JPH11181512A - Steelmaking method and steelmaking equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently execute the dephosphorizing refining and decarburizing refining in the same converter. SOLUTION: This method is for steelmaking using a converter, in which firstly, the dephosphorizing reaction is mainly executed in the converter, and after completing the dephosphorizing refining, molten iron in the converter is discharged into a molten iron receiving ladle and slag in the converter after discharging the molten iron, is discharged into a discharging slag pan, and the molten iron discharged into the molten iron receiving ladle, is again charged into the converter after discharging the slag, and the decarburizing refining is mainly executed, and after completing the decarburizing refining, the molten steel in the converter is discharged into a steel receiving ladle and the molten iron in the following charge is charged under condition of remaining the slag in the converter after discharging the molten steel, and the dephosphorizing refining is mainly executed. In the steel-making equipment, in which after dephosphorizing refining in the converter, the molten iron after refining, is once discharged to the outside of the converter and charged into the same converter to execute the decarburizing refining, the ladle for receiving the molten steel after decarburizing refining and a ladle truck, and an exclusive ladle for receiving the molten iron after dephosphorizing refining and an exclusive ladle truck separated from the above ladle and the ladle carriage, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steelmaking method and a steelmaking facility for efficiently performing de-P refining and decarburization refining in a converter.

[0002]

2. Description of the Related Art Conventionally, hot metal pretreatment (mainly de-P refining) has been carried out using a torpedo car. Recently, however, attention has been paid to a technique for performing hot metal pretreatment in a converter for the purpose of consolidating the equipment. Conventionally, there has been a method of performing de-P refining and decarburizing refining with one converter (for example, "Nishiyama Memorial Lecture" No. 54, 55, Iron and Steel Institute of Japan, P130). However, in this method, after the de-P refining, the molten metal is discharged, the slag is discharged, and then the molten metal is recharged, decarburized and refined, and the molten steel and the slag are discharged again. The large heat loss and the time required for the waste work led to a decrease in productivity due to an increase in the cycle time in the converter process.

On the other hand, as disclosed in, for example, JP-A-6-41624, there is a technique in which a degassing furnace and a decarburizing furnace are separately provided as dedicated furnaces, and degassing and decarburization are performed using two converters, respectively. . According to this method, since the de-P refining furnace and the decarburizing refining furnace are separated from each other, there is no mixing of the de-P slag into the decarburizing refining, so that slag can be recycled without adverse effects such as re-P during decarburizing refining. It is.

[0004]

However, even in this method, the decarburized slag is once discharged out of the furnace and charged into the degassing furnace, so that heat loss occurs. Since the slag once discharged out of the pan is charged into the converter again, a container for safe transport, or a work process such as decooling of the slag or crushing for charging into the converter is required. That time is also required. In addition, the de-P decarburization process is a series of steps in two converters, and usually, the de-P refining time is shorter than the decarburization refining time, and a vacant time is generated on the de-P refining side, further increasing productivity. Lower.

[0005] Further, since two operation converters are required, equipment is restricted.

[0006]

SUMMARY OF THE INVENTION The present invention advantageously solves the above problems, and its gist is the following steel making method and steel making apparatus as described in the claims. [1] The following processes: 1) De-P refining is mainly performed in the converter, 2) After the completion of the de-P refining, the molten metal in the converter is discharged to a receiving pan, and 3) Next, the molten metal is discharged. The slag in the converter is discharged into a waste pan, 4) the molten metal discharged into the receiving pan in the above step 2) is again charged into the converter after discharging the slag, and 5) mainly decarburization. Refining is performed. 6) After the decarburization refining is completed, the molten steel in the converter is discharged to a steel receiving pan. A steelmaking method comprising:

[2] After de-P refining in the converter, the molten metal after the refining is once discharged out of the converters, and then re-charged into the converter to perform decarburization refining. Pots and pan trucks that receive molten steel after refining, and separate from the pots and pan carts
A steelmaking facility comprising: a dedicated pot for receiving molten metal after refining;

[3] The shape of the dedicated pot for receiving the molten metal after the de-P refining is such that the received molten metal can be charged into the converter, and the dedicated pot is placed in the converter from below the furnace. [2] The steelmaking facility according to [2], further comprising a converter work floor having an opening for moving to a position where the steel is charged. [4] When the dedicated pan for receiving the molten metal after the de-P refining is mounted on the dedicated pan carriage, the upper end of the dedicated pan is lower than the lower end of the converter bodies when the converter stands upright. [2] or [3].

A feature of the present invention is that decarbonizing and decarburizing refining are performed in the same converter, and at that time, decarburized slag is left in the converters to efficiently use steel for decharging the next charge. Method and steelmaking equipment.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, the refining method of the present invention will be described. In the refining method of the present invention, desulfurized hot metal, de-Si hot metal, or ordinary hot metal is charged into a converter, and first, de-P refining is performed. After the de-P refining, the molten metal is discharged, and then, after the de-P, the slag is discharged to a waste pan. Thereafter, the discharged molten metal after de-P is again
It is charged into the same furnace where de-P refining was performed, and decarburization refining is performed. After the decarburization refining, the molten steel is discharged, but after the decarburization, the slag is not discharged and remains in the converters, and in that state, the next charge of hot metal is charged and the next deP refining is started. Since the decarburized slag has a high basicity and a low P concentration, it is suitable for slag for de-P refining.Furthermore, immediately after decarburization, the slag is left in the converters. Since slag itself can be reused as well as slag sensible heat can be used as it is, heat loss is extremely small even when recycled for scouring. In addition, work time required for processing such as discharging and grinding of slag and charging is not required, and productivity can be improved. Next, the steelmaking equipment of the present invention will be described.

