Process points of cold drawing precision seamless pipe

Industrial control of cold drawn precision seamless steel pipe production includes condition control such as die design, annealing, pickling, lubrication, etc. At the same time, capillary quality inspection and maintenance work should also be carried out.

The production of cold-drawn precision seamless steel pipes requires attention to control:

1. Capillary: Pay attention to whether the thickness of the capillary wall is uniform. If the thickness of the capillary wall is found to be uneven, surface polishing must be done. In addition, whether the inside and outside of the capillary is flat and there are no bumps and defects. Once bumps or defects are found, they should be dealt with in time.

2. Re-inspection: For the re-inspection of the capillary, the main work of the re-inspection is to ensure that there are no cracks and defects on the outside of the capillary.Be sure to remove the pockmarks and folds in the capillary.

3. Tools: It is a requirement for tools. Generally, the use of cold drawing is that the surface finish of the tool is relatively high. Only when the surface finish of the tool is high, the smoothness of the cold drawn steel pipe will be high.In addition, the dimensional accuracy and hardness requirements of the mold are also relatively high, so it is also very important for us to choose a good abrasive tool in the production, and the phenomenon that the abrasive tool sticks to the steel must not occur.

4. Annealing: Annealing is a very important process in the production of all cold drawn tubes. The quality of annealing affects 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: During the sulfuric acid pickling process, the precision seamless steel pipe is prone to form “black slag” mainly composed of Fe2O3 and Fe3O4, and form black spots on the surface in the subsequent production. Fe2O3 and Fe3O4 are easily soluble in hydrochloric acid. To prevent the formation of black spots, add 5-10 g/l of NaCl to the acid pool.

6. Lubrication: Lubricating resin should be selected as lubricant. This lubrication is distinctly different from phosphating plus lubrication (saponification). Drawn steel pipes show the original color of the iron matrix, with a high finish and aesthetic appearance, just like cold rolled pipes.