JPH01129920A - Oxygen lance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an oxygen lance that reduces base metal adhesion in converter steelmaking.

[Prior art] Conventionally, in converter blowing, the slag covering the molten metal expands greatly due to the large amount of CO gas generated at the peak of decarburization of the molten metal, resulting in a state of so-called slag forming, which causes the oxygen lance to is buried in this formed slag.

In this case, the slag is attached to the buried portion of the lance, and a large number of iron particles contained in the slag are attached to the lance together with the slag.

Furthermore, after the peak decarburization period has passed, the so-called oxygen-controlled blowing period in which the amount of oxygen supplied controls the decarburization rate, and the so-called carbon-controlled blowing period in which the carbon content in the steel bath controls the decarburization rate. The above-mentioned slag forming condition tends to subside as the blowing period progresses, but during this blowing period, the proportion of FeO in the slag increases, and this FeO is reduced to [C] in the steel bath. There is a risk that the bumping phenomenon of the CO gas will cause so-called spitting in which molten steel is scattered, and the molten steel will adhere to the lower part of the oxygen lance, solidify, and fuse to the copper tube that forms the outer cylinder of the oxygen lance. There is. If slag adheres, it can be easily peeled off and removed, but if the molten steel is fused, it is very difficult to remove it. This is called base metal adhesion, and when these overlap and grow,
The outside diameter of this part is unusually large, and since the oxygen lance is suspended through the opening of the exhaust gas hood, it rises,
It interferes with the descent of the furnace and becomes a serious hindrance to converter loss business.

To avoid this, when the metal adhesion occurs, the oxygen lance is replaced before it grows.

[Problems to be solved by the invention] However, replacing the oxygen lance due to metal adhesion shortens the life of the oxygen lance, and increasing the frequency of lance replacement leads to a decrease in work efficiency. , all of which increase production costs.

The present invention has been made in view of such circumstances, and
The purpose is to prevent metal adhesion and provide an oxygen lance.

[Means and effects for solving the problems] The oxygen lance of the present invention is an oxygen lance used in converter steelmaking, and is characterized in that the lower half of the outer cylinder of the lance is made of a copper tube.

Traditionally, copper tubes have been used for the outer cylinders of oxygen lances, but since this is made of copper tubes with high thermal conductivity as mentioned above, the molten steel adhering to the copper tubes, whose interior is water-cooled, is rapidly cooled. Even if it is attached, it is easily peeled off without being fused.

[Example code] The invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing an oxygen lance of the present invention and its related equipment. The oxygen lance 20 of the present invention has a triple tube structure, with the inner tube at the center serving as an oxygen passage, and the outer tube serving as a descending and ascending passage for cooling water. A ring 21 is provided near the center of the oxygen lance 20, an outer cylinder 22 below this ring is made of a copper tube, and an outer cylinder 25 above it is made of a copper tube. A copper oxygen nozzle 23 is attached to the tip of the oxygen lance.

The operation of the oxygen lance constructed as above will be explained. A steel bath 11 and slag 12 are charged into a converter 10, and oxygen blowing is performed by an oxygen jet 24 ejected from an oxygen nozzle 23 provided at the tip of an oxygen lance 20. The exhaust gas generated here is exhausted from the exhaust gas hood 13.

The exhaust gas hood 13 is provided with a through hole 14 through which the oxygen lance 20 passes and a hole cone 15 that seals between the through hole 14 and the lance 20.
The ring 21 attached to the lance 20
The hole cone 15 is supported as the lance 20 rises, and it is raised together with the lance 20.

When slag forming or spitting occurs in the oxygen blowing wire, molten steel is scattered from the steel bath 11 and deposited on the outside 1122 under the oxygen lance. Since the outer cylinder 22 is made of copper and is water-cooled from the inside, the attached molten steel is easily peeled off without being fused.

In addition, to give a specific numerical example of this example, converter 10
Capacity is 250T, outer diameter of oxygen lance is 400 am
, the length from the tip of the oxygen lance 20 to the ring 21 is 1
It is 1.5m.

[Effects of the Invention] According to the present invention, the lower half of the oxygen lance used in the oxygen blowing wire of the converter is made of a water-cooled copper tube, so that the oxygen lance is not blown away during blowing. Molten steel is not deposited on the outer cylinder, and base metal adhesion is prevented.

Therefore, the frequency of oxygen lance replacement is reduced and manufacturing costs are reduced.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the oxygen lance of the present invention and the surrounding converter-related equipment. 10... Converter, 11... Steel bath, 12... Slag,
13... Exhaust gas hood, 14... Penetration port, 15...
- Hole cone, 20...Oxygen lance, 21...Ring, 22.25...Outer cylinder, 23...Oxygen nozzle.

Claims (1)

[Claims] An oxygen lance used in converter steelmaking, characterized in that the lower half of the outer cylinder of the lance is made of a copper tube.