This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX425S, 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 SI50BX425S
The AirTAC Airtac SI50 Standard Cylinder SI50BX425S 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 SAI50BX425S, 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 → SAI50BX425S
- 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 SI50BX425S
The AirTAC SI50BX425S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 425mm stroke, and a SUS304 stainless steel rod. Delivering 982N push force at 0.5MPa, it is replaced by the SAI50BX425S. This direct upgrade matches the G1/4 port, M16x1.5 thread, and 30mm cushions.
The SAI features an upgraded piston seal using two Y-shaped elements for low start-up pressure. The original -S magnet supports legacy CS1-B/DS1-B sensors, while the SAI accepts current AirTAC switches.
Airtac SI50 Standard Cylinder SI50BX425S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX425S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX425S |
| 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 SAI50BX425S 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 SAI50BX425S 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 SI50BX425S
| 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 SI50BX425S Is Used
Stainless Rod Diverter
Uses the SUS304 rod to resist washdown moisture while diverting packages along a 425mm stroke path.
Vertical Lift Gate
Lifts a 50kg access panel using the 982N push force at 0.5MPa, guided externally to prevent rod bending.
Long Stroke Ejector
Ejects machined parts from a fixture over 425mm, relying on the 30mm adjustable cushions for end-of-stroke deceleration.
Replacing the Airtac SI50 Standard Cylinder SI50BX425S with the SAI50BX425S
To replace the SI50BX425S, order the SAI50BX425S to retain the exact ISO 15552 mounting interface, 425mm stroke, and G1/4 port. Confirm your mounting accessory (LB, FA, TC) and the -B SUS304 rod option for corrosion resistance. The 982N push force at 0.5MPa can be stepped up to 1374N at 0.7MPa, or drop to a 40mm bore (628N) if lower force is acceptable. At 425mm, prevent rod bending by using an external guide to absorb side loads. A plain cylinder drifts on air loss; for load holding, specify an external pilot check valve or the SAIL lock variant. The cushion only decelerates.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX425S
- ✓ 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 SI50BX425S FAQ
Yes, the SI50BX425S is discontinued. The direct replacement is the SAI50BX425S. It is dimensionally interchangeable per the ISO 15552 mounting interface, retaining the same 50mm bore, 425mm stroke, G1/4 port, and output force.
The G1/4 port feeds a 50mm bore yielding 982N push and 825N pull at 0.5MPa. Push force is 1374N at 0.7MPa and 1767N at 0.9MPa, with a theoretical max of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX425S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX425S replacement — usually within 7-8 hours.