This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI125AX450S, 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 SI125 Standard Cylinder SI125AX450S
The AirTAC SI125 Standard Cylinder SI125AX450S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø125mm bore and 450mm stroke, G1/2 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI125AX450S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ125 mm
- Stroke450 mm
- Port sizeG1/2
- Acting typeDouble acting
- Rod threadM27×2.0
- StatusDiscontinued → SAI125AX450S
- 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 SI125 Standard Cylinder SI125AX450S
The AirTAC SI125AX450S is a discontinued double-acting ISO 15552 profile cylinder with a 125mm bore and 450mm stroke. Featuring a SUS420J2 stainless piston rod, it delivers 6136 N push force at 0.5 MPa via a G1/2 port. The direct replacement is the SAI125AX450S, sharing the same ISO 15552 mounting interface, bore, stroke, force, port, and accessories.
The SAI upgrade features two Y-shaped one-way piston seals for low start-up pressure and long life. The -S magnet works with legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL and BSAI lock variants the SI lacked.
Airtac SI125 Standard Cylinder SI125AX450S Technical Specifications
| Model | Airtac SI125 Standard Cylinder SI125AX450S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI125AX450S |
| Bore size | Ø125 mm |
| Stroke | 450 mm |
| Acting type | Double acting |
| Port size | G1/2 |
| Rod thread | M27×2.0 |
| 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 – 500 mm/s |
| Cushion | Adjustable, 40 mm |
| Max standard stroke | Up to 1500 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI125AX450S carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø125mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 6136 N | 5734 N |
| 0.7 MPa | 8590 N | — |
| Max (@1.0 MPa) | 1251 kgf | |
The SAI125AX450S produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI125 Standard Cylinder SI125AX450S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 125 | Bore size in mm. |
| ×450 | 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 SI125 Standard Cylinder SI125AX450S Is Used
Heavy Stamp Press Feed
Drives robust 450mm stroke clamps to feed thick sheet metal into stamping presses, utilizing the 6136 N push force at 0.5 MPa.
Automated Welding Index
Shifts heavy automotive chassis sub-assemblies between robotic welding stations, relying on the SUS420J2 rod for weld-spatter resistance.
Replacing the Airtac SI125 Standard Cylinder SI125AX450S with the SAI125AX450S
To replace the SI125AX450S, order the SAI125AX450S. Confirm the ISO 15552 interface, 450mm stroke, G1/2 port (PT/G/NPT), M27x2 rod thread, and mounting accessory. The -S magnet enables CS1-B/DS1-B sensors (the SAI uses current AirTAC switches). Size both ways: the 100mm bore yields 3927 N push at 0.5 MPa, while the 160mm bore yields 10053 N. A plain cylinder drifts on air loss—the cushion only decelerates—so use a pilot check valve or the SAIL/BSAI lock variant for load holding. For the 450mm stroke, use external guides to prevent rod bending and side-load wear.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI125AX450S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI125 Standard Cylinder SI125AX450S FAQ
Yes, the SI125AX450S is discontinued. The direct replacement is the SAI125AX450S. It is dimensionally interchangeable per ISO 15552, retaining the same 125mm bore, 450mm stroke, G1/2 port, and mounting interface. The SAI simply upgrades the piston seal to two Y-shaped elements for lower start-up pressure and longer life.
The air port is G1/2. The thrust ratings are: 6136 N push and 5734 N pull at 0.5 MPa; 8590 N push at 0.7 MPa; 11045 N push at 0.9 MPa; and a theoretical maximum force of 1251 kgf at 1.0 MPa. Operating speed is 30-500 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI125AX450S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI125AX450S replacement — usually within 7-8 hours.