The hydraulic tube is cylinder-like shaped tubing device that when attach to hydraulic systems, allow for the passage of fluids within and among components. The tube standard specifies dimensions for cold drawn finishing and seamless precision steel tubes. Cold drawn process provides the tube with close dimensional tolerances, increase material strength and enhanced machinability. Therefore, hydraulic tubes are suitable in high performance piping system application.

 They typically have a length of approximately 6 meter long. To order tubes, user has to measure the tube outside diameter and inside diameter. Where the wall thickness is of significance, the tubes may ordered in terms of outside diameter and wall thickness or inside diameter and wall thickness.

There are two type of material grade, ST52.4 and ST37.4. ST52.4 is high tensile strength tube means it has higher permissible working pressures by reduced tube wall thickness, and leading to reduced system overall weight. Please refer to chemical composition for ST52.4 and ST37.4 tube material:

Tensile strength ranges for ST52.4 from 490 N/mm² to 630 N/mm², while the ranges for ST37.4 are from 340 N/mm² to 480 N/mm². Different steel grades lead to different yield strengths too. The minimum yield strength for ST52.4 is 355 MPa and while for ST37.4 is 235 MPa. However, if the steel tubes with a thickness that is smaller than 3.0MM and an outside diameter that is smaller than 30MM and, the minimum yield strength is 10 MPa lower.