JPS5831018A - Slag cutting method used for molten steel vessel - Google Patents

Abstract

PURPOSE:To quickly prevent a slag from being mixed into an outflow molten metal flow, by detecting a variation of weight of a ladle, which increases as a molten metal flows in, and controlling or cutting off the outflow molten metal flow by a slag stopper when said variation has reached a set value. CONSTITUTION:In the course of outflow of steel, the first set value of weight of a ladle 5 is detected by a load inspecting device 6 (it is shown that depth of a molten metal in a converter 1 has reached a prescribed value), a slag stopper 3 is inserted into the converter 1 by operating an operating device 4, and a steel outflow port 2 is stopped temporarily. Subsequently, after a prescribed interval of time has passed, the stopper 3 is raised by a set extent, a prescribed gap is made between the lower end of the stopper and the inside of the converter of the steel outflow port 2, and the outflow of steel is started again. Subsequently, the second set vlaue of weight of the ladle 5 is detected by the detector 6 (a state immediately before a slag is mixed into an outflow molten metal flow is shown), and the inside of the converter of the steel outflow port 2 is stopped by operating the device 4. After that, the converter 1 is erected and is brought to a blowing position.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a slag cutting method that prevents as much as possible the mixing of slag into the flow of molten metal when tapping molten metal from a molten metal container such as a converter or a ladle.

- Taking a converter as an example, the ratio of slag to molten tablets in the converter after blowing generally varies depending on the steelworks, but is considered to be about 13.0% by weight (26 volumetric units) on average. In addition, the amount of slag mixed into the ladle is as shown in the graphs shown in Figures 1 and 2 when slag cutting is not performed.It is clear from these graphs that the amount of slag flowing into the ladle is accelerated by the expansion of the tap hole. increase. Furthermore, Figure 3 shows the steel tapping time due to the tilting of the converter and the steel tapping time (*steel + steel
g) Indicates the relationship between depth, where p and vl represent the amount of molten steel that can be tapped without slag being mixed in, and horse represents the amount of slag that flows into the ladle. If the above v1 and V amounts are calculated, v, = A@Cq-aoo = aoo*c5Laso
Ac, i this Vl: V, -380: 2.7=140: 1
becomes.

However, A: Tap area C: Flow rate coefficient Assuming that slag and metal can be reliably distinguished from the above calculation, the amount of slag mixed into the ladle will be 1 /
It should be possible to make it around 140. However, as mentioned above, the ladle actually contains about 1/2 o of slag. This is because at the final stage of steel tapping, a state in which a large amount of slag is mixed, that is, a state shown in Figure 4, continues for several tens of seconds, and visual observers still judge such a state to be a metal zone. Conceivable.

Conventionally, various types of methods and devices have been developed to reduce the large amount of slag mixed in the tapped steel. A typical example of this is shown in FIG. 5, which was disclosed by the present applicant in Ihara No. 1853-78910, in which a mounting stopper is dropped to prevent slag from being discharged. However, this method or device has a complicated structure due to the installation of a stopper and a weir, and once the stopper has been dropped, it cannot be lifted again, which may cause major linear problems due to malfunction. Ta.

Figure 6 shows a method of installing a sliding nozzle device at the tapping port of a converter, which reduces the amount of syslag mixed in to 1/2 compared to the conventional method.
4 @It is strangely decreasing. However, in actual work, there are considerable maintenance problems, and it has not yet been possible to completely remove the slag mixed in the tapping stream. 7th
In the figure, slag cutting is carried out by introducing slag balls, but this method has a problem in that it expects the slag balls to set naturally in the tap hole.

Figure 8 shows a field coil attached to the tapping port.The change in impedance of the coil is detected to distinguish between metal and slag, and it is possible to stop tapping by passing the furnace at an appropriate time, or by using air again. This method involves blowing away slag in the flow of molten steel, and it is possible to clearly detect changes in impedance in areas where slag or slag is flowing out alone, making it possible to completely cut slag without taking into account individual differences among viewers. However, when metal and slag mix due to entrained slag, etc., and transition to the region where steel is tapped, the change in impedance does not appear noticeably, so molten steel,
It is very difficult to identify slag. Therefore, even if the effluent is blown away with air or the steel furnace is raised to stop the steel tapping during the steel tapping process where the region of 0 continues for several tens of seconds. Since no measures have been taken to prevent slag entrainment, it is difficult to completely cut the slag, and there are drawbacks such as a decrease in the yield of steel tapping, and it is still far from perfect.

Conventional methods have been described above, but up to now these methods have had their advantages and disadvantages, and have not necessarily produced a satisfactory slag cutting effect, and the development of an optimal method or device has been delayed.

The present invention was created in view of the current situation and is a round product.The purpose of the present invention is to be able to easily and accurately detect the change from a molten metal flow to a slag flow, and then quickly prevent slag from being mixed in. Provides a method for cutting slag into the molten metal flow using a stopper.

・This fourth invention places a ladle under the molten metal outlet of the molten metal container,
A molten metal container characterized in that a change in the weight of the ladle, which increases with the inflow of the molten metal flow, is detected, and when the weight of the ladle reaches a set value, the flow of molten metal poured out from the molten metal container is controlled or cut off by a sphage stopper. This relates to a slag cutting method used for.

The slag cutting method according to the present invention will be specifically explained below with reference to an embodiment shown in FIG.

