This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX550S, 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 SI50AX550S
The AirTAC Airtac SI50 Standard Cylinder SI50AX550S 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 SAI50AX550S, 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 → SAI50AX550S
- 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 SI50AX550S
The AirTAC SI50AX550S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50 mm bore, 550 mm stroke, G1/4 port, and a SUS420J2 stainless steel rod. Delivering 982 N push force at 0.5 MPa, it is replaced by the SAI50AX550S. This direct successor retains the exact interface, bore, stroke, force, and mounting, fitting existing fixtures perfectly.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life. The SAI family also adds SAIL, SAIF, and BSAI lock variants the SI lacked. Your -S magnet works with legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50AX550S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX550S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX550S |
| 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 SAI50AX550S 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 SAI50AX550S 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 SI50AX550S
| 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 SI50AX550S Is Used
Long-Stroke Vertical Lift
Raises and lowers 50 kg platforms through 550 mm of travel, relying on external linear guides to prevent rod bending during the extended vertical cycle.
Pallet Diversion Gate
Actuates heavy routing gates along material handling lines, utilizing the 982 N thrust at 0.5 MPa to push loaded pallets smoothly onto secondary tracks.
Stainless Rod Washdown
Drives mechanism arms in moist or mildly corrosive industrial environments using the SUS420J2 stainless piston rod option for enhanced corrosion resistance.
Replacing the Airtac SI50 Standard Cylinder SI50AX550S with the SAI50AX550S
To replace the SI50AX550S, order the SAI50AX550S, confirming the ISO 15552 mounting interface, 50 mm bore, 550 mm stroke, G1/4 port, and mounting accessory. The -A denotes a SUS420J2 stainless rod, and -S indicates the magnet for CS1-B/DS1-B switches. For sizing both ways: a 40 mm bore yields 628 N push at 0.5 MPa, while a 63 mm bore yields 1559 N. Note that a 550 mm stroke requires external guides to prevent rod bending and side-load wear. A plain cylinder drifts on air loss; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX550S
- ✓ 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 SI50AX550S FAQ
Yes, the SI50AX550S is discontinued. The direct replacement is the SAI50AX550S. It is dimensionally interchangeable per ISO 15552, maintaining the same 50 mm bore, 550 mm stroke, G1/4 port, and mounting interface to fit existing fixtures directly.
The bore features a G1/4 air port. Force ratings are 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 maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX550S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX550S replacement — usually within 7-8 hours.