This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX250SN, 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 SI50AX250SN
The AirTAC Airtac SI50 Standard Cylinder SI50AX250SN is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX250SN, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX250SN
- 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 SI50AX250SN
The AirTAC SI50AX250SN is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 250mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50AX250SN, a direct upgrade retaining the exact ISO 15552 mounting interface, stroke, and output force. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life.
This specific SKU includes the -A SUS420J2 stainless piston rod for corrosion resistance, an -S magnet for legacy CS1-B/DS1-B sensors, and an -N NBR seal rated for -20 to +70 C. Note that a plain cylinder drifts on air loss; the cushion only decelerates. For load holding, explore the SAIL lock or BSAI clamp-lock variants the SI line lacked.
Airtac SI50 Standard Cylinder SI50AX250SN Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX250SN |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX250SN |
| Bore size | Ø50 mm |
| Stroke | 250 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 SAI50AX250SN 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 SAI50AX250SN 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 SI50AX250SN
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×250 | 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 SI50AX250SN Is Used
Package Diversion
Actuates routing gates on packaging lines, utilizing the 982N push force to smoothly redirect moderate-weight cartons at speeds up to 800 mm/s.
Stainless Tooling
Ideal for light machining or clamping fixtures where ambient moisture might cause corrosion, leveraging the SUS420J2 stainless steel piston rod.
Replacing the Airtac SI50 Standard Cylinder SI50AX250SN with the SAI50AX250SN
To replace the SI50AX250SN, order the SAI50AX250SN. It drops directly into existing fixtures per ISO 15552 mounting dimensions, matching the 50mm bore, 250mm stroke, M16x1.5 rod thread, G1/4 port, and 30mm cushions. Confirm your mounting accessory (LB, FA, TC, etc.) and retain the -S magnet for current AirTAC switches. When sizing, neighboring bores offer different forces: a 40mm bore yields 628N push at 0.5MPa, while a 63mm bore yields 1559N. If your stroke of 250mm or longer introduces side-load risks, use guide rails to prevent rod bending. Because standard cylinders do not hold load without live air, integrate an external pilot check valve or choose the SAIL air-released lock variant for secure positioning.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX250SN
- ✓ 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 SI50AX250SN FAQ
Yes, the SI50AX250SN is discontinued. The direct replacement is the SAI50AX250SN. It shares the same ISO 15552 mounting interface, 50mm bore, 250mm stroke, G1/4 port, and force ratings, fitting existing fixtures perfectly while adding an upgraded piston seal.
The 50mm bore uses a G1/4 air port. At 0.5MPa it provides 982N push and 825N pull force. At 0.7MPa push is 1374N, and at 0.9MPa push is 1767N. The theoretical maximum force is 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX250SN
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX250SN replacement — usually within 7-8 hours.