JPS5836663B2 - Method for manufacturing magnetic ferronitskel alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a magnetic ferronickel alloy that is inexpensive and capable of being attracted by a magnet.

Ferronickel alloys are used as raw materials for stainless steels and special steels, and to some extent for their preparation, and are usually produced by the ferronickel smelting method.

The ferronickel smelting method is carried out by melting or semi-melting nickel-containing oxide ore such as garnierite ore in an electric furnace, melting furnace, rotary kiln, etc. and reducing it with 6 carbonaceous reducing agents. In the operation of
It is adjusted to obtain crude ferronickel with an i + O o content of 18% by weight or more (Co is usually 1/20 or less of Ni).

However, the crude ferronickel produced in this way is S
．． Since it contains impurities such as , 0, Si, Mn, P, and Or, after further treatments such as desulfurization, decarburization, and desiliconization,
It is a ferronickel alloy in the form of granulated shot or ingots.

In the past, low carbon ferronickel (00.02% by weight or less) from which impurities were sufficiently removed through such treatment was mainly used, but in recent years it has been used in various special steel smelting methods including stainless steel smelting methods. Technological innovations have been made in melting furnaces, peripheral equipment, etc., and ferronickel alloys for raw materials and to some extent adjustments have been changed from low carbon ferronickel to carbon 0.25 to 3.
High carbon ferronickel containing 0% by weight has come to be used (by the way, those with a carbon content of 0.02 to 0.25% by weight, which is between low carbon and high carbon, are called medium carbon ferronickel. ).

The reason for this is that high-carbon ferronickel can be obtained by simply desulfurizing crude ferronickel, and in some cases even requires a simpler desiliconization process; This is because it is simple and can be manufactured at low cost.

However, conventionally used low-carbon ferronickel is magnetic, so it can be attracted to a magnet and moved and charged in the same way as iron scrap, but normally produced high-carbon ferronickel is generally magnetic. This has the disadvantage that such a magnetic transfer means cannot be applied.

For this reason, there has been a desire for an inexpensive nickel alloy that is low in carbon and has magnetic properties comparable to that of nickel.

The present invention was made in response to such a request, and provides a method for manufacturing a magnetic ferronickel alloy that can be attracted by a normal moving magnet.

To achieve this objective, the present invention provides shot-shaped magnetic nickel alloys in which Ni is 18 to 29% by weight, Si is 0.5% by weight or less, and C is 6.15% by weight.
A molten ferronickel alloy containing at least 0.213
is 18-29% by weight, C is 6.15-0.213Xx+
0.5X (y 0.5) weight% or more [where X is Ni%
, y is Si%], and the molten ferronickel alloy containing at least 0.1% by weight is pulverized.

Furthermore, when obtaining an ingot-shaped magnetic ferronickel alloy, when Ni is 18-29% by weight and Si is 0.5% by weight or less, C is 64 5-0.21 3Xx% by weight or more (
When the amount of Si is 0.5% by weight or more, C is 6.1 5-0.2 1 3Xx + 0.5X (
y-0.5) weight% or more (X is Ni%, y is Si%
) and at least 0.1% by weight of the molten nickel alloy is poured into the mold, and the temperature of the alloy is 1200°C.
to 800°C at a cooling rate of 50°C/min or more.

The present invention will be explained in detail below.

First, low-carbon nickels with various Ni contents were used as starting materials, and a carbon source was added to them in various proportions, melted, and pulverized to obtain nickel alloy shots.

The Ni and C contents of the various types of ferronickel alloy shots obtained were analyzed, and the magnetic strength was measured.

When the strength of magnetism for each Ni and C content is plotted on coordinates with the Ni and C contents as axes, as shown in FIG. 6 2 7-0.0 1 8 1 Xx weight% (
However, it was found that the magnetism is weak in the region B where X is Ni%) or more, and the magnetism suddenly becomes stronger in the region A where it is less than this.

As a result of examining the shot obtained by the above method by X-ray diffraction, C was 0.6 2 7-0.0 1 8 1×
It was found that region B containing X weight % or more is austenite, and region A below this is martensite.

From this experimental result, ordinary low-carbon nickel has zero carbon.
．． Since the content was 0.02% by weight or less, it was confirmed that martensitic transformation occurred during water pulverization treatment and strong magnetism was exhibited.

On the other hand, the commonly obtained high carbon ferrite nickel is Ni18~2
3% by weight and 1.0 to 2.5% by weight of carbon, it was confirmed that even when pulverized, it did not undergo martensitic transformation and became weakly magnetic austenite in region B.

However, when a carbon source was added to this high-carbon ferronickel shot, it was melted and pulverized, and surprisingly, ferronickel shot with ferromagnetic properties comparable to low-carbon ferronickel shot was obtained.

Therefore, high carbon ferronickel with various Ni content is used as a starting material, these 6 carbon sources are added in various proportions, melted, and pulverized to make ferronickel alloy shot.
The various kinds of shots obtained were analyzed for alloy fraction and the strength of carbon magnetism was measured.

