42CrMo4

The Unique Demands of Agricultural Hydraulic Cylinders Agricultural equipment uses large hydraulic cylinders for tractors, combines, and loaders. A typical cylinder might have a 150mm bore through 2 meters of barrel. BTA drilling is the standard method for these large diameters because single-lip gun drills cannot handle the material removal rate required for production efficiency. I have set up BTA drilling cells for three different agricultural equipment manufacturers, and each one had slightly different requirements based on their cylinder designs. ...

The Nature of Mining Cylinder Work Underground mining equipment uses heavy-duty hydraulic cylinders for roof supports, boom arms, and drilling rigs. These cylinders are built tough because the working conditions are harsh. I have drilled cylinders for roof support jacks that operate at 300 bar hydraulic pressure and see continuous duty cycles for years without replacement. The bore diameter is typically 100-250mm through 1-3 meters of barrel. I use BTA drilling with cutting speed at 60-80 m/min and feed at 0.12-0.18 mm/rev. The material is usually high-strength steel like 42CrMo4. This material has a tensile strength of 900-1100 MPa and machines well with carbide tooling. The challenge is that 42CrMo4 work-hardens if the feed drops below 0.08 mm/rev, so I keep the feed consistent through the entire bore. ...