This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X400SN, with the same bore, stroke, output force, port and mounting, so it fits the same application. The SAI replacement keeps the same ISO 15552 mounting interface, bore, stroke, output force and accessories, so it drops straight into existing fixtures. It is the current-production version of this cylinder with an upgraded piston seal.
Airtac SI50 Standard Cylinder SI50X400SN
The AirTAC Airtac SI50 Standard Cylinder SI50X400SN is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 400mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X400SN, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke400 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X400SN
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac SI50 Standard Cylinder SI50X400SN
The AirTAC SI50X400SN is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 400 mm stroke. It delivers 982 N push force at 0.5 MPa via a G1/4 port. AirTAC replaced it with the SAI50X400SN, a direct upgrade sharing the exact ISO 15552 mounting interface, bore, stroke, output force, port size and accessories. The SAI uses an upgraded piston seal featuring two Y-shaped one-way elements for long life and low start-up pressure.
This -S magnet model supports legacy CS1-B/DS1-B sensors, while the -N NBR seal handles -20 to +70 C (a Viton H option extends this to 150 C). The SAI family also adds SAIL, SAIF and BSAI lock variants absent from the SI line.
Airtac SI50 Standard Cylinder SI50X400SN Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X400SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X400SN |
| Bore size | Ø50 mm |
| Stroke | 400 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M16×1.5 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 800 mm/s |
| Cushion | Adjustable, 30 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI50X400SN carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø50mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 982 N | 825 N |
| 0.7 MPa | 1374 N | — |
| Max (@1.0 MPa) | 200 kgf | |
The SAI50X400SN produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI50 Standard Cylinder SI50X400SN
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×400 | Stroke length in mm. |
| -S | Optional built-in magnet for sensor position sensing. |
Legacy SI-family variants: SID (double rod), SIJ (adjustable stroke) — each maps to its SAI equivalent (SID→SAID, SIJ→SAIJ). Rod material: carbon steel (blank) / SUS420J2 (A) / SUS304 (B).
Where the Airtac SI50 Standard Cylinder SI50X400SN Is Used
Package Diverting
Drives diverter arms on sorting lines, utilizing the 982 N push force to redirect parcels reliably over the 400 mm travel.
Vertical Lift Gates
Raises lightweight access gates or barriers.
Material Ejection
Ejects machined parts from fixtures. The adjustable 30 mm air cushions decelerate the rod smoothly at stroke ends despite high cycle speeds.
Replacing the Airtac SI50 Standard Cylinder SI50X400SN with the SAI50X400SN
To replace the SI50X400SN, order the SAI50X400SN. Confirm the ISO 15552 mounting interface, 50 mm bore, 400 mm stroke, G1/4 port (PT/G/NPT thread options) and your mounting accessory (LB, FA, TC, etc.). The -S magnet enables current AirTAC switches (legacy used CS1-B/DS1-B), and the -N NBR seal is standard. For sizing both ways: neighbouring bores are 40 mm (628 N push) and 63 mm (1559 N push) at 0.5 MPa. At 400 mm stroke, prevent rod bending by guiding the load externally to avoid side-load damage. A plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X400SN
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI50 Standard Cylinder SI50X400SN FAQ
Yes, the SI50X400SN is discontinued. The direct replacement is the SAI50X400SN. It is dimensionally interchangeable per ISO 15552, matching the 50 mm bore, 400 mm stroke, 982 N force, G1/4 port and mounting interface, so it fits existing fixtures directly.
This double-acting cylinder has a G1/4 air port. It delivers 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical max of 200 kgf at 1.0 MPa. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X400SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X400SN replacement — usually within 7-8 hours.