When the results were plotted on the Ni and C content coordinates, it was found that when Si was 0.5% by weight or less, N
i 1 C is 6.15 in the range of 8 to 29% by weight
Region C of 0.213Xx weight% or more (X is Ni%)
It turns out that it becomes ferromagnetic.

Further, when X-ray diffraction was performed on the shot of this ferromagnetic region C, it was found to be austenite.

Although the reason behind this phenomenon G has not yet been fully elucidated, the iron-nickel phase diagram {this shows that magnetic autenite exists at a Ni content of 30% by weight or more, and this magnetic range is lowered by the inclusion of carbon. It is speculated that 6 points will be transferred to the Ni side.

Coarse ferronickel normally contains about 1/20 of Co as Ni, but Co has almost no effect on magnetism.

Further, the impurities Or and Mn are usually 2.5% by weight or less and 0.5% by weight or less, respectively, and these levels have almost no effect on magnetism.

However, Si has an influence when it is 0.5% by weight or more.

According to the above experiment, when Si is contained at 0.5% by weight or more, the boundary between weakly magnetic region B and ferromagnetic region C is 6.1 5-0.2
1 3 XX (where X is Ni%) moves in parallel to the high carbon side (this movement width is 0.5 X (y-0.5
) weight% (y is Si%).

When C becomes 0.1% by weight or less, martensitic transformation occurs as described above.

Therefore, to obtain a magnetic nickel shot,
Assembling and pulverization are necessary, but first, the nickel alloy must be in the above-mentioned molten state before pulverization.

For a certain amount of adjustment, use Ni scrap, nickel oxide, etc.
It is preferable to use carbon-containing substances such as i-source and graphite powder.

Alternatively, the operating conditions of ferronickel smelting may be selected so that a portion of the crude ferronickel produced falls within the above-mentioned range after desulfurization and partial desiliconization.

Next, in order to pulverize the molten iron nickel alloy, the molten metal can be dropped into water in the form of droplets, the molten metal can be poured into stirring water, or the molten metal can be pulverized by the known method of pulverization, in which the molten metal is poured into a large amount of water. means can be applied.

Although the above description is based on a shot-shaped ferro-nickel alloy, an ingot-shaped magnetic ferro-nickel alloy can be obtained by a similar method.

That is, after pouring the molten ferronickel alloy prepared into the above-mentioned mold into a mold, it was heated from 1200°C to 800°C for 50°C.
If the material is rapidly cooled at a cooling rate of 0.degree. C./min or higher, a highly magnetic Fekuchi nickel alloy can be obtained.

However, if it is rapidly cooled from 1150°C, only weak magnetism can be obtained.

Although almost satisfactory results can be obtained by rapid cooling from 1200°C to 800°C, it is desirable to rapidly cool to 600°C if possible.

Also, the higher the cooling rate, the better; the preferred cooling rate is 70°C.
/minute or more.

To achieve such a cooling rate, it is preferable to use a water-cooled mold, or to apply means such as jetting water or blowing cold air after the molten metal has solidified.

As described above, the method of the present invention does not require any special process, and can easily obtain magnetic ferronickel shot through the conventional water crushing process by simply adjusting the fraction of the molten ferro-nickel alloy to the required range. In addition, in the case of ingots, only a slight reinforcement of the cooling method is required, so the manufacturing cost is lower than that of low carbon ferronickel, and the intended purpose is fully satisfied.

Next, comparative examples and examples of the present invention will be described.

Comparative Example-1 Crude ferronickel molten metal obtained by reducing and melting garnierite ore in an electric furnace was desulfurized with CaC2, and a high carbon ferrite with a low Si content was obtained by desulfurizing it with CaC2 and partially desiliconizing and decarburizing it by oxygen blowing. Transfer 1 lot of molten nickel, approximately 15 tons, to a ladle and boil to a depth of 2.
．． 2. in a 5m aquarium. It flows in with water at 5 m9/min,
The water was crushed in about 15 minutes.

The molten metal temperature was about 1450°C.

Also, the granulated ferronickel shot is continuously taken out from the water tank and dried.

Table 1 shows the analytical values and magnetic strength of two lots of ferronickel shot thus obtained.

The magnetic strength is measured using an electromagnet with a variable magnetic flux density, and is expressed in terms of the magnetic flux density c (gauss) when 10 g of nickel is attracted to the electromagnet.

Therefore, the smaller the number, the stronger the magnetism.

This value is about 90 to 110 Gauss for low-carbon Feikuchi nickel with a martensitic structure.

From the Ni grade in Table 1, the grade to become a ferromagnetic region is 6.
．． 1 5-0.2 1 3 Xx (X is Ni%)
Calculated from 1.57 and 1.57 for Experiments 1 and 2, respectively.
61%, and the Si grade is 0.68 and 0.7, respectively.
Since it is 0%, 6.1 5-0.2 1 3Xx+0
．． 5 X (y-0.5) (X is Ni%, y
When calculating the C grade to become a ferromagnetic region using Si%), it becomes 1.6 6 and 1.7 1%, respectively, and it is understood that in both experiments 1 and 2, the C grade is low and weakly magnetic austenite. , corresponding to the magnetic flux density in the table.

