Customized Lifting Chain

Alloy Chain Grade 80 or Grade 100 should be used for overhead lifting. ASTM states that alloy chain shall be able to elongate a minimum of 20% before fracture (7.3.5). To ensure that alloy chain consistently meets this requirement, ASTM requires the use of certain alloying elements in the manufacturing of the steel for alloy steel chain. These alloys can vary from company to company, but some key requirements are specified by ASTM. The alloy properties also improve the wear and tear that the chain will experience.  Note that when chain is in use, no amount of stretch is allowed.

One of the safety measures implemented was to place chain in Grades based on the ultimate breaking strength of that chain. This number is what we see today G30, G43, G70, G80 & G100 and the common chain grades. The number after each letter is N/mm2. For example, G80 means that the maximum stress on the chain at ultimate strength is 800 newtons per millimeter squared.

The safety measure was identifying which types of chain are appropriate and strong enough for overhead lifting. Anytime we move or lift a load it is dangerous. Moving a load along the ground has the advantage that the ground is supporting the load. We have to overcome the coefficient of friction to move the load. The chain’s working load limit does not have to match the weight of the load. It needs to be able to handle the tension applied, which is based on the surface that it is being moved over plus some fraction of the weight of the load. This can be calculated using formulas.

If we lift that same load off the ground, we now have to overcome gravity. The chain’s working load limit will have to be of sufficient strength to support the weight of the load plus any additional forces imposed by angles and hitch type(s) used.

The primary function of lifting chains is to facilitate safe and efficient lifting and rigging operations. They are used to create a secure connection between the load and the lifting device. Lifting chains distribute the load's weight evenly, ensuring stability and reducing the risk of load shifting or accidents. They allow for controlled lifting, lowering, and positioning of heavy loads with precision. Lifting chains provide reliable load-bearing capabilities, enabling the safe movement of objects in various industries, including construction, manufacturing, and logistics.