What should be paid attention to when producing seamless pipes?

Seamless pipes are made of steel ingots or solid pipe blanks through perforation into capillary pipes, which are then hot-rolled, cold-rolled or cold-drawn. It occupies an important position in my country's steel pipe industry. So what should be paid attention to when producing seamless pipes?

1) Pay attention to whether the thickness of the embryo pipe wall is uniform. If it is found that the wall thickness of the embryo pipe is uneven, the surface polishing treatment must be carried out. In addition, pay attention to whether the inside and outside of the embryo tube are flat and there are no bumps and defects. Once the bumps or defects are found, they should be dealt with in time.

2) The re-inspection of the embryo pipe. The main work of the re-inspection is to ensure that there are no cracks and defects on the outside of the capillary pipe, check these problems in the capillary pipe and make corresponding elimination instructions, and be sure to remove the pockmarked surface and folding phenomenon in the capillary pipe.

3) Requirements for tools. Generally, the tools used for cold drawing have relatively high requirements on the surface finish. Only when the surface finish of the tool is high, the finish of the cold drawn seamless pipe will be high; in addition, the dimensional accuracy and hardness of the mold are also relatively high. Therefore, 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 seamless pipes. The quality of annealing affects both the performance of the steel pipe and the removal of oxide scale on the surface of the steel pipe.

5) Pickling. In the process of sulfuric acid pickling, the seamless pipe is prone to form "black slag" mainly composed of Fe2O3 and Fe3O4, and it is easy to 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 5-10g/l NaCl to the acid pool.

6) Lubrication. Resin is used as lubricant as much as possible. This kind of lubrication is obviously different from phosphating and lubrication (saponification). The cold drawn seamless pipe presents the true color of iron matrix, and has the beautiful appearance and luster of cold-rolled pipe. And high finish. The industrial control of the production of seamless pipes includes the control of mold design, pickling, lubrication, annealing and other conditions, and at the same time, work should be done in the quality inspection and refurbishment of hot rolled pipes.

The production process of seamless pipe can be divided into two types: cold-drawn and hot-rolled. Hot-rolled steel pipe is delivered in hot-rolled state or heat-treated state, and cold-rolled steel pipe is delivered in heat-treated state. Due to the small width-to-thickness ratio of the steel plate, the accuracy of the hot-rolled steel pipe dimension requirements are relatively low, and not prone to plate shape problems.

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Precautions when forming seamless steel pipes"

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