FIG. 1 is a schematic diagram showing second to fourth inventions of the present application which are rational steelmaking facilities in carrying out the first invention of the present application. First, the steelmaking equipment of the second invention
The molten metal after refining is provided with a special pot and a special pan carriage different from the molten steel after decarburizing refining. Since the molten steel after decarburization goes to the casting process after receiving the molten metal, the temperature of the molten metal is high and the temperature control accuracy is also required. For this reason, it is necessary to heat the steel receiving pan to just before receiving the molten steel. However, the provision of the dedicated pan makes it possible to heat the steel receiving pan even during the hot-water receiving operation after the removal of the molten steel. The temperature is stabilized, and the operation stability of the subsequent secondary refining process or casting process is improved.

When the hot and cold steel pans are shared, it is necessary to temporarily store the empty pans after re-charging the hot metal into the converter after de-P, which requires a lot of work and space. This necessitates a problem that productivity and the like are deteriorated. Next, the steelmaking equipment of the third invention has a shape in which the molten metal received by the dedicated pan for receiving the molten metal after de-Ping can be directly charged into the converter, and generally has a shape having a “crow mouth”. In addition, an opening is provided in the converter work floor, so that the pot can be lifted from below the furnace to the charging position of the converter. As a result, it is possible to minimize the required time from the discharge of the molten metal after the removal of P to the charging of the molten metal into the converter again.

Further, the steel making equipment of the fourth invention is characterized in that
A dedicated pan for receiving the molten metal is loaded on the dedicated cart,
It is specified that the height of the upper end of the pot when traveling is lower than the lower end position of the furnace body when the converter stands upright (when the converter bodies are at the lowest position). This is because the furnace body tilts due to work such as repair of the converter, but it is possible to pass through the pot below the converter furnace without depending on the operation state of the converter.

[0014]

FIG. 2 shows an example of a time schedule when the present invention is applied to an actual machine. First, ordinary hot metal is charged into a converter, and P removal is performed. After the completion of the P-free refining, the P-free hot metal is poured into a hot water receiving pan, and the P-free slag remaining in the converter furnace is completely discharged into a waste pan.

[0015] Next, the hot pot containing the hot metal from which the hot metal has been removed is lifted from the bottom of the furnace through the opening of the working floor of the converter to the converter charging side, and recharged into the converter to perform decarburization refining. carry out. After the decarburization refining, the hot water is discharged into the steel receiving pan as before, but the decarburized slag remaining in the furnace is used as it is for the decharging of the next charge, so the hot metal of the next charge is left in the furnace and the hot metal of the next charge is removed. Charge and de-P refining.

[0016] Here, the steel receiving pot for receiving the molten steel after the decarburization refining can be heated until immediately before receiving the steel, so that a stable operation without a thermal trouble or the like becomes possible. In addition, the entire time schedule becomes lean, and an integrated refining process from hot metal pretreatment to decarburization refining with high productivity can be realized.

[0017]

By applying the steel making equipment of the present invention, de-P decarburization is efficiently performed without waste in one converter. Moreover, since the decarburized slag is left in the furnace and used for de-P refining of the next charge, heat loss is small and there is no waste work after decarburization, so the cycle time of the converter process can be reduced. And productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a layout diagram schematically showing one embodiment of a steel making facility of the present invention.

FIG. 2 is a diagram showing a time schedule when the present invention is applied.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Seiji Yamamoto 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Corporation Kimitsu Works (72) Inventor Kazuaki Saito 1 Kimitsu, Kimitsu-shi, Chiba Nippon Steel Kimitsu Works, Ltd.

Claims (4)

[Claims] 1. The following steps 1) to 7): 1) De-P refining is mainly performed in a converter, and 2) After the completion of the de-P refining, the molten metal in the converter is discharged to a receiving pan. ) Next, the slag in the converter after discharging the molten metal is discharged to a waste pan, and 4) the molten metal discharged to the receiving pan in the above step 2) is again charged into the converter after discharging the slag. ) Mainly decarburizing and refining, 6) After completion of decarburizing and refining, discharge molten steel in the converter into a steel receiving pan, and 7) remove hot metal of the next charge while leaving slag in the converter after discharging the molten steel. A steelmaking method comprising: charging and mainly performing de-P refining. 2. A steelmaking facility in which after de-P refining in a converter, the molten metal after the refining is once discharged out of the converters and then charged again into the converter to perform decarburization refining. A steelmaking facility comprising: a pot and a pot truck receiving the molten steel of the above (1); and a special pot and a pot truck receiving the molten metal after de-P refining separately from the pot and the pot truck. 3. A special pot for receiving the molten metal after the de-P refining is shaped so that the received molten metal can be charged into a converter, and the special pot is transferred from below the furnace to the converter. 3. A steelmaking facility according to claim 2, further comprising a converter work floor having an opening for moving to a charging position. 4. When a dedicated pan for receiving the molten metal after the de-P refining is mounted on the dedicated pan carriage, an upper end of the dedicated pan is
The steelmaking equipment according to claim 2 or 3, wherein the converter is lower than a lower end of the converter bodies when the converter stands upright.