JPS61201714A - Method for adding alloy - Google Patents

Abstract

PURPOSE:To add a high vapor pressure material at a high yield so as to comply with a target value by putting the high vapor pressure material into a porous refractory vessel, evaporating the material by the heat of a molten steel and adding the vapor thereof through the pores of the vessel into the molten steel. CONSTITUTION:The air permeable porous refractory vessel 4 connected with a refractory pipe 3 is immersed into the molten steel 2 contained in the vessel 1 for the molten steel. The high vapor pressure material 5 such as powder and granular metallic Ca is put through the pipe 3 into the vessel 4 and the aperture at the top end of the pipe 3 is closed. The material 5 in the vessel 4 is evaporated by the heat of the molten steel 2 and is discharged through the pores of the vessel 4 into the molten steel 2. The addition of the material 5 into the molten steel 2 at a high yield is made possible by the above-mentioned method. Since the generation of smoking and boiling, etc., is obviated, the working environment is satisfactorily maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to an alloy addition method used for adding high vapor pressure substances to molten steel with good yield. For example, Ca-treated steel, Ca-containing steel, Pb-containing steel. When melting steel such as Te, Bi, Se steel, M o , W steel, etc., substances that have a strong tendency to vaporize at the temperature of the molten steel, such as Ca, are used during the steelmaking process. It may be necessary to add high vapor pressure substances such as PbO, Te, Bi, Ss, MoO3, WO3, etc. whose boiling point is below the molten steel temperature. Conventionally, when such high vapor pressure substances are added to molten steel, they are added in a solid state.For example, iron liquid 1ica wire is used, powder of the high vapor pressure substance is injected,
The method used is to wrap it in the shape of a bullet and throw it into molten steel. (Problems to be Solved by the Invention) However, in such conventional alloy addition methods, the above-mentioned high vapor pressure substance is added in a solid state. (1) Evaporation occurs before high vapor pressure substances are dissolved in molten steel, resulting in a significantly lower yield. (2) When high vapor pressure substances are added to molten steel, smoke is generated, which worsens the working environment. (3) High vapor pressure substances vaporize rapidly within the molten steel, causing severe boiling, which is dangerous for work. (4) It is difficult to use it as a target component due to poor yield. There were problems such as. This invention was made by focusing on the conventional problems as described above, and it is possible to add a high vapor pressure substance to molten steel with a high yield, and it is possible to easily add a substance to a target value. It is an object of the present invention to provide a method for adding alloys that can be carried out without causing deterioration of the working environment due to smoke generation, boiling, etc. [Structure of the Invention] This invention provides the following features when adding a high vapor pressure substance to molten steel:
The high vapor pressure substance is placed in a porous refractory container and vaporized by the heat of the molten steel, and is added to the molten steel through a vent hole in the porous refractory container. . In the alloy addition method according to the present invention, for example, as shown in FIG. After putting the high vapor pressure substance 5 in the form of powder into the container, the upper end opening of the refractory pipe 3 is closed with a plug or the like, and the high vapor pressure substance 5 in the refractory container 4 is vaporized by the heat of the molten steel 2.
The high vapor pressure substance 5 is added by flowing into the molten steel 2 through a vent in the refractory container 4 . In another embodiment, a powdery high vapor pressure substance 5 is added to the refractory container 4 using a carrier gas such as Ar gas.
Alternatively, the high vapor pressure substance 5 in the refractory container 4 can be vaporized by the heat of the molten steel 2 and flowed into the molten steel 2. Furthermore, in another embodiment, as shown in FIG. 2, the molten steel 2 placed in the molten steel container 1 is supported by a refractory support member 6, and a powdery high vapor pressure substance 5 is contained inside the molten steel 2. The porous refractory container 4 containing the refractory material is immersed, and the high vapor pressure substance 5 in the refractory container 4 is vaporized by the heat of the molten steel 2, and the molten steel 2 is passed through the ventilation hole of the refractory container 4. It is also possible to add the high vapor pressure substance 5 by flowing it into the tank. (Example 1) This example shows a component of 345C (C:
