This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X400SFTC, 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 SI50X400SFTC
The AirTAC Airtac SI50 Standard Cylinder SI50X400SFTC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 400mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X400SFTC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke400 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X400SFTC
- 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 SI50X400SFTC
The AirTAC SI50X400SFTC is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 400mm stroke. It delivers 982 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI50X400SFTC, a direct sharing the exact FTC trunnion mounting, bore, and output force.
The SAI upgrade features a modernized piston seal using two Y-shaped one-way elements for lower start-up pressure and longer life. This FTC-mounted unit includes a magnet for CS1-B/DS1-B sensors, and the SAI family adds lock variants like SAIL and BSAI absent in the SI line.
Airtac SI50 Standard Cylinder SI50X400SFTC Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X400SFTC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X400SFTC |
| Bore size | Ø50 mm |
| Stroke | 400 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 SAI50X400SFTC 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 SAI50X400SFTC 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 SI50X400SFTC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×400 | 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 SI50X400SFTC Is Used
Long-Stroke Diversion
Pushes packages across a 400mm transfer gap with 982 N of force at 0.5 MPa, utilizing the FTC trunnion to absorb pivot stress.
Assembly Press
Applies up to 200 kgf maximum clamping force at 1.0 MPa, relying on adjustable 30mm air cushions to decelerate the load at stroke end.
Replacing the Airtac SI50 Standard Cylinder SI50X400SFTC with the SAI50X400SFTC
To replace the SI50X400SFTC, order the SAI50X400SFTC keeping the 50mm bore, 400mm stroke, G1/4 port, and FTC trunnion mount. If you need more force, the 63mm bore yields 1559 N push at 0.5 MPa; for less, the 40mm bore gives 628 N. Because this is a 400mm stroke, use an external guide to prevent rod bending and side-load wear. A plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock or pilot check valve for load holding. The built-in magnet works with legacy CS1-B/DS1-B switches, while the SAI uses current AirTAC sensors.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X400SFTC
- ✓ 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 SI50X400SFTC FAQ
Yes, the SI50X400SFTC is discontinued. The direct replacement is the SAI50X400SFTC. It shares the identical ISO 15552 mounting interface, 50mm bore, 400mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly.
The G1/4 port feeds a 50mm bore yielding 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and 1767 N push at 0.9 MPa. The theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X400SFTC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X400SFTC replacement — usually within 7-8 hours.