This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX400, 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 SI50AX400
The AirTAC Airtac SI50 Standard Cylinder SI50AX400 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 SAI50AX400, 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 → SAI50AX400
- 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 SI50AX400
The AirTAC SI50AX400 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 via a G1/4 port. The direct replacement is the SAI50AX400, which matches the exact bore, stroke, force, port and ISO 15552 mounting interface for existing fixtures. This specific SKU features a SUS420J2 (A) stainless steel piston rod for corrosion resistance, but ships without a magnet, meaning it cannot accept CS1-B/DS1-B sensors.
The SAI upgrade introduces an upgraded piston seal using two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds SAIL, SAIF and BSAI lock variants absent from the legacy SI line.
Airtac SI50 Standard Cylinder SI50AX400 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX400 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX400 |
| 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 SAI50AX400 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 SAI50AX400 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 SI50AX400
| 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 SI50AX400 Is Used
Diverting Gate Actuation
Drives routing flaps on packaging lines where the 982 N push force at 0.5 MPa easily overcomes flap inertia and product flow resistance over the 400 mm travel.
Stainless Rod Washdown
The SUS420J2 stainless piston rod suits damp or mildly corrosive environments, pushing tooling components 400 mm without rusting the exposed rod surface.
Replacing the Airtac SI50 Standard Cylinder SI50AX400 with the SAI50AX400
To replace the discontinued SI50AX400, order the SAI50AX400. Confirm the ISO 15552 mounting interface, 50 mm bore, 400 mm stroke, G1/4 port (PT/G/NPT thread options) and your specific mounting accessory. Because this SKU lacks the -S magnet, it cannot support CS1-B/DS1-B sensors; order a magnet-equipped SAI if position detection is required. This variant uses the SUS420J2 stainless rod (A); specify default carbon steel if corrosion resistance is unnecessary. Sizing both ways: a 63 mm bore offers 1559 N push at 0.5 MPa, while a 40 mm bore provides 628 N. A plain cylinder does not hold load without live air (the cushion only decelerates); for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. For the 400 mm stroke, use external guides to prevent rod bending and side-load damage.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX400
- ✓ 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 SI50AX400 FAQ
Yes, the SI50AX400 is discontinued. The direct replacement is the AirTAC SAI50AX400. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 400 mm stroke, G1/4 port and mounting interface, but features an upgraded piston seal.
The 50 mm bore features a G1/4 air port and delivers 982 N push and 825 N pull at 0.5 MPa. At 0.7 MPa it pushes 1374 N, and the theoretical maximum force is 200 kgf at 1.0 MPa. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX400
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX400 replacement — usually within 7-8 hours.