This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX425, 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 SI50BX425
The AirTAC Airtac SI50 Standard Cylinder SI50BX425 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 SAI50BX425, 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 → SAI50BX425
- 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 SI50BX425
The AirTAC SI50BX425 is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 425mm stroke, and a SUS304 stainless steel piston rod. Delivering 982N push force at 0.5 MPa via a G1/4 port, it is replaced by the SAI50BX425. This direct upgrade shares the exact ISO 15552 mounting interface, bore, stroke, and force.
The SAI upgrade utilizes two Y-shaped one-way piston seals for low start-up pressure and long life. This no-magnet SKU cannot accept a sensor, unlike legacy CS1-B/DS1-B setups. For high heat, Viton H seals raise the temperature limit to 150 C.
Airtac SI50 Standard Cylinder SI50BX425 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX425 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX425 |
| 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 SAI50BX425 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 SAI50BX425 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 SI50BX425
| 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 SI50BX425 Is Used
Stainless Rod Diverter
Ideal for diverting items on a washdown conveyor line, utilizing the 425mm stroke and SUS304 rod for corrosion resistance while providing 982N push force at 0.5 MPa.
Long-Stroke Gate Actuator
Drives 425mm equipment safety gates on automated machinery, requiring external guide rails to prevent rod bending during the extended travel.
Replacing the Airtac SI50 Standard Cylinder SI50BX425 with the SAI50BX425
To replace the SI50BX425, order the SAI50BX425, confirming the ISO 15552 interface, 50mm bore, 425mm stroke, G1/4 port, and SUS304 rod. This non-magnetic SKU cannot take a switch; order a magnet-equipped SAI if sensing is needed. For sizing, a 40mm bore yields 628N push at 0.5 MPa, while a 63mm bore yields 1559N. At 425mm, prevent rod bending by using an external guide to manage side loads. A plain cylinder drifts on air loss; the cushion only decelerates. For load holding, use an external pilot check valve or the SAIL/BSAI lock variant.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX425
- ✓ 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 SI50BX425 FAQ
Yes, the AirTAC SI50BX425 is discontinued. The direct replacement is the SAI50BX425. It is dimensionally interchangeable per ISO 15552, matching the 50mm bore, 425mm stroke, 982N force, G1/4 port, and SUS304 rod material.
It features a G1/4 air port. The thrust ratings are: 982N push and 825N pull at 0.5 MPa; 1374N push at 0.7 MPa; 1767N push at 0.9 MPa; with a theoretical maximum force of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX425
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX425 replacement — usually within 7-8 hours.