JPS59157213A - Treatment of molten metal - Google Patents

Abstract

PURPOSE:To add inexpensively various Mg and Ca alloys into a molten iron by inserting a steel core having a bulging part at the lower part into a treating ladle, mounting a molded treating material having a hollow cylindrical shape at the lower part of the bulging part and charging the molten iron into the treating ladle while preventing said material from floating. CONSTITUTION:An Mg alloy or Ca alloy such as an Fe-Si-Mg alloy, Fe-Si-Mg- Ca alloy, Fe-Si-Mg-Ca-RE alloy, Fe-Si-Mg-RE alloy or the like is used for a molded treating material 8 which is formed into a hollow cylindrical or doughnut shape provided with a through-hole at the central part. A core steel bar 1 provided with a bulging part 2 at the lower part is inserted into a treating ladle 11 and the material 8 is mounted at the part below the bulging part 2. When a molten metal 13 to be treated is charged into the ladle 11, the material 8 adds the Mg alloy and Ca alloy into the molten metal 13 while said material is prevented from floating.

Description

[Detailed description of the invention] Hot metal or m01 for ductile cast iron, desulfurization and deoxidation
There are various ideas for introducing low boiling point substances such as magnesium and calcium into molten metals of 1 and 2.

These metals are usually used as alloys with other metals, such as ferron-recon magnesium, nickel-magnesium, calcium-silicon, etc., or impregnated into porous bodies, such as magnesium-impregnated coke or magnesium-impregnated paddle iron. There are methods such as using a compression molded magnesium powder and refractory material or metal powder. However, in order to introduce these into hot water, a plunger is usually used. It was usually contained in a bell-shaped or inverted cage-shaped container and forced into the molten metal.

A simple pouring method and sand inch method are also known for this purpose, but they have the disadvantage that the yield is not good and high concentrations cannot be used. The drawback was that it required huge equipment costs and could only be put to practical use in a factory that mass-produced all culms.

The present invention relates to a method for advantageously adding Mg alloy or Ca alloy to a molten metal to be treated using a rod-shaped planer provided with an inner bulge.

Of the various methods of adding low-boiling substances such as magnesium and calcium into molten metal, the plunger method is considered to be the most accurate in the following respects. The reaction start time is always constant because the required amount can be accurately weighed to the bottom after accurately weighing the molten metal to be treated and the temperature is sufficiently controlled. This is because the simple Sanderch method has uneven start of reaction depending on the method of tapping the hot water, and also unevenness in the temperature at which the treatment agent is applied to the hot water depending on the temperature of the ladle.The amount of hot water for the reaction also varies.

Therefore, it was necessary to use a large number of processing agents in consideration of these factors, and compared to methods that were rather competitive, this method has outstanding accuracy and yield. (The plunger method, which is technologically superior, had the following drawbacks in terms of work. Normally, when a constant amount of hot water is to be continuously treated, graphite Plungers have been used to exert their power, but because they are made of graphite, they are expensive, and because they need to contain processing agents, their outer periphery is large and difficult to withstand rapid temperature changes. The thin shaft part is prone to cracking, and even though there is no damage, the plunger main body part cracks or falls off, resulting in a short lifespan.

For this reason, it was necessary to thoroughly preheat and retain heat before and after use. Another problem with graphite internal plungers is that the holes are inevitably clogged by slag that adheres to the interior and ventilation holes. The internal capacity was reduced, and as a result, it was necessary to clean the inside surfaces and holes while the slag was still soft and red-hot.

Cleaning the hole and inner surface of a red-hot plunger that has been used during hot work is extremely hard work, and is dangerous as droplets of hot metal and red-hot slag may fall. This point was a drawback of the graphite plunger method. However, if a refractory other than graphite is used, a bell-shaped refractory like this is not suitable for sudden heat reversing work. @ Ushi was.

On the other hand, a plunger made of steel plate is used to force an unspecified amount of treatment agent into the molten metal. For example, 1 ton processing, 1.5 ton processing, 3 ton processing, etc.
Since the amount of treatment varies and having to preheat a graphite plunger of a different size each time is very problematic both in terms of work and cost, we decided to use a steel plate as it is a one-time consumable item. I have made and used a plunger made of aluminum, but the production cost is extremely high, and the slow reaction melts, requiring a thick copper plate for the entire culm.As such, it is troublesome and expensive. In order to avoid using a planter, a method of making Mg alloys and additives with alignment and pushing them into the molten metal is called the alloy block method and has been put into practical use, but it ensures that the added alloy is at the bottom of the molten metal. In order to keep it in place until (・), it is necessary to make the centering considerably thicker, and in order to prevent cracking during the time of addition, a complicated framework such as blades must be built for the centering, and the alloy adhesion resistance is lower than the centering cost. It was inevitable that the cost of assembling the clavicle would be extremely high even though it was a one-time consumable item.

