Full definition
Steel bar transmitting piston force to the exterior of the cylinder. Surface finish is critical for seal life: Ra 0.1-0.4 µm. Standard coatings: hard chrome electroplating (20-25 µm, HV 900-1100) or high-carbon chrome. REACH-compliant alternatives: HVOF (tungsten carbide), electroless nickel, ceramic coating (Al₂O₃). Steel grade: 42CrMo4 or 1.0503. Dimensional tolerance: f7-h8. Surface hardness: 58-62 HRC.