JPS6111306B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an additive alloy for introducing antimony into cast iron. It is generally known that when ferrite appears in a cast iron base, both hardness and tensile strength decrease. In recent years, it has been found that adding a small amount of antimony to cast iron is extremely effective in preventing the formation of ferrite in cast iron. In addition, the amount of antimony added to molten cast iron may be as small as 0.01 to 0.06%.
It has also been found that adding more than this will actually reduce the tensile strength. Conventionally, antimony added for the above purpose is all refined and used as metallic antimony, so antimony oxide and vapor are generated when added to high-temperature molten metal. Recently, there has been an increase in the addition of antimony to high-temperature molten metals to suppress ferrite in cast iron at a relatively low cost, but antimony oxides and steam generated have become a major problem in terms of the working environment. As is already known, antimony oxides and vapors are considered to be extremely harmful. Therefore, in factories with extremely strict working environments, tin was used to suppress ferrite, even though it was expensive and had no fear of generating oxides or vapors. The following is generally said about the harmfulness of antimony. Antimony metal itself is not toxic, but its compounds, especially oxides and vapors, can cause neurological disorders and headaches.
Symptoms are said to include pain, vomiting, enlarged thyroid gland, and decreased reproductive function. In order to improve the hardness and tensile strength of cast iron at a low cost, the present invention makes it possible to safely and reliably add antimony to molten cast iron, and at the same time to reduce the amount of antimony oxide and vapor caused by the addition of antimony. The purpose is to prevent the production of harmful substances such as pollution, and to prevent pollution. In the present invention, antimony is added to prevent the formation of ferrite, which causes a decrease in the hardness and tensile strength of cast iron. Basically, antimony is added to prevent the formation of harmful substances caused by the addition of antimony, and In order to ensure the addition of antimony, antimony was alloyed with silicon and added in the form of a ferrosilicon antimony alloy consisting of 5 to 50% by weight of antimony, 25 to 70% by weight of silicon, and the balance iron and unavoidable impurities. It is something. In addition, if the content of antimony is less than 5% by weight, the addition effect cannot be sufficiently obtained, and if the content of antimony is less than 5% by weight,
If it exceeds this range, it will not be possible to sufficiently suppress the generation of oxides and steam, so it is set in the above range. Silicon is added to suppress the generation of antimony oxides and vapors, but if its content is less than 25% by weight, its effect will not be sufficiently obtained;
If it exceeds this, the effect will be saturated, so it was set in the above range. In general, the more alloyed the metal is, the more difficult it becomes to generate oxides and vapors of the metal. It has been found that alloying antimony with silicon, commonly used as a cast iron component, dramatically reduces the amount of oxides and vapors generated during high temperature additions. In other words, it has become possible to put into practical use a ferrosilicon antimony (Fe-Si-Sb) alloy by replacing the inexpensive and effective antimony with tin at the same time as the inoculation operation. However, in order to be more thorough in terms of pollution, if the alloy added according to the present invention comes into contact with the boundary between the molten metal surface and the atmospheric surface when adding high-temperature molten metal (in a situation where the alloy floats on the surface of the molten metal) )
In order to completely prevent the generation of antimony trioxide, alkaline earth metals, which have a much higher affinity for oxygen than antimony, are sometimes contained. Calcium has the strongest affinity for oxygen, so calcium is the most suitable, followed by magnesium.