0.42-0.48 wt-1.%j, Si: 0, 15-0, 35 wt%,
Mn: “0゛60-0.90% by weight, P: 0.
0.030% by weight or less, S: 0.035% by weight or less), and as shown in FIG. Porous refractory container 4 made from CaO-based refractory
A high vapor pressure substance 5 made of granular metal Ca is put into the refractory container 4 through the refractory pipe 3, and the container is closed with a stopper, and the metal Ca vaporized by the heat of the molten steel 2 is transferred to the refractory. The molten steel 2 is caused to flow out from the vent hole of the container 4 into the molten steel 2.
The Ca content therein was set to 0.0020% by weight. As a result, the Ca addition yield to achieve the above Ca content was approximately 45%. (Comparative Example 1) When tapping a molten steel container containing molten steel with a composition of S45C at an angle, an iron-coated Ca wire was added to reduce C in the molten steel.
The a content was set to 0.0020% by weight. As a result, the Ca addition yield to achieve the above Ca content was approximately 25%. (Example 2) A porous refractory container 4 made from an MgO-based refractory was immersed in molten steel 2 made of 345C placed in a molten steel container 1 in the same manner as in Example 1, and a refractory pipe 3 A high vapor pressure substance 5 made of powdered metal Te is fed into the refractory container 4 together with Ar gas, and the metal Te vaporized by the heat of the molten steel 2 is poured into the molten steel 2 through the vent hole of the refractory container 4. The Te content in the molten steel 2 was made to be 0.05% by weight. As a result, the Te addition yield to achieve the above Te content was approximately 65%. (Comparative Example 2) When tapping a molten steel container containing molten steel having a composition of 345C at an angle, metallic Te particles were added so that the Te content in the molten steel was 0.05% by weight. As a result, the yield of Te addition to achieve the above Te content was approximately 50%. (Example 3) As shown in FIG. 2, in the molten steel 2 made of 345C placed in the molten steel container 1, a porous steel made from an MgO-based refractory and containing powdered PbO was placed inside the molten steel container 1. Refractory container 4
was immersed in the molten steel 2, and the PbO vaporized by the heat of the molten steel 2 was allowed to flow out into the molten steel 2 from the vent hole of the refractory container 4, so that the Pb content in the molten steel 2 was 0.18 weight. As a result, the yield of PbO addition to achieve the above Pb content was approximately 85%. (Comparative Example 3) When tapping a molten steel container containing molten steel with a composition of 345C at an angle, Pb0 grains were added to reduce the Pb content in the molten steel to 0.
．． The content was adjusted to 18% by weight. As a result, the yield of PbO addition to achieve the above Pb content was approximately 60%. [Effect of the Invention J As explained above, according to the present invention, when adding a high vapor pressure substance to molten steel, the high vapor pressure substance is placed in a porous refractory container and is heated by the heat of the molten steel. Since it is vaporized and added to the molten steel through the vent hole of the porous refractory container, high vapor pressure substances such as Ca, PbO, Te, Bi, Se, MoO3 are added to the molten steel.
゜It is possible to add WO2 etc. with a high yield, and it is easy to add to the target value, and it maintains a good working environment because it does not cause smoke or boiling as in the case of conventional methods. Ca-treated steel,
Ca-containing steel, Pb-containing steel, Te. The very excellent effect that steels such as Bi, Se steel, Mo-containing steel, and W steel can be produced at low cost is brought about.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional explanatory views showing the procedure for adding alloys in each embodiment of the present invention. 1... Molten steel container, 2... Molten steel, 4... Porous refractory capacity, 5... High vapor pressure substance. Patent applicant Daido Steel Co., Ltd. Representative Patent Attorney Yutaka Oshio Figure 1 Figure 2

Claims (2)

[Claims] (1) When adding a high vapor pressure substance to molten steel, the high vapor pressure substance is placed in a porous refractory container, vaporized by the heat of the molten steel, and then added through the vents of the porous refractory container. A method for adding an alloy, comprising adding the alloy by flowing into the molten steel. (2) The method for adding an alloy according to claim (1), wherein the porous refractory container is made of a material containing the same component or a material having the same component system as the high vapor pressure substance.