This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X425, 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 SI50X425
The AirTAC Airtac SI50 Standard Cylinder SI50X425 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 SAI50X425, 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 → SAI50X425
- 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 SI50X425
The AirTAC SI50X425 is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore and 425 mm stroke, delivering 982 N push force at 0.5 MPa via its G1/4 port. AirTAC replaced this legacy unit with the SAI50X425, a direct sharing the exact interface, bore, output, and mounting. The SAI upgrades the piston seal to two Y-shaped one-way elements for lower start-up pressure and longer life.
Because this SKU lacks a magnet (-S), it cannot accept position sensors; legacy CS1-B/DS1-B switches only fit magnetized versions. The SAI family also introduces SAIL and BSAI lock variants absent in the SI line for secure load holding.
Airtac SI50 Standard Cylinder SI50X425 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X425 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X425 |
| 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 SAI50X425 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 SAI50X425 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 SI50X425
| 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 SI50X425 Is Used
Package Diversion
Drives sorting pop-up arms on packaging lines, utilizing the 425 mm stroke to redirect goods smoothly at high throughput speeds.
Pallet Handling
Actuates pushers during pallet loading stations, where the 982 N push force at 0.5 MPa easily overcomes carton sliding resistance.
Material Lowering
Controls the descent of light fixtures in assembly zones, requiring external flow controls since the cushion only decelerates at end-stroke.
Replacing the Airtac SI50 Standard Cylinder SI50X425 with the SAI50X425
To replace the SI50X425, order the SAI50X425 and confirm the ISO 15552 mounting interface, 50 mm bore, 425 mm stroke, G1/4 port (PT/G/NPT), and accessory type (LB, FA, TC, etc.). This non-magnet SKU cannot take a sensor; if sensing is needed, select an SAI50X425S. A standard cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock or pilot check valve for held loads, or specify an SAIL/BSAI variant. At 425 mm, prevent rod bending by guiding the load externally. If downsizing, a 40 mm bore yields 628 N push; if upsizing, a 63 mm bore provides 1559 N at 0.5 MPa.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X425
- ✓ 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 SI50X425 FAQ
Yes, the SI50X425 is discontinued. The direct replacement is the SAI50X425. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 425 mm stroke, output force, G1/4 port, and mounting interface to fit existing fixtures perfectly.
This double-acting cylinder features a G1/4 air port and M16x1.5 rod thread. It delivers 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.
Request a Quote for the SAI50X425
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X425 replacement — usually within 7-8 hours.