This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X1800, 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 SI50X1800
The AirTAC SI50 Standard Cylinder SI50X1800 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 1800mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X1800, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke1800 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X1800
- 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 SI50X1800
The AirTAC SI50X1800 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 1800mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. Because 1800mm exceeds the 1200mm standard maximum for this bore, it is a non-standard, made-to-order item requiring external guides to prevent rod bending.
You must order the direct replacement SAI50X1800. It shares the exact ISO 15552 mounting interface, bore, stroke, force, and port. The SAI features an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. Note this SKU lacks a magnet (-S), so it cannot take a CS1-B/DS1-B sensor.
Airtac SI50 Standard Cylinder SI50X1800 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X1800 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X1800 |
| Bore size | Ø50 mm |
| Stroke | 1800 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 SAI50X1800 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 SAI50X1800 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 SI50X1800
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×1800 | 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 SI50X1800 Is Used
Long-Stroke Transfer
Pushes workpieces between distant machining stations over 1800mm, requiring external guide rails to prevent rod sagging.
Elevating Gate
Actuates heavy vertical lifting doors where the 982N push force at 0.5MPa handles the 50kg dynamic load with a safe margin.
Material Diversion
Drives large pneumatic flap diverters on packaging lines, using the 30mm adjustable air cushions to decelerate the long travel.
Replacing the Airtac SI50 Standard Cylinder SI50X1800 with the SAI50X1800
To replace the SI50X1800, order the SAI50X1800, confirming the ISO 15552 interface, 50mm bore, 1800mm stroke, G1/4 port (PT/G/NPT thread options), and mounting accessory (LB, FA, CA, TC). This non-standard 1800mm stroke exceeds the 1200mm max, so add external guides to prevent rod-bending side loads. For sizing both ways: a 40mm bore gives 628N push, while a 63mm bore yields 1559N at 0.5MPa. A plain cylinder drifts on air loss—the cushion only decelerates—so for load holding use an external pilot check valve or the SAIL/BSAI lock variant. If self-valve control is needed, the SAIF variant fits bores 32-100.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X1800
- ✓ 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 SI50X1800 FAQ
Yes, the SI50X1800 is discontinued. The direct replacement is the SAI50X1800. It is dimensionally interchangeable per ISO 15552, retaining the same 50mm bore, 1800mm stroke, G1/4 port, and mounting fixtures.
This double-acting cylinder has a G1/4 air port. It generates 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 SAI50X1800
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X1800 replacement — usually within 7-8 hours.