JPS6010083B2 - Cast iron treatment agent consisting of porous briquettes of specific composition and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cast iron treatment agent comprising porous briquettes of a specific composition for producing spheroidal graphite cast iron or desulfurized iron, and a method for producing the same.

The present applicant has already developed a technology in the above-mentioned technical field.
No. 186513 describes the following invention.

Individual lengths range from 1'8 to 9 inches (approximately 0.32-22 inches).
9), width 1/64 to 1/64 inch (approximately 0.04-2.5
A certain amount of irregularly sized ferrous metal scrap pieces with a thickness ranging from 1 to 100 mils (approximately 0.002 mm) and thickness of The density is 1.2 to 4.0 m/cc with intricate gaps between each piece obtained by pressing under pressure, the porosity is 50 to 85%, and the transverse tensile strength is at least about Based on the total amount of the intertwined network structure (14 kg) and the structure and magnesium present in the above-mentioned gap,
A porous iron-based metal body impregnated with magnesium for use in the desulfurization of molten iron-based metals, characterized in that it comprises magnesium in an amount of 8 to 55% by weight.

In the iron and steel industry, there is a need to reduce the sulfur content of metal products obtained by treating ferrous raw metals in the molten state with desulfurization agents. Magnesium metal is a strong deoxidizer and desulfurizer. However, since "magnesium metal boils at low temperatures," when adding metallic magnesium to molten iron, even though the volume increases rapidly, a violent reaction is triggered as the magnesium metal evaporates. Various methods have been used to reduce this violent reaction by gradually introducing magnesium metal into the metal system.

One of these methods to reduce violent reactions is to impregnate porous bodies with magnesium metal and introduce these magnesium-impregnated porous bodies into molten ferrous metals. Under these conditions, the impregnated magnesium metal is released at a sufficiently slow rate that violent reactions are kept to a minimum. Monster bodies include porous coke, carbon and graphite as well as ceramic bodies such as quicklime, limestone blocks and dolomite.

Furthermore, porous iron bodies impregnated with magnesium are also used.

These known iron bodies are sponge iron, in which the iron particles are very closely cemented together to form a porous structure. Sponge iron itself is cheap to manufacture and use. Forming large porous structures from sponge iron requires the use of expensive means. The pores in sponge iron are extremely small, so when magnesium-impregnated sponge iron is immersed in molten iron, the release of magnesium may be too slow for optimal operation. It's also too quiet. Sponge iron also contains oxides that react violently with magnesium, which impairs efficiency.
Another conventionally used method is to pressurize iron particles and magnesium particles together to produce iron rickets containing magnesium; each particle used in this method has a size of 4 to 6 mesh. (All mesh dimensions used in this specification are Tyler screen sizes.) When these briquettes are used to desulfurize molten iron, the structure of the iron that remains as the magnesium melts is clearly weakened, and therefore magnesium is released extremely rapidly, resulting in a violent reaction.In order to solve the above-mentioned problems, the applicant has completed the above-mentioned invention.
Disclosed in an existing application.

When the metal obtained by compressing scrap impregnated with magnesium metal within the values specified in the invention is used for desulfurization of molten iron, it does not involve violent reactions and quickly releases magnesium metal. do. Special face Showa 49-865
The structure disclosed in No. 13 can also be used for the production of spheroidal graphite cast iron, but we have now found that it can be impregnated with an even smaller amount of magnesium metal. It has been found that using a metal structure that is more efficient and generates less smoke. More particularly, the present invention relates to a cast iron treatment agent for use in the construction of spheroidal graphite cast iron or desulfurized iron.

32~22.9 skin width 0.04~24 arc~thickness 0.
00254 ~ 0.254 skin ~ compressed together in a disordered state with intricate gaps between each piece, but with a lateral tensile strength of at least 0.14k9 and greater than 4.0 t/cc So 6.

Consisting of an aggregate of irregular ferrous metal scrap pieces forming an intertwined silk-like body with a density of 3 cc or less and a porosity of 20% or more and less than 50%, and magnesium impregnated in the interstices, The present invention provides a cast iron treatment agent characterized in that the amount of magnesium is 5% by weight or more and less than 1% by weight based on the total weight of the aggregate and the magnesium.

When the treatment agent of the present invention is used in the production of spheroidal graphite cast iron, the reaction of magnesium is gradual, and therefore the decrease in the amount of magnesium due to volatilization is very small, and therefore the efficiency of using magnesium ink is very high.

Approximately 21'2 to 51'2 pounds (tortoise. 13-2450k)
9) Magnesium is used to form 1 ton of spherical iron.

This molten iron treatment agent made of porous briquettes is manufactured by selecting from scrap iron pieces, especially steel chips, within the following size ranges, as described in Tokuhan No. 86513/1983. Ru.

