This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX425, 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 SI40 Standard Cylinder SI40BX425
The AirTAC Airtac SI40 Standard Cylinder SI40BX425 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 425mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX425, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke425 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX425
- 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 SI40 Standard Cylinder SI40BX425
The AirTAC SI40BX425 is a discontinued double-acting ISO 15552 profile cylinder with a 40 mm bore and 425 mm stroke. Delivering 628 N push force at 0.5 MPa, it features a SUS304 stainless piston rod for corrosion resistance. The direct replacement is the SAI40BX425, matching the bore, stroke, G1/4 port, and ISO 15552 mounting interface.
The SAI upgrade introduces a two Y-shaped one-way piston seal for low start-up pressure and long life. This SKU lacks a magnet and cannot take a sensor. For safe sizing, expect a working load of 377 N or a 32 kg vertical lift. The SAI family also adds SAIL, SAIF, and BSAI lock variants absent in the SI line.
Airtac SI40 Standard Cylinder SI40BX425 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX425 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX425 |
| Bore size | Ø40 mm |
| Stroke | 425 mm |
| Acting type | Double acting |
| Port size | G1/4 |
| Rod thread | M12×1.25 |
| 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, 27 mm |
| Max standard stroke | Up to 1200 mm |
Specifications follow the official AirTAC SI datasheet (now discontinued). The SAI40BX425 carries the same ISO 15552 ratings. Confirm against the product label before installation. Thread options: PT / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
The SAI40BX425 produces the same force from the same bore. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac SI40 Standard Cylinder SI40BX425
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | 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 SI40 Standard Cylinder SI40BX425 Is Used
Stainless Rod Diverters
Actuates routing gates on washdown conveyor lines where the SUS304 rod resists moisture and corrosion.
Packaging Pushers
Provides 628 N push at 0.5 MPa to index cartons, with the 425 mm stroke allowing extended reach.
Replacing the Airtac SI40 Standard Cylinder SI40BX425 with the SAI40BX425
To replace the SI40BX425, order the SAI40BX425. Confirm the ISO 15552 mounting interface, 40 mm bore, 425 mm stroke, G1/4 port, and your specific mounting accessory. The SUS304 rod is retained. Since this is a no-magnet SKU, it cannot accept position sensors. If you need load holding on air loss, note that standard cushions only decelerate; use an external pilot check valve or the SAIL/BSAI lock variant. With a 425 mm stroke, use external guides to prevent rod bending and side loads. If sizing up or down, the 32 mm bore offers 402 N push at 0.5 MPa, while the 50 mm bore provides 982 N.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX425
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac SI40 Standard Cylinder SI40BX425 FAQ
Yes, the SI40BX425 is discontinued. The direct replacement is the SAI40BX425. It matches the ISO 15552 mounting interface, 40 mm bore, 425 mm stroke, force, and G1/4 port, fitting existing fixtures perfectly.
The G1/4 port bore delivers 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N at 0.9 MPa, and a 128 kgf max at 1.0 MPa. The cushion only decelerates; it does not hold the load on air loss.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX425
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX425 replacement — usually within 7-8 hours.