This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X40S, 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 SI50X40S
The AirTAC Airtac SI50 Standard Cylinder SI50X40S 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 SAI50X40S, 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 → SAI50X40S
- 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 SI50X40S
The AirTAC SI50X40S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 40mm stroke, delivering 982N push force at 0.5MPa. It features a G1/4 port, M16x1.5 rod thread, and a built-in magnet for CS1-B/DS1-B switches. AirTAC replaced this legacy unit with the SAI50X40S, a direct upgrade retaining the exact ISO 15552 mounting interface, bore, and stroke.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and extended life, while adding SAIL, SAIF, and BSAI lock variants absent from the SI line. Rod material options include carbon steel, SUS420J2, or SUS304.
Airtac SI50 Standard Cylinder SI50X40S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X40S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X40S |
| 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 SAI50X40S 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 SAI50X40S 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 SI50X40S
| 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 SI50X40S Is Used
Clamping Mechanisms
Ideal for mid-force clamping of workpieces in machining fixtures, utilizing the 982N push force at 0.5MPa with precise 40mm travel.
Short-Stroke Diverting
Suitable for actuating small diverters or gates on conveyor lines where a compact 40mm stroke and G1/4 port integration are required.
Replacing the Airtac SI50 Standard Cylinder SI50X40S with the SAI50X40S
To replace the discontinued SI50X40S, order the SAI50X40S. Confirm the ISO 15552 mounting fixture, 50mm bore, 40mm stroke, G1/4 port (PT/G/NPT), and the -S magnet requirement. When sizing, consider neighboring bores: a 40mm bore yields 628N push at 0.5MPa, while a 63mm bore provides 1559N. If the application requires load holding during air loss, note that standard cylinders drift and the air cushion only decelerates; use an external rod lock, pilot check valve, or the SAIL/BSAI lock variants. For this 40mm stroke, side-load rod-bending is minimal, but guides should still carry the payload.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X40S
- ✓ 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 SI50X40S FAQ
Yes, the SI50X40S is discontinued. The direct replacement is the AirTAC SAI50X40S. It features the same ISO 15552 mounting interface, 50mm bore, 40mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly. The SAI uses an upgraded two Y-shaped piston seal for lower start-up pressure.
The 50mm bore features a G1/4 air port and an M16x1.5 rod thread. Force output is 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N push at 0.9MPa, and a theoretical maximum of 200kgf at 1.0MPa. Operating speed is 30-800mm/s.
Request a Quote for the SAI50X40S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X40S replacement — usually within 7-8 hours.