This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X400S, 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 SI50X400S
The AirTAC Airtac SI50 Standard Cylinder SI50X400S 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 SAI50X400S, 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 → SAI50X400S
- 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 SI50X400S
The AirTAC SI50X400S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 400mm stroke. Delivering 982N push force at 0.5MPa, it features a G1/4 port and M16x1.5 rod thread. The direct replacement is the SAI50X400S, matching the exact interface, force, and mounting.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and longevity. The SAI family adds SAIL, SAIF, and BSAI variants lacking in the SI line. This -S model uses CS1-B/DS1-B sensors, while Viton H seals raise temps to 150C.
Airtac SI50 Standard Cylinder SI50X400S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X400S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X400S |
| 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 SAI50X400S 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 SAI50X400S 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 SI50X400S
| 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 SI50X400S Is Used
Package Diversion
Actuates routing gates on 50kg class package conveyors where the 400mm travel shifts parcels between sorting lanes.
Vertical Pressing
Provides up to 589N safe working force for light-duty pressing or holding tasks, benefiting from the 30mm adjustable cushion.
Pallet Handling
Drives 400mm stroke stops and lifts in automated storage systems, requiring external guides to manage rod side-load.
Replacing the Airtac SI50 Standard Cylinder SI50X400S with the SAI50X400S
To replace the SI50X400S, order the SAI50X400S keeping the identical 50mm bore, 400mm stroke, G1/4 port, and ISO 15552 mounting. Confirm your thread option (PT/G/NPT) and mounting accessory (LB, FA, TC, etc.). The -S suffix means a magnet for CS1-B/DS1-B switches; the SAI uses current AirTAC switches. For sizing, neighboring bores are 40mm (628N push @0.5) and 63mm (1559N). At 400mm stroke, use external guides to prevent rod bending and side-load wear. Plain cylinders drift without air; for load holding use the SAIL lock, BSAI clamp-lock, or an external pilot check valve.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X400S
- ✓ 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 SI50X400S FAQ
Yes, the SI50X400S is discontinued. The direct replacement is the SAI50X400S. It is dimensionally interchangeable per ISO 15552, offering the same 50mm bore, 400mm stroke, 982N force, G1/4 port, and mounting interface.
The 50mm bore has a G1/4 port. Force ratings are: 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N push at 0.9MPa, and a theoretical max of 200kgf at 1.0MPa. Speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X400S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X400S replacement — usually within 7-8 hours.