This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50AX155S, 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 SI50AX155S
The AirTAC Airtac SI50 Standard Cylinder SI50AX155S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 155mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50AX155S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke155 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50AX155S
- 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 SI50AX155S
The AirTAC SI50AX155S is a discontinued double-acting ISO 15552 profile cylinder featuring a 50mm bore, 155mm stroke, and a SUS420J2 stainless steel rod. It delivers 982 N of push force at 0.5 MPa. AirTAC replaced this legacy unit with the SAI50AX155S, a direct upgrade retaining the exact ISO 15552 mounting interface, G1/4 port, and M16x1.5 rod thread.
The SAI successor introduces an upgraded piston seal utilizing two Y-shaped one-way elements for extended longevity and lower start-up pressure. The original SI50AX155S includes a piston magnet for legacy CS1-B/DS1-B sensors, while the SAI family also adds SAIL, SAIF, and BSAI lock variants previously unavailable.
Airtac SI50 Standard Cylinder SI50AX155S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50AX155S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50AX155S |
| Bore size | Ø50 mm |
| Stroke | 155 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 SAI50AX155S 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 SAI50AX155S 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 SI50AX155S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×155 | 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 SI50AX155S Is Used
Stainless Rod Actuation
Leverages the SUS420J2 rod for mid-force (982 N) positioning in environments where moisture or minor corrosive elements would degrade a standard carbon steel rod.
Non-Standard Stroke Diverting
Uses the exact 155mm stroke to push packages or divert product flows on a line, fitting tight machinery envelopes where standard 150mm or 160mm strokes fail.
Vertical Lift Gates
Raises and lowers lightweight access gates or safety barriers up to 50 kg, utilizing the 50mm bore and adjustable 30mm air cushions to prevent end-of-stroke slamming.
Replacing the Airtac SI50 Standard Cylinder SI50AX155S with the SAI50AX155S
To replace the discontinued SI50AX155S, order the SAI50AX155S. Confirm your ISO 15552 mounting fixtures (LB, FA, TC, etc.), the 155mm stroke, G1/4 port, and the -S magnet requirement. Because 155mm is a non-standard stroke, verify your hard stops and cushion adjustment. If you need to scale up or down, neighboring bores are 40mm (628 N push @0.5 MPa) and 63mm (1559 N push @0.5 MPa). Note that a plain ISO 15552 cylinder does not hold load without live air; the cushion only decelerates. For load holding on air loss, use an external pilot check valve or the SAIL/BSAI lock variant. The -A rod material (SUS420J2) provides corrosion resistance versus standard carbon steel.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50AX155S
- ✓ 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 SI50AX155S FAQ
Yes, the SI50AX155S is discontinued. The direct replacement is the SAI50AX155S. It shares the exact same ISO 15552 mounting interface, 50mm bore, 155mm stroke, output force, G1/4 port, and SUS420J2 stainless rod, fitting directly into your existing fixtures.
The bore is 50mm with a G1/4 air port. At 0.5 MPa it provides 982 N push and 825 N pull force. At 0.7 MPa push is 1374 N, and at 0.9 MPa it is 1767 N. The theoretical maximum force is 200 kgf at 1.0 MPa. It operates at speeds of 30-800 mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50AX155S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50AX155S replacement — usually within 7-8 hours.