Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
Monel 400 Eye Bolts - DIN 580 / ASME B18.15 Lifting & Rigging
Monel® 400 eye bolts (also called Monel 400 lifting eye bolts, UNS N04400 eye bolts, nickel-copper alloy 400 lifting eyes, 2.4360 ringschrauben in DIN nomenclature) are forged-eye fasteners with a threaded shank and a closed-loop head that accepts a shackle, hook or sling. The eye geometry is hot-forged from parent bar, producing continuous grain flow around the loop and through the shank-to-shoulder fillet. The head form is qualified to DIN 580 (metric shoulder eye), ASME B18.15 (imperial pattern) or BS 4278 (collared eye). Material chemistry follows ASTM F468 for bar stock through 1-1/2 inch and ASTM B564 for larger forging stock. Monel® is a registered trademark of Special Metals Corporation; TorqBolt is not authorized by, affiliated with or endorsed by Special Metals. The reason to choose nickel-copper for the eye is the same as for deck flanges and pump bolting: flowing seawater, hydrofluoric acid and chloride exposure sit inside the Monel 400 envelope where austenitic stainless and zinc-plated carbon steel fail by pitting and stress corrosion cracking.
Eye Bolt Geometry Types
Four eye geometries cover the bulk of marine and chemical-plant rigging. Each is forged from the same Monel 400 stock; the difference is the head profile and the qualified load angle.
| Geometry | Standard | Qualified load angle | Typical service |
|---|---|---|---|
| Shoulder eye (forged) | DIN 580 / ASME B18.15 type 1 | 0 to 45 degrees off vertical | Marine deck lifting, naval crane points |
| Non-shoulder eye | ASME B18.15 type 2 | Vertical only | Light tie-down, instrument hoist |
| Collared eye | BS 4278 | 0 to 90 degrees with load chart | Heavy offshore lifting, single-leg sling |
| Lag eye (wood-thread) | ASME B18.15 type 3 | Vertical only | Timber decking, temporary rigging |
The shoulder is the controlling feature. A DIN 580 shoulder eye bears flat against the mating surface and transfers angled load through the shoulder rather than through the shank fillet. Without the shoulder, every angled lift bends the shank at the thread root, the highest stress concentration in the part. ASME B30.26 prohibits angled lifts on non-shoulder eyes.
Standards: DIN 580, ASME B18.15, BS 4278
DIN 580 is the metric reference for forged shoulder eye bolts (ringschrauben). The standard fixes the ring diameter (D1), the shoulder diameter (D2), the thread length and the proof-load coefficient by nominal thread size M8 through M100. ASME B18.15 is the imperial reference covering 1/4 inch through 1-1/2 inch with three head types (shoulder, non-shoulder, lag). BS 4278 covers collared eye bolts qualified for single-leg lifting at any angle through 90 degrees with a published load chart per nominal size. Each standard prescribes a proof-load test at twice the rated WLL with witnessed marking. Material substitution to Monel 400 follows the procurement rule: the eye geometry meets DIN 580 / B18.15 / BS 4278 and the chemistry meets ASTM F468 class A (UNS N04400, weldable) or class B (UNS N04405, free-machining).
Size Range and Working Load Limit
WLL is a function of nominal thread size, eye geometry and load angle. The table gives DIN 580 shoulder eye WLL for vertical and 45-degree off-vertical lift, design factor 5:1 per ASME B30.26.
| Nominal thread | Ring ID (mm) | Shoulder dia (mm) | WLL vertical (kg) | WLL 45 degrees (kg) | Proof load (kg) |
|---|---|---|---|---|---|
| M8 | 20 | 20 | 140 | 55 | 280 |
| M10 | 25 | 25 | 230 | 90 | 460 |
| M12 | 30 | 30 | 340 | 135 | 680 |
| M16 | 35 | 35 | 700 | 280 | 1400 |
| M20 | 40 | 40 | 1200 | 475 | 2400 |
| M24 | 50 | 50 | 1800 | 720 | 3600 |
| M30 | 60 | 60 | 3200 | 1280 | 6400 |
| M36 | 72 | 72 | 4600 | 1840 | 9200 |
| M42 | 80 | 80 | 6300 | 2520 | 12600 |
| M48 | 90 | 90 | 8500 | 3400 | 17000 |
Imperial WLL scales similarly: 1/2 inch B18.15 shoulder eye carries 1300 lb vertical, 5/8 inch 2200 lb, 3/4 inch 3250 lb, 1 inch 5200 lb. The 60 percent reduction applies at 45 degrees off vertical.
