For high-pressure hydraulic cylinders, seamless steel pipes such as ST52 (E355), SAE 4140 (42CrMo), 37Mn, and 34CrMo4 are widely used, adhering to standards like DIN 2391, ASTM A519, and GB 18248. These grades offer the necessary strength, toughness, and precision to ensure safety and performance under extreme pressures. Selection depends on specific pressure requirements, environmental conditions, and manufacturing processes like honing or heat treatment.






