Length 1'8 to 9 inches (approximately 0.32-22.
Autumn) Width 1'64 to mountain inch (approximately 0.04-2
．． 54) Thickness: 1 to 100 mils (approximately 0.002 mm - 0.254 mm) Scrap metal pieces within this size range typically have a high density of 0.1 to 1.0 mm/cc. are doing.

In the present invention, these metal pieces are compressed to form a ferrous metal network having a density of greater than about 4.0 and less than 6.3 min/cc.

The porosity of this tissue is 20 or more and less than 50%, and at least 2. It has a short transverse tensile strength of approximately 0.14 k9/ground). This iron-based metal network structure is then immersed in molten magnesium metal and held there for several minutes to allow molten magnesium metal to seep into the gaps.The impregnated structure is removed from the molten magnesium and cooled. , the molten magnesium is solidified. This cooling is preferably carried out in the absence of an oxidizing atmosphere.
One preferred method for cooling the compacted and impregnated metal body is to submerge the impregnated silk-like body in an oil bath. The final product consists of a porous structure comprising a compressed metal network impregnated with magnesium metal.

This structure contains at least 5% by weight and less than 1% by weight of magnesium metal, based on the total weight of the impregnated metal body. The porous iron-based metallographic structure of the present invention is superior to porous bodies produced by conventional techniques in impregnating magnesium. The porous body of the present invention is not only capable of absorbing and retaining a desired amount of magnesium. When used to desulfurize iron, it releases magnesium metal in a short period of time without causing a violent reaction. The porous body also retains structural strength while releasing magnesium. This is necessary to prevent violent reactions from occurring and is advantageous as the magnesium is released in a controlled manner. Furthermore, by using this specific type of porous body impregnated with magnesium, the iron-based metal remaining in the porous body is dissolved into the molten metal. This type of ferrous metal body is strong enough to withstand processing prior to impregnation, yet retains the desired amount of magnesium metal. It has also been found that porous bodies of this material can be produced from readily available raw materials. This is also an advantage.

The density of the compressed iron-based metal network is 6.3/cc
In higher cases, the amount of magnesium contained in this compressed tissue will be below 5% by weight. If the magnesium content is below 5% (by weight), large amounts of scrap metal may be added to the molten iron along with the magnesium, and the molten metal may then be sufficiently cooled. This cooling effect is not desirable. As mentioned above, the amount of magnesium contained in the scrap iron structure is preferably below 18% (by weight) when used in the production of spheroidal graphite cast iron. Above this amount, the reaction will be faster but not as vigorous. Within this range, the reaction is still fast, but slow enough to prevent large amounts of magnesium from volatilizing. Scrap metal scraps useful in this invention include iron, etc. is more preferably steel.

As mentioned above, the scrap metal pieces must be within a specified size range. If the scrap pieces used are outside this specified size range, impregnation into the metal network will be difficult and/or the magnesium release rate may deviate from the preferred values.
The most desirable types of scrap metal are those that fall within the ranges previously specified, have irregular shapes, and have various sizes.

The most desirable material is fine metal chips or a jumble of short metal pieces. In the present invention, the compressed porous metal body produced may also be impregnated with an alloy.

Particularly desirable alloys for use include alkali metals, aluminum, silicon and rare metals such as cerium, lanthanium, or misch metals.
These are rare metal alloys such as metals, or magnesium alloys containing these metals. The term "magnesium" used in this specification is ~
It shall mean both magnesium metal and alloys of magnesium metal. The molten iron treatment comprising impregnated compressed porous steel structures produced in accordance with the present invention has the following advantages over those of the prior art:

'1} It has a certain porosity and therefore can hold a desired amount of magnesium metal.

{2} The produced eel-containing structure is strong in structure and can withstand high temperatures until it releases magnesium during processing of molten iron.

t3} The immersion structure contains 5% by weight or more and less than 5% by weight of magnesium, and is used to manufacture L-spheroidal graphite cast iron.The reaction at this time volatilizes much of the magnesium content. It is slow enough to prevent this, but far enough away. The reaction time for the release of magnesium from the impregnated structure is typically 1'2-10 minutes. {4} The magnesium-containing structures produced in the present invention have a uniform composition and provide reproducible results when used in processing molten iron.

(5'The addition of certain types of magnesium-impregnated horizontal structures (using iron or steel as skirtings) to the molten iron eliminates the need for subsequent removal of the structure from the molten iron.

{6} The scrap metal melts after the magnesium is released, which melts the iron and eliminates the need to remove the carrier after plowing.

Scrap metal is generally coated with oil.

