Precautions of Cold Drawn Precision Seamless Steel Pipe

Cold-drawn precision seamless steel pipe with no outer layer of oxide layer, high pressure without leakage, high precision, high finish, cold bending is not deformed, flared flat no cracks, the surface has been made for anti-rust treatment and other characteristics, mainly for mechanical structure, hydraulic equipment and automotive motorcycles pneumatic or hydraulic components, such as cylinders or cylinders.

Cold-drawn basic process is: hot-rolled capillary -> capillary inspection, grinding -> capillary pickling -> capillary pickling recheck -> cold drawing -> fine pull the road before straightening -> pickling, lubrication -> fine pull -> pre-finished product -> storage.

Production needs attention control:
1, Capillary
Tubular wall thickness to be uniform, less internal and external surface defects; to configure the outer surface of the hole polishing and cleaning equipment.

2, Re-examination
Compared with ordinary cold drawn steel pipe, cold drawn precision seamless pipe production increased hot pickling pickling process, mainly to ensure that the outer surface of the tube without folding, cracks and other defects, excluding the existence of the inner surface of the fold, a serious scribing , Pitted and other defects of the capillary.

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

4, Annealing
Annealing in all the cold drawn tube production is a very important process, the quality of the annealed both affect the performance of the steel tube also affect the removal of the oxide scale. Cold drawn precision steel tubes need to be equipped with non-oxidizing bright annealing furnace equipment.

5, Pickling
Precision seamless steel pipe in the pickling process is easy to form Fe2O3, Fe3O4-based "black slag" in the subsequent production 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
Resin should be used as a lubricant, this lubrication and phosphating plus lubrication (saponification) compared to a clear distinction, drawn out of the iron pipe showing the true nature of the iron, both high finish and cold-rolled tube-like appearance color.

Industrial control of the production of cold-drawn precision seamless steel pipe includes mold design, annealing, pickling, lubrication and other conditions control, at the same time should be in the capillary quality testing, renovation work. In addition, heat treatment is also very important.