Notes of cold drawn precision steel pipe

Cold-drawn precision steel pipe with internal and external wall without oxidation layer, to withstand high pressure without leakage, high precision, high finish, cold bending is not deformed, flared flat no cracks, the surface has been anti-rust treatment, etc., mainly for mechanical structure , Hydraulic equipment and automotive motorcycles pneumatic or hydraulic components, such as cylinders or cylinders.

The basic process of cold drawing is: hot-rolled capillary; capillary inspection, grinding; capillary pickling; after pickling pickling; cold drawn; fine pull straight before the line; pickling, lubrication; Processing;

Production need to pay attention to control:
1, Capillary
Capillary wall thickness to be uniform, less inside and outside the surface defects; to configure the external surface polishing and hole defect cleaning equipment.

2, Re-examination
Compared with ordinary cold drawn steel pipe, cold drawn precision steel pipe production increased the hot-rolled capillary pickling re-inspection process, mainly to ensure that the outer surface of the capillary without folding, cracks and other defects, excluding the inner surface of the fold, Dumplings and other defects of the capillary.

3, Tools
General cold drawn precision steel pipe production tools used in the surface finish requirements Ra0.4 above, dimensional accuracy of H3 or more, hardness requirements above HRC70. At the same time require the drawing process can not appear head or die sticky steel phenomenon.

4, Annealing
Annealing is a very important step in the production of all the cold drawn tubes. The quality of the annealing affects both the performance of the steel pipe and the removal of the scale. Cold drawn precision steel pipe needs to be equipped with no oxidation bright annealing furnace equipment.

5, Pickling
Precision steel pipe in the acid pickling process is easy to form Fe2O3, Fe3O4-based "black slag", in the subsequent production of the formation of surface dark spots. Fe2O3, Fe3O4 soluble in hydrochloric acid, in order to prevent the formation of dark spots in the acid pool by adding 5-10g / l of NaCl.

6, Lubrication
Should be used as a lubricant lubricant, this lubrication and phosphating plus lubrication (saponification) compared to a significant difference, drawn out of the iron tube showing the true nature of the iron matrix, both high gloss and cold rolled like a beautiful appearance color.