JP2973563B2 - Pouring control method of pressure type automatic pouring furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pouring control method for a pressure type automatic pouring furnace, and more particularly to a method for controlling a pouring pressure of a molten metal chamber so as to maintain an accurate pouring amount of the molten metal. In connection with this, it includes those with a stopper at the tap hole and those without.

[0002]

2. Description of the Related Art As a conventional example of a pouring control method for a pressure type automatic pouring furnace having no stopper, Japanese Patent Publication No. 61-4315 is known.
Japanese Patent Publication No. 3 (Reference 1), Japanese Patent Publication No. 61-43154 (Reference 2), Japanese Patent Publication No. 61-47629 (Reference 3)
As a conventional example of a pouring control method of a pressure stopper type automatic pouring furnace, JP-A-63-180363 (Reference 4), JP-A-63-101070 (Reference 5) and the like are known. It has been known. The pouring control method of the pressurized automatic pouring furnace having no stopper described in Literatures 1 to 3 is approximately as follows. A pressure-type automatic pouring furnace having a top tap hole communicating with the bottom of the closed melt chamber through a tap channel is used.Before pouring, a base pressure corresponding to the melt weight measured by a load cell is applied to the melt chamber. A step is used in which the level of the hot water in the tapping path is held at a pre-level just before tapping, and at the time of pouring, the base pressure is applied with a shot pressure and the head at the tap is used for pouring. Pouring speed (kg / sec)
Is based on the head at the tap and the diameter of the tap,
It is determined according to Bernoulli's theorem. When the pressure in the molten metal chamber is released after a desired pouring time, pouring is stopped and a desired amount of molten metal is poured into a mold or the like. This is hereinafter referred to as a first embodiment. Document 4 is a pressure stopper type. Here, before pouring, a base pressure corresponding to the weight of the molten metal measured by the load cell is applied to the molten metal chamber to maintain the level of the molten metal in the molten metal path at a pre-level immediately before the molten metal is melted. A step of pouring with a head at the tap hole when the shot pressure is further applied to the base pressure while being opened is used. Then, the stopper of the tap hole is closed to finish pouring. This is hereinafter referred to as a second embodiment.

[0003] Document 5 is a pressure stopper type and shows two modes. The first one is the same as in the second embodiment. The later, aspect 3 is that before pouring, a base pressure corresponding to the weight of the molten metal measured by the load cell is applied to the molten metal chamber to maintain the level of the molten metal in the tapping channel at a pre-level immediately before the molten metal is poured. A step of applying a shot pressure to the base pressure and then pouring the molten metal with a head at the tap hole when the tap of the tap port is opened is used. Then, the stopper of the tap hole is closed to finish pouring.

[0004] Although not cited in the literature, the pressurized stopper type of mode 4 does not use shot pressure, the stopper of the tap hole is opened at the time of pouring, and the base pressure corresponding to the weight of the molten metal measured by the load cell is adjusted to the molten metal. A step of pouring with a head at the tap when added to the chamber is used. Then, the stopper of the tap hole is closed to finish pouring. Also, the pressure stopper type of the embodiment 5 does not use the shot pressure, and applies a base pressure corresponding to the weight of the molten metal measured by the load cell to the molten metal chamber at the time of pouring, and then adjusts the discharge when the stopper of the molten metal outlet is opened. A process of pouring with a head at the gate is used. Then, the stopper of the tap hole is closed to finish pouring.

As described in the above-mentioned reference 2, the base pressure for maintaining the molten metal at the pre-level must be changed for each pouring, as described in the above-mentioned document 2, as described in the above-mentioned document 2. Instead, the target value of the base pressure is determined according to the value measured by the load cell. In the pouring operation, the relationship between the melt weight and the base pressure is linearly (linear function) programmed in the control system from the maximum melt weight to the minimum melt weight.

[0006]

By the way, if the molten metal is reduced by repeating the pouring, and the operation is continued by repeating the charge receiving the supply of the molten metal or the cooling material from the outside, the relationship between the molten metal weight and the base pressure is kept constant. If the control is performed as a linear function of the coefficient, the level of the level of the tapping path cannot be maintained at the pre-level immediately before tapping before pouring. At this time, the base pressure is manually adjusted to maintain the pre-level immediately before tapping, and the coefficient of the linear function is finely adjusted from time to time. When it is necessary to adjust the base pressure and the coefficient, it has been observed that slag adheres to the inner wall of the molten metal chamber. However, the adhesion of the slag is not uniform and grows on the inner wall, so the above adjustment is required every few charges. Even then, the correct pre-level cannot be maintained, resulting in an error in the pouring amount and a defective casting. An object of the present invention is to provide a pouring control method for a pressurized automatic pouring furnace that can control the pressure of a molten metal chamber so as to maintain an accurate pouring amount of molten metal.

