M-3SEW6U3X/420MG24N9K4 Rexroth Seat Shut-off Valve 420bar

Product Overview

Models such as M-3SEW6U3X/420MG24N9K4 and M-3SEW10C15/630MG24N9K4 belong to the Bosch Rexroth M-3SEW series of direct-operated directional seat (poppet) valves designed for shut-off and directional control. Featuring air-gap DC solenoids with detachable coils, they comply with ISO 4401 mounting standards. Every unit undergoes rigorous 100% simulated operating-condition testing and offers excellent drop-in interchangeability with equivalent seat valves. The poppet design provides true leak-free closure of the blocked port and reliable switching even after prolonged periods under pressure, making these valves ideal for high-pressure hydraulic systems that demand high sealing integrity and operational safety.

Technical Specifications 

• Model examples: M-3SEW6U3X/420MG24N9K4, M-3SEW10C15/630MG24N9K4
• Valve type: Direct-operated directional seat (poppet) valve (3/2 or 2/2-way) for shut-off
• Nominal size: NG6 (Size 6) or NG10 (Size 10)
• Mounting interface: ISO 4401-03 (NG6) or corresponding NG10 standard
• Symbols: U, C etc. (depending on specific model)
• Maximum operating pressure: 420 bar or 630 bar (depending on model)
• Maximum flow: 25 l/min (NG6); 40 l/min (NG10)
• Actuation: Air-gap DC solenoids with detachable coil
• Supply voltage: 24 VDC (G24)
• Electrical connection: N9K4 (3-pole device connector according to DIN EN 175301-803)
• Component series: 3X (NG6) or 1X (NG10)
• Weight: approx. 1.5 kg (NG6); approx. 3.5 kg (NG10 double-solenoid configuration)
• Protection class: IP65 (with correctly mounted mating connector)
• Seal material: NBR or FKM (depending on configuration)
• Hydraulic fluid compatibility: HL, HLP, HLPD, HVLP, HVLPD, HETG, HEES, HEPG, HFDU, HFDR, etc.

Key Technical Advantages

1. True leak-free poppet design: Hardened seat and ball combination achieve zero leakage in the closed port, with reliable switching even after long periods under pressure — ideal for safety-critical and high-pressure holding circuits.
2. Air-gap solenoids with detachable coils: Coils can be replaced and rotated 90° without opening the pressure-tight chamber, simplifying maintenance while delivering stable magnetic force and reliable switching.
3. Excellent drop-in interchangeability: Strict compliance with ISO 4401 mounting face and standardized electrical interfaces allows direct replacement of equivalent seat valves, minimizing system modification costs and downtime.
4. High-pressure capability and safety features: Rated up to 420/630 bar, with optional concealed manual override, enhancing system safety and operational flexibility.
5. Precision machining and long service life: High-accuracy valve body and hardened seat construction deliver extremely low internal leakage, strong contamination resistance and long-term operational stability.

Application Areas

Injection moulding machines, die-casting machines, metal-forming equipment, machine-tool hydraulics, safety locking circuits, high-pressure holding systems, packaging machinery, automated production lines and other medium-to-high-pressure hydraulic circuits requiring zero-leakage shut-off and reliable switching.

Expert Maintenance Tips

1. Verify mounting surface flatness and roughness before installation; use specified bolts (M5 for NG6, higher grade for 630 bar NG10) and tighten to the recommended torque; fit seals correctly to prevent external leakage.
2. Maintain recommended fluid cleanliness per ISO 4406; use hydraulic fluids compatible with the installed seal material. Thoroughly bleed the system before first start-up to avoid cavitation.
3. Use standard-compliant shielded cables for electrical connections and keep supply voltage within 24 VDC ±10%. The coil can be rotated to facilitate wiring.
4. Manual override (if fitted) should only be operated within the allowable system pressure range. Clean and protect the valve during long-term storage; always perform functional and leakage tests before recommissioning.
5. Do not disassemble the seat and internal sealing elements. Seal replacement or repairs should be performed only by technicians experienced with Rexroth products; verify zero-leakage performance before returning the valve to service.