250mm Bore Double-Acting Trunnion Mount Mill-Type Hydraulic Cylinder for Heavy Duty Applications

CDH1 Mill-Type Cylinder, 250mm Bore, Double-Acting, Trunnion Mount, Rexroth Compatible

Cylinder barrel fabricated from 27SiMn / ST52-3 honed seamless tube, roller-burnished to Ra ≤ 0.2 μm internal finish. Multi-segment bolted flange construction allows modular reconfiguration.

Piston rod in CK45 / 42CrMo4 alloy steel, induction hardened to HRC 52-58, hard chrome plated to 25-40 μm thickness. Surface hardness HV 850-1050 with 96+ hour salt spray resistance per ASTM B117.

Rod wiper and rod seal housing separated for staged contamination control. Sealing system using Parker / Merkel profile geometry:

• PTFE step-cut primary seal with NBR energizer
• Polyurethane buffer ring and double-lip rod wiper
• Static seals: O-ring + PTFE backup ring per ISO 3601
• End cushioning: adjustable needle valve type at both head and cap ends

MP5 trunnion mount located at cylinder centerline, machined from forged 42CrMo steel with hardened bearing surface. Rod end fitted with spherical plain bearing (self-aligning, maintenance-free type with grease nipple) to absorb misalignment.

Full dimensional interchangeability with Rexroth CDH1 MP5 series. Bolt pattern, port locations, and mounting interface match OEM specifications. Accepts standard Rexroth CDH1 seal kits and spare parts.

Each unit hydrostatically tested at 35 MPa (1.4× rated) for 5 minutes, followed by full-stroke cycling at 0.5 MPa to verify seal integrity, side load tolerance, and cushioning consistency. Inspection certificate and material traceability report included.

Designed for sustained 250 Bar operation with high side load resistance in applications including:

• Steel mill AGC (Automatic Gauge Control) cylinders
• Heavy-duty forging press main ram
• Continuous casting machine mold oscillation
• Mining shovel boom actuation
• General mill-type applications