[0007]

According to a first aspect of the present invention, there is provided a method for controlling a pouring operation of a pressurized automatic pouring furnace, the method comprising the steps of: A pouring control method, which includes a step of pouring the molten metal by a head at the tap hole when a pressure corresponding to the weight of the molten metal measured by a load cell is applied to the molten metal chamber, from a maximum molten metal weight to a minimum molten metal weight. At a plurality of arbitrary points, the relationship between the adjusted base pressure and the molten metal weight when the correct pre-level is held is stored in a memory, and after the subsequent charging, the base pressure is controlled by a control value according to the adjusted base pressure of the memory. Is controlled.

In a second aspect of the present invention, in the method of the first aspect, the step of applying the base pressure corresponding to the weight of the molten metal measured by the load cell before pouring into the molten metal chamber. The method comprises a step of maintaining the level of the hot water in the tapping path at a pre-level immediately before tapping, and pouring the molten metal with a head at the tap when the shot pressure is further applied to the base pressure. It relates to the first aspect of the section of the prior art.

In a third aspect of the present invention, in the method of the first aspect, before the pouring, a base pressure corresponding to the weight of the molten metal measured by a load cell is applied to the molten metal chamber before pouring. A step of maintaining the level of the molten metal in the road at a pre-level just before tapping, opening the tap of the tap at the time of pouring, and pouring with the head at the tap when the shot pressure is further applied to the base pressure. It consists of It relates to the above-mentioned mode 2.

In accordance with a fourth aspect of the present invention, there is provided a method for controlling pouring of a pressurized automatic pouring furnace according to the first aspect of the present invention, wherein, before pouring, a base pressure corresponding to the weight of the molten metal measured by a load cell is applied to the molten metal chamber. From the step of maintaining the level of the molten metal in the road at a pre-level immediately before tapping, applying a shot pressure to the base pressure at the time of pouring, and then pouring with the head at the tap when the stopper of the tap is opened. It becomes. It relates to the above-mentioned mode 3.

[0011]

The present invention will be described with reference to FIG. The tapping path 3 in a pressurized automatic pouring furnace having a tapping port 4 at the upper end communicating with the bottom of the closed molten chamber 2 through the tapping path 3.
The pre-level immediately before the tapping of the hot water level is ha. The base pressure applied to the melt chamber to maintain the pre-level is P, the melt weight measured by the load cell in any state from the maximum melt weight to the minimum melt weight is W, and the total horizontal sectional area of the tapping channel and the receiving channel. Is A, and the horizontal sectional area of the molten metal chamber is B, the relationship between W and P is expressed by the following equation (6). P = −W / B + γha (A + B) / B (6)

The process of deriving the equation (6) will be described in the section of the embodiment. From equation (6), the slope when W increases is a negative coefficient 1
/ B. When the cross section of the melt chamber 2 is a cylinder or the like and the slag 8 does not adhere, B is constant,
The relationship between the melt weight W and the base pressure P may be linear (linear function). However, when slag adheres and B is not constant, the curve must be an unspecified curve instead of a straight line. Therefore, at any of a plurality of points from the maximum melt weight to the minimum melt weight, the base pressure is manually adjusted to maintain a correct pre-level, and the relationship between the adjusted base pressure and the melt weight at that time is stored in a memory, and thereafter, After charging, if the base pressure is controlled by the tracing control value in accordance with the adjusted base pressure of the memory, a sufficiently accurate pre-level is maintained, and if the shot pressure ΔP is added to perform the pouring, the accurate pouring amount is cast. And so on.

The difference between the pouring control methods of the pressure stopper type automatic pouring furnaces of Inventions 3 and 4 from the above is that the stopper is used and the timing of applying the shot pressure to the opening of the stopper. However, this is the same as the step of pouring with the head at the tap hole when a pressure corresponding to the weight of the molten metal measured by the load cell is applied to the molten metal chamber, and has the same operation as the above operation.

