High Strength Forging Hydraulic Cylinder Barrel with 1200 Tons for Heavy Duty Press Machine

Detailed Paremeter

Application 

The hydraulic cylinder barrel is applicable to various heavy-duty hydraulic cylinder for all kinds of hydraulic press machines.

Extrusion press hydraulic cylinder

Casting press hydraulic cylinder

Hot press hydraulic cylinder

Forging press hydraulic cylinder

Injection press hydraulic cylinder

Product Procedure

Ingot / Round steel blanking → Heating & forging to form cylinder blank → Normalizing after forging → Rough turning of both ends & outer circle → Rough boring of inner hole → Quenching and tempering heat treatment → Secondary stress relief annealing → Semi-finish boring → Finish boring → Inner hole honing / roller burnishing → Cylinder bottom / flange welding → Post-weld stress relief → Finish turning of outer circle, end face & sealing surface → Non-destructive testing → Hydrostatic / hydraulic pressure test → Cleaning and rust prevention.

1.Blank Preparation: Forged Tube Blank

Raw Materials: Large continuous casting ingot of 45 steel / large-size round steel

Heating Regime: Uniform heating at 1180～1220℃ with holding for thorough heating

Forging Process

Open die forging → Punching → Mandrel drawing → Round sizing, to form thick-walled tubular blanks

Forging Control Requirements

Final forging temperature ≥ 800℃. Low-temperature forging is strictly prohibited to avoid forging cracks.

Post-Forging Pre-Treatment

Normalizing shall be conducted immediately after forging: 830～850℃, air cooling.

Functions: Refine forged grains, eliminate residual forging stress, improve machinability, and prevent blank cracking.

2. Rough Machining Process

• Cut to fixed length by sawing / gas cutting with reasonable machining allowance reserved;

• Heavy-duty lathe: Facing both ends and rough turning the outer circle;

• Deep hole drilling & boring machine: Rough boring of inner hole;

• Single-side reserved machining allowance: 4～6 mm;

• Correct defects such as eccentricity, uneven wall thickness and bending caused by forging.

3. Core Heat Treatment: Quenching and Tempering (Key Process)

45 steel cylinder tubes must undergo quenching and tempering to improve overall strength, toughness and resistance to internal pressure deformation.

• Quenching: Holding at 820～840℃ → water quenching

• High-temperature Tempering: Holding at 560～620℃ → air cooling

Mechanical Property Requirements

• Hardness: HB 220～260

• Tensile Strength ≥ 650 MPa

• Yield Strength ≥ 355 MPa

Functions: Ensure pressure resistance, burst resistance and fatigue resistance of cylinder tubes.

Supplement: Low-temperature stress relief annealing at 530～560℃ shall be performed after tempering to release cutting stress from rough machining and completely avoid deformation in subsequent finish machining.

4. Precision Inner Hole Machining

Semi-finish boring → Finish boring to guarantee the basic precision of inner hole straightness and cylindricity.

Final Inner Hole Finishing (Alternative Options)

• Option A (Preferred, for hydraulic press cylinders): Heavy-duty honing

• Option B (Cost-effective solution): Cold rolling

5. Welding Process (Cylinder Bottom, Flange, Oil Port Seat)

Pre-Welding Preparation

Machine welding grooves; preheat thick-walled components to 120～180℃.

Welding Method

Adopt submerged arc welding / CO₂ gas shielded welding, with carbon steel welding wires of matching material selected.

Mandatory Post-Welding Process

Post-welding stress relief annealing at 550℃ to eliminate welding residual stress and prevent weld cracking and fluid leakage in service.

6. Finish Machining & Forming

• Finish turn the outer circle, positioning steps and mounting flange sealing surfaces at both ends;

• Turn inner hole clamping grooves, dustproof grooves, oil port threads and flange sealing positions.

7. Finished Product Inspection & Pressure Resistance Test

Dimensional Inspection

Test critical dimensions including inner diameter, roundness, cylindricity, straightness and wall thickness uniformity.

Non-Destructive Testing (NDT)

• Forged blanks and cylinder barrels: UT (Ultrasonic Testing)

• Weld seams: MT (Magnetic Particle Testing) / PT (Liquid Penetrant Testing); no cracks, inclusions or other defects allowed.

Pressure Resistance Test

The test pressure is 1.5 times the rated working pressure. Maintain pressure for 30 minutes with no leakage or abnormal conditions.

Feature

Mechanical properties: The forged structure is dense with fine grains, and the overall strength and rigidity are good. It is resistant to pressure, deformation, and static loads.

Material advantages: low cost, excellent machinability, short production cycle, high cost-effectiveness

Main Facility

• Forging&heat treatment equipment

• Machining equipment

• Inspection equipment

Package