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chain grade information

Chain Grades: Comparing Grade 30, Grade 43, Grade 70, Grade 80, Grade 100, and Grade 120 Chain

When selecting the right chain for your application, understanding the different grades available is crucial. Chains are graded based on their strength, durability, and suitability for specific tasks. These grades represent the strength and durability of the material - the higher the number, the stronger the chain.

We turned one of our most popular blog posts on the differences between chain grades into a simple chart for quick and easy comparison. We also added information on the Grade 30 and Grade 43 chains. (While we don't sell these grades on our website, you can always call in to order them.)

Read on to learn more about the differences between chain grades offered through US Cargo Control and their uses.


chain grade information

Chain Grades by Use

Each chain grade offers unique benefits catered to specific applications. Selecting the appropriate chain grade depends on the requirements of these applications. Understanding the differences helps you select the right one for the job, ensuring safety, efficiency, and longevity. Below are the different chain grades offered through US Cargo Control:

Grade 30

    • General purpose economical chain.
    • Low tensile strength; prone to stretching under heavy loads.
    • Used in a variety of industries and jobs including light construction, agricultural applications, and the marine industry.

Grade 43

    • General purpose economical chain.
    • Stronger than Grade 30; offers better resistance to wear and tear.
    • Typically used for container securement, logging, farming, towing, marine applications, and as general purpose utility chain.

Grade 70

    • Made from a higher strength, heat-treated carbon steel that has a load rating approximately 20 percent higher than Grade 43.
    • The gold chromate finish makes it easy for DOT officials to recognize.
    • Typically used by truckers, loggers, and highway crews for load securement and towing.

Grade 80

    • The most economical choice that is suitable for overhead lifting.
    • A high strength, heat-treated alloy chain that can be used as a sling component for overhead lifting as well as heavy-duty tow chain.

Grade 100

    • A high strength, heat-treated alloy chain.
    • Has approximately 25 percent higher strength than Grade 80.
    • Primarily used as a sling component for overhead lifting. Popular in construction, manufacturing, and rigging applications.

Grade 120

    • An ultra-premium high strength chain designed specifically for the rigorous requirements of overhead lifting applications.
    • The links have a unique square shape and it has approximately 50 percent higher strength compared to Grade 80.
    • There are currently no official standards for Grade 120 chain in the U.S. or Europe, however, it does meet or exceed the standards of Grade 100 chain.

chain working load limits

Safety Standards for Chain

Organizations like ASTM (American Society of Testing & Materials), ASME (American Society of Mechanical Engineers), and OSHA (Occupational Safety & Health Administration) have released safety standards and regulations for various materials and grades of a chain.

Essentially, it's a formal way of recognizing and documenting that not all chain is created equally and therefore, it should not all be used for the same applications.

ASTM Chain Specification

What do A413, A391, and A973 all mean? Those are simply how the ASTM categorizes and references their specification standards. Each specification outlines the different manufacturing and testing requirements as well as the appropriate performance standards, grades, and applications.

Determining Chain Grades

Chain grades are a standard method for showing the ultimate breaking strength (tensile strength) of a chain. Grades help determine what sort of applications are appropriate for a given chain.

Chain grades are determined by calculating newtons per square millimeter, using the formula “N/mm2”. Where "mm" is the area of the two cross-sections of a single chain link, and "N" is newtons. A newton is approximately 0.224805 lbs.

So, to determine a chain grade, manufacturers must find the ultimate breaking strength. Then, divide that number by .224805 to determine the ultimate breaking strength in newtons.

Next, take that number and divide it by the total area of two cross-sections of a single link. That number is the chain grade.

You could reverse this formula to determine the ultimate breaking strength if all you know is the chain grade.

Note: chain grades advertised by manufacturers are one-tenth of the actual mathematical grades. So grade 80 is really 800, and grade 120 is 1,200.

Determining Chain Working Load Limits

Working load limit (WLL) of a chain is another designated safety measure. WLL is a weight significantly less than the weight that would cause a chain to fail (tensile strength). WLL = MBL / SF. Where MBL is the minimum breaking load and SF is the safety factor.

A safety factor is the ratio between allowable stress and actual stress. In other words, it's the ratio between the chain strength and the expected maximum stress. In lifting and rigging applications, factors such as gravity and the additional force caused by angles must be considered.

Always adhere to the WLL to ensure a chain does not break or wear quicker than it should.

More Articles You May Like:

How USCC Creates High-Quality Custom Chain Slings

Protect Valuables with Strong Security Chain

Ratchet Chain Binder Handles: Break Strength Test

Transport Chain & Load Binders 101

Working Load Limit, Break Strength, & Safety Factor: What are the Differences?


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