JPS6289548A - Method and apparatus for adding inoculant - Google Patents

Abstract

PURPOSE:To prevent the generation of a hard spot defect of a casting by fixing the dropping port of an inoculator to an outflow port of a tilting type ladle in such a manner as to maximize the rate of inoculation at the start of pouring and decreasing the rate of dropping according to tilting of the ladle. CONSTITUTION:The inoculator 6 is fixed to the position right above the outflow port 1 in the body part of the horizontal cylindrical ladle 2 by tilting the same about 10 deg. toward a frame 3 side in such a manner that the dropping hole 5 is positioned perpendicular at the start of pouring. Said inoculator is made freely attachable and detachable by means of a supporting arm 17 and a bracket 18. The dropping of the inoculant (a) is started when a rod 9 is pulled up by a solenoid 10. The inoculator 6 tilts as well as the ladle 2 tilts. The dropping rate of the inoculant (a) decreases gradually with a decrease in the pouring temp. to prevent the generation of the hard spot defect of the casting by the excessive inoculation. The inoculator 6 is adequately inclined in a side direction as well to prevent the radiant heat of pouring. The inoculator is covered with a stainless steel outside plate 15, asbestos 14, asbestos 12 and ceramic fibers 13 to prevent the thermal influence of the internal device.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for adding an inoculant to a molten metal stream exiting a ladle and to an apparatus used directly for carrying out this method.

BACKGROUND OF THE INVENTION The amount of inoculant added to the molten metal stream needs to be varied depending on the humidity of the molten metal. In other words, when the molten metal temperature is high,
Calculate the inoculum yield and add a large amount of inoculant, decreasing as the temperature decreases. This is because if the same amount of inoculant as at high temperature is added after the temperature has dropped, the melted f-[ will become hard spots and impair the mechanical properties and workability of the casting. Therefore, the amount of inoculation needs to be decreased as the temperature of the molten metal decreases.

Further, as an example of a conventional device for adding an inoculant to a ladle, there is Japanese Utility Model Application Publication No. 54-184320. However, this device does not meet the above requirements at all because the amount of inoculant added increases as the tilting angle of the ladle increases.

<Problems to be solved by the invention and means thereof> The present invention seeks to provide an inoculant addition method developed in consideration of the above-mentioned needs, and an apparatus directly used for carrying out the method. And configure it as follows.

The invention of the method fixes the inoculation device with the drop hole facing the molten metal outlet of a tilting ladle, and adjusts the tilting angle of the ladle to
This method of adding an inoculant is characterized in that the amount of inoculant falling is set to the maximum amount at the start of pouring, and thereafter the amount of falling inoculant is gradually decreased as the tilting progresses.

In the invention of the device, the inoculating device is fixed with a falling hole facing the outlet of the molten metal in a tilting ladle, and the inoculating device is sequentially tilted according to the tilting angle of the ladle, thereby controlling the amount of inoculant that falls into the molten metal. This inoculant addition device is characterized in that the inoculant is added to the molten metal flow at a maximum at the start and then gradually reduced as the tilting progresses.

According to the invention of the method, the falling amount of the inoculant is maximized at the peak of the molten metal temperature at the start of pouring, and thereafter decreases as the molten metal temperature decreases as the number of times of pouring progresses, so that the molten metal temperature increases. A large amount of inoculant will not be added after descending. Therefore, there is no risk that part of the inoculant will not completely dissolve and become a hard spot that will impair the mechanical properties and workability of the casting.

Further, according to the invention of the device, the inoculation device is fixed with the drop hole facing the outlet of the tilting ladle, and the inoculation device and the ladle are sequentially tilted in the tilting direction from the upright state. For this reason, the shape projected directly below the drop hole gradually changes from a circle to an oval. For this reason, the amount of inoculant falling reaches its maximum at the beginning of the first pouring, and then gradually decreases. In other words, when the molten metal is full at the start of pouring, the temperature is high, and as the number of pours progresses, the molten metal decreases and the temperature of the molten metal decreases as time passes.
This naturally reduces the amount of additives falling.

<Example> Examples of the present invention will be described below based on the drawings. First, let's start with an explanation of the device. FIG. 1 is a front view of the device, and FIGS. 2 to 4 are explanatory diagrams showing its usage. According to FIG. 1, a cylindrical ladle 2 having a molten metal outlet l on the negative side is provided, and the outer end of the pivot shaft of the ladle 2 is supported by a frame 3 so as to be tiltable. Attach an annular handle 4 to one outer end of the pivot shaft, turn the handle 4 in the direction of arrow A, tilt the ladle 2 toward the outlet 1, and pour out the molten metal from the outlet l. ◇This tilting type handle! To 42, fall hole 5'?
:Fix the inoculation device 6 in a slightly inclined state facing the outlet 1.

The inoculation device 6 has a configuration as shown in FIG. 5, and has a drop hole 5 with a circular cross section for dropping the inoculant a into the bottom of a cylindrical container 7, and a longitudinal guide in the center of the inside. A cylinder 8 is provided, and a rod 9 for a stopper is housed inside the cylinder 8 so as to be able to move up and down. The upper end of the rod 9 is connected to the solenoid IO via a coil spring, and the drop hole 5 is closed by the coil spring, and the rod 9 is sucked upward by the solenoid 10. to open. A tape-shaped asbestos seal is wound around the outer circumference of the container 7 to form a heat insulating layer 12, and the inner wall is lined with ceramic #fiber to form a heat insulating layer 13 as well, and an asbestos heat insulating plate 14 is placed at the bottom. Attach.

