The Alloy Chain Difference
Grade 80 and Grade 100 alloy steel chains are the only chain grades certified for overhead lifting applications under ASME B30.9 and EN 818-2. Unlike lower-grade carbon steel chains (Grade 30, 43, 70), alloy chains are manufactured from specially formulated steel, individually heat-treated, and proof-tested to ensure consistent, reliable performance under the most demanding conditions.
Metallurgical Comparison
| Property | Grade 80 | Grade 100 |
|---|---|---|
| Tensile Strength | 800 N/mm² (116,000 psi) | 1,000 N/mm² (145,000 psi) |
| Steel Type | Alloy steel (Mn-Cr-Mo-Ni) | Premium alloy steel (Cr-Ni-Mo-V) |
| Heat Treatment | Quenched & tempered | Quenched & tempered (tighter control) |
| Hardness (HRC) | 26-36 | 32-39 |
| Elongation at Break | ≥20% | ≥17% |
| Impact Toughness | Good (-40°C rated) | Very Good (-40°C rated) |
| Fatigue Life | Good (20,000+ cycles at 50% WLL) | Excellent (30,000+ cycles at 50% WLL) |
Working Load Limit Comparison
| Chain Size (mm) | Chain Size (inches) | Grade 80 WLL (lbs) | Grade 100 WLL (lbs) | Grade 100 Advantage |
|---|---|---|---|---|
| 6mm | ~1/4″ | 2,650 | 3,500 | +32% |
| 8mm | ~5/16″ | 4,500 | 5,700 | +27% |
| 10mm | ~3/8″ | 7,100 | 8,800 | +24% |
| 13mm | ~1/2″ | 12,000 | 15,000 | +25% |
| 16mm | ~5/8″ | 17,900 | 22,600 | +26% |
| 20mm | ~3/4″ | 28,300 | 35,300 | +25% |
| 22mm | ~7/8″ | 34,200 | 42,700 | +25% |
| 26mm | ~1″ | 47,700 | 59,700 | +25% |
| 32mm | ~1-1/4″ | 72,300 | 90,400 | +25% |
Design Factor
Both Grade 80 and Grade 100 chain slings use a 4:1 design factor per ASME B30.9:
WLL = Minimum Breaking Force ÷ 4
This means a Grade 80 chain rated at 7,100 lbs WLL has a minimum breaking force of 28,400 lbs. The 4:1 factor accounts for dynamic loading, wear, and material variability.
Weight Savings with Grade 100
The primary practical advantage of Grade 100 is weight savings. Because Grade 100 is 25% stronger at the same diameter, you can use one size smaller chain for the same WLL:
- Example: A 10mm Grade 80 chain (WLL 7,100 lbs) weighs 2.2 kg/m. An 8mm Grade 100 chain (WLL 5,700 lbs… too low). A 10mm Grade 100 chain (WLL 8,800 lbs) weighs 2.2 kg/m but has 25% more capacity.
- Better example: For a 12,000 lb WLL requirement: 13mm Grade 80 weighs 3.8 kg/m vs 10mm Grade 100 at 2.2 kg/m — a 42% weight reduction for equivalent capacity.
For riggers who handle slings all day, this weight reduction significantly reduces fatigue and improves safety.
