What are the ways to improve the quality of cold drawn seamless pipes?

What are the ways to improve the quality of cold drawn seamless pipes?

1. Improve the heating process

If the heating temperature is too high or the heating time is too long, it will cause the zinc ash to adhere to the surface layer of the cold-drawn seamless tube blank substrate, which is difficult to eliminate. In order to prevent the unclean phosphorus removal caused by heating, under the standard of the production process, the heating time of the billet is improved and adjusted by steel grades and specifications.

2. Detailed phosphorus removal process

Four times of phosphorus removal are carried out in the rough rolling process to ensure that the first zinc ash is removed neatly. In the fine rolling link, the frequency of fine phosphorus removal is increased according to the thickness of the cold-drawn seamless pipe. The cold rolling of 20-30mm thick specifications should increase the fine phosphorus removal at least once, and the thin and thick specifications above 30mm need to increase the frequency. In addition, it should be raised at least once before rolling, so that the total frequency of phosphorus removal in the rolling process is not less than the requirement, so as to ensure the actual effect of phosphorus removal.

3. Laminar flow in the middle of refrigeration

The laminar flow refrigeration processing technology of the intermediate billet is carried out. After rolling, the thick steel plate has a good shape, and the surface layer after laminar flow refrigeration is gray-green and high-density, and the surface quality is improved.

4. Increase the length of the billet

The extension design plan is implemented for the first and last raw materials, and one piece of agreement material is changed at the beginning and the end of the special-shaped steel plate.

5. Improve the production process

Improve the cold rolling operation level. Basically, the flat rolling process can be selected for cold rolling for different thin and thick specifications. In this way, the cold rolling time is reduced, the air oxidation time in the high temperature section is reduced, and the surface quality of the cold drawn seamless pipe is improved.

6. Adjust the temperature of the unwinding furnace

Under the condition that the unwinding standard is reached, the temperature of the unwinding furnace is moderately reduced, the steel grades, specifications and thicknesses of the rolled products and the total width of the cross section are integrated, and the temperature of the unwinding furnace is optimized and adjusted to reduce the defects caused by the loops of the wire rope drum. resulting frequency.

7. Raise the finish rolling temperature

Under the premise of ensuring the characteristics of cold-drawn seamless pipes, the final rolling temperature is moderately increased to improve the plastic deformation of the surface zinc ash.