[0014]

1 is a sectional view of a pressure type automatic pouring furnace having no stopper showing the relationship between pressure and head, FIG. 2 is a graph showing the relationship between molten metal weight and base pressure in FIG. 1, and FIG. 3 is FIG. 5 is a flowchart for measuring and storing an adjustment base pressure in FIG. This embodiment relates to the second aspect of the invention, that is, the first aspect of the related art. The outline of the structure of the pressure type automatic pouring furnace will be described with reference to FIG. 1. The top end of the molten metal chamber 2 closed by the furnace lid 1 communicates with the top end of the molten metal chamber 2 through the tapping path 3 and the upper end connected with the receiving path 5. And the weight of the entire furnace can be measured with a load cell 7. Slag 8 may adhere to the inner wall of the melt chamber 2.

Referring to FIG. 1, the relationship between the base pressure and the size of the furnace for maintaining the level of the hot water in the hot water path at the pre-level just before the hot water is obtained. Next, how this relationship changes due to the adhesion of slag. Find out. Assume that the origin of the head h = 0 is, for example, at the time of the minimum melt weight that can be poured as shown in the figure. If the weight of the melt that can be poured with the head of h0 at the atmospheric pressure P0 is W, the weight of the melt that cannot be poured is WN, and the weight of the furnace itself is WF, the measured value of the load cell is WL = W + WN + WF. The total horizontal cross-sectional area of the tapping path and the hot-water path is A, and the horizontal cross-sectional area of the molten metal chamber is B. Now, it is assumed that the base pressure P is increased to raise the level of the molten metal in the hot water path to a pre-level ha immediately before the molten metal is discharged (the same applies to the hot water receiving path), and the head of the molten metal chamber drops to hb.

The following equation can be obtained from the same conditions of the pressure, the balance of the head, and the amount of movement of the molten metal. P = γ (ha−hb) (1) A (ha−h0) = B (h0−hb) (2) In order to eliminate hb in equation (1), hb is calculated from equation (2). Aha−Ah0 = Bh0−Bhb Bhb = Bh0 + Ah0−Aha = (A + B) h0−Aha∴hb = h0 (A + B) / B−ha A / B (3) Substituting into (1), P = γ [ha−h0 (A + B) / B + ha A / B] = γ [ha (A + B) / B−h0 (A + B) / B] ∴P = γ (ha−h0) ( A + B) / B (4) Here, if h0 can be represented by W, P can be represented by W. W = γh0 (A + B) ∴h0 = W / [γ (A + B)] (5) Substituting equation (5) into equation (4), P = γ ｛ha−W / [γ (A + B) ] {(A + B) / B} P = -W / B + γha (A + B) / B (6)

Equation (6) expresses the relationship between the base pressure P and the molten metal weight W for maintaining the level of the hot water in the hot water path at the pre-level ha just before the hot water is discharged. The constant is the size of the furnace. In equation (6), when W is plotted on the horizontal axis and P is plotted on the vertical axis, W = 0, that is, the base pressure P at the time of the minimum melt weight is expressed by the second term on the right side of equation (6). Increasing slope is negative coefficient 1
/ B indicates a straight line (although the time lapse of pouring is a direction in which W decreases). When the cross section of the melt chamber 2 is a cylinder or the like and the slag 8 does not adhere, B is constant, and as described in the section of the prior art, in practice of the pouring operation, from the maximum melt weight to the minimum melt weight. The relationship between the melt weight W and the base pressure P may be linear (linear function). However, when slag adheres and B is not constant, it must be a curve instead of a straight line, and this curve also changes variously according to the slag adherence. Therefore, at any of a plurality of points from the maximum melt weight to the minimum melt weight, the base pressure is manually adjusted to hold the correct pre-level visually or the like, and the relationship between the adjusted base pressure and the melt weight at that time is determined by the control system. The problem can be solved at once if the program is stored in the memory of the program, and after the charging, the base pressure is controlled by the copying control value in accordance with the adjusted base pressure of the memory. The memory contents must be changed every few charges to maintain a sufficiently accurate pre-level and the shot pressure Δ
If P is added, casting of an accurate pouring amount can be performed.

In the graph showing the relationship between the weight of the molten metal and the base pressure shown in FIG. 2, (a) shows that the slag does not adhere and B is constant, and (b) shows that the slag adheres but there is a conventional straight line correction. (C) is based on equation (6) and according to the method of the present invention. In the conventional method (b), the pre-level is not yet accurate, and there is an error in the pouring amount. The flowchart for measuring and storing the adjustment base pressure shown in FIG. 3 represents an adjustment base pressure setting operation at an arbitrary molten metal weight. After the pre-level manual adjustment, the melt weight W and the adjustment base pressure P are measured and stored in the memory. After the pouring has been performed an arbitrary number of times, the pre-level is manually adjusted as necessary and the result is stored. When the weight of the molten metal reaches the minimum weight, the molten metal is received and the flow is executed again. The memory uses a microcomputer or a programmable controller (PC).

Although the above-described embodiment is a pouring control method for a pressure type automatic pouring furnace having no stopper, the pouring control method for a pressurized stopper type automatic pouring furnace described in the section of the prior art is also applicable to the above-described method. The example method can of course be used and has the same effect.

[0020]

According to the present invention, even when the slag adheres to the molten metal chamber and the correct pre-level cannot be maintained, the adjusted base pressure for manually adjusting the base pressure and maintaining the correct pre-level is stored in the memory. After the subsequent charging, the base pressure is controlled by the copying control value according to the adjusted base pressure of the memory, so that a sufficiently accurate pre-level is always maintained, and the effect that the pouring of the accurate pouring amount can be performed by a simple procedure. is there. The method of the present invention has an effect that it can be used for various modes of the pouring control method for a pressurized automatic pouring furnace with or without a stopper.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a pressure-type automatic pouring furnace without a stopper showing a relationship between a pressure and a head.

FIG. 2 is a graph showing the relationship between the molten metal weight and the base pressure in FIG.

FIG. 3 is a flowchart for measuring and storing an adjustment base pressure in FIG. 1;

[Explanation of symbols]

2 Molten chamber 3 Outlet path 4 Outlet port 5 Receiving path 6 Receiving port 7 Load cell 8 Slag A Total horizontal cross-sectional area of the outflow path and receiving path B Horizontal cross-sectional area of the melting chamber P Base pressure W Melt weight WL Load cell measurement Value (a) Relationship between W and P where B is constant without slag adhered (b) Conventional slag adhered but corrected by a straight line (c) Based on equation (6), according to the method of the present invention ha Pre-level Δh Head corresponding to shot pressure

Claims (4)

(57) [Claims] 1. A pouring control method for a pressurized automatic pouring furnace provided with a top pouring port communicating with a bottom of a closed molten chamber through a pouring path, wherein the pressure corresponding to the molten weight measured by a load cell is determined. In a process having a step of pouring with a head at the tap hole when the molten metal is added to the molten metal chamber, an adjusted base pressure when holding a correct pre-level at any of a plurality of points from a maximum molten metal weight to a minimum molten metal weight. A pouring control method for a pressurized automatic pouring furnace, characterized in that a relation with the molten metal weight is stored in a memory, and after charging, the base pressure is controlled by a control value according to the adjusted base pressure in the memory. 2. A method for controlling the pouring of a pressure type automatic pouring furnace according to claim 1, wherein the step of applying a base pressure corresponding to a weight of the molten metal measured by a load cell to the molten metal chamber before the pouring. A pressurizing method comprising: maintaining the level of the hot water in a hot water path at a pre-level immediately before hot water is supplied, and pouring the molten metal by a head at the hot water outlet when a shot pressure is further applied to the base pressure during hot water pouring. Automatic pouring furnace pouring control method. 3. A method for controlling the pouring of a pressure type automatic pouring furnace according to claim 1, wherein the step of adding a base pressure corresponding to the weight of the molten metal measured by a load cell before pouring into the molten metal chamber. A step of maintaining the level of the molten metal in the road at a pre-level just before tapping, opening the tap of the tap at the time of pouring, and pouring with the head at the tap when the shot pressure is further applied to the base pressure. A pouring control method for a pressurized automatic pouring furnace characterized by comprising: 4. A pouring control method for a pressure type automatic pouring furnace according to claim 1, wherein in said step, before pouring, a base pressure corresponding to a weight of the molten metal measured by a load cell is applied to said molten metal chamber. From the step of maintaining the level of the molten metal in the road at a pre-level immediately before tapping, applying a shot pressure to the base pressure at the time of pouring, and then pouring with the head at the tap when the stopper of the tap is opened. A method for controlling the pouring of a pressurized automatic pouring furnace.