This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX850S, 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 SI50AX850S
The AirTAC Airtac SI50 Standard Cylinder SI50AX850S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 850mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX850S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke850 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX850S
- 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 SI50AX850S
The AirTAC SI50AX850S is a discontinued double-acting ISO 15552 profile cylinder featuring an extruded aluminum barrel and adjustable air cushions. It delivers a thrust of 982 N at 0.5 MPa through its 50 mm bore and 850 mm stroke. The direct replacement is the SAI50AX850S, which matches the original ISO 15552 mounting interface, bore, stroke, output force, G1/4 port, and mounting accessories.
The SAI upgrade introduces an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. For this model, the -A suffix denotes a SUS420J2 stainless steel piston rod for corrosion resistance, and the -S indicates a piston magnet for legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50AX850S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX850S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX850S |
| Bore size | Ø50 mm |
| Stroke | 850 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 SAI50AX850S 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 SAI50AX850S 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 SI50AX850S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×850 | 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 SI50AX850S Is Used
Long-Stroke Diversion
Pushes packages across transfer lines using the 850 mm stroke, relying on the 982 N thrust at 0.5 MPa to overcome lateral friction.
Actuated Guarding
Deploys large machine safety doors over a wide span, taking advantage of the adjustable 30 mm air cushions at both ends.
Replacing the Airtac SI50 Standard Cylinder SI50AX850S with the SAI50AX850S
To replace the SI50AX850S, order the SAI50AX850S. Confirm the ISO 15552 mounting interface, the 50 mm bore, the 850 mm stroke, the G1/4 port, and your specific mounting accessory. The SAI family adds SAIL (air-released lock), SAIF (built-in 4M valve), and BSAI (clamp-lock) variants the SI lacked. A plain cylinder drifts on air loss since the cushion only decelerates; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI variant. With an 850 mm stroke, prevent rod bending by using an external guide to manage side loads. If sizing up or down, note the 40 mm bore offers 628 N push at 0.5 MPa, while the 63 mm bore provides 1559 N.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX850S
- ✓ 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 SI50AX850S FAQ
Yes, the SI50AX850S is discontinued. The direct replacement is the SAI50AX850S. It is dimensionally interchangeable per ISO 15552, matching the 50 mm bore, 850 mm stroke, output force, G1/4 port, and mounting fixtures.
This double-acting cylinder uses a G1/4 air port. It delivers a push force of 982 N and a pull force of 825 N at 0.5 MPa. At 0.7 MPa the push force is 1374 N, and the theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX850S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX850S replacement — usually within 7-8 hours.