This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the direct replacement SAI50BX400, 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 SI50BX400
The AirTAC Airtac SI50 Standard Cylinder SI50BX400 is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 400mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the direct replacement is the SAI50BX400, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke400 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → SAI50BX400
- 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 SI50BX400
The AirTAC SI50BX400 is a discontinued double-acting ISO 15552 profile cylinder with a 50mm bore, 400mm stroke, and SUS304 stainless steel rod. It delivers 982 N push and 825 N pull at 0.5 MPa. AirTAC replaced this legacy unit with the SAI50BX400, a direct upgrade retaining the exact ISO 15552 mounting interface, G1/4 port, and 200 kgf max force.
The SAI upgrade features a modernized piston seal with two Y-shaped one-way elements for low start-up pressure and extended life. Because this specific SKU lacks a magnet (-S), it cannot accept position sensors.
Airtac SI50 Standard Cylinder SI50BX400 Technical Specifications
| Model | Airtac SI50 Standard Cylinder SI50BX400 |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | SAI50BX400 |
| Bore size | Ø50 mm |
| Stroke | 400 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 SAI50BX400 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 SAI50BX400 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 SI50BX400
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×400 | 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 SI50BX400 Is Used
Stainless Rod Diverter
Ideal for pushing packages on a line where the SUS304 rod resists moisture, utilizing the 982 N push force over the 400mm travel.
Long Stroke Press
Drives material plungers or forming pads down a 400mm path, relying on adjustable end cushions to decelerate the load smoothly.
Replacing the Airtac SI50 Standard Cylinder SI50BX400 with the SAI50BX400
To replace the SI50BX400, order the SAI50BX400. Verify your ISO 15552 mounting accessory (LB, FA, TC, etc.), the G1/4 air port, and the M16x1.5 rod thread. Since this SKU has no magnet, it cannot support legacy CS1-B/DS1-B switches; if sensing is needed, specify an SAI50X400S. Sizing options: dropping to a 40mm bore yields 628 N push at 0.5 MPa, while stepping up to 63mm provides 1559 N. At 400mm stroke, prevent rod bending by using an external guide to absorb side loads. Note that a standard cylinder drifts on air loss; for load holding, use an external pilot check valve or explore the SAIL/BSAI lock variants.
Replacement checklist
- ✓ Same ISO 15552 interface → SAI50BX400
- ✓ 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 SI50BX400 FAQ
Yes, the SI50BX400 is discontinued. The direct replacement is the SAI50BX400. It shares the identical ISO 15552 mounting interface, 50mm bore, 400mm stroke, G1/4 port, and output force, fitting directly into existing fixtures.
This double-acting cylinder features a G1/4 air port and an M16x1.5 rod thread. It delivers 982 N push and 825 N pull at 0.5 MPa, 1374 N push at 0.7 MPa, 1767 N push at 0.9 MPa, and a theoretical maximum of 200 kgf at 1.0 MPa.
Related AirTAC SAI Cylinders
Request a Quote for the SAI50BX400
Send us the quantity and destination. We confirm price, stock and lead time on the SAI50BX400 replacement — usually within 7-8 hours.