This coating may be removed before bonding if desired. One method of degreasing is to heat the scrap and incinerate the oil. This heating can be done either before or after compaction. Good. However, it is economically advantageous to heat the compacted metal to simultaneously remove oil and subheat the metal before compressing the scrap metal and then placing it in molten magnesium for impregnation. When heating scrap metal before adding it to molten magnesium, great care must be taken to avoid excessive oxidation of the scrap metal.

The oxides present “react with magnesium metal,
When used in the processing of ferrous metals, it can intensify the reaction and consume significant amounts of magnesium, reducing efficiency. The increase should not exceed 3% and preferably should not exceed 1%.

Preheating temperature in air is approximately 5000F (approximately 26000F)
) to 10,000 F (approximately 540 q0).

Temperatures up to around 12,000F (approximately 650o○) can also be used; however, in this case, the preheating time should not exceed 1 hour.Of course, if the preheating is performed in a non-oxidizing atmosphere, the preheating temperature The upper limit of is not critical.

When storing magnesium-impregnated structures, care must be taken to prevent magnesium from reacting with moisture. This can be done by enclosing the impregnated structure in a suitable container or placing the impregnated structure in a metal can with an airtight lid.
This can be easily achieved by adding a desiccant together. EXAMPLES In order to explain the present invention in more detail, examples are shown below.

Example 1 In this example, scrap iron briquettes were made using a roll mother briquette making machine.

This machine has the following specifications. roll diameter
12 inches (approximately 30.5 arcs) Number of briquettes 32 roll motor 20 horsepower feed motor 5 horsepower Roll separation was adjusted so that the briquettes had a density of 6.2 cc.

Used in this example. The steel scraps have a thickness of 5 threads and 10 mils (approximately Q0127-Q.0254 width I〆8-?
n6 Ijichi (about D.

32-1.

11 cases) and length 3〆8-2 inches (approximately 0.

95-5.08 cases).

The steel shavings are placed in a worm gear type feeder and the roll motor speed is adjusted to p. .91) 2 inches deep (approximately 1827 skins)
Each briquette had a weight of about 46 kg.

Accurate measurements of volume were made by the mercury dilation method - the volume was 7.4 cc After incineration of the oil in the open of a Q 9000F (approximately 48 G0) - the briquettes were immersed in molten magnesium. The average weight increase due to magnesium metal immersion was 6%. Example 2 Using the method described in Example 1, the roll separation is increased using a shimstok to reduce the density of the briquettes to 5.1 cc.

The weight of the briquettes was measured to be 38 cm and the volume to be 7.5 cc. The treated briquettes were immersed in molten magnesium again, resulting in an average weight increase of 12%.
3 The product containing 6% magnesium produced in Example 1 was used to produce desulfurized iron.

The treated iron was heated to 24°C at 26,500F.
It was 00 pounds (about 1100k9). The amount of added product containing magnesium is 54 lbs.
9). This corresponds to adding 2.7 pounds of magnesium per ton of metal being treated. The initial sulfur content in the iron was 0.035%. When the release time of magnesium was measured, it was found to be about 5 times the sand. The final amount of sulfur in the iron was measured to be 0.007.
%Met. The iron produced was ductile. Remaining magnesium was measured at various times after treatment. The results are as follows. Time Residual magnesium 0 0.035% 1 minute 3 bait sand
0.034% 3 minutes
0.033% 3/4 inkstone sand 0.03
3% 6 min 0.033% Example 4 The 12% magnesium product produced in Example 2 was used to produce desulfurized iron.

The amount of metal processed was 2400 pounds at 26800F (about 1472C). The magnesium containing product was added in an amount of 30 pounds. This corresponds to 3.1 pounds (approximately 1.36 k9) of magnesium added per ton of metal to be treated. The initial sulfur content in the iron was 0.037%. The reaction time was about 1 minute. The final value of sulfur content in the iron was determined to be 0.010%.

The obtained iron was ductile. The remaining magnesium is expressed as a function of time as follows: time
Residual magnesium 0 0.035% 1/3 sand
0.035% 3 minutes
0.033% 4 minutes 3 Uta sand 0.033% 6 minutes
0.034% Example 5 In this example, the same size steel shavings as described in Example 1 were used.

78.5 mm of this steel milling material is compressed into a compression chamber (diameter 13'4 inches (approximately 4.45 arcs), height 3 inches (approximately 7.62 arcs)).
24 tons of 1 square inch (approximately 6
．． 4516) to a diameter of 1.858 inches (approximately 4.72 inches) and a height of 0.315 inches (approximately 0.80 inches).
0 arc) briquettes were manufactured.

The density of this briquette was 5.61 m/cc. The compressed briquettes were incubated at 9600F for 10 minutes, thereby incinerating any oil on the crumbs.

