This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX25S, 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 SI50AX25S
The AirTAC Airtac SI50 Standard Cylinder SI50AX25S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 25mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX25S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke25 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX25S
- 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 SI50AX25S
The AirTAC SI50AX25S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 25mm stroke. It features an extruded aluminum barrel, a SUS420J2 stainless piston rod, and delivers 982 N push force at 0.5 MPa. The direct replacement is the SAI50AX25S, which retains the exact G1/4 port, M16x1.5 thread, and ISO 15552 mounting interface.
The SAI upgrade introduces a two Y-shaped one-way piston seal for lower start-up pressure and longer life. The original -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI family expands options with SAIL, SAIF, and BSAI lock variants.
Airtac SI50 Standard Cylinder SI50AX25S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX25S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX25S |
| Bore size | Ø50 mm |
| Stroke | 25 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 SAI50AX25S 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 SAI50AX25S 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 SI50AX25S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×25 | 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 SI50AX25S Is Used
Short-Stroke Clamping
Ideal for securing stainless workpieces in machining fixtures where the 25mm stroke and SUS420J2 rod resist corrosion.
Package Diverting
Provides rapid 50 kg diverting force on packaging lines, utilizing the 30-800 mm/s speed range for high throughput.
Pallet Stops
Acts as a reliable pneumatic stop for light pallets, delivering 982 N push force at 0.5 MPa to halt loads safely.
Replacing the Airtac SI50 Standard Cylinder SI50AX25S with the SAI50AX25S
To replace the SI50AX25S, order the SAI50AX25S. Confirm the ISO 15552 mounting interface, 50mm bore, 25mm stroke, G1/4 port, and the -S magnet for current AirTAC switches. If sizing up or down, adjacent bores are 40mm (628 N push @0.5 MPa) and 63mm (1559 N push @0.5 MPa). The -A rod specifies SUS420J2 stainless steel for corrosion resistance. A plain cylinder drifts on air loss; the air cushion only decelerates. For load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX25S
- ✓ 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 SI50AX25S FAQ
Yes, the SI50AX25S is discontinued. The direct replacement is the SAI50AX25S. It is dimensionally interchangeable per ISO 15552, keeping the same 50mm bore, 25mm stroke, G1/4 port, and mounting interface.
The G1/4 port bore delivers a push of 982 N and pull of 825 N at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical max of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX25S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX25S replacement — usually within 7-8 hours.