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Main Clamping Cylinder


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This main clamping cylinder is the core actuator at the welding station of high-speed rail flash-butt welding machines, mounted in pairs between the welder's main frame and the movable clamping block. Before welding, it forcefully pushes the movable jaw closed under hydraulic power and maintains a constant clamping force, rigidly locking the two rail ends to be welded. During welding, it works together with the upsetting cylinder to resist upset reaction forces and prevent rail slippage. An ultra-large bore, short-stroke heavy-duty design delivers a maximum clamping force of up to 866 kN. Combined with a large-diameter thick-walled piston rod, alloy bronze guide bushings, multiple high-pressure composite seals, and a hydraulic load-holding lock, it provides absolutely reliable, leak-free clamping force under the severe conditions of frequent outdoor welding, intense vibration, and weld spatter — a cornerstone ensuring the quality of flash-butt welded joints for continuous high-speed rail.

Brand:
PAZON

Main Clamping Cylinder Clamping Cylinder Hydraulic Cylinder Hydraulic Cylinder Rail Welding Machine

Product Description

Bore: Φ210 mm
Rod: Φ80 mm (thin rod design to maximize full-bore clamping area)
Stroke: 150 mm (short stroke for rapid jaw clamping/release)
Operating pressure: continuous 25 MPa, max 31.5 MPa (per rail clamping force requirements)
Max push force: 866 kN (at 25 MPa, full-bore side)
Max pull force: ~740 kN (at 25 MPa, annular side, for jaw release)
Breakaway pressure: ≤0.5 MPa
Piston velocity: <0.5 m/s (fast clamping response)
Operating frequency: intermittent heavy-duty, 1 clamping cycle per weld
Internal leakage: ≤0.02 ml/min (at 25 MPa, over seal service life)
Static holding: ≤0.1 mm piston drift over 10 min under full clamping force (with hydraulic lock & accumulator)
Temperature range: -20 ℃ to +80 ℃ (standard); -40 ℃ to +120 ℃ customizable
Suitable for: high-speed rail flash-butt welding machines, mobile rail welding vehicles, etc.

Features & Benefits

Massive Clamping Force for Rigid Locking
The barrel is forged from high-yield-ratio quenched and tempered alloy steel, with FEA-optimized end caps and 100% UT/MT inspected welds. The large-diameter thick-walled piston rod is precision hard-chrome plated, maintaining absolute structural stability under extreme clamping force and preventing any workpiece movement during welding.
Absolute Holding & Fail-Safe Locking
Standard integrated hydraulic lock, counterbalance valve, and accumulator ensure the jaws remain firmly locked at the rated clamping force even if the hydraulic power unit stops or hoses rupture, preventing the welding gap from opening and guaranteeing weld quality.
High Side-Load Resistance & Heavy-Load Guidance
Embedded wide bronze alloy guide rings with precision clearance control effectively resist the enormous eccentric moments generated during upsetting, preventing rod scoring.
Multi-Stage Seals & Weld Spatter Protection
A metal scraper ring and multiple heavy-duty wipers at the gland completely shield the cylinder from welding spatter, metal chips, and outdoor slurry. The main seal is a high-temperature polyurethane and filled PTFE composite, guaranteeing zero external leakage over its entire service life.
Compact Short-Stroke Design
The 150 mm stroke is optimized for the welding machine’s clamping mechanism, providing sufficient opening space while keeping the overall envelope to a minimum for integration into the compact welder frame.
Optional Intelligent Monitoring
Built-in pressure and displacement sensors can be integrated to monitor clamping force and jaw displacement in real time, enabling intelligent welding process control via the welder’s main control system.