When I reweighed this briquette, it was 77.5 m.
The oil removed is 1. The amount was % Marugame. The pricket was then immersed in molten magnesium at 14,000F (approximately 7,600C) for 10 minutes. After dipping, the briquettes were removed from the molten magnesium, cooled, and reweighed. This briquette showed a weight of 88.0 mm and 11. Contained $% by weight of magnesium metal. EXAMPLE 6 In this example, the same steel mill 167 mm was milled at a pressure of 50 tons per square inch (6.4516 mm) to a diameter of 13'.
4 inches (approx. 4.45 arc), height 6 inches (approx. 15.2
4 kites) was compressed in a compression chamber.

The resulting briquettes had a diameter of 1.8 inches, a height of 0.653 inches, and a density of 6.13 mm/cc. 9 compressed briquettes
Heat to 600F (approximately 51 degrees Fahrenheit), which incinerates all of the oil on the crumbs. The briquette was reweighed and found to be 15.3 yen, with 8.4% oil removed. This briquette was then heated to 14,000F (approximately 760F).
One powder was soaked in molten magnesium (00).

After soaking, the briquettes are taken out from the molten magnesium,
Cool and reweigh. This briquette had a weight of 171.0 kg and contained 10.5% by weight of magnesium. When the briquettes obtained in Examples 5 and 6 were used to treat molten iron, the release of magnesium metal was far away.

Moreover, no additional magnesium was lost.
In the following examples, rather than using magnesium metal alone, a magnesium alloy was used to impregnate the scrap metal network.

Examples 7-8 In this example, the steel shavings described in Example 1 were placed in a compression chamber (13.4 inches in diameter).
5 skin), height 3 inches (approximately 7.62)) and insert it into the
square inch (approximately 6.

A pressure of 11.0 tons was applied per cylinder.

The dimensions of the resulting briquettes are 1.86 inches in diameter (approximately 4
．． 72) height 0.36 inches (approx.

915 sections), and the density was 4.6 knots.

The compressed briquettes obtained in Example 7 were then heated to 8000F.
(approximately 4270C) for 30 minutes to incinerate the oil on the ground crumbs.

After preheating, the compressed briquettes of Example 7 were added to the melt of magnesium metal alloy containing 50% misch metal.
The briquettes obtained after soaking for 0 minutes were 17. Contains 2% by weight of magnesium misch, metal. In Example 8, briquettes having a density of 4.96 mm were used.

The briquettes were ripened and then macerated for a minute in molten magnesium metal containing 16% by weight of calcium metal; the resulting briquettes contained 15% by weight of magnesium-calcium metal. These briquettes obtained in Examples 7 and 8 contain not only magnesium metal but also metal.

Contains metal or calcium. ``These can also be used in the treatment of molten ferrous metal in the same manner as the briquettes obtained in the examples given above.As can be seen from the description and examples given above, the desired amount An improved type of molten iron treatment agent is obtained which consists of a strong iron-based metal network suitable for impregnation with magnesium metal.

Claims (1)

[Scope of Claims] 1. A cast iron treatment agent comprising porous briquettes for producing spheroidal graphite cast iron or desulfurized iron, each having a length of 0.32 to 22.9 cm and a width of 0.04 cm. ~2.4c
m, thickness between 0.00254 and 0.254 cm, randomly compressed together with intricate gaps between each piece, and a transverse tensile strength of at least 0.14 kg/cm^2. , 6.3g/cc above 4.0g/cc
It consists of an aggregate of irregular iron-based metal scrap pieces forming an intertwined network having a density of 20% or more and a porosity of less than 50%, and magnesium impregnated in the gaps; The amount is 5% by weight or more and 18% by weight based on the total weight of the aggregate and the magnesium.
A cast iron treatment agent characterized in that the amount is less than or equal to 2. A method for producing a cast iron treatment agent comprising a porous briquette for producing spheroidal graphite cast iron or desulfurized iron, comprising:
They have a bulk density of 0.1 to 1.0 g/cc, and have a length of 0.32 to 22.9 cm and a width of 0.04 to 2.54 cm, respectively.
and a scrap piece of ferrous metal with a thickness of 0.00254 to 0.254 cm, and the piece has a density of 4.0 g/c.
Above c, 6.3/cc or less, porosity 20% or more 50%
less than and transverse tensile strength of at least 0.14 kg
/cm^2, and the metal network is placed in a magnesium bath, and the amount of magnesium is 5% by weight or more and less than 18% by weight based on the total weight of the network and the magnesium. 1. A method for producing a cast iron treatment agent comprising porous briquettes, which comprises soaking the porous briquettes for a certain period of time under conditions such that the amount of porous briquettes becomes 100% of the molten magnesium.