This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X355S, 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 SI50X355S
The AirTAC Airtac SI50 Standard Cylinder SI50X355S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 355mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X355S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke355 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X355S
- 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 SI50X355S
The AirTAC SI50X355S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 355mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. The direct replacement is the SAI50X355S, matching the exact interface, force, and mounting.
The SAI upgrade features a new piston seal with two Y-shaped one-way elements for low start-up pressure and long life. This -S model includes a piston magnet for legacy CS1-B/DS1-B sensors, while the SAI uses current AirTAC switches. A Viton H seal option raises the -20 to 70C range up to 150C.
Airtac SI50 Standard Cylinder SI50X355S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X355S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X355S |
| Bore size | Ø50 mm |
| Stroke | 355 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 SAI50X355S 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 SAI50X355S 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 SI50X355S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×355 | 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 SI50X355S Is Used
Package Diverting
Actuates routing gates on packaging lines where the 982N push force and 355mm travel easily redirect moderate loads.
Component Ejection
Pushes machined parts out of a fixture using the full 355mm extension, requiring external guides to prevent rod bending.
Replacing the Airtac SI50 Standard Cylinder SI50X355S with the SAI50X355S
To replace the SI50X355S, order the SAI50X355S. Verify the ISO 15552 mounting interface, 50mm bore, 355mm stroke, G1/4 port (PT/G/NPT), and mounting accessory. The -S suffix means a magnet is present for position sensing. For sizing, the 50mm bore yields 982N push at 0.5MPa; dropping to a 40mm bore gives 628N, while a 63mm bore provides 1559N. Because stroke is 355mm, use an external guide to prevent rod bending and side loads. A plain cylinder drifts on air loss; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X355S
- ✓ 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 SI50X355S FAQ
Yes, the AirTAC SI50X355S is discontinued. The direct replacement is the SAI50X355S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 355mm stroke, 982N force, G1/4 port, and mounting interface.
The 50mm bore features a G1/4 air port and a 20mm rod. It delivers 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, and a theoretical max of 200kgf at 1.0MPa. The adjustable air cushion is 30mm at each end.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X355S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X355S replacement — usually within 7-8 hours.