In addition, a heat reflecting plate 15 made of a lightweight material such as aluminum or stainless steel with high heat reflectance is attached to the side of the ladle 2 of the container 7 to efficiently reflect the high heat received from the molten metal in the ladle 2. This protects the solenoid 10 inside the container 7 in combination with the heat insulating layers 1g and t3. A replenishment port 16 for inoculant & is provided protruding from the upper side of the container 7.

The container 7 configured in this manner is supported by the support arm 17. The support arm 17 is detachably fixed by inserting a bracket 18 provided at the base end into the support portion 19 of the ladle 2. A heat-resistant cord 20 leading to the solenoid 10 is inserted into the support arm 17 . The installation angle of the inoculation device 6 is approximately 10° to the right (frame 3 side) with respect to the vertical direction when viewed from the right side (handle 4 side), and tilted at an appropriate angle to the right (handle 4 side) when viewed from the front. Adjustable and fixed. The reason why the container is tilted by approximately 100 degrees toward the frame 3 side is that when the drawer @2 is tilted and pouring begins, the container 7 becomes vertical and the shape projected directly below the drop hole 5 is circular, so that the falling amount of the inoculant a is This is to maximize it. Also, when viewed from the front, the reason for tilting the angle appropriately to the right (handle 4 side) is that solenoid 1
This is to avoid heating to 0 and to set the amount added.

Next, the invention of this method will be explained. In the above device,
After filling the ladle 2 with molten metal, when the ladle 2 is tilted in the direction of arrow A using the handle 4, the molten metal in the ladle 2 flows out when the ladle 2 is tilted approximately 10 degrees, and the tilted container 7 is tilted to the right side. When viewed from above, it is almost vertical. When power is supplied to the solenoid 10 connected by the heat-resistant cord 2°, the rod 9 is attracted by the solenoid 10 and rises, thereby opening the drop hole 5. When the drop hole 5 opens, the inoculant a in the container 7
However, at this time, since the drop hole 5 is facing straight down, the inoculant a falls most easily and reaches the maximum amount. That is, when the tank is full and the humidity of the molten metal is high, the amount of inoculant a added becomes maximum.

As the ladle 2 is gradually strengthened as the ladle 2 is poured further, the inclination of the container 7 becomes larger and the shape of the drop hole 5 when viewed from below changes to a flat ellipse. The elliptical shape becomes smaller as the slope increases. Therefore, the falling amount of inoculant a decreases as the molten metal temperature decreases over time. This relationship is shown in the graph of Figure 6, where the horizontal axis is the elapsed time hand, the left vertical axis is the casting temperature (0C), and the right vertical axis is the falling amount of inoculant a in % (falling amount/casting weight). X100) is displayed. As is clear from this graph, the falling amount of inoculant a is related to the temperature of the molten metal and decreases in proportion to the elapsed time. Therefore, it is possible to add the inoculant a in an amount appropriate to the decreasing temperature of the molten metal.

<Effects of the Invention> According to the method of the present invention, the falling amount of the inoculant is reduced as the molten metal temperature decreases as the pouring progresses, so that a large amount of inoculant is added after the molten metal humidity has decreased. Never. Therefore, there is no risk that part of the inoculant will not completely dissolve and become a hard spot that will impair the mechanical properties and workability of the casting. The inoculating device is fixed facing the ladle, and as the ladle is tilted, the inoculating device is sequentially tilted from the upright position in the tilting direction. For this reason, the shape projected directly below the drop hole gradually changes from a circle to an ellipse, so the amount of inoculant falling is maximum at first and then gradually decreases. In other words, when the molten metal is full at the start of pouring, the temperature is high, and as the number of pours progresses, the amount of molten metal decreases and the humidity of the molten metal decreases over time, so the amount of additives falling naturally decreases.

[Brief explanation of drawings]

Fig. 1 is a front view showing the device directly used for carrying out the method of the present invention, Figs. 2 to 4 are explanatory views showing the same state of use, Fig. 5 is a vertical sectional front view showing the inoculation device, and Fig. 6 is It is a graph showing the relationship between elapsed time, casting temperature, and falling amount. 1-Outlet 2-Ladle 5-Drop hole 6-Inoculation device a -Inoculation agent Hisashi Matsumoto

Claims (1)

[Claims] 1. Fix the inoculating device with the drop hole facing the molten metal outlet of the tilting ladle, and adjust the amount of inoculant falling to the maximum at the start of pouring by adjusting the tilting angle of the ladle. A large amount, and as the tilt progresses,
A method for adding an inoculant characterized by gradually reducing the amount of falling. 2. Fix the inoculating device with the drop hole facing the molten metal outlet of the tilting ladle, and by sequentially tilting the inoculating device according to the tilting angle of the ladle, the amount of inoculant falling can be measured at the start of pouring. An inoculant addition device characterized in that the inoculant is added to the molten metal flow while gradually decreasing the inoculant as the tilting progresses.