Note that this example is applied to slag cutting at the tap port of a converter, and (1) in the figure shows the converter in a tilted state, (
2) is a tapping port, (3) is a slag stopper that is operated by a stopper operating device (4) installed on the tapping port (2) and outside the furnace, and (5) is a tapping port. Ladle placed under the steel mouth (2)-1/ant! A load detector such as a load cell that detects the weight of the ladle (5) that is mounted on the traveling trolley (7) and receives molten steel, and (8) is sent from the load detector (6). The control signal that comes from the operating device (4
This converter converts the signal into an operating signal and transmits it to the operating device (4).

In this example, first, during tapping, the load detector (6)
Detect the first set value of the ladle (6) weight. This indicates that the molten steel depth I4 in the converter has reached a constant value.
), actuate the operating device (4) to close the slag stopper (3).
into the converter (2), and close the inside of the tap port (2) with the lower end of the slag stopper (first
Figure 0) After a predetermined period of time (several seconds) has elapsed with zero rinsing, the slag stopper (3) is raised by a set amount to create a predetermined gap between the lower end of the slag stopper and the inside of the tapping port (2). (Figure 11). Then, the load detector (6) detects the tuna 2 set value of the weight of the ladle (5) (this indicates just before slag is mixed into the molten metal flow in the molten metal outlet), and operates the operating device (4) again. and close the inside of the furnace at the tapping port (2) (Fig. 12). Then, the converter (1) is erected (Fig. 13)
This effectively prevents slag from entering the molten steel flow.

Note that there are various types of devices that can be used to operate the slag stopper (3) in the converter, and specific examples thereof are shown in FIGS. 14 and 15.

The illustrated operating device c! D is attached in the form of a jib crane to a building support column (to) that is erected on the working floor on the front side of the converter (2), and is generally horizontal on the working floor on the front side of the furnace. The stopper support arm (goods) held in the state, the slag stopper (3) suspended from the tip of the stopper support arm (goods), and the arm guide that surrounds the stopper support arm so that it can move forward and backward. Tube (to),
An arm feeding mechanism that is attached to the arm guide tube (2) and allows the stopper support arm to move forward and backward into the converter pronation. One end is rotatably connected to the base end of the arm guide tube (to). Vertical arm support shaft (end) that is pivoted and is attached midway to the horizontal mounting lip (end) of the building support column (2) so that it can be raised and lowered and rotated (around the axis) via bearing action, stopper support An arm elevating mechanism (2) consisting of a vertical arm support (2) parallel to the vertical arm support (2) to raise and lower the arm; The arm rotation mechanism (to) installed in parallel with the mounting lip (2) and the vertical arm support shaft (to) at one end
The arm elevating mechanism (2) is constructed by connecting the arm to the middle of the arm and connecting the other end to the tip of the arm guide tube (to). The structure of the slag stopper (3) is shown in detail in FIGS. 16 to 17. Slag stopper as shown
(3) is a stopper suspension rod connected to the lower end large cylinder (B). It is suspended in a swinging state by inserting it into the suspension pivot pin θ which is attached to the tip of the stopper arm support rod (4). One end of the co-moveable lever (to), which has a pivot fin attached to the tip of the rotary lever, is in contact with the other end of the rotating lever.
1! A control device such as a limit device (not shown) via I
By doing this, the amount of rise of the slag stopper (3) after it contacts the inner surface of the tap hole can be adjusted.

With the above configuration, the drive device is a slag stopper (3)
can be freely operated within the converter (2), and the above-mentioned slag cutting can be performed accurately.

As described above, the slag cutting method according to Zero-Hatsu 1jiK has the following effects.

(The transition from the molten metal flow to the slag flow at the 11 m hot water outlet can be easily detected by the change in ladle weight, and the mixing of the slag can be effectively prevented.

(2) The slag stopper can be brought over the molten metal outlet in a timely manner, and slag can be prevented from being mixed into the molten metal due to swirls at the final stage of tapping.

(3) A sharp slag cut can be made at the end of tapping (4) Prevent damage to the slag stopper and stopper support arm as much as possible f:! Ru.

[Brief explanation of the drawing]

Figures 1 and 2 are graphs showing part of the amount of slag mixed in the ladle, tapping time, and number of charges, and Figure 3 is a graph showing (molten steel + slag) l#! at the tapping port. Fig. 4 is an explanatory diagram showing the mechanism of slag inclusion, Figs. An explanatory diagram of the cutting method, Figures 10 to 13 are process diagrams, 111114
The figure is a front view of the operating device used in the same method, FIG. 15 is a plan view of the same, and FIG. 16 is a partially sectional front view of the slag stopper.
FIG. 17 is an explanatory diagram of the state in which the slag stopper is attached to the support arm. Patent applicant: Nisshin Steel Co., Ltd. (and 1 other person) Agent: Moritada Ito (and 1 other person) Figure 6 Figure 9 Figure 11 Figure 6

Claims (1)

[Claims] 1. A ladle is placed below the molten metal outlet of the molten metal container, and a change in the weight of the ladle, which increases as the molten metal flows in, is detected, and when the weight of the ladle reaches a set value, a slag stopper is installed. A slag cutting method used in a molten metal container characterized by controlling or blocking the flow of molten metal poured out from the molten metal container at a molten metal container. The container is fixed according to the tilting angle of the container, the molten metal flows out through the same gap, and when the slag starts flowing out, the molten metal outlet is closed by the slag stopper to separate the molten steel and the slag. Slag cutting method 0 used in the bath water container described in item 1