This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X550STC, 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 SI50X550STC
The AirTAC Airtac SI50 Standard Cylinder SI50X550STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 550mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X550STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke550 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X550STC
- 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 SI50X550STC
The AirTAC SI50X550STC is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 550mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. AirTAC replaced this EOL unit with the SAI50X550STC, a direct sharing the same interface, force, and TC trunnion mount.
The SAI upgrade features a two Y-shaped one-way piston seal for low start-up pressure and long life. The SAI family also adds SAIL lock and BSAI clamp-lock variants the SI lacked. This -S SKU uses CS1-B/DS1-B sensors, while the SAI takes current AirTAC switches.
Airtac SI50 Standard Cylinder SI50X550STC Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X550STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X550STC |
| Bore size | Ø50 mm |
| Stroke | 550 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 SAI50X550STC 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 SAI50X550STC 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 SI50X550STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×550 | 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 SI50X550STC Is Used
Long-Stroke Diversion
Drives a 550mm divert arm on a packaging line, relying on the 982N thrust at 0.5MPa to push cartons cleanly onto adjacent lanes.
Multi-Stage Ejection
Executes extended 550mm parts ejection from a machine bed, using adjustable end cushions to decelerate the 20mm rod smoothly.
Replacing the Airtac SI50 Standard Cylinder SI50X550STC with the SAI50X550STC
To replace the SI50X550STC, order the SAI50X550STC. It drops into existing fixtures per the ISO 15552 mounting interface, matching the 50mm bore, 550mm stroke, G1/4 port, M16x1.5 rod thread, and TC trunnion mount. Keep the -S magnet for CS1-B/DS1-B legacy sensors; the SAI uses current AirTAC switches. If you need more force, the neighbouring 63mm bore offers 1559N push at 0.5MPa; if less is needed, the 40mm bore gives 628N. A plain cylinder drifts on air loss—the cushion only decelerates—so use a pilot check valve or SAIL/BSAI lock for load holding. At 550mm, prevent rod bending by guiding the load externally.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X550STC
- ✓ 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 SI50X550STC FAQ
Yes, the SI50X550STC is discontinued. The direct replacement is the SAI50X550STC. It shares the identical ISO 15552 mounting interface, 50mm bore, 550mm stroke, output force, G1/4 port, and TC trunnion mounting, fitting existing fixtures directly.
This 50mm bore cylinder uses a G1/4 air port. It generates 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, and a theoretical maximum of 200kgf at 1.0MPa. Operating speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X550STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X550STC replacement — usually within 7-8 hours.