This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX40S, 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 SI50AX40S
The AirTAC Airtac SI50 Standard Cylinder SI50AX40S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 40mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX40S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke40 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX40S
- 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 SI50AX40S
The AirTAC SI50AX40S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore, 40 mm stroke, and a SUS420J2 stainless steel piston rod. It delivers 982 N push force at 0.5 MPa via a G1/4 port. The direct replacement is the SAI50AX40S, which maintains identical ISO 15552 mounting dimensions, output force, and stroke.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. This -S model includes a piston magnet for legacy CS1-B/DS1-B sensors, while the SAI family adds SAIL lock, SAIF valve, and BSAI clamp variants.
Airtac SI50 Standard Cylinder SI50AX40S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX40S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX40S |
| Bore size | Ø50 mm |
| Stroke | 40 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 SAI50AX40S 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 SAI50AX40S 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 SI50AX40S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×40 | 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 SI50AX40S Is Used
Stainless Rod Clamping
Ideal for short-stroke clamping in machining fixtures where the SUS420J2 rod resists moisture and coolant.
Package Diverting
Provides reliable 982 N push force at 0.5 MPa for diverting moderate-weight packages on packaging lines.
Pallet Stopper
Acts as a robust pneumatic stopper for palletized goods, utilizing the 40 mm stroke for rapid actuation.
Replacing the Airtac SI50 Standard Cylinder SI50AX40S with the SAI50AX40S
To replace this discontinued SI50AX40S, order the SAI50AX40S. Verify your ISO 15552 mounting interface, 50 mm bore, 40 mm stroke, G1/4 port, and M16x1.5 rod thread. The -A denotes the SUS420J2 stainless rod, and -S indicates the magnet for CS1-B/DS1-B switches (the SAI uses current AirTAC switches). If you need more force, the 63 mm bore yields 1559 N push at 0.5 MPa; if less is required, the 40 mm bore provides 628 N. Note that plain cylinders drift without live air, so for load holding consider an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX40S
- ✓ 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 SI50AX40S FAQ
Yes, the SI50AX40S is discontinued. The direct replacement is the SAI50AX40S. It is dimensionally interchangeable per ISO 15552, keeping the same 50 mm bore, 40 mm stroke, G1/4 port, and mounting interface.
This double-acting cylinder uses a G1/4 port. It generates 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX40S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX40S replacement — usually within 7-8 hours.