How is Chain Made?
Our chain starts as rod made to our exacting requirements from American steel mills. Each coil is inspected, labeled, and tracked through our factory via our data network. The rod will be cleaned and drawn into an exact wire diameter, then stored ahead of the chain making departments.
Chain is produced in small groups of equipment, or cells. These cells include formers, welders, calibrators, and sometimes twisters. The former receives the wire, stamps the grade and trace code on it, then cuts it to approximately to the length required of a chain link. This piece is formed into a link which interconnects with the previously formed link, creating a chain from the wire formed links.
The chain then passes to the welder where each link is machine welded electrically with no filler by heating the edges of the wire ends and forging them together. The excess material is trimmed.
After the chain is formed and welded it’s calibrated to ensure the consistency of the length of each link. This process also tests the strength of the chain, especially concentrating on the welded section.
Samples of the welded chain are cut from the production run several times per shift to be tested to verify the integrity of the weld and to check physical properties. Data from each test is stored electronically for future reference.
Some chains are twisted for use in cross chains that contact the road in tire chains.
Once inspected, the chain is loaded into a storage box to await the next operation.
The next process is determined by the grade of chain and any special customer requirements. Some chain will be sent to our quench and temper induction heat treaters, where it’s heated to between 1600 and 1700 degrees F, quenched in water, and then tempered at 400 to 600 degrees.
From here, the chain will be proof tested automatically to twice its working load limit. These chains will be put in drums or cut for assembly into many products, primarily tow and binder chains and agricultural safety chains. Please note that all chains when used must not be loaded to more than their rated working load limit and only alloy chain should be used for overhead lifting.
For other grades of chain such as proof coil or high test no heat treating is needed. So the next process after form and weld would be package, shot blasting, hot dip galvanizing, zinc plating or other special coatings. Finished welded chain is packaged, ready for shipment, but likely it will but cut and assembled into an assortment of assembled products. The chain is then shipped to a customer where it is ready for usage or resale.