If you think about it this way, plungers always receive the molten metal to be treated, adjust the weight, temperature, and ingredients, and then forcefully push it all the way to the bottom of the molten metal, making it hard and stable. This is an ideal addition method in that it is possible to obtain a high yield.

Despite this, it is not often used because of the problems of cleaning the inside of the plunger and the ventilation holes (which resist the heat of slag), the hassle of heat retention and preheating before and after use, and the fact that graphite refractories are not used. There was a problem with the height of the mold due to the bell-shaped molding, and there was also the inconvenience of not being able to follow the increase or decrease in the processing mold size.

The method of treating molten metal of the present invention completely overturns the concept of the conventional treatment method using a planter, regardless of whether it is made of graphite, steel, or other refractory materials.
Unlike the self-contained type, which must be inserted and pushed into the bell-shaped interior, the idea is completely different in that the outside of the plunger can be accessed.

To explain with the drawings, FIG. 1 is a sectional view of a conventional bell-shaped plunger, and FIG. 2 is a donut-shaped or hollow Mg alloy or Ca
This is an example of an alloy-based treatment agent.・1 Figure 3 is a cross-sectional view of a rod-shaped plunger with a bulge at the bottom according to the present invention.
is a steel rod with a central core, and 2. is a bulge fixed by explosion welding or bolts or other means. This material may be the same as the copper core, or may be made of special steel, ductile cast iron,
It can be made of various different materials such as cast iron. The point is that it is only necessary to maintain the processing time, and 3 is graphite or a refractory material coated thereon in order to extend the life of the copper core as much as possible, if necessary. 4. is a part into which a molten metal processing agent formed into a donut shape, such as a circle or a rectangular tube, is charged, and this hollow processing agent is made of FeSi Mg alloy or F.
e -S 'i-M g-Ca -RE alloy, Fe
-S i -M g -Ca-based alloy, Fe -S
i-Mg-RE alloy, re-Si Mg-Ca
-RE-Ea alloys and these Fe -S i -M
l'l i , Cu + B a , R in g-based alloy
E.

Ca+Zr+Mn+Sn+Ti Various types of S that combine these abilities
iMg alloy, Ni-Mg alloy, Fe-
Ni-Mg alloy, Cu-Mg alloy and N
i-Ca alloy, Fe-S i-Ca alloy, other Ca-based alloys, etc. Alloys of low boiling point substances and active metals such as magnesium and rare earth elements such as calcium and are hollow or doughnut-shaped. The processing agent 8 molded into the mold is attached. (As a related patent, the Japanese Patent Publication No. 57-15
There are 78. ) This rod-shaped plunger can be used not only once but multiple times by using a thick steel rod or by applying a refractory coating to the surface. These copper cores only need to be inserted into the hole of the donut-shaped processing agent, and all that is required is to create a bulge using explosion welding, bolt insertion, or other methods, so high-quality shapes and materials are not required at all, so misrolled products and Low-grade items such as scraps are fine;
The steel ring plunger, which requires complicated manufacturing and machining, is fundamentally cheaper. 5. is a gap of 114" which was made wide to make it easier to charge the copper core. However, if the gap is large like this, there is a risk that it will fall off when it is installed. To prevent this, put something in the gap 5,6.
You can pack it in, but make sure to prevent it from falling out. ! 7 may be wrapped around the upper part of the bulge 2. This drop-off prevention wire 7 may be placed on the molding treatment agent IK in advance, or may be arbitrarily wrapped after the device. Or hang the metal fitting on the side 1m9. You can also attach it. These methods of preventing falling off do not need to be strong; they only need to be strong enough to last until charging.

This is because when it is charged into the molten metal, it is pushed up by buoyancy and is supported by the bulge 2. The violent reaction of the treatment agent after the welding process progresses outward. The outer periphery, top, and bottom of this treatment agent may be coated with a steel plate to reduce damage and reaction during transportation. Also, detachable part 4. Of course, it is also possible to have more than one. However, the advantages described below are generally used when discussing a single attachment part. It has a decisive advantage. The advantage is that it can follow the increase and decrease of the molten metal being processed.

In the case of a self-contained plunger, it is completely impossible to charge more than the specified capacity, and if there is a lot of slag, the capacity may be less than the specified capacity, but it is still a large amount. It was virtually impossible to do so.

