JPS6067614A - Raw material for steel making - Google Patents

Abstract

PURPOSE:To enable low melting point metals to contain uniformly in molten steel with good yield by using pelletized powder mixture of said low melting point metals and iron or other metals. CONSTITUTION:Low melting point metals such as Pb, Bi and the like are added to the steel for improving the properties to machining of the steel, wherein powders of Pb and Bi the particle size is 0.1mm. or less, are mixed with other metal powder, which may be acceptable to contain in Fe and other free cutting steels, in such wide range or ratio as 5:95-95:5. The mixture is formed to briquet shape having 5-50mm. in size or cylindrical shape of 30mm. in dia. and about 15mm. in height. By adding this into molten steel, free cutting steel can be obtained without lowering yield of steel due to oxidation or evaporation and/or remaining by precipitation of Pb and Bi etc. at the bottom part of the molten steel.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steelmaking raw material to which a low melting point material is added for use in the production of C-containing steel containing a low melting point material as an alloying component.

For example, in the production of free-cutting steel, low melting point metals such as [3i and] IJ are added to molten steel as alloying components. However, when such low 11 point metals are added in the form of powder or particles, they quickly melt due to the heat of molten steel.
Some of it evaporates and is oxidized, resulting in a low yield in the steel.Since 181 and Pb have a higher specific gravity than FO, when lump CIA is added, they accumulate at the bottom of the container and become uniform. IP matching is difficult. powder or particles
It was attempted to add i;/1 to rl-t of ev<+, but it was difficult to make the apparent specific gravity larger than that of molten steel.
Because it is difficult, it is not very effective. Alternatively, Bi or P
There is a technique in which a wire wrapped in iron is prepared and the required width is continuously fed into the molten steel to add it, but this requires a separate feed device for the production of W-V. , 2j
Invite strike J%. Therefore, the most commonly practiced method at present is to place Bi or Pb powder on a carrier gas and blow it into molten steel.

An object of the present invention is to make it possible to add metals with low melting points and high specific gravity, such as 3i and Pb, more easily and with a high yield.

IJA for adding low melting point materials of the present invention that achieves this purpose
Steel raw materials are made by mixing powder of an alloy component made of a low melting point material with powder of iron or other alloy components and forming the mixture into a pellet shape.

The low melting point material is typically [3i, Pb, or a mixture thereof, but the present invention is generally useful for adding materials with a melting point of 800° C. or lower, and can also be applied to compounds.

The shape is arbitrary as long as it does not interfere with pelletization, and particles with a diameter of 5 mm or less can be used, but usually particles with a diameter of 1 mm or less can be used.
Powder of mm or less is easy to use.

Powders or particles of iron or other alloy components to be mixed with the powder and pelletized can be selected as long as their addition does not substantially change the molten steel components.

In some cases, the addition of J: may be necessary to obtain the desired alloy composition.

Alternatively, you can use a combination of elements to create υ-C. .

The form of the powder is similar to the one produced in Bere 7i (any particle with a diameter of about 1 mm can be used, but it is generally preferable to use a very fine powder, especially if the particle size of the low fAli point material is 1 mm or so). mm or more 12una'A
Powder of 11 m or less is J: Yes.

Combining low melting point 44 materials with iron or other alloy components 1811
In this case, the /J specific gravity of the pellet is determined together with pellet 1~molding conditions, so the appropriate /J specific gravity is 1.
η to be J: Sea urchin selection J is 0, 1[・ri31
-11, (low melting point material): (ridge or other alloy component) = 5:95 to 95:5, or 1)) can be selected. In addition, if necessary for molding, use an appropriate binder.

The pellets are formed according to the powder forming technique (can be carried out using a press or roll). However, a cylindrical shape with a diameter of 30 mm to 50 mm, for example, a diameter of 30 mm + nn Select the above-mentioned compounding ratio and molding conditions to obtain the appropriate Kaza specific gravity. If the pellet is too heavy, it will reach the bottom of the container before it is completely melted; if it is too light, it will melt on the surface of the molten metal. As a result, low melting point materials may evaporate or oxidize.

The mechanism by which the steelmaking raw material of the present invention exhibits a good yield is considered to be as follows. That is, when the pellet is thrown into molten steel, the iron or other alloy in the pellet absorbs the heat of the molten steel, suppressing the temperature rise of the low melting point material, and if the specific gravity of the pellet is appropriate, the pellet 1 ~ settles in the molten steel without being significantly deformed, progresses at an appropriate speed and gradually melts from the surface, and when the temperature of the whole pellet reaches or exceeds the melting point of the iron or other alloying components, the entire pellet is melted. It melts and diffuses uniformly into the molten steel.

The low yield of low melting point materials is not only cost-effective, but also increases the rate of progress to the desired alloy composition, reduces the amount of dust (for example, Pb0) in the waste, and The IYi pirates will have the benefit of shouldering the burden of handling the process.

11 Prepare Bi powder and Pb powder with a particle size Q of 5 mm or less. 0 gold powder (C
: 0.1%, MU: 0.7%, the remainder is essentially Fe)
and compounded according to the t II precept shown in Table 1, and by press molding,
It was made into a cylindrical pellet with a diameter of 30 mm and a height of 15 mm.

Table 1 No. s;- Mr. L Shoepu JL (substitute coating) DLl 50
− 50 −− 2 25 − 75 −1 10 − 90 4 70 − 30 −− 5 50 50 −− 6 20 20 60 −− 7 2020 30 30 These pellets 1 to 1 were heated to molten tf at a temperature of 1600°C.
4 (C: 0.1%, Mu: 1.2%, the remainder is substantially F
e) The content of 81 Pb in the ingot obtained by casting was measured and the yield was examined.

For comparison, 3i particles (diameter 3 mm) or Pb particles (
The yield was investigated when a steel sheet with a diameter of 2 mm was directly put into molten steel.

The above results are shown in Table 2. It is clear that according to the present invention, the yield of low melting point products is improved.

Table 2 1 dan ``L mouse car dan ±'' L mouse sea 1 65% -% 2 73 - 3 85 - 4 58 - 5 81 6 68 75 7 70 27 △ 13 - Bi powder addition 8 38 Pb powder Addition C1537 Bi 10Pb (50+50) Addition Patent Applicant Daido Toku IA #9 Co., Ltd. Ne1- Agent Patent Attorney Sodai Suga

Claims (3)

[Claims] (1) A steelmaking raw material for adding a low melting point material, which is obtained by mixing powder of an alloy component made of a low melting point material with powder of iron or other alloy components and forming the mixture into a bellet shape. (2) 5 to 95% low melting point material in proportion. Steelmaking raw material according to claim 1, in which iron or other alloying components each account for 95 to 5%. (3) The steelmaking raw material according to claim 1 or 2, wherein the low 811 point material is a mixture of Bi, PB, or 3i and pH.