Understanding G80 Chain Specifications, Grades and Proper Shortening

Understanding G80 Chains

G80 chains, sometimes referred to as G80 clevis chains, are robust chains used for lifting and rigging applications. They get their name from having a working load limit (WLL) or safe working load of 80,000 pounds or 36,287 kilograms. These high strength chains have integrated clevises, making them easy to shorten and adjust to the proper working length.

Chain Specifications

G80 chains are made from heat treated alloy steel for added durability and resistance to abrasion. Each clevis fitted link has a minimum breaking strength of 400,000 pounds or 181,436 kilograms. The chains measure approximately 1-1/4 inches between inner faces and have integrated clevises spaced every 12 inches along the chain.

The integrated clevises allow for simplified shortening and adjustment of the chain length by removing links as needed. This avoids the need for loose clevises that can introduce weakness or flexibility into the rigging system. The heat treated steel ensures the chains have consistent strength and longevity even when shortened.

Chain Grades

G80 chains are available in various grades from leading manufacturers to suit different purposes:

• Grade 80 - General purpose
• Grade 80X - Increased wear resistance
• Grade 100 - High strength
• Grade 120 - Maximum strength

The different grades have slightly different dimensions and specifications to suit their intended uses. Selecting the correct grade for the application helps balance strength, weight, and cost considerations.

Shortening and Installation

One of the main benefits of integrated clevis G80 chains is the ability to remove links to shorten the chain to precisely fit the application. This helps eliminate excess chain slack while still retaining the full working load limit. Some key tips when shortening G80 chains include:

• Only use manufacturer approved tools and procedures
• Make clean perpendicular cuts to preserve link strength
• Discard damaged links to prevent premature failure
• Cap cut ends to prevent unravelling
• Ensure at least 3 free links remain for proper articulation

When installing shortened G80 chains, carefully inspect for any damaged links including cracks, gouges, wear, or deformation. Use approved grade 80 alloy steel master links or chain connectors to join chain ends. Do not exceed working load limits in the specific configuration.

Usage Considerations

While G80 chains are robust, proper usage practices are important to maximize safety and chain life:

• Avoid sharp bends which can overstress links
• Use edge protectors when chains contact sharp surfaces
• Keep chains properly lubricated
• Frequently inspect for worn, damaged, or deformed links
• Replace suspect links instead of trying to repair them

Rotating chains while in use helps distribute wear over multiple links. Chains should be permanently removed from service when link thickness decreases by 15% or more. This avoids failures due to progressive reductions in link strength.

The Importance of Proper Installation

While Grade 80 chains themselves are robust, they must be properly shortened and installed to achieve their working load rating. Cutting the chain cleanly avoids notches or damage that becomes crack initiation points. The cut must be perpendicular to the link to avoid reduced strength in one direction.

Capping the cut ends prevents unravelling and further damage. Discarding visibly damaged links eliminates defects that could lead to premature failure. Using properly rated connectors where the chain has been shortened ensures the load rating carries through the entire system.

With attention to detail during shortening and installation, G80 chains can retain their impressive 36,000 kg working load limit. They can safely lift massive loads through complex rigging arrangements. But defects or poor installation practices reduce strength margins and safety factors, risking damage, equipment loss, or accidents.

The integrity G80 chains starts with the manufacturing quality controls and proper heat treatment. It continues with those shortening and installing the chains following best practices. This ensures optimal strength and safety for critically important lifting set-ups.

FAQs

What is the working load limit of a G80 chain?

G80 chains have a working load limit (WLL) or safe working load of 80,000 pounds or 36,287 kilograms.

Why shorten G80 chains instead of using loose clevises?

Integrated clevises allow shortening without flexibility or weakness being introduced. Loose clevises can bend and deform, reducing the chain's working load limit.

What are some key considerations when shortening G80 chains?

Use manufacturer approved tools and procedures, make clean perpendicular cuts, discard damaged links, cap cut ends, and ensure at least 3 free links remain for flexibility.

How often should G80 chains be inspected and replaced?

Chains should be frequently inspected for damaged links which should be replaced. Chains should be replaced when link thickness decreases by 15% due to wear and reduced strength.