This model is discontinued
AirTAC has phased out the SI series. You can still order this code here: we ship the drop-in replacement B04-SAIJ50X250-50S, 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 B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S
The AirTAC Airtac B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S is a double-acting ISO 15552 (orig. ISO 6431) profile-barrel cylinder with a Ø50mm bore and 250mm stroke, G1/4 air ports and adjustable end cushioning. This model is discontinued — the drop-in replacement is the B04-SAIJ50X250-50S, which matches its ISO interface, bore, stroke, force and mounting.
- BoreØ50 mm
- Stroke250 mm
- Port sizeG1/4
- Acting typeDouble acting
- Rod threadM16×1.5
- StatusDiscontinued → B04-SAIJ50X250-50S
- 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 B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S
The AirTAC B04-SIJ50X250-50S is a double-acting single-rod ISO 15552 adjustable-stroke cylinder. The B04- prefix marks this as a construction-machinery dedicated variant, mechanically identical to the base SIJ50X250-50S. It features a 50mm bore, G1/4 port, M16x1.5 rod thread, and a nominal 250mm stroke. An external stop screw lets you trim the extend stroke by up to 50mm on-site, giving a usable extend range of 200-250mm. This stop sets the end position but is not a load lock. This SIJ model is discontinued; the exact drop-in replacement is the SAIJ50X250-50S, retaining the same ISO 15552 interface, bore, stroke, force, and mounting.
Force output matches the standard single-rod SAI family: push 982N and pull 825N at 0.5MPa, up to 1767N push at 0.9MPa. The SAIJ replacement uses an upgraded piston seal with two Y-shaped one-way elements for low start-up pressure and long life. For sizing, a safe working load is roughly 589N (about 60% of the 982N push at 0.5MPa), translating to a 50kg vertical lift with a 2:1 margin. The -S suffix denotes a built-in piston magnet for legacy CS1-B/DS1-B switches. A plain cylinder drifts on air loss; for held loads use an external rod lock or the SAIL/BSAI lock variant.
Airtac B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S Technical Specifications
| Model | Airtac B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S |
|---|---|
| Series | SI ISO 15552 profile cylinder (discontinued) |
| Replacement | B04-SAIJ50X250-50S |
| Bore size | Ø50 mm |
| Stroke | 250 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 B04-SAIJ50X250-50S 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 B04-SAIJ50X250-50S produces the same force from the same bore — a true drop-in on output. Actual usable force is lower than theoretical; size with a margin.
Model Code: Airtac B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S
| SI | ISO 15552 profile-barrel cylinder (discontinued). |
|---|---|
| 50 | Bore size in mm. |
| ×250 | 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 B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S Is Used
Excavator Cover Positioning
Field-tunes the extend stroke on heavy-equipment access panels, allowing on-site adjustment of the opening reach without swapping cylinders.
Crane Component Actuation
Provides adjustable end-positioning for locking mechanisms on construction-machinery booms, trimming the stroke precisely to match field-worn linkages.
Concrete Pump Valve Control
Allows on-site stroke trimming for diverter valves in harsh environments, dialing in the exact 200-250mm travel needed for flow routing.
Replacing the Airtac B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S with the B04-SAIJ50X250-50S
To replace the discontinued B04-SIJ50X250-50S, use the SAIJ50X250-50S drop-in. It preserves the 50mm bore, 250mm nominal stroke, 50mm adjust window, G1/4 port, and ISO 15552 mounting dimensions. When sizing both ways, the neighboring 40mm bore yields 879N push at 0.7MPa, while the 63mm bore yields 2182N push at 0.7MPa. Choose the 50mm adjust window if your field tuning requires trimming up to 50mm off the maximum 250mm extend stroke. Mounting options include FA, LB, and TC brackets. The -S magnet supports legacy CS1-B/DS1-B switches, while the SAIJ replacement uses current AirTAC switches. For strokes of 300mm or longer, verify side-load limits to prevent rod binding.
Replacement checklist
- ✓ Same ISO 15552 interface → B04-SAIJ50X250-50S
- ✓ Same bore / stroke / force
- ✓ Port/thread type (PT/G/NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Mounting reused (FA/FB/CA/CB/CR/LB/TC)
Airtac B04-SIJ Construction Machinery Special ISO Standard Cylinder B04-SIJ50X250-50S FAQ
Yes, the B04-SIJ50X250-50S is discontinued. The exact drop-in replacement is the SAIJ50X250-50S. The B04- prefix simply marks it as a construction-machinery dedicated variant; mechanically it is identical to the base SIJ50X250-50S. The SAIJ replacement shares the same ISO 15552 interface, 50mm bore, 250mm stroke, 50mm adjust window, and G1/4 port.
It is a double-acting single-rod cylinder with a 50mm bore and G1/4 port. Force ratings are: push 982N / pull 825N at 0.5MPa, push 1374N at 0.7MPa, push 1767N at 0.9MPa, and a theoretical max of 200kgf at 1.0MPa. The external stop screw provides a 50mm adjust window, allowing you to trim the extend stroke from the 250mm maximum down to 200mm on-site. The stop sets end position and is not a load lock.
Related AirTAC SAI Cylinders
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