Calcium is best because the calcium oxide film it generates is strong, so it has a particularly strong effect of preventing oxidation of antimony in this alloy. However, magnesium, barium, and strontium are all effective in quickly fixing oxygen that absorbs oxygen near the alloy and becomes harmful antimony trioxide. For such a purpose, the upper limit of these alkaline earth metal elements is set at 10% because it is sufficient to achieve the purpose. Similarly, rare earth elements have an overwhelmingly higher affinity for oxygen than antimony, so they are effective in preventing oxidation of antimony and improving yield. Furthermore, one of the purposes for containing rare earth elements is when the alloy according to the present invention is used in ductile cast iron.
Generally, antimony is said to be an element that inhibits the spheroidization of graphite in ductile cast iron, and is one of the elements that should be avoided. However, in the case of extremely thick ductile cast iron, there is a phenomenon in which the spheroidization in the center tends to collapse, and in such cases antimony
It is said that adding a very small amount of about 0.005% can greatly improve the spheroidization situation. When antimony is added to a casting for this purpose, if the cross section of the casting has both a thick part and a thin part, antimony works to improve the graphite shape in the thick part, but it improves the graphite shape in the thin part. On the contrary, it exhibits a complex action that inhibits the spheroidization of graphite. However, when the alloy of the present invention is used for the purpose of improving the shape of graphite in thick-walled parts of cast iron, the rare earth elements show an excellent effect in neutralizing the spheroidal inhibiting effect of antimony on thin-walled parts. In order to prevent the effect of inhibiting graphite spheroidization in thin-walled parts of ductile cast iron, the additive alloy according to the present invention may contain up to 10% of rare earth elements. Furthermore, the alloy of the present invention can exhibit an even more synergistic effect by containing an element that stabilizes pearlite and increases strength by incorporating it into cast iron. These elements include tin, nickel, chromium, molybdenum, manganese, vanadium, tungsten, copper, niobium, etc. However, if each of these elements is contained in an amount of 20% or more, the antimony alloy loses its low price, and cast iron In order to avoid the requirement of stabilizing pearlite without generating white pig iron in the base, the upper limit was set at 20%〓〓〓〓〓
The total amount is set at 20%. The alloy of the present invention may contain up to about 1% of sulfur, phosphorus, aluminum, and other incidental elements and impurities depending on the raw material situation, but the amount added in actual operations is very small, for example, 0.05% to 0.2%. Therefore, it is not a problem. In carrying out the present invention, ferrosilicon,
Metals or alloys such as ferrochrome, copper, ferronitkel, ferromanganese, calcium silicide, tin, etc. may be added at the same time as the alloy of the present invention, and fluorite,
At least one type of flux such as magnesium fluoride, calcium chloride, shelf sand, soda ash, calcium carbide, graphite, etc. may be used simultaneously. According to the present invention, high quality cast iron can be easily obtained by adding antimony, which is inexpensive and highly effective, to molten cast iron without disturbing the working environment, and has extremely high industrial utility value. Examples will be described below. Example 1 C3.15%, Si2.05 melted in a 5-ton low frequency furnace
%, Mn 0.70%, P 0.035%, S 0.047%, and the balance was Fe by pouring 200 kg of molten metal into a red-hot ladle with the following alloys and/or metals on the bottom. The structure and mechanical properties of each cast iron were tested. Sb45%, Si39.5%, impurity mainly Al0.4
%, the balance is Fe, the present alloy 0.08%, and Fe
-Si grains (75%Si) 0.2% Sb10%, Si51%, impurities mainly Al0.7%,
Inventive alloy 0.36% consisting of Ca 0.2% and balance Fe 0.09% metallic tin and 0.25% Fe-Si (75% Si) 0.036% metallic antimony and Fe-Si grains (75%)
Si) 0.25% Fe-Si grains (75%Si) 0.25%

