The inner and outer walls of cold-drawn precision steel tubes have no oxide layer, withstand high pressure, no leakage, high precision, high smoothness, no deformation during cold bending, flat bell mouth without cracks, and rust-proof surface treatment. It is mainly used in mechanical structure, hydraulic equipment and pneumatic or hydraulic components of automobiles and motorcycles, such as cylinders or cylinders.


The basic process of cold drawing is: hot-rolled capillary; capillary inspection, grinding; capillary pickling; pickling after pickling; cold drawing on-line front straightening; pickling, lubrication; treatment;


Production needs attention to control:
1. Capillaries
The capillary wall thickness is uniform, and the inner and outer surface defects are few. It is equipped with external surface polishing and hole defect cleaning equipment.


2. Re-examine
Compared with common cold-drawn steel tubes, hot-rolled capillary pickling re-inspection process is increased in the production of cold-drawn precision steel tubes. The main purpose is to ensure that there are no defects such as folding and cracking on the outer surface of capillary tubes, excluding wrinkles on the inner surface and capillary defects such as dumplings.


3. Tools
Generally, cold-drawn precision steel pipe production tools require surface finish of Ra0.4 or more, dimensional accuracy of H3 or more, and hardness of HRC70 or more. At the same time, it is required that the phenomenon of sticking steel on the head or die should not occur during wire drawing.


4. Annealing
Annealing is a very important step in all cold-drawn pipe production. The quality of annealing affects not only the performance of steel pipe but also the removal of oxide scale. Cold-drawn precision steel tubes need to be equipped with non-oxidation bright annealing furnace equipment.


5. pickling
Fe2O3 and Fe3O4-based "black slag" are easily formed in the pickling process of refined acid steel pipes, and black spots on the surface are formed in subsequent production. Fe2O3 and Fe3O4 are soluble in hydrochloric acid, in order to prevent the formation of black spots by adding 5-10g/l of NaCl into the acid pool.


6. Lubrication
It should be used as lubricant lubricant. This lubrication is significantly different from phosphating plus lubrication (saponification). The pulled iron pipe shows the true nature of the iron matrix. It has both high gloss and cold rolled appearance.