RU2635489C1 - Method for preparing blast furnace air tuyere for operation - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: cleaning of outer sleeve and blasting part by the metal shot, spraying of the aluminium-containing gas-thermal coating on them, installation of a heat-insulating insert in the inner sleeve with an air gap therebetween and heat treatment. Heat treatment of the tuyere with the coating is carried out before the insert installation. After the insert is installed, it is pressed by ring on the flange side, which is welded to the inner sleeve.

EFFECT: extension of insert service life.

1 dwg

Description

The invention relates to the field of metallurgy and can be used in preparation for the operation of air tuyeres of blast furnaces.

A known method of preparing for operation the air lance of a blast furnace, including cleaning the outer cup and the back of the metal shot, spraying them with an aluminum-containing gas-thermal coating, installing heat insulation in the inner cup and heat treatment (RF patent No. 21215043, C21B 7/16, 12/11/01).

In this method, as a thermal insulation, a layer of refractory lining is formed tightly adjacent to the inner glass. Such a lining may be destroyed when the lance is installed in the furnace, as experiencing shock loading, or during operation due to various thermal expansion of the lining and the inner glass.

The closest in technical essence to the proposed invention is a method of preparing for operation an air lance of a blast furnace, in which a ceramic insert is used as thermal insulation, installed in an inner glass with an air gap between them (RF patent No. 144987, С21В 7/16, 15.04. fourteen).

The disadvantage of this technical solution is that it lacks information on the procedure for establishing the insert and heat treatment of the lance. The insert may be destroyed at the heat treatment stage or during operation due to oscillatory movements.

The technical result of the invention is to increase the life of the insert.

The technical result is achieved by the fact that in the method of preparing for operation the air lance of the blast furnace, including cleaning the outer cup and the back of the metal shot, spraying them with an aluminum-containing gas-thermal coating, installing a heat-insulating insert in the inner cup with an air gap between them and heat treatment, heat treatment of the lance with the coating is carried out before the insert is installed, and after the insert is installed, it is pressed by a ring from the flange side, which is welded to the inner glass.

The heat treatment of the coated lance is carried out before the insert is installed, in order to exclude the possibility of destruction of the insert at the lance heat treatment stage. After the insert is installed, it is pressed by the ring on the flange side, which is welded to the inner cup to prevent premature destruction of the insert due to its fluctuations during operation of the lance. These features together provide the achievement of a technical result.

The method is as follows.

After cleaning the outer cup (1) (Fig. 1) and the tuyere part (2) of the tuyeres with an aluminum shot, an aluminum-containing gas-thermal coating (3) is sprayed, heat treatment of the tuyere with a coating is carried out, and a heat-insulating insert (4) is installed in the inner cup (5) with air gap (6) between them. Next, the insert (4) is pressed by the ring (7) from the side of the flange (8), which is welded to the inner cup (5). After that, the flange (8) is welded.

Example

The outer cup and the back of the lance were cleaned with steel chipped shot. An aluminum coating was sprayed onto the prepared surface by the method of electric arc metallization. Next, the lance was heat treated — diffusion annealing. After that, a ceramic insert with an air gap between them was installed in the inner glass. At one end, the insert rested on the back of the body, the other end was pressed with a steel ring, which was welded to the inner glass. Next, the flange was welded.

A batch of experimental tuyeres made by the proposed method was installed on a blast furnace. They were compared with serial tuyeres in which the insert was not pressed by a ring. For comparison, experimental and serial tuyeres with approximately the same service life after replacement were selected. The inserts on the experimental tuyeres remained intact or had small cracks. The inserts on serial tuyeres were in large cracks with breakaway parts or were completely destroyed.

A batch of tuyeres was also made in which the insert was installed before heat treatment. After heat treatment, part of the inserts had cracks.

Therefore, heat treatment of the coated tuyere prior to installation of the insert and pressing of the insert by the ring on the flange side increase the life of the insert.

Claims (1)

The method of preparation for operation of the air tuyere of the blast furnace, including cleaning the outer cup and the back of the metal shot, spraying them with an aluminum-containing gas-thermal coating, installing a heat insulating insert in the inner cup with an air gap between them and heat treatment, characterized in that the heat treatment of the tuyere with a coating is carried out before insert installation, and after installing the insert on the flange side, press it with a ring that is welded to the inner cup.

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