Hydraulic steel tubes ST52.4 are tubes made in accordance to DIN 2391 / DIN 2445. ST52.4 is a high grade steel material, it can withstand higher working pressure with same tube OD size compare to ST37.4 material.
The finishing for grade ST52.4 tubes are in NBK finishing, which is normalized, phospated, and oiled inside and outside. Hydraulic tubes ST52.4 are measured by Outer Diameter (OD) and in varies tube thickness (THK). Difference of OD and tube thickness lead to different working pressure.