[Table] Example 2 3.2% C, 1.95% Si, melted with 3 tons of Kyupora,
Composition of Mn0.75%, P0.055%, S0.08%, remaining Fe
100 kg of raw water at 1450°C, 0.1% of the present invention alloy consisting of 40% Sb, 7% Ca, 40.5% Si, and the remainder Fe and 0.2% Fe-Si grains (75% Si).
% added. 0.08% metallic tin and 0.2% Fe-Si grains (75%Si)
% added. Only 0.2% of Fe-Si particles (75% Si) was added.

[Table] Example 3 C3.3%, Si2%, melted in a 300Kg high frequency furnace,
The following tests were conducted on 100 kg of 1600°C molten metal containing 0.6% Mn, 0.035% P, and 0.065% S. 〓〓〓〓〓
0.4% of metallic antimony powder was added. Sb40%, Ca5%, Mg1%, Ba1%, Cr3%,
1% of an alloy consisting of 2% Mn, 3% Cu, and 30% Si was added. Result

[Table] Example 4 C3.85%, Si2.36%, molten in a 5 ton low frequency furnace,
The ductile base melt consisting of 0.31% Mn, 0.030% P, and 0.015% S was subjected to the following treatments, and each treated molten metal was placed on the outer edge of a 25 m/m Y block 15 mm x 15 mm.
The spheroidization of the thick center of the Y block and the center of the thin wall of the Y block cast in an integral flan sand mold with a thin wall of mm x 40 mm was observed. As Mg4.5%, Ca5%, Si45%, Al1% residue
Mg alloy consisting of 1.3% Fe and Fe-Si (75% Si)
0.3% was added to the molten metal by the Sanderch method and cast into the sand mold. Same amount of Mg alloy as 8% Sb, 45% Si, balance
Antimony alloy 0.1% consisting of Fe and Fe-Si (75
%Si) 0.25% was added to the molten metal and cast into the sand mold. The same Mg alloy with the same amount of Sb8%, RE7.5%,
Antimony alloy consisting of 45% Si and remaining Fe 0.1%
0.25% of Fe--Si (75% Si) was added to the molten metal and cast into the sand mold.

[Table] Example 5 C2.85%, Si1.4%, melted in a 5 ton low frequency furnace,
FC source water consisting of Mn0.8%, P0.043%, S0.058%
After the following additions were made to 200Kg, each test piece was cast into a 30mmφ test piece. 38% Sb, 38% Si, 1% Al, 0.1% alloy consisting mainly of Fe, and 0.3% 75% Fe--Si were added. As Sb40%, Si42%, Ca5%, Al1% residue
0.1% of an alloy consisting of Fe and 0.3% of 75% Fe-Si were added. 0.1% of an alloy consisting of 38% Sb, 25% Si, 1% Al, 10% Ca, and residual Fe and 0.3% 75% Fe-Si were added. Sb38%, Si25%, Al0.8%, Cr10%, Cu9
%, alloy consisting of residual Fe 0.1% and 75% Fe--Si 0.3%
was added. Sb38%, Si25%, Al0.8%, Cr7.5%, Mo6.3
%, Nb5.8%, balance Fe alloy 0.1% and 75%
Fe—0.3% of Si was added. Only 75% Fe—0.3% Si was added.

[Table] 〓〓〓〓〓

Claims (1)

[Claims] 1. An additive alloy for introducing antimony into cast iron, consisting of 5 to 50% by weight of antimony, 25 to 70% by weight of silicon, and the balance iron and unavoidable impurities. 2. An additive alloy for introducing antimony into cast iron, which contains 10% or less of an alkaline earth metal in an alloy consisting of 5 to 50% by weight of antimony, 25 to 70% by weight of silicon, the balance being iron and unavoidable impurities. 3. An additive alloy for introducing antimony into cast iron, which contains 10% or less of a rare earth element in an alloy consisting of 5 to 50% by weight of antimony, 25 to 70% by weight of silicon, the balance being iron and unavoidable impurities. 4 An alloy consisting of 5 to 50% by weight of antimony, 25 to 70% by weight of silicon, the balance iron and unavoidable impurities, with an alloy selected from the group consisting of nickel, copper, chromium, manganese, molybdenum, vanadium, tin, tungsten, and niobium. Additive alloy for introducing antimony into cast iron, containing 20% or less of one or more of the above. 5 An alloy consisting of 5 to 50% by weight of antimony, 25 to 70% by weight of silicon, the balance iron and unavoidable impurities, with 10% or less of alkaline earth metal, nickel,
An additive alloy for introducing antimony into cast iron, containing 20% or less of one or more selected from the group consisting of copper, chromium, manganese, molybdenum, vanadium, tin, tungsten and niobium.