This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X425S, 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 SI50X425S
The AirTAC Airtac SI50 Standard Cylinder SI50X425S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 425mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X425S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke425 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X425S
- 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 SI50X425S
The AirTAC SI50X425S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore and 425mm stroke. It delivers 982 N of push force at 0.5 MPa through a G1/4 port. AirTAC replaced this legacy unit with the SAI50X425S, a direct replacement matching the exact ISO 15552 mounting interface, bore, stroke, output force, and accessories.
The SAI upgrade introduces a refined piston seal utilizing two Y-shaped one-way elements for low start-up pressure and extended life. For holding loads, note that a standard cylinder drifts without live air; consider the SAIL lock or BSAI clamp-lock variants.
Airtac SI50 Standard Cylinder SI50X425S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X425S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X425S |
| Bore size | Ø50 mm |
| Stroke | 425 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 SAI50X425S 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 SAI50X425S 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 SI50X425S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×425 | 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 SI50X425S Is Used
Material Diverting
Actuates diverter arms on packaging lines, utilizing the 425mm stroke to shift products between parallel conveyor belts smoothly.
Long-Reach Ejection
Pushes machined parts out of a CNC enclosure, where the extended 425mm reach clears the work zone completely before the next cycle.
Replacing the Airtac SI50 Standard Cylinder SI50X425S with the SAI50X425S
To replace the SI50X425S, order the SAI50X425S. Confirm the ISO 15552 mounting interface, the G1/4 port, the M16x1.5 rod thread, and the -S magnet for CS1-B/DS1-B legacy sensors. The SAI family also adds the SAIF self-valve variant (bores 32-100) absent in the SI line. Sizing both ways: a neighboring 40mm bore yields 628 N push at 0.5 MPa, while a 63mm bore offers 1559 N. Because this is a 425mm stroke, add external guides to prevent rod bending and side-load damage. A plain cylinder does not hold load on air loss; use an external rod lock, pilot check valve, or the SAIL/BSAI variants for secure holding.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X425S
- ✓ 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 SI50X425S FAQ
Yes, the SI50X425S is discontinued. The direct replacement is the SAI50X425S. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 425mm stroke, G1/4 port, and mounting interface, but features an upgraded piston seal.
The 50mm bore uses a G1/4 air port. Force output is 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. Operating speed is 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X425S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X425S replacement — usually within 7-8 hours.