下列因素作用下產生塑性變形的加工方法
外力作用下，在模具的幫助下，重新分配和轉移金屬的體積，以形成
所需的零件或坯料。冷镦工艺最适合生产标准的
螺栓、螺絲、螺帽、鉚釘和銷等緊固件

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.材料與結構

• 通常由 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.

• 外觀： Matte black finish.

• Benefits:

  • 耐腐蝕性： 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.常見應用

• 農業機械 (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.

• 成本效益高： 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).