Alloy Steel Chain Sling
What grades of chain are acceptable for overhead lifting, and why?
Only alloy steel chain Grade 80 or Grade 100 is acceptable for overhead lifting in most North American regulations. These grades are heat-treated alloy steels designed with ductility, controlled elongation, and predictable failure modes, manufactured and tested to ASTM specifications for sling service. Lower-grade carbon or hardware-store chain lacks standardized WLL for overhead lifts and may brittle-fracture without visible stretch.
How do alloy steel chain slings behave when overloaded, and what is the inspection impact?
Alloy steel chain slings tend to stretch when overloaded, rather than snapping instantly. Plastic deformation (stretch) in links is a critical rejection criterion; WorkSafeBC/Yukon require removal or repair if stretch or deformation is observed, and OSHA requires removal if link size is below minimum. Once stretch is observed, the sling must be removed from service as residual strength and WLL are unknown.
What are the mandatory identification elements for compliance in BC/Yukon and OSHA-covered facilities?
For BC/Yukon: each alloy steel chain sling must be permanently identified with size, manufacturer's grade and WLL, length and number of legs, and name or mark of sling manufacturer. For OSHA: size, grade, rated capacity (WLL), and sling manufacturer. For California: markings must show recommended safe working load, hitch type(s), angle basis, and number of legs (if >1).
An alloy steel chain sling is a purpose-built assembly of welded alloy steel chain and end fittings used to attach and lift loads with cranes or other hoisting equipment. Designed and rated per ASME B30.9 and OSHA/WorkSafeBC requirements, it is manufactured from heat-treated Grade 80 or Grade 100 alloy steel, proof-tested to a specific Working Load Limit (WLL), and permanently identified with size, grade, WLL, length, leg count, and manufacturer.
On the shop floor, alloy steel chain slings are primary rigging tools for handling heavy, rugged, or hot loads such as steel billets, forgings, dies, and machinery. They are used in crane and hoist lifting with straight, choker, or basket hitches, including multi-leg bridle arrangements. Selection requires only Grade 80 or 100 alloy steel chain; hardware-store chains are prohibited. All attachments must have rated capacity at least equal to the chain. Each sling must carry permanent ID tags showing size, grade, WLL, reach, leg count, and manufacturer. Pre-use daily inspections check for wear, stretch, deformation, cracks, nicks, gouges, corrosion, burned links, and missing tags. Annual thorough inspections by a qualified person are mandatory, with records kept. Temperature limits apply: not above 260°C (500°F) per WorkSafeBC, and permanent removal above 1000°F (538°C) per OSHA. Proof testing is required for new or repaired slings.
Using non-rated or mis-identified chain: Hardware-store chain or chain slings with missing/illegible ID tags are used, violating requirements for Grade 80/100 alloy steel and permanent identification. This leads to unknown capacity, overload, and sudden failure.
Ignoring sling angle, hitch type, and load distribution: Treating WLL as valid regardless of leg angle or hitch configuration, such as using multi-leg bridles at low angles without WLL reduction, causing chain overload even when total load is below nominal WLL.
Poor inspection and removal-from-service practices: Inadequate daily visual checks and annual thorough inspections, continued use despite wear, stretch, cracks, nicks, gouges, corrosion, heat damage, or opened hooks, and failure to document inspections or permanently remove severely worn or heat-damaged slings.