JB/ZQ hydraulic cylinders for heavy metallurgical equipment are widely used in metallurgical industries, such as iron and steel smelters, vanadium and titanium smelters, precious metal smelters, and small metal smelters; they are also used in metallurgical machinery, heavy engineering, mining equipment, etc. This series of products has 13 kinds of cylinder diameters, 3 kinds of speed ratios, and 8 kinds of installation types, which can constitute 66 varieties. The oil port of the hydraulic cylinder with a cylinder diameter of Φ40～Φ200mm adopts fine thread, and the oil port of the hydraulic cylinder with a cylinder diameter of Φ220～Φ320mm adopts flange connection.