In the case of the processing method using the rod-shaped plunger of the present invention, this can be easily carried out. In other words, even if the attachment/detachment part is the same, you only need to increase or decrease the diameter of the treatment agent, even if you use the same rod-shaped plunger! [By changing the dimensions of the filler, it is possible to easily treat any amount of molten metal. In addition, if it is difficult to keep several types of processing agents in stock, the attachment/detachment section 3. It is also possible to leave the number 17 for a long time and attach a plurality of them, such as one or three, as necessary. In this way, the cost of slightly lengthening the attachment/detachment part is negligible, and the temperature drop caused by the jumper and t can be completely ignored. Using a capacitor with a capacity larger than the required one in order to be able to track the temperature (in return, the cost is high, and the capacity to withstand the person itself becomes extremely large, resulting in a large temperature drop.Furthermore, the present invention The advantage of molten metal processing using a rod-shaped plunger is that preheating and heat retention are less troublesome. Among conventional plungers, those with steel cages are used only once, so this point is completely unnecessary. However, those made of graphite and refractories had to be preheated very carefully.In other words, if they are not heated gradually over a long period of time, the later life will be significantly affected and initial cracking will occur. Post-heat retention was also an important way to preserve life.In fact, most of the reasons why bell-shaped plungers are discarded are due to cracks in the bell-shaped body, or due to cracks between the bell-shaped plunger and the shaft. This was due to damage to the gap.

As described above, the shaft part is scrapped due to damage to a portion of the bell-shaped plunger and several pairs of the bell-shaped plungers, even though there is no previous damage, and the lifespan of the shaft is normally said to be approximately 1 to 50 times. However, unlike the bell type, the method using a steel rod-shaped plunger as in the present invention does not have a thin wall part. Because the steel rod shape is completely unrelated to rapid heating and cooling, the delicate thin wall part does not undergo violent reactions. There is no need to consider thermal shock at all, and this tendency can be avoided by using refractories that are resistant to thermal shock or have a small coefficient of expansion, such as silicon nitride or silicon carbide, when necessary. It becomes more and more sophisticated.

Further, when considering the new surface of the bulging portion 8.0 by dividing it vertically, the bulging portion 8.0 may be bulged in any shape such as a semicircle, a triangle, a square, or any other shape. Unfortunately, it would be good if the floating of the hollow molded object could be prevented.◇However, when using a thick steel rod for the purpose of multiple use, care must be taken to prevent the droplets from breaking when the plunger is pulled up. For this reason, it is preferable to use a trapezoidal cross section with a sloped top surface of the bulge, but in the case of the present invention, since the core is originally copper, even if the piping is used multiple times, it is difficult to clean the piping after use. c! There is no need for consideration.

The actual insertion process is shown in Figure 4. As shown in Figure 1, the plunger can be forcibly pushed into the molten metal in the same way as a normal bell-type plunger by free fall from a crane or by other methods. Various types of M shaped into cylindrical, rectangular, or donut shapes using a Kuzu exterior plunger.
This is a method of adding g < alloy or Ca alloy, and it eliminates the concept that the conventional addition of low boiling point substances using a plunger (although reliable, is expensive and complicated), and at the same time, it is cost-effective and easy to use. The advantage of being able to reliably process molten metal is great in industrial production, and the range of application is that it can be used in all kinds of insertion work for Mg-based alloys and Ca-based alloys.Examples will now be described.

Example 1゜Ca, 7%, Si2.1%, Mn0 melted in a low frequency furnace
．． 35%, 30.022%, volume r'35o o K
Take 7 in a pot and add MglO% and S to a graphite plunger.
i45%, g F e's F'e S i M g
A graphite spheroidization process was performed by filling and pressing 5-4Q 71J of 5K7. Similar molten metal 50' OK!
7 is the same as the 60 mm diameter of Misroll steel.
A 1φ rod-shaped plunger made of steel with a bulge made by welding 15 (11) in a cross shape and having a bulge with a length of 150M and coated with alumina refractory. Q 1171φ, height 11
10% Mg similar to the above, with outer and inner periphery covered with thin steel plates.
, 45%Si Fe-Si-Mg alloy hollow donut shape O Reprint of the specification (no changes to the contents) The above result: The method of the present invention does not require careful handling of the plunger, even if it is handled roughly. In addition to these advantages, it is extremely low cost, and the reactions of M and G are gentle and last for a long time (J) It has been found that the Mg yield is high and the spheroidization ability is excellent.

