LDY Metallurgical Electric Hoist High-Temperature Upgrade
Key Takeaways Kelude Heavy Industry has completed the high-temperature upgrade validation for its LDY metallurgical electric hoist: Class H insulated motor (180°C) with cast-iron heat-dissipation shroud, dual-brake standard configuration, manganese-phosphated wire rope (rated for 200°C), and 35CrMo alloy steel hook block. The hoist passed an 8-hour full-load test at 80°C ambient temperature with a temperature-rise margin of ≥20%, and the solution has been incorporated into the standard configuration.
In July 2026, the Kelude Heavy Industry technical center completed validation of the high-temperature upgrade for the electric hoist used on its LDY metallurgical foundry crane. After an 8-hour continuous full-load test at an 80°C ambient temperature, the temperature rise of every critical component on the upgraded YHII metallurgical electric hoist remained within 80% of the insulation-class limit — a milestone that underscores Kelude's growing technical capability in the metallurgical foundry crane sector.
Why the Upgrade Was Needed
Although metallurgical foundry cranes and general bridge cranes share a similar structural design, their working environments could not be more different. Standard cranes operate in ambient temperatures ranging from -20°C to +40°C, while metallurgical foundry cranes must run continuously in high-radiation heat environments of 60°C to 200°C — with some workstations facing the direct threat of molten metal splash. Using a standard electric hoist in a metallurgical environment is a serious safety hazard.
Conventional metallurgical electric hoists suffer from several chronic weaknesses:
- Inadequate motor insulation: Standard Class F insulation (rated for 155°C) ages rapidly under prolonged high heat, with failure rates 3–5 times higher than expected.
- Single-brake safety risk: When hoisting molten metal, a brake failure is catastrophic.
- Short wire rope service life: Bright-finish wire rope loses significant strength in environments above 100°C.
- Hook block material not heat-resistant: Standard hooks lose hardness at elevated temperatures, creating a risk of deformation and fracture.
- Grease breakdown at high temperatures: Conventional grease deteriorates quickly in environments above 80°C.
Upgrade Details
1. Hoisting Motor Upgrade: Class H Insulation + Cast-Iron Heat-Dissipation Shroud
| Upgrade Item | Upgrade Front(Standard Hoist) | Upgrade Rear(YHIIMetallurgical Duty) |
|---|---|---|
| Insulation Class | FClass(155℃) | HClass(180℃) |
| Enclosure Material | Aluminum Alloy | Cast Iron + Cooling Fins |
| Protection Rating (IP) | IP44 | IP54 |
| temperature risesafety margin | Margin Approx.10% | Margin≥20% |
| Heat-Resistant Testing | factory Standard Testing | 80℃Ambient8Hours Full load Testing |
H-class insulation materials are rated for continuous operation at temperatures up to 180°C. Combined with the heat-dissipating fins on the cast-iron housing, heat dissipation efficiency improves by approximately 30% compared to aluminum enclosures, ensuring the motor temperature rise consistently stays below the insulation class limit.
2. Braking System Upgrade: Dual Brake as Standard
In compliance with the mandatory requirements of YB/T 5031-2018 "Technical Specification for Metallurgical Crane Manufacturing," the upgraded LDY series metallurgical electric hoist features two independent brakes on the hoisting mechanism as standard:
- Main brake: A normally closed brake integrated into the conical rotor motor (engages automatically upon power loss)
- Auxiliary brake: An additional electromagnetic disc brake mounted on the high-speed shaft of the gearbox
The two brakes operate independently—if one brake fails, the other remains fully capable of holding the rated load. This configuration is fundamentally different from standard electric hoists, which are equipped with only a single brake.
3. Wire Rope Upgrade: Manganese-Phosphated Coating
The upgraded wire rope features a manganese-phosphate coating process, setting it apart from conventional bright-finish wire ropes:
| performance indicators | Bright finish Wire Rope | phosphated wire rope |
|---|---|---|
| Temperature Resistance Upper Limit | 100℃ | 200℃ |
| Wear Resistance(Comparison) | Reference Value | Lifting3~5Times |
| Resistancefatigue life | Reference Value | Lifting2~3Times |
| Corrosion Resistance | Fair | Excellent |
Additionally, the rope groove is coated with Molybdenum disulfide high-temperature grease, which retains its lubricating properties even at temperatures up to 200°C, effectively reducing friction and wear between the wire rope and the pulley.