Example-1 Comparative Example-1: 10:6 ferronickel shots and 40.9 g each of graphite electrode powder were prepared, melted at 1500°C, and then pulverized using a small granulation equipment.

Table 2 shows the analytical values and magnetic strength of the obtained granulated water shot.

That is, in the raw material rod experiment, C was added to %1 and 2% to obtain a certain range of the Ni grade and C grade of the present invention (thus, a highly magnetic nickel shot similar to martensite was obtained.

Example-2 Ni scrap was added at 300 ml each for 10 ml of the nickel shot of Comparative Example 1. ! i' was prepared, melted at 1500°C, and then pulverized.

Table 3 G shows the analytical values and magnetic strength of the obtained granulated water shot.

That is, by adding Ni to the raw material lot experiment doors 1 and 2 and setting the range of the Ni grade and C grade of the present invention, a high-magnetic nickel shot comparable to martensite was obtained.

Comparative Example-2 High 8i high carbon ferronickel molten metal obtained by desulfurizing crude ferronickel molten metal produced in an electric furnace in a low frequency induction furnace was
The mixture was transferred to a ladle at 0°C and pulverized in the same manner as in Example-1.

Table 4 shows the analytical values and magnetic strength of the obtained shots.

That is, 6.1 5-0.2 1 3 X indicating the ferromagnetic region
x 10. 5 X (y-o.5) (X is Ni%
, y is Si%), the C grade was 3.43%, and the C grade was low as well as the Ni grade, and it was estimated that it was a weakly magnetic onutenite.

Example-3 400g of Ni scrap was mixed with 10Kp of Hue mouth nickel shot of Comparative Example-2, melted at 1400℃, part of it was pulverized, and the rest was made into 4 molds to form ingots of about 500F. were injected into each.

The molds into which the molten metal was poured were placed in a heat insulating furnace and maintained at 1200°C, and then taken out one after another and subjected to various cooling treatments.

Cooling treatment is water injection at 1200℃, soo' from 1200℃
There were three types of cooling: ioo° C./min up to c and 50° C./min. For comparison, an experiment was also conducted in which cooling was performed from 1200° C. to 800° C. at 40° C./min.

Note that after cooling to 800°C, it was left to cool at room temperature.

Table 5 shows the magnetic strength after these treatments.

The analysis values of the obtained shot and ingot were Ni24.
3, C2.09, and Si 2.24% by weight.

From this table, adjust the range of the molten metal so that the Ni grade and C grade of the present invention are achieved, and
It can be seen that by cooling down to 00° C. at a cooling rate of 50° C./min or more, a highly magnetic nickel shot or ingot similar to martensite can be obtained.

Example 4 Several types of garnierite ores were blended so that the Ni and C grades of the present invention were obtained, and the Ni/Fe ratio was high. Anthracite was blended and burned in a rotary kiln. It was reduced and melted in a furnace.

Crude ferronickel produced in an electric furnace was desulfurized in a low frequency induction furnace, then transferred to a ladle and granulated in the same manner as in Example-1.

Table 6 shows the analytical values and magnetic strength of the obtained ferronickel shot.

In other words, it can be seen that high-carbon nickel with high magnetism comparable to that of low-carbon ferronickel can be obtained.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between Ni and C contents and magnetic strength.

Claims (1)

[Claims] INi 18-29% by weight, Si 0.5% by weight or less, C6
．． 1 5-0.2 1 3Xx weight% or more (X is N
i%) and at least O O. A method for producing a magnetic ferronickel alloy, which comprises pulverizing a molten ferronickel alloy containing 1% by weight or more. 2 Ni 18-29% by weight, Si 0.5% by weight or more,
06.15-0.213Xx+0.5X(y 0.5
) weight% or more (where X is Ni% and y is Si%) and at least co. 1. A method for producing a magnetic ferro-nickel alloy, which comprises pulverizing a molten ferro-nickel alloy in an amount of i% by weight or more. 3 Ni 18-29% by weight, Si 0.5% by weight or less,
06.15 0.213Xx weight% or more (X is N
i%) and at least 0 0. A molten ferronickel alloy of 1% by weight or more is poured into a mold, and the temperature of the alloy is 1%.
A method for producing a magnetic ferronickel alloy, characterized by rapidly cooling from 200°C or higher to 600°C to SOO°C at a cooling rate of 50°C/min or higher. 4Ni 18-29% by weight, Si 0.5% by weight or more, '0
6.15-0.213XxO. 5 (y 0.5
) weight % or more (where X is Ni% and y is Si%) and at least CO. A molten ferronickel alloy of 1% by weight or more is poured into a mold, and the temperature of the alloy is increased from 1200°C or higher to 6.
1. A method for producing a magnetic nickel alloy, characterized by rapidly cooling from 00°C to 800°C at a cooling rate of 50°C/min or more.