Manufacturing Standards
ASME B30.9 (North America)
- Covers alloy chain slings for overhead lifting
- Requires proof testing of each sling at 2 × WLL
- Specifies inspection criteria, removal criteria, and training requirements
- Design factor: 4:1
EN 818-2 (Europe)
- Specifies requirements for Grade T(8) and Grade T(10) chain — equivalent to Grade 80 and 100
- Requires CE marking and Declaration of Conformity
- Each chain individually proof tested at 2.5 × WLL
- Traceability required from raw material to finished product
AS 2321 (Australia)
- Grade T chain for lifting purposes
- Similar requirements to EN 818 with additional marking requirements
Sling Configurations and Capacity
| Configuration | Capacity Factor | 10mm Grade 80 | 10mm Grade 100 |
|---|---|---|---|
| Single leg, vertical | 1.0 | 7,100 lbs | 8,800 lbs |
| Single leg, 60° angle | 0.866 | 6,149 lbs | 7,621 lbs |
| Single leg, 45° angle | 0.707 | 5,020 lbs | 6,222 lbs |
| 2-leg, 60° angle | 1.732 | 12,297 lbs | 15,242 lbs |
| 2-leg, 45° angle | 1.414 | 10,039 lbs | 12,443 lbs |
| 3/4-leg, 60° angle* | 1.732 | 12,297 lbs | 15,242 lbs |
*3 and 4-leg slings rated same as 2-leg per ASME B30.9 (only 2 legs assumed to carry load)
Inspection Requirements
Before Each Use
- Check for stretched links (any link elongated >5% from original)
- Check for wear (any link worn >10% of original diameter)
- Look for nicks, gouges, or surface cracks
- Verify hooks have functional safety latches and no deformation
- Check that identification tags are readable
Annual Thorough Inspection
- Dimensional measurement of representative links
- Magnetic particle or dye penetrant testing if cracks suspected
- Verification of all markings and tags
- Documentation in written inspection records
When to Choose Grade 100 Over Grade 80
- Riggers handle slings frequently: Weight savings reduce worker fatigue and injury
- Tight clearance lifts: Smaller chain fits through tighter spaces
- High-cycle applications: Grade 100’s superior fatigue life extends service intervals
- New sling purchases: The 30-50% cost premium pays for itself in ergonomic benefits and longer life
When Grade 80 Is Fine
- Occasional use: If slings are used infrequently, the weight and fatigue advantages of Grade 100 are less significant
- Budget-constrained operations: Grade 80 is fully certified for overhead lifting and has decades of proven performance
- Existing inventory: No need to replace working Grade 80 slings — they remain fully compliant
Common Mistakes to Avoid
Avoiding these common errors can prevent equipment failure, regulatory violations, and serious safety incidents in the field.
- Mixing Chain Grades in the Same Assembly: Using a Grade 70 transport chain with Grade 30 hardware creates a weak link at the lowest-rated component. Always match all components including chain, hooks, and connectors to the same grade or higher.
- Shock Loading a Chain: Chains are rated for static loads. A sudden jerk or impact can generate forces 2-5 times the static weight, which can cause instant failure, especially in Grade 30 proof coil chain with minimal stretch capacity.
- Using the Wrong Grade for the Application: Grade 30 is for general purpose only, not overhead lifting or transport. Grade 70 is required by DOT for cargo securement. Grade 80 and 100 are for overhead lifting. Using the wrong grade violates OSHA and DOT regulations.
- Neglecting Chain Inspection: Chains should be inspected link by link before each use. Look for stretched links (elongation beyond 5%), nicks, gouges, corrosion, and bent or twisted links. Any of these defects requires immediate retirement per ASME B30.9.
- Improper Chain Shortening: Never tie a knot in a chain or use bolts through links to shorten it. These methods create stress concentrations that reduce capacity by 50% or more. Use a chain shortening clutch or grab hook designed for the chain grade.
Frequently Asked Questions
What makes Grade 100 chain worth the price premium over Grade 80?
Grade 100 offers 25% higher Working Load Limit than Grade 80 at the same chain diameter. This means you can use a smaller, lighter chain for the same load capacity — a 3/8-inch Grade 100 chain has the same WLL as a 1/2-inch Grade 80 chain but weighs 40% less. For applications involving frequent manual handling, long sling assemblies, or weight-sensitive environments like aerospace, the reduced weight justifies the 30-50% cost premium.
Can Grade 80 and Grade 100 components be mixed in one sling?
Never mix grades in a single sling assembly. Each component must be the same grade — chain, hooks, master links, and coupling links all must match. A Grade 80 hook on a Grade 100 chain downgrades the entire sling to Grade 80 WLL. Manufacturers color-code components for identification: Grade 80 is typically blue, Grade 100 is orange or purple. All components must carry legible grade markings per NACM and ASTM standards.
What is the proof test load for Grade 80 vs Grade 100 chain?
Proof test load is 2.5 times the Working Load Limit for both Grade 80 and Grade 100 chain per NACM specifications. For example, a 3/8-inch Grade 80 chain with 7,100 lb WLL has a proof test load of 17,750 lbs and a minimum breaking force of 28,300 lbs. Grade 100 same size has 10,600 lb WLL, 26,500 lb proof test, and 42,400 lb minimum breaking force. Proof testing should be performed by the manufacturer, not in the field.