This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40BX325, 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 SI40BX325
The AirTAC Airtac SI40 Standard Cylinder SI40BX325 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 325mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40BX325, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke325 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40BX325
- 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 SI40BX325
The AirTAC SI40BX325 is a discontinued double-acting ISO 15552 profile cylinder with a 40mm bore, 325mm stroke, and SUS304 stainless steel rod. It delivers 628N push force at 0.5MPa. The direct replacement is the SAI40BX325, sharing the same G1/4 port, M12x1.25 thread, and ISO 15552 mounting interface for seamless fixture integration.
The SAI upgrade features an advanced two-piece Y-shaped piston seal for low start-up pressure and extended life. Note this non-magnetic SKU cannot accept a sensor. For higher temperatures, Viton H seals raise the limit to 150C.
Airtac SI40 Standard Cylinder SI40BX325 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40BX325 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40BX325 |
| Bore size | Ø40 mm |
| Stroke | 325 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 SAI40BX325 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 SAI40BX325 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 SI40BX325
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×325 | 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 SI40BX325 Is Used
Stainless Rod Diverter
Ideal for pushing light packages on a washdown conveyor line where the SUS304 rod resists moisture and corrosion over the 325mm travel.
External Guided Press
Handles 377N working load for light pressing tasks, provided an external guide supports the rod over the extended 325mm stroke to prevent binding.
Replacing the Airtac SI40 Standard Cylinder SI40BX325 with the SAI40BX325
To replace the SI40BX325, order the SAI40BX325, confirming the ISO 15552 mounting interface, 325mm stroke, G1/4 port, and SUS304 rod. This non-magnetic version cannot hold a position switch; if sensing is needed, select an SAI with the -S magnet option. Because this is a 325mm stroke, use external guides to prevent rod bending and side-load damage. The 40mm bore yields 628N push at 0.5MPa; if less force is needed, drop to a 32mm bore (402N), or step up to 50mm (982N). A plain cylinder will drift without live air; for load holding, use an external pilot check valve or the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40BX325
- ✓ 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 SI40BX325 FAQ
Yes, the SI40BX325 is discontinued. The direct replacement is the SAI40BX325. It is dimensionally interchangeable per ISO 15552, retaining the same 40mm bore, 325mm stroke, 628N force, G1/4 port, and mounting interface.
This 40mm bore cylinder uses a G1/4 port. It generates 628N push and 528N pull at 0.5MPa, 879N push at 0.7MPa, 1130N push at 0.9MPa, and a theoretical maximum of 128kgf at 1.0MPa. The rod end thread is M12x1.25.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40BX325
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40BX325 replacement — usually within 7-8 hours.