1. Specifications & Capability
FUSHUN METAL forges the main working cylinder bodies of hydraulic presses in 42CrMo4 (1.7225) and 34CrMo4 (1.7220), 800-2000 mm in outside diameter. The cylinder is forged as a single piece, then bored and honed to the finished bore.
Forging the cylinder from a single piece eliminates the longitudinal weld of a rolled-and-welded cylinder, removing the weakest point of the pressure boundary.
| Grade | Standard | Outside Diameter |
|---|---|---|
| 42CrMo4 / 1.7225 | EN 10250-3 | 800-2000 mm |
| 34CrMo4 / 1.7220 | EN 10250-3 | 800-2000 mm |
2. Components & Service Conditions
The main working cylinder contains the hydraulic fluid that drives the press ram, holding the full working pressure on every stroke. Its wall is a thick pressure boundary, and the bore must be smooth and dimensionally accurate for the piston seals.
A rolled-and-welded cylinder has a longitudinal weld that is the weakest point under cyclic pressure; a forged cylinder removes that weld entirely. The quenched and tempered 42CrMo4 provides the strength for the wall thickness, and boring plus honing produces the surface finish and accuracy the piston seals require. Full-section ultrasonic testing confirms freedom from the internal defects that could fail under pressure.
3. Grade Equivalents – 42CrMo4 / 34CrMo4
| Designation | Standard | Notes |
|---|---|---|
| 42CrMo4 / 1.7225 | EN 10250-3 | Standard cylinder steel |
| 34CrMo4 / 1.7220 | EN 10250-3 | Lower-carbon option |
| AISI 4140 | SAE J404 | US equivalent of 42CrMo4 |
| 40Cr | GB/T 3077 | Reference only, not used in certification |
| Grade | C | Si | Mn | Cr | Mo |
|---|---|---|---|---|---|
| 42CrMo4 (1.7225) | 0.38-0.45 | 0.40 max | 0.60-0.90 | 0.90-1.20 | 0.15-0.30 |
| 34CrMo4 (1.7220) | 0.30-0.37 | 0.40 max | 0.60-0.90 | 0.90-1.20 | 0.15-0.30 |
The chromium and molybdenum give the hardenability for uniform strength through the thick cylinder wall.
4. Manufacturing Process
Forging. FUSHUN METAL forges the cylinder as a single piece on a 20/80 MN fast forging press, eliminating the longitudinal weld.
Heat treatment. The cylinder is quenched and tempered for the ordered strength.
Machining. The bore is drilled, bored and honed to the required diameter and surface finish.
Testing. Full-section UT, dimensional and pressure verification, with full traceability.
5. Standards & Certification
Press cylinders are supplied to EN 10250-3, with inspection certificates under EN 10204 3.1. FUSHUN METAL holds ISO 9001 and AS9120B certification.
Related forgings: press columns and press crossbeams.
6. Typical Applications
Main working cylinders
Cylinder bodies for hydraulic press main rams.
Return cylinders
Cylinders for press return strokes.
Extrusion presses
Cylinder bodies for metal extrusion presses.
Hydraulic machinery
Cylinders for heavy hydraulic machinery.
7. Inquiry Essentials
To quote your press cylinder, please provide the cylinder drawing, the bore diameter and wall thickness, and the working pressure.
