Seamless precision steel pipe is used in hydraulic & pneumatic cylinder ,automobile and other mechanical device .Feature: high precision and high brightness, the inner and outer surface of the tubes have high cleanness without oxid, mechanical properties of the final tubes also come out excellent, promising no leakage under high pressure, no deformation after cold-bent and no cracks when flaring and flattening, ensuring the efficient operation in all service.

Standard: DIN2391 part 2 , DIN EN10305-1, DIN17175 etc;
Material: ST35,ST45,ST52.
Manufacturing method: cold-rolled / cold-drawn
Delivery condition: BK,BKS,SR,GBK,NBK.

Chemical composition of precision seamless steel pipe:

Cold-finished/hard(cold-finished as-drawn) BK: No heat treatment after the last cold-forming process. The tubes therefore have only low deformability.

Cold-finished/soft(lightly cold-worked)  BKW: After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits.

Annealed GBK: After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum.

Normalized NBK: The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum.