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cold-drawn precision seamless steel pipes

Company News

cold-drawn precision seamless steel pipes
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Precautions and control points for the production of cold-drawn precision seamless steel pipes

Date:2022-03-22View:472Tags:cold-drawn precision seamless steel pipes
Cold-drawn precision seamless steel pipe has the characteristics of no oxide layer on the inner and outer walls, no leakage under high pressure, high precision, high finish, no deformation after cold bending, no cracks in flaring and flattening, and anti-rust treatment on the surface. It is mainly used for mechanical structures. , hydraulic equipment and pneumatic or hydraulic components of automobiles and motorcycles, such as cylinders or oil cylinders. The basic production process of cold drawn precision seamless steel pipe is:
     

Hot-rolled capillary —> capillary inspection and grinding —> capillary pickling —> re-inspection after capillary pickling —> cold drawing —> straightening before fine drawing —> pickling and lubrication —> fine drawing —> before finished product Processing -> Warehousing.


precision seamless steel pipes


Production requires attention to control:
1. Capillary
The capillary wall thickness should be uniform, and the inner and outer surface defects should be less; the outer surface polishing and inner hole defect cleaning equipment should be equipped.

2. Recheck
Compared with ordinary cold-drawn steel pipes, the production of cold-drawn precision seamless pipes adds a pickling re-inspection process for hot-rolled capillary tubes, mainly to ensure that the outer surface of the capillary tube is free from defects such as folds and cracks, and to eliminate folds and serious scribing on the inner surface. , pitted surface and other defects of the capillary.

3. Tools
Generally, the surface finish of the tools used in the production of cold-drawn precision seamless steel pipes is required to be above Ra0.4, the dimensional accuracy is above H3, and the hardness is required to be above HRC70. At the same time, it is required that no plug or die sticking to steel occurs during the drawing process.

4. Annealing
Annealing is a very important process in the production of all cold drawn pipes. The quality of annealing affects both the performance of the steel pipe and the removal of scale. Cold-drawn precision steel pipes need to be equipped with non-oxidative bright annealing furnace equipment.

5. Pickling
Precision seamless steel pipes are prone to form "black slag" mainly composed of Fe2O3 and Fe3O4 during the sulfuric acid pickling process, and form black spots on the surface in subsequent production. Fe2O3 and Fe3O4 are easily soluble in hydrochloric acid. To prevent the formation of black spots, add 5-10g/l NaCl to the acid pool.

6. Lubrication
Resin should be used as lubricant, which is obviously different from phosphating and lubricating (saponification). It has a beautiful appearance and luster like a cold-rolled tube.
  
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