Chain grade numbers are shorthand for tensile strength — the grade is roughly the chain's ultimate strength in newtons per square millimeter ÷ 10. But the number that actually matters on a jobsite is the line between grades: which chains may lift overhead, and which may only tie down.
The Grade Ladder
| Grade | Material | Approved use |
|---|---|---|
| G30 (Proof Coil) | Low carbon | General utility — never lifting |
| G43 (High Test) | Carbon | Towing, logging, tie-down — never lifting |
| G70 (Transport) | Heat-treated carbon | DOT load securement — never lifting |
| G80 | Heat-treated alloy | Overhead lifting — the standard |
| G100 | Heat-treated alloy | Overhead lifting — ~25% stronger than G80 |
| G120 | Premium alloy | Overhead lifting — highest strength-to-weight |
Why Only Alloy Lifts
Grades 80+ are quenched-and-tempered alloy steel with the ductility to stretch visibly before failing and toughness verified for impact — carbon chains can fail abruptly without warning. OSHA and ASME B30.9 restrict sling chain to alloy grades, and every link is embossed with its grade mark (8, 80, or 800; 10, 100; 12, 120). No embossing = no lifting, full stop.
Spotting Grades in the Field
G70 transport chain is usually gold chromate — the yellow chain on every flatbed — and its color is the fastest way to catch it sneaking into a lifting bridle. G80/G100 are typically black or blue-painted alloy with embossed marks. Color is a hint, embossing is the fact.
Matching Components
Hooks, master links, and connecting links must match the chain grade — a G70 hook on G100 chain caps the whole assembly at the weakest component (and disqualifies it from lifting entirely). Mechanical coupling links for lifting chain must be the manufacturer's rated alloy connectors, never quick links or lap links.
Working Load Snapshot (G80)
Typical single-leg WLL: 9/32" = 3,500 lb, 3/8" = 7,100 lb, 1/2" = 12,000 lb, 5/8" = 18,100 lb. G100 runs about 25% above each. Verify against the manufacturer's chart for the chain in hand.
Chain by the Foot or Assembled
G70 transport and G80/G100 alloy chain from our chain collection, cut to length, with fittings and complete sling assemblies. Grade, size, length, and fittings into the quote form at the top of the page — quotes answered during business hours.