Material Spec: ASTM F468 and B564
Smaller eye bolts (M8 through M30, 1/4 inch through 1 inch) are forged from ASTM F468 bar stock with class A chemistry (UNS N04400, sulfur 0.024 max, weldable). Larger eye bolts (M36 through M100, 1-1/4 inch and above) come from ASTM B564 forging stock where the upset volume exceeds bar capacity. F468 sets the bolt mechanical floor: tensile 70 to 130 ksi (483 to 896 MPa), yield 30 ksi min (207 MPa), elongation 20 percent, hardness 60 HRB to 25 HRC. B564 forgings carry the same nickel-copper chemistry to ASTM B164 with mechanicals matched to the F468 envelope. The 25 HRC hardness cap clears NACE MR0175 sour-service automatically.
| Element | Min % | Max % | Notes |
|---|---|---|---|
| Nickel (Ni + Co) | 63.0 | - | Cobalt counts toward nickel |
| Copper | 28.0 | 34.0 | Balance with nickel |
| Iron | - | 2.5 | Residual |
| Manganese | - | 2.0 | Deoxidizer |
| Carbon | - | 0.30 | Weldability cap |
| Sulfur | - | 0.024 | Class A weldable; class B 0.025 to 0.060 |
| Silicon | - | 0.50 | Residual |
Applications
Marine deck lifting is the volume application: naval ships run Monel 400 eye bolts as pad-eye attachments on bulkheads, deck tie-down points and crane anchor lugs where the surface sees continuous saltwater wash. Stainless 316 lifts the same load at lower cost but pits under the head where chloride concentrates beneath the shoulder.
Chemical-plant pump removal is the second cluster. Refineries running HF alkylation, sulfuric acid storage and chloride brine cooling install Monel 400 lifting lugs on pump casings, agitator drives and column manhole covers. Offshore wellhead christmas trees get a Monel 400 lifting eye welded to the body so workover hoists do not penetrate the pressure boundary at a corroded thread. Naval crane attachment, submarine deck fittings, desalination plant pump lifting and shipyard rigging round out the set. Cross-reference marine applications and HF acid resistance for service-specific guidance.
Inspection and Load Testing
Every eye is proof-load tested to twice the WLL before shipment, witnessed and stamped on the shoulder. The test holds load for one minute; the eye is inspected for permanent set, crack initiation at the shoulder fillet and thread-root distortion. Dye-penetrant inspection per ASTM E165 follows on every part above 1 inch nominal. Hardness is checked on the shoulder per ASTM F468 section 11; tensile per F606 on one sample per heat lot. The certificate ships as EN 10204 type 3.2 with the proof-load number, WLL rating, rigging standard and heat traceability. Sour-service shipments add the NACE MR0175 statement. Marking is the manufacturer ID plus the F468 grade (F 468U class A, F 468V class B).
Frequently Asked Questions
WLL of a Monel 400 eye bolt? Set by the rigging standard (DIN 580, ASME B18.15 or BS 4278) and load angle. A DIN 580 M16 shoulder eye runs roughly 700 kg WLL vertical; 280 kg at 45 degrees off-axis. Design factor 5:1 per ASME B30.26 for overhead lifting.
Shoulder vs non-shoulder eye bolt? Shoulder eye (DIN 580 / B18.15 type 1) transfers angled load through the shoulder up to 45 degrees off vertical. Non-shoulder eye is rated for vertical lift only; angled loading bends the shank at the thread root, prohibited by ASME B30.26.
Why Monel 400 over stainless? Monel 400 holds up in flowing seawater, hydrofluoric acid and salt-spray where 316L pits and cracks. Default for naval deck fittings, offshore lifting points and chemical-plant pump removal lugs.
Proof-load tested? Yes. Each eye is proof-load tested to twice the WLL per ASME B18.15 section 7 or DIN 580 section 8, witnessed and stamped. Certificate ships as EN 10204 type 3.2 with proof-load number and WLL rating.
Related Products
Companion items: Monel 400 bolts (parent BOFU page), Monel 400 forgings (raw form for larger eyes), ASTM B564 (forging stock spec), ASTM F468 (bolt material spec). For sour service, cross-reference NACE MR0175. Broader application picture: marine applications and seawater corrosion. Full alloy reference on the main monel400.com page.
Request a Quote
For Monel 400 eye bolt pricing, lead time and certification documentation send nominal thread size, eye geometry (shoulder / non-shoulder / collared / lag), applicable rigging standard, WLL requirement and quantity to info@torqbolt.com or WhatsApp +91-22-66157017. Ex-Mumbai price and lead time returned within one working day. Domestic India 5 to 10 working days; export through JNPT to 40+ countries with the proof-load certificate, NACE MR0175 statement and EN 10204 type 3.2 mill test certificate in the document pack.
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