This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X400SFA, 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 SI50X400SFA
The AirTAC Airtac SI50 Standard Cylinder SI50X400SFA 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 SAI50X400SFA, 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 → SAI50X400SFA
- 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 SI50X400SFA
The AirTAC SI50X400SFA is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 400mm stroke. Delivering 982N push force at 0.5MPa via a G1/4 port, it is replaced by the direct replacement SAI50X400SFA, which matches the bore, stroke, force, and FA flange mounting.
The SAI upgrade features two Y-shaped one-way piston seals for low start-up pressure and long life. The SI -S magnet works with CS1-B/DS1-B sensors, while the SAI family adds SAIL lock, SAIF valve, and BSAI clamp variants.
Airtac SI50 Standard Cylinder SI50X400SFA Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X400SFA |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X400SFA |
| 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 SAI50X400SFA 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 SAI50X400SFA 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 SI50X400SFA
| 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 SI50X400SFA Is Used
Long-Stroke Diverting
Drives a 400mm diverting arm on a packaging line, utilizing the 982N push force to shift products between parallel conveyor belts reliably.
Fixture Actuation
Extends clamping fixtures 400mm outward into machining cells, using the FA flange mount to secure the ISO 15552 profile body rigidly.
Replacing the Airtac SI50 Standard Cylinder SI50X400SFA with the SAI50X400SFA
To replace the SI50X400SFA, order the SAI50X400SFA. Verify the ISO 15552 FA flange interface, 50mm bore, 400mm stroke, G1/4 port, and the -S magnet for current AirTAC switches. At 0.5MPa it pushes 982N; neighbouring bores offer 628N (40mm) or 1559N (63mm). For the 400mm stroke, use an external guide to prevent rod bending and side-load wear. A plain cylinder drifts on air loss; for load holding, use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X400SFA
- ✓ 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 SI50X400SFA FAQ
Yes, the SI50X400SFA is discontinued. The direct replacement is the SAI50X400SFA. It shares the identical ISO 15552 mounting interface, 50mm bore, 400mm stroke, output force, G1/4 port, and FA flange, fitting existing fixtures perfectly.
The G1/4 port feeds a 50mm bore that delivers 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, and a theoretical max of 200kgf at 1.0MPa. It operates at 30-800mm/s with a 30mm adjustable cushion.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X400SFA
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X400SFA replacement — usually within 7-8 hours.