Matters needing attention in the production of cold drawn steel tubes

The cold drawn precision seamless steel pipe has the characteristics of no oxidation layer inside and outside, high pressure and no leakage, high precision, high smoothness, cold bending, flat surface and no crack. It is mainly used in mechanical structure, hydraulic equipment and pneumatic or hydraulic pressure components of motorcycles, such as cylinders or oil cylinders.

The basic process flow of cold drawing is: hot rolling pipe - > wool pipe inspection, repair grinding - > hair pipe acid washing - > hair tube acid washing after reinspection - > cold drawing - > fine drawing before straightening - > acid washing, lubrication - > fine pull - > finished product before finishing - > storage.

Production needs to be controlled.

1. The thickness of the capillary wall should be uniform and the defects of inside and outside surface should be few.

2.  Reexamination

Compared with ordinary cold drawn steel pipes, the production of cold drawn precision seamless tube has increased the process of pickling and reinspection of hot rolled pipe. It is mainly to ensure the defects of the outer surface of the capillary, such as no folding and crack, and eliminate the defects of the inner surface, such as folding, serious line, and facial defects.

3.  Tools

The surface smoothness of the tools used in the production of cold drawn precision seamless steel tubes is above Ra0.4, and the size accuracy is above H3, and the hardness is more than HRC70. At the same time, the phenomenon of sticking of the head or die can not occur in the drawing process.

4.  Annealing

Annealing is a very important procedure in the production of all cold drawn tubes. The quality of annealing affects not only the performance of steel pipes but also the removal of iron oxide scales. The cold drawn precision steel tubes need to be equipped with no oxidizing bright annealing furnace equipment.

5.  Pickling

The black slag, which is mainly composed of Fe2O3 and Fe3O4, is easily formed in the process of sulfuric acid pickling for precision seamless steel pipes, and surface black spots are formed in subsequent production. Fe2O3 and Fe3O4 are easily soluble in hydrochloric acid. In order to prevent the formation of black spots, 5-10g/l NaCl is added into the acid pool.

6.  Lubrication

The resin should be used as a lubricant. This lubrication is distinctly different from the phosphating and lubricating (saponification). The steel tube drawn out has the original color of the iron matrix, with both high finish and beautiful cold-rolled tube like color.

The industrial control of the production of cold drawn precision seamless steel pipe includes the control of mould design, annealing, acid washing, lubrication and so on. At the same time, we should do a good job in the quality inspection and repair of the capillary. RAY precision seamless steel tube company always insists on making better products for our customers, and strictly control every step.