4. Hook Block Upgrade: 35CrMo Alloy Steel
| Upgrade Item | plain hook | Metallurgical Hook |
|---|---|---|
| Enclosure Material | 20Steel/40Cr | 35CrMoAlloy Steel |
| Heat treatment | normalizing | quenching and tempering |
| Surface Hardness | HRC 20~25 | HRC 35~40 |
| High Temperature Strength(200℃) | Lowering Margin Approx.30% | Lowering Margin Approx.10% |
Quenched and tempered 35CrMo alloy steel hooks retain over 90% of their room-temperature strength at 200°C, and when paired with a hook latch, they ensure safe lifting and transport in high-temperature environments.
Configuration Options at a Glance
Kelude Heavy Industry offers the LDY metallurgical foundry crane in three configuration grades to suit your operational needs:
| configuration Grade | Applicable Temperature | motor insulation | Brake | Wire Rope | Applicable Duty Station |
|---|---|---|---|---|---|
| Standard | ≤50℃ | HClass | Double Brake | Phosphate Coating | Casting Fettling, Sand Mold Handling |
| Reinforced | 50~100℃ | HClass+Cooling Shroud | Double Brake | Phosphate Coating+high-temperature grease | Near Pouring Station |
| High-Temperature Duty | 100~200℃ | HClass+Cooling Shroud+Thermal Insulation | Double Brake | Phosphate Coating+Molybdenum disulfide | Ladle Tilting, Short-Duty Operation Above Furnace |
Verification Results
During factory acceptance testing in July 2026, the upgraded YHII metallurgical electric hoist ran continuously for 8 hours at an ambient temperature of 80°C. Key measured data:
- Hoisting motor winding temperature rise: 108K (H-class limit: 180K, 40% margin)
- Brake disc surface temperature: max 76°C (no braking performance degradation)
- Wire rope surface temperature: max 62°C (no phosphated coating delamination)
- Gearbox oil temperature: 68°C (within normal range)
All indicators meet or exceed YB/T 5031-2018 standard requirements. The verification procedure has passed technical review and is now included in the standard configuration for the LDY series. For special high-temperature service requirements, Kelude can provide further customized solutions.
FAQ
Q: How much more does an H-class insulated motor cost compared to a standard F-class motor?
A: H-class insulated motors cost roughly 15–25% more than F-class. However, in metallurgical service, F-class motors fail 3–5 times more often than H-class. Factoring in downtime losses, H-class delivers a lower life cycle cost. All Kelude LDY hoists come standard with H-class insulation.
Q: Is the dual brake system simply two identical brakes?
A: No — the two brakes are not identical. The main brake uses the normally closed brake built into the conical rotor motor, while the auxiliary brake is an electromagnetic disc brake mounted on the high-speed shaft of the gearbox, with independent brake control. The two braking systems operate on different principles and are fully independent — failure of one does not affect the other.
Q: How much longer does phosphated wire rope last compared to ordinary wire rope?
A: In high-temperature metallurgical environments, manganese phosphated wire rope delivers 2–3 times the fatigue life of ordinary bright-finish wire rope, with 3–5 times better wear resistance, and can withstand temperatures up to 200°C. The phosphate coating forms a micro-porous oil reservoir on the wire surface, reducing reliance on high-temperature grease.
Q: Can an existing standard LD hoist be retrofitted to metallurgical-grade LDY?
A: The feasibility and cost of retrofitting a standard LD hoist to metallurgical-grade LDY depend on scope: upgrading the motor to H-class insulation, adding the dual brake system, replacing the wire rope, and installing heat shields on the main girder — these items account for roughly 40–60% of the cost of a complete new hoist. If the existing equipment is already more than 5 years old, purchasing a new LDY is generally the more cost-effective option.
