This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX155S, 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 SI50BX155S
The AirTAC Airtac SI50 Standard Cylinder SI50BX155S 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 SAI50BX155S, 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 → SAI50BX155S
- 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 SI50BX155S
The AirTAC SI50BX155S is a discontinued double-acting ISO 15552 profile cylinder with a 50 mm bore, 155 mm stroke, and a SUS304 stainless steel rod. It delivers 982 N push and 825 N pull at 0.5 MPa through a G1/4 port. The direct replacement is the SAI50BX155S, matching the bore, stroke, force, port, and ISO 15552 mounting interface for existing fixtures.
The SAI upgrade features an improved piston seal with two Y-shaped one-way elements for low start-up pressure and long life. The SAI family also adds SAIL, SAIF, and BSAI lock variants absent in the SI line.
Airtac SI50 Standard Cylinder SI50BX155S Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX155S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX155S |
| 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 SAI50BX155S 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 SAI50BX155S 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 SI50BX155S
| 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 SI50BX155S Is Used
Stainless Rod Clamping
Ideal for fixture clamping in washdown areas, utilizing the SUS304 rod and 982 N push force to secure components during machining.
Short Stroke Diversion
Handles package diverting on conveyors with a 155 mm nonstandard stroke, providing rapid 30-800 mm/s actuation.
Replacing the Airtac SI50 Standard Cylinder SI50BX155S with the SAI50BX155S
To replace this SI50BX155S, order the SAI50BX155S and confirm the ISO 15552 mounting interface, 50 mm bore, 155 mm stroke, G1/4 port, and the -S magnet for CS1-B/DS1-B switches. Note that 155 mm is a nonstandard stroke. If you need more force, the 63 mm bore yields 1559 N push at 0.5 MPa; if less force is acceptable, the 40 mm bore provides 628 N. This plain cylinder does not hold load without live air, so for vertical applications use an external rod lock, pilot check valve, or the SAIL/BSAI lock variant. The 155 mm stroke is short, but for any stroke over 300 mm, add a guide to prevent rod bending.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX155S
- ✓ 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 SI50BX155S FAQ
Yes, the SI50BX155S is discontinued. The direct replacement is the SAI50BX155S. It is dimensionally interchangeable per ISO 15552, retaining the same 50 mm bore, 155 mm stroke, G1/4 port, and mounting interface.
This double-acting cylinder has a G1/4 port. It delivers 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, and a theoretical maximum force of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX155S
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX155S replacement — usually within 7-8 hours.