This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X155S, 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 SI50X155S
The AirTAC SI50 Standard Cylinder SI50X155S 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 SAI50X155S, 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 → SAI50X155S
- 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 SI50X155S
The AirTAC SI50X155S is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 155mm stroke. Delivering 982N push and 825N pull at 0.5MPa via a G1/4 port, it is replaced by the direct replacement SAI50X155S.
The SAI upgrade retains all dimensions and forces but adds a two Y-shaped one-way piston seal for low start-up pressure. The -S magnet supports CS1-B/DS1-B switches, and Viton H seals raise temps to 150C.
Airtac SI50 Standard Cylinder SI50X155S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X155S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X155S |
| 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 SAI50X155S 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 SAI50X155S 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 SI50X155S
| 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 SI50X155S Is Used
Package Diverting
Actuates diverter arms on packaging lines, using the 155mm stroke to push cartons cleanly onto adjacent conveyors with 982N force.
Pallet Stop Gate
Controls pallet flow in low-profile assembly zones, raising and lowering a physical stop gate that handles up to 50kg vertical loads safely.
Clamp Actuation
Drives mid-force clamping fixtures for machining or welding, holding workpieces securely using the G1/4 double-acting air supply.
Replacing the Airtac SI50 Standard Cylinder SI50X155S with the SAI50X155S
To replace the SI50X155S, order the SAI50X155S with the same ISO 15552 mounting interface, 155mm stroke, G1/4 port, and -S magnet. If you need more force, the 63mm bore yields 1559N at 0.5MPa; if less, the 40mm bore gives 628N. For load holding on air loss, note that plain cylinders drift and cushions only decelerate—use an external pilot check valve or the SAIL/BSAI lock variants. The 20mm rod and M16x1.5 thread fit existing fixtures. At 155mm stroke, side-load is minimal, but always guide the load to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X155S
- ✓ 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 SI50X155S FAQ
Yes, the SI50X155S is discontinued. The direct replacement is the SAI50X155S. It is dimensionally interchangeable per ISO 15552, matching the 50mm bore, 155mm stroke, G1/4 port, and mounting hardware, but features an upgraded two Y-shaped piston seal for longer life.
The 50mm bore features a G1/4 air port and M16x1.5 rod thread. It delivers 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, 1767N at 0.9MPa, and a theoretical max of 200kgf at 1.0MPa. Operating speed is 30-800mm/s.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X155S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X155S replacement — usually within 7-8 hours.