Alloy Steel Chain Grade 80 (often abbreviated as G80) is a high-strength, heat-treated alloy steel chain designed primarily for overhead lifting applications. It is a significant step up in strength from carbon steel chains like Grade 30, Grade 43, and even Grade 70, making it suitable for demanding lifting and rigging tasks where safety and reliability are paramount.

Here’s a detailed look at its key features, applications, and limitations:

Key Features:

• Material: Manufactured from high-quality alloy steels, such as manganese steel, chromium-molybdenum steel, or nickel-chromium-molybdenum steel. The specific alloy composition is crucial for achieving the required strength and toughness.
• Heat Treatment: Undergoes a precise quenching and tempering process. This critical heat treatment optimizes the steel’s properties, resulting in high tensile strength, excellent wear resistance, and good elongation properties before breaking.
• Grade Marking: Clearly marked with “8,” “80,” or “G80” at regular intervals to ensure easy identification of its grade, which is essential for safety and compliance. Some manufacturers may also include their brand name or identification marks.
• Construction: Typically features a short link design. Shorter links provide better flexibility and allow the chain to conform more easily to the shape of the load, reducing stress concentrations. Welded links ensure the integrity and strength of the chain.
• Strength: Offers a significantly higher Working Load Limit (WLL) compared to lower-grade chains of the same size. This allows for lifting heavier loads with a smaller and lighter chain, improving efficiency and handling.
• Surface Finish: Commonly available with a black oxide finish or painted (often black or blue) to provide some corrosion resistance. Other finishes like galvanized or self-colored with oil are also possible.
• Proof Test: All G80 chains are 100% proof-tested by the manufacturer at a load typically twice the Working Load Limit (2:1 ratio) to verify their structural integrity.
• Design Factor: Generally has a design factor of 4:1 (Minimum Breaking Load to Working Load Limit), providing a substantial safety margin for lifting operations.
• Elongation: Designed to exhibit a minimum elongation of 20% before breaking under overload conditions. This characteristic provides a visual warning of impending failure, enhancing safety during lifting.
• Temperature Resistance: Can be used within a specific temperature range (typically -40°C to 200°C) without a reduction in the Working Load Limit. Load limits may need to be reduced at higher temperatures; manufacturers provide specific temperature derating charts.
• Meets Standards: Manufactured to comply with various international standards such as EN 818-2, ASTM A391, NACM specifications, and others, ensuring consistent quality and performance.

Common Applications:

Grade 80 alloy steel chain is specifically designed and approved for overhead lifting and is widely used in various industries, including:

• Construction: Lifting and positioning heavy materials and components on construction sites.
• Manufacturing: In-plant lifting and material handling processes.
• Automotive Industry: Lifting engines, machinery, and other heavy parts.
• Aerospace Industry: Lifting and positioning aircraft components.
• Material Handling: Use in chain slings, chain hoists, and other lifting devices.
• Rigging: Creating lifting assemblies for various lifting applications.
• Warehousing and Logistics: Moving and stacking heavy goods.
• Oil and Gas Industry: Offshore and onshore lifting operations.
• Mining: Lifting equipment and materials in mining environments.

Important Limitations:

• Specifically for Lifting: G80 chain is primarily designed for overhead lifting and should not be used for tie-down or load securement applications. For those applications, Grade 70 chain is typically preferred.
• Working Load Limit (WLL): Never exceed the marked Working Load Limit. Overloading can lead to chain failure and serious accidents.
• Shock Loads: Avoid sudden impacts or jerking forces, as these can significantly increase the stress on the chain and potentially cause failure.
• Regular Inspection: Frequent inspection for wear, deformation, corrosion, bent or twisted links, and any other damage is crucial. Damaged chains must be removed from service immediately.
• Proper Use and Training: Lifting operations using G80 chain should only be performed by trained and qualified personnel who understand safe lifting practices and the proper use of lifting equipment.
• Compatibility of Fittings: Ensure that all hooks, shackles, links, and other fittings used with G80 chain have a Working Load Limit equal to or greater than the chain itself and are also approved for lifting.
• Environmental Conditions: While G80 chain offers good strength and wear resistance, exposure to highly corrosive environments or extreme temperatures beyond the specified range can degrade its performance.

Sizes and Specifications:

G80 alloy steel chain is available in a range of sizes, with specifications varying accordingly:

• Nominal Size (Diameter): Typically ranges from 6 mm to 32 mm or even larger.
• Working Load Limit (WLL): Increases significantly with the chain diameter, ranging from just over 1 ton to over 30 tons for the largest sizes.
• Minimum Breaking Load: Four times the Working Load Limit.
• Weight per Meter: Increases with the chain diameter.
• Link Dimensions (Inside Length and Width): Vary depending on the chain size and manufacturer.

How It’s Sold:

G80 alloy steel chain is commonly sold:

• By the Meter/Foot: Cut to the specific length required for a lifting application or sling assembly.
• In Drums or Reels: For larger quantities.
• Assembled Slings: Pre-fabricated chain slings with various configurations (single leg, multi-leg) and end fittings, ready for lifting.

When selecting G80 alloy steel chain, it is crucial to choose the correct size and Working Load Limit for the intended lifting task, considering the weight of the load and the specific requirements of the lift. Always prioritize safety and adhere to all relevant regulations and manufacturer’s guidelines for the safe use of lifting equipment.