Product Summary

Longze Heavy-Duty Lifting Eye Bolts (DIN 580 / ASME B18.15) are premium forged fasteners designed for the safe lifting and suspension of heavy machinery, motors, and

control cabinets. Manufactured in Yongnian, China, our eye bolts are produced via high-pressure drop-forging to ensure a continuous grain flow, providing maximum structural

integrity and resistance to shock loads. Whether for a 50-ton transformer or a marine engine installation, Longze eye bolts deliver the certified Working Load Limit (WLL) and safety factors required for critical rigging and lifting operations.

• ✔ Drop-Forged Integrity: Unlike cast alternatives, our forged eye bolts eliminate internal porosity and air pockets, ensuring the shank and ring can withstand rigorous vertical and angular tension.

• ✔ Certified Safety Factor: Every batch is engineered to a 4:1 or 5:1 safety factor, with the Working Load Limit (WLL) clearly embossed on the ring for instant on-site verification.

• ✔ Precision Tapped Threads: Our threads are CNC-machined after forging to ensure a perfect 6g fit, allowing the bolt to seat flush against the surface—a critical requirement for preventing shank bending.

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• Standards: DIN 580 (Metric), ASME B18.15 (Imperial / Shoulder Pattern), ISO 3266.

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• Diameter Range: M6 to M100 | 1/4" to 4".

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• Property Class: C15E (Forged Steel) | Stainless Steel 304 (A2) & 316 (A4).

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• Load Pattern: Shoulder Type (Required for angular lifting) / Plain Type (Vertical only).

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• Surface Finish: Hot Dip Galvanized (HDG), Zinc Plated, Plain/Oiled, Electropolished (SS).

Mechanical Properties & Material Standards

• Matching the steel grade to the structural requirements of the transmission line.

• Material Type	Grade / Standard	Tensile Strength	Yield Strength	Hardness Range
  Forged Carbon Steel	C15E / A105	340 - 470 MPa	235 MPa	110 - 150 HB
  Stainless 304	A2-70	700 MPa	450 MPa	200 - 280 HV
  Stainless 316	A4-80	800 MPa	600 MPa	240 - 320 HV
  Alloy Steel	42CrMo	1000+ MPa	900 MPa	32 - 38 HRC

Working Load Limits (WLL) - DIN 580

• Certified vertical and angular load capacities for standard metric eye bolts.

• Thread Size (D)	Vertical Load (kg)	45° Side Load (kg)	Eye Inner Dia (d2)	Shank Length (L)
  M12	340 kg	240 kg	30 mm	20.5 mm
  M16	700 kg	500 kg	35 mm	27.0 mm
  M20	1,200 kg	860 kg	40 mm	30.0 mm
  M24	1,800 kg	1,290 kg	50 mm	36.0 mm

Galvanizing & Corrosion Resistance

• Ensuring 30+ years of service life in corrosive environments.

• Surface Treatment	Coating Thickness	Salt Spray Test	Best Application	Appearance
  Zinc Plated	8 - 12 μm	72 - 144 Hours	Indoor Machinery	Clear / White
  Hot Dip Galv.	≥ 45 μm	500 - 800 Hours	Outdoor Infrastructure	Dull Grey
  SS316 Polished	N/A	1000+ Hours	Marine / Chemical	Mirrored
  Powder Coated	60 - 80 μm	240+ Hours	Identification / Safety	Red / Yellow

Avoid Pitfalls:

• Angular Loading Risks: DIN 580 eye bolts are designed for vertical lifts. For side-loading or angular lifts, the WLL reduces significantly (see table). We recommend our Shoulder Pattern Eye Bolts for any lift exceeding a 15° angle.

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• Incomplete Seating: If the eye bolt isn't screwed in fully (flush against the load surface), the shank is subjected to bending stress, which can lead to sudden failure. Longze ensures thread relief at the base of the shank for a tight fit.

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• Hydrogen Embrittlement: For high-strength alloy steel eye bolts that are electro-galvanized, we perform strict 8-hour de-embrittlement baking to prevent brittle fracture under heavy tension.

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Perfect Fit Assembly:

• Matched Lifting Nuts: Pair our eye bolts with Longze DIN 582 Eye Nuts for a complete through-hole lifting solution.

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• Thread Compatibility: Ensure the internal thread of your equipment is clean and to the correct depth (at least 1.5x the bolt diameter) to guarantee the eye bolt carries the full rated load.

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Quality Control & Logistics:

• ISO 9001 Certified: 5-step QC including Magnetic Particle Inspection (MPI) to detect surface cracks, 2x WLL Proof Load testing, and material spectrometer analysis.

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• Sea-Worthy Packaging: Individually bagged or layer-packed with protective wrap to prevent ring-to-ring impact damage, then crated in reinforced wooden boxes for maritime export.

• Q: Can I use DIN 580 eye bolts for side-pulling? A: Only if the WLL is adjusted according to the 45° load ratings. For 90° pulling, we recommend our Swivel Hoist Rings which rotate 360° to accommodate any lifting angle.

• Q: Do you offer ASME B18.15 Imperial sizes? A: Yes, we manufacture both "Plain" and "Shoulder" patterns in UNC/UNF threads for the North American and Middle Eastern markets.