Example 2. C3.7%, Si2%, MnQ melted in a 2°8 ton low frequency furnace
, 4%, 30.020% or less (D 1420 'CC1
Five tons of 1'J hot water were cast into a product with a wall thickness of 150M using the following methods.

■ A plunger made of steel plate with a thickness of 65 toughness and a steel rod of 508φ
It was created with M g 13% and 8145%.
, AJl, 8%, balance Fe 30 ingot of Mg alloy with 1.5%, 9 in 75 was put into the molten ladle (((Pushed) ■ Center steel bar 5 (length of 3501N1
In order to do this, the same 50
2 pieces of wood cut to a length of 3008 mφ (A) (Create a steel bar-shaped blunt gear with a bulge by welding it in rows, and cut the outer periphery with an outer circumference of 3301'llφ, an inner diameter of 70Mφ, and a height of 350M. 6. The inner circumference is coated with a 45 mm thick copper plate, and the lower surface is coated with L(7) M g ']-3%, 8
A mold and donut-shaped molded mass of Mg alloy consisting of 145%/l and 731.8% remaining Fe was placed in a mold and then pushed into the molten metal in a ladle.

The results are shown in the table below.

7 on the statement? (No change in content) Implementation (column 3゜8 tons of Ca, 5%, Si 1.8%,
M n Q, 5%, S O, (195%, 1450
The following methods were tried to desulfurize two tons of source water at °C.

■ A candy-like item made of Fe-Si-Mg alloy consisting of 20% Mg, 3145%, AJ 1.6%, and the remainder Fa, with 42Mφ scraps and 11 hermits attached to a 20 to 9 type alloy block. After taking the bath, I pushed it into the ladle.

■ The length of the attachment part is 250mm and the diameter of the steel bar is 30mm.A steel bar with a diameter of 30mm is cut into 300mm diameter steel bars with a bulge welded in a -1-shape. The outer circumference is 265mm diameter, the inner diameter is 130mm diameter, and the outer circumference is covered with a 45mm copper plate, and the - side and outer circumferential surface are coated with a thick layer of gyriconde refractory. Mg20 so that it reacts only from the bottom
%, Si 45%, AJl, 6%, remaining Fe
-S i -M 20~ type cylindrical molding S i of M g alloy
-Mg alloy was attached and pushed into the ladle molten metal, and the results were as shown in the following table.

As a result of the above, the production cost is 20% lower than that of Chianti, which is more complicated.
It has been found that hot metal can be treated advantageously even by using an Mg alloy treatment agent that is inexpensive and has a long reaction time.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a conventional bell-shaped plunger, and FIG. 2 is a hollow chamber (molded Mg alloy and Ca
@ Implementation of gold processing agent, one example of embodiment, 1 Figure 3 is hollow molding M
FIG. 4 is a sectional view showing an example of an embodiment of the present invention, in which the alloy treatment agent is attached to a rod-shaped plunger used in the present invention and is 9#i "+" so as to be introduced into molten iron. 1...Central steel rod, 2...Floating prevention bulge, 3.
Applied fireproof material, 4. Shield part made of treatment agent, 5. Treatment MJ
1. Gap between the agent and the attachment part, 6. Packing material, 7. Falling prevention 11.
- Wire, 8. Mg and Ca alloy processing agent, 9. Hook fitting, 10. Covering preparation, Moon.. Processing ladle, 12.. Processing lid, 13.. Processing molten metal. (2) Part A 2 Engraving of drawings (no change in content) ) Prisoner 3 Procedural amendment March 1980/fi' 1T1 1 Indication of case Patent application No. 202660 of 1982 2 Title of invention Molten metal processing method 3 Relationship with the case of the person making the amendment Patent applicant

Claims (1)

[Claims] 1 Hollow cylindrical or doughnut-shaped P'e -3i -Mg @gold, Fe-3i molded with a through hole approximately in the center
-Mg-Ca alloy, Fe-81-Mg -Ca -R
E@gold, Fe751-Mg with RE, other materials containing N1, Cu, Zr+Ba, Ti, Mn, Sn, etc., Mg alloys such as Ni-Mg alloy, Ca-S
When adding pure Mg-based additives such as Ca alloys such as i-alloys and Ni-Ca alloys, pure Mg, and pure Mg mixed with RE or RE gold alloys to hot metal, molten steel, and other molten metals, A bulge is provided at the bottom of the copper core by welding, porting, or other methods, and the hollow cylindrical or donut-shaped molding agent float is attached to the bottom of the bulge. A method for processing molten metal in which various Mg alloys and various Ca alloys are added to molten metal while preventing it from occurring.