This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX425S, 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 SI50AX425S
The AirTAC Airtac SI50 Standard Cylinder SI50AX425S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 425mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX425S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke425 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX425S
- 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 SI50AX425S
The AirTAC SI50AX425S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore, 425 mm stroke, and SUS420J2 stainless steel rod. Delivering 982 N push force at 0.5 MPa, it is replaced by the SAI50AX425S. This direct upgrade retains the exact G1/4 port, M16x1.5 thread, and 30 mm cushions, fitting existing fixtures.
The SAI features an upgraded piston seal with two Y-shaped elements for low start-up pressure. The -S magnet works with legacy CS1-B/DS1-B sensors, while a Viton H seal option raises heat resistance to 150 C.
Airtac SI50 Standard Cylinder SI50AX425S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX425S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX425S |
| Bore size | Ø50 mm |
| Stroke | 425 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 SAI50AX425S 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 SAI50AX425S 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 SI50AX425S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×425 | 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 SI50AX425S Is Used
Diverting Gate Actuation
Drives routing flaps on packaging lines, utilizing the 982 N push force at 0.5 MPa to deflect heavy cardboard cartons reliably.
Stainless Rod Clamping
Applies clamping pressure in humid washdown areas using the SUS420J2 rod option, resisting corrosion while cycling at 30-800 mm/s.
Replacing the Airtac SI50 Standard Cylinder SI50AX425S with the SAI50AX425S
To replace the SI50AX425S, order the SAI50AX425S, confirming the ISO 15552 interface, 50 mm bore, 425 mm stroke, G1/4 port, and SUS420J2 rod. Size both ways: the 40 mm bore yields 628 N push at 0.5 MPa, while the 63 mm bore provides 1559 N. Because the 425 mm stroke is long, use external guides to prevent rod bending and side-load wear. The cushion only decelerates; it does not hold load on air loss. For secure holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX425S
- ✓ 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 SI50AX425S FAQ
Yes, the SI50AX425S is discontinued. The direct replacement is the SAI50AX425S. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 425 mm stroke, output force, G1/4 port, and mounting interface.
The 50 mm bore features a G1/4 port and provides 982 N push and 825 N pull at 0.5 MPa. At 0.7 MPa push is 1374 N, and the theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX425S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX425S replacement — usually within 7-8 hours.