Grade 70 transport chain is almost always identifiable by its gold/yellow finish and link stampings (“G7,” “70,” or “T”). Grade 80 and 100 lifting chains are marked with “8,” “80,” “10,” or “100” on individual links and typically come with a test certificate. Proof coil and high test chain are harder to distinguish visually — if you cannot positively identify the grade, do not use the chain for lifting or legal cargo securement. When in doubt, replace it with new, traceable, properly marked chain.

Proof testing means every length of chain leaving the factory has been subjected to a tensile load equal to a defined multiple of its WLL (typically 2x for Grades 30–70, and 2.5x for Grades 80 and 100) to verify that no links fail, crack, or deform at that load. It is a quality assurance test — not a load rating test — and does not mean the chain can be used at that proof load in service.

Chain size refers to the nominal diameter of the steel bar used to form the links — measured at the straight section of the link, not across the weld. Always measure the wire diameter, not the link width or length. Using a vernier caliper on an unworn section of link gives the most accurate measurement.

No. Field welding of chain links is never acceptable for load-bearing, lifting, or securing applications. The heat of welding changes the metallurgical properties of alloy or heat-treated chain unpredictably, eliminating any meaningful safety assurance. Replace damaged chain with new certified chain.

Chain should be cleaned, lightly lubricated with oil, and hung on properly rated storage hooks or racks — never left coiled on a damp floor. Lifting chain must be stored with its test certificate and inspection records. Keep different grades clearly separated to prevent misidentification and misuse.