Cast Crane Drums per JB/T 9006-2010

Materials and Construction

Kelude supplies cast drums in all standard specifications. Drums are manufactured from HT250 grey cast iron for small and medium cranes (rated load ≤50t) or ZG270-500 cast steel for large-tonnage cranes (rated load >50t) and applications subject to heavy impact. Raw castings undergo stress-relief treatment to eliminate casting stress—grey cast iron drums receive artificial aging (heated to 530–550°C and held for 3–5 hours), while cast steel drums are normalized. The standard specifies that wall thickness is determined by wire rope diameter and lifting capacity, with a minimum wall thickness of 8 mm. Drum diameter D ≥ 20d (where d is the wire rope diameter), and drum length is set by rope storage capacity and the number of winding layers.

Drum groove machining requirements—rope groove radius R ≈ 0.53–0.55d, groove depth h ≈ 0.35–0.4d, and pitch p ≈ d + 2 mm. Groove surface roughness Ra ≤ 12.5 μm. Spiral grooves must transition smoothly with no sharp edges. Grooves are machined on CNC lathes to ensure consistent accuracy across production runs. For multi-layer winding, drums must be fitted with end flanges that extend at least 2 times the wire rope diameter above the outermost rope layer.

The standard sets strict requirements for the casting process—drum castings must be uniform in material composition and dense in structure. Carbon equivalent for grey cast iron drums is controlled within 3.0%–3.3% to ensure good fluidity and moderate shrinkage during casting. Cast steel drums are poured at 1520–1560°C. After casting, drums are descaled to remove sand adhesion and fins from internal cavities and external surfaces. Critical load-bearing areas must be free from casting defects such as porosity, shrinkage cavities, sand holes, and cracks.

Heat treatment requirements—grey cast iron drums undergo artificial aging to relieve casting stress: heated to 530–550°C, held for 3–5 hours, then furnace-cooled to below 200°C before air cooling. Cast steel drums are normalized: heated to 880–920°C, held, then air-cooled. Post-treatment hardness must be uniform across the drum—hardness variation at any cross-section must not exceed HB30. Drum groove surfaces are induction-hardened to improve wear resistance, with a hardened layer depth of at least 2 mm.

Inspection and Scrapping Criteria

Every cast drum undergoes visual inspection for casting defects and dimensional verification of wall thickness, diameter, and groove parameters. Drums must pass a static load test at 1.25 times the rated load, held for 10 minutes, with no permanent deformation or cracks detected. In service, groove wear is checked every 500 operating hours. A drum must be scrapped if any of the following conditions occur: cracks are found, groove wear depth exceeds 2 mm, wall thickness is reduced by more than 20%, or drum deformation causes wire rope derailment.

Drum Installation Requirements

After installation, the drum must rotate freely without binding, and the drum shaft levelness must not exceed 1/1000. The wire rope should be wound evenly on the drum, leaving at least 2 safety wraps. Each end of the rope is secured with clamping plates—a minimum of 2 plates per end. The drum bearing housing requires regular lubrication, and the bearing operating temperature must stay at or below 80°C. Casting defects in the cast drum, such as porosity or sand holes, may be repaired by welding after evaluation, provided they are not in load-bearing areas.

Standard inspection methods for drum groove wear involve using a dedicated groove template or caliper to measure groove depth and radius. The drum must be scrapped when groove wear depth exceeds 2 mm. Wall thickness is measured with an ultrasonic thickness gauge. For drum bearing housing clearance checks, bearings should be replaced when radial clearance exceeds 1.5 times the original value. Drum base bolts require periodic inspection and tightening.

FAQ: Drum Casting, Design & Maintenance