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Which is stronger, grade 43 or grade 70 chain?

Author: Minnie

Apr. 29, 2024

Comparing Chain Grades

We turned one of our most popular posts, "What are the Differences Between Grade 70 Chain, Grade 80 Chain, Grade 100 Chain, and Grade 120 Chain?", into a simple chart for quick and easy chain grade comparison.

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We also added information on the Grade 30 chain and Grade 43 chain. While we don’t sell these grades on our website, you can always call in to order them. 

Typical Chain Uses

Grade 30

General purpose economical chain. Used in a variety of industries and jobs including light construction, agricultural applications, and the marine industry.

Grade 43

Typically used for container securement, logging, farming, towing, marine applications, and as general purpose utility chain.

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.

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. The most economical choice that is suitable for overhead lifting.

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

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.


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

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With competitive price and timely delivery, Lieying Group sincerely hope to be your supplier and partner.

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.

Learn more about transport chain and load binders.

Answer any questions you have by talking with our product experts. Give our team a call at (877) 923-0349 or send us an email to customerservice@uscargocontrol.com.

 

Chain grade 43 vs. 70

You can use anything you want to tie down a load as long as you do not cause abrasion points and stay within the Working Load Limit (WLL) of the tie down material.
3/8 Manila rope has a WLL of 205 lbs. Use enough of it and you could use this to tie anything down.

The chain you are looking at is differant size.
The grade 70 is 5/16 and is rated at 4700 lbs
The grade 43 is 3/8 and is rated at 5400 lbs

The thing you have to watch with H.F. is the hooks. They must be marked with the WLL also.

Another problem some have with chain is they buy big heavy duty chain and hook it to the rub rail or some other weak point on the trailer. Any tie down is only as strong as the weakest point.

The company is the world’s best Lifting Chain supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.

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