This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI40AX850, 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 SI40AX850
The AirTAC Airtac SI40 Standard Cylinder SI40AX850 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø40mm bore and 850mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI40AX850, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ40 mm
- Stroke850 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM12×1.25
- StatusDiscontinued → SAI40AX850
- 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 SI40AX850
The AirTAC SI40AX850 is a discontinued double-acting ISO 15552 profile cylinder with an extruded aluminum barrel, delivering 628 N push force at 0.5 MPa through a 40 mm bore. It features a SUS420J2 stainless steel piston rod (A option) and an 850 mm stroke. AirTAC replaced this legacy unit with the SAI40AX850, a direct sharing the exact ISO 15552 mounting interface, bore, stroke, output force, G1/4 port, and accessories.
The SAI upgrade introduces a refined piston seal using two Y-shaped one-way elements for extended life and lower start-up pressure. Because this specific SKU lacks the -S magnet, it cannot accept position sensors like the legacy CS1-B/DS1-B switches.
Airtac SI40 Standard Cylinder SI40AX850 Technical Specifications
| Model | Airtac SI40 Standard Cylinder SI40AX850 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI40AX850 |
| Bore size | Ø40 mm |
| Stroke | 850 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 SAI40AX850 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 SAI40AX850 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 SI40AX850
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 40 | Bore size in mm. |
| ×850 | 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 SI40AX850 Is Used
Long-Reach Diversion
Drives sorting flappers on packaging lines where the 850 mm stroke clears wide conveyor belts, utilizing the 628 N push force at 0.5 MPa.
Stainless Rod Actuation
Actuates sliding doors or dampers in mildly humid environments using the SUS420J2 stainless steel rod option for corrosion resistance.
Replacing the Airtac SI40 Standard Cylinder SI40AX850 with the SAI40AX850
To replace the SI40AX850, order the SAI40AX850 and verify the ISO 15552 mounting interface, 40 mm bore, 850 mm stroke, G1/4 port (PT/G/NPT thread options), and your specific mounting accessory. Because this SKU has no -S magnet, it cannot support switches; if sensing is needed, select an SAI model with the S suffix for current AirTAC switches. For load holding, note that a plain cylinder drifts on air loss—the cushion only decelerates—so use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. At 850 mm, prevent rod bending by guiding the load externally. If downsizing, a 32 mm bore yields 402 N push; if upsizing, a 50 mm bore provides 982 N at 0.5 MPa.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI40AX850
- ✓ 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 SI40AX850 FAQ
Yes, the SI40AX850 is discontinued. The direct replacement is the SAI40AX850. It shares the identical ISO 15552 mounting interface, 40 mm bore, 850 mm stroke, output force, and G1/4 port, fitting existing fixtures perfectly.
This double-acting cylinder has a G1/4 air port. Force ratings are 628 N push and 528 N pull at 0.5 MPa, 879 N push at 0.7 MPa, 1130 N push at 0.9 MPa, and a theoretical maximum of 128 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI40AX850
Send us the quantity and destination. We confirm price, stock and lead time on the SAI40AX850 replacement — usually within 7-8 hours.