This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX400S, 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 SI50AX400S
The AirTAC SI50 Standard Cylinder SI50AX400S 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 SAI50AX400S, 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 → SAI50AX400S
- 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 SI50AX400S
The AirTAC SI50AX400S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 400 mm stroke. It delivers 982 N push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI50AX400S, a direct upgrade sharing the exact same mounting interface, bore, stroke, and output force.
The SAI replacement features an upgraded piston seal with two Y-shaped one-way elements for lower start-up pressure and longer life. This specific SKU includes a SUS420J2 stainless steel rod (-A) and a piston magnet (-S) for legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50AX400S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX400S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX400S |
| 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 SAI50AX400S 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 SAI50AX400S 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 SI50AX400S
| 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 SI50AX400S Is Used
Package Diverting
Pushes packages across conveyor belts with a 400 mm reach, relying on the adjustable air cushions to decelerate the rod smoothly.
Stainless Rod Actuation
Operates in mildly corrosive environments using the SUS420J2 stainless steel piston rod option for extended durability.
Replacing the Airtac SI50 Standard Cylinder SI50AX400S with the SAI50AX400S
To replace the discontinued SI50AX400S, order the SAI50AX400S. Confirm the ISO 15552 mounting interface, the 50 mm bore, the 400 mm stroke, the G1/4 port, and your specific mounting accessory. Because this is a long 400 mm stroke, use external guides to prevent rod bending and premature seal wear from side loads. If you need to scale up, a 63 mm bore offers 1559 N push at 0.5 MPa; scaling down to a 40 mm bore yields 628 N. The -A rod is SUS420J2 stainless steel, and the -S magnet works with legacy CS1-B/DS1-B switches (the SAI uses current AirTAC switches). Note that a standard cylinder drifts without live air; for load holding, use an external rod lock, a pilot check valve, or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX400S
- ✓ 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 SI50AX400S FAQ
Yes, the SI50AX400S is discontinued. The direct replacement is the AirTAC SAI50AX400S. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 400 mm stroke, output force, G1/4 port, and mounting interface.
The 50 mm bore cylinder operates at 30-800 mm/s. It generates 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa. The air cushion travel is 30 mm at each end.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX400S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX400S replacement — usually within 7-8 hours.