This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50X350STC, 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 SI50X350STC
The AirTAC Airtac SI50 Standard Cylinder SI50X350STC is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 350mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50X350STC, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke350 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50X350STC
- 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 SI50X350STC
The AirTAC SI50X350STC is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore and 350mm stroke. It delivers 982N push force at 0.5MPa via a G1/4 port. AirTAC replaced this legacy unit with the SAI50X350STC, a direct upgrade sharing the exact ISO 15552 mounting interface, TC trunnion mount, stroke, and force.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. For applications needing load holding on air loss, the SAI family introduces SAIL and BSAI lock variants the SI lacked. The -S magnet supports legacy CS1-B/DS1-B sensors.
Airtac SI50 Standard Cylinder SI50X350STC Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50X350STC |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50X350STC |
| Bore size | Ø50 mm |
| Stroke | 350 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 SAI50X350STC 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 SAI50X350STC 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 SI50X350STC
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×350 | 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 SI50X350STC Is Used
Material Diversion
Drives a sorting flap on a packaging line, using the 350mm stroke to redirect cartons into secondary lanes with 982N of push force.
Vertical Lowering
Lowers light fixtures or components up to 50kg at a controlled rate, relying on the adjustable 30mm air cushion to decelerate before the end of travel.
Gate Actuation
Opens and closes access doors on machine guards, utilizing the TC trunnion mount to accommodate the pivot arc during the 350mm extension.
Replacing the Airtac SI50 Standard Cylinder SI50X350STC with the SAI50X350STC
To replace the SI50X350STC, order the SAI50X350STC. Confirm the ISO 15552 TC trunnion mounting, 50mm bore, 350mm stroke, G1/4 port, and the -S magnet. If downsizing, a 40mm bore yields 628N push at 0.5MPa; if upsizing, a 63mm bore provides 1559N. Note that a plain cylinder drifts on air loss as the cushion only decelerates, so for load holding use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. At 350mm, prevent rod bending by using an external guide to manage side loads.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50X350STC
- ✓ 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 SI50X350STC FAQ
Yes, the SI50X350STC is discontinued. The direct replacement is the SAI50X350STC. It shares the same ISO 15552 mounting interface, 50mm bore, 350mm stroke, output force, G1/4 port, and TC mount, fitting existing fixtures perfectly.
The 50mm bore uses a G1/4 air port and features a 20mm rod with an M16x1.5 thread. It generates 982N push and 825N pull at 0.5MPa, 1374N push at 0.7MPa, and a theoretical maximum of 200kgf at 1.0MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50X350STC
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50X350STC replacement — usually within 7-8 hours.