A Complete Guide to the Selection, Operation, and Maintenance of Shackles in Cold Environments

In port loading and unloading, offshore engineering, mining, wind power installation, and lifting operations in high-latitude regions, shackles often need to be used for extended periods in frigid environments. However, low temperatures are not simply a matter of being “a little colder”—they directly affect the mechanical properties of metal materials, thereby impacting lifting safety. Understanding and mitigating this change is crucial for ensuring the safety of every critical lift.

How Low Temperatures Affect the Material Properties of Shackles？

Most shackles are made of carbon steel or alloy steel, which offer good strength and toughness under normal temperatures. However, in cold environments, steel undergoes the following changes:

1️⃣ Decreased Toughness and Increased Brittleness

As temperatures drop, the ductility and energy absorption capacity of steel significantly decrease.

Under impact or sudden loading, it becomes more prone to brittle fracture.

2️⃣ Increased Sensitivity to Shock Loads

In low-temperature conditions, a shackle’s ability to resist shock loads is weakened.

The risk significantly increases during operations such as lifting, sudden stops, swinging, or under wind loads.

👉 This is precisely why “avoiding shock loads” is emphasized even more in cold regions.

What is the Standard Low-Temperature Operating Range for Shackles?

Based on mainstream industry standards and manufacturer specifications:

🔹 Recommended Temperature Range for Conventional Alloy Steel Shackles

Approximately -40°C to +200°C (-40°F to 400°F)

Within this range, the shackle can maintain its Rated Working Load (WLL).

⚠️ Important Note:

Below -40°C (-40°F), ordinary shackles are no longer suitable by default.

Key Precautions for Using Shackles in Cold Environments

1️⃣ Strictly Prohibit Shock Loads

• Avoid sudden lifting, abrupt stops, or violent swinging.
• The lifting process should be smooth, slow, and controlled.

2️⃣ Do Not Modify or Weld Shackles

• Alterations such as welding, drilling holes, or grinding may compromise the material structure.
• In low temperatures, these modifications can lead to the propagation of hidden cracks.

3️⃣ Ensure Low-Temperature Compatibility of All Components

• The entire system, including lifting eyes, wire ropes, slings, and pins, must be suitable for low-temperature use.
• Merely replacing shackles with low-temperature-rated ones does not eliminate all risks.

4️⃣ Consider Reducing Working Load When Necessary

• Under “exceptionally hazardous conditions” such as extreme cold, strong winds, or offshore operations.
• It is recommended that professionals evaluate and appropriately reduce the use of the Working Load Limit (WLL).

Points for Inspection and Maintenance in Cold Environments

Under low-temperature conditions, the inspection frequency and standards for shackles should be higher than in normal environments.

Key Pre-Use Inspections:

• Check for cracks, deformations, or abnormal wear.
• Ensure the pin thread operates smoothly without jamming.
• Verify that markings (WLL, specifications, manufacturer) are clearly legible.

Post-Use and Periodic Inspections:

• Pay special attention to the contact areas between the pin and the shackle body.
• If any cracks or signs of suspected embrittlement are found, immediately cease use.

Conclusion: Low Temperature is No Minor Issue

In cold environments, shackle failure is often not due to overload, but rather because the material loses its essential toughness under low temperatures.

Selecting appropriate shackles, adhering to their operating temperature ranges, avoiding shock loads, and enhancing inspection practices are all critical to ensuring lifting safety.