JPS6199539A - Nonferrous clad ingot and its production - Google Patents

Abstract

PURPOSE:To obtain an ingot having good quality even if the difference in m.p. between a core material and insert-casting material is >=150 deg.C in the stage of producing the low-melting nonferrous clad ingot by controlling the casting temp. of the molten insert- casting material and the rising speed of the molten metal surface in a casting mold according to the m.p. of the core material and liquidus line temp. of the inset-casting material. CONSTITUTION:The thickness of the solidified shell of the molten metal is smaller as the difference (the degree of overheating of the molten metal) DELTAT between the casting temp. of the molten metal of the insert-casting material and the liquids line temp. of the insert-casting material for said material is larger in the case of using an Ni-Cu alloy having 1,340 deg.C m.p. for the core material and a carbon steel having 1,520 deg.C liquidus line temp. for the insert-casting material. The thickness of the above- mentioned shell is smaller as the initial temp. of the core material surface is higher. The initial temp. degreases parabolically with an increase in the rising speed V of the molten metal surface in the casting mold and the core material component leaks to the insert-casting material side at >=300 deg.C initial temp. The combination of the degree DELTAT of overheating of the molten metal and the speed V is controlled in a suitable range in order to prevent the leakage from the above-mentioned result and the range thereof varies with the m.p. of the core material.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to clad ingots produced by the casting method as raw materials for clad materials made of dissimilar metal materials with different melting points, particularly non-ferrous metals with relatively low melting points as core materials. The present invention relates to a non-ferrous clad ingot using a ferrous material with a relatively high melting point as the walnut material, and a method for producing the non-ferrous clad ingot using walnut.

Conventional technology In general, clad materials are made by covering the surface of ferrous materials such as carbon steel, low alloy steel, and high alloy steel with various non-ferrous metal materials that have a lower melting point than the ferrous material. At the same time, it can demonstrate the excellent properties unique to non-ferrous metal materials that cannot be obtained.
It has various advantages, such as being much cheaper than forming the entire body with non-ferrous metal materials, and can compensate for the strength that non-ferrous metal materials tend to lack with ferrous materials, and has recently been used in various fields. It has become so. For example, a clad material made by coating steel with a 90% Cu-10% N1 alloy known as cupronickel has excellent seawater resistance and is relatively inexpensive, so it has been put to practical use in seawater desalination equipment, etc., and is also used as Monel metal. Known 70%N+ -30
% Cu alloy is used in petrochemical plants and the like because it has extremely excellent corrosion resistance.

As methods for producing such cladding materials, overlay methods, assembly rolling methods, explosive bonding methods, and diffusion methods have been developed and put into practical use. Crotch inside the mold as material! However, the so-called casting method (for example, JP-A-58-119479), in which the other metal material is poured and solidified and the core material is cast, has also been put into practical use.

Problems to be solved by the invention Among the above-mentioned cladding material manufacturing methods, the overlay method,
In the assembly rolling method, explosion bonding method, diffusion method, etc., the number of man-hours in the manufacturing process is extremely high, and therefore the manufacturing cost is extremely high.In addition, the equipment cost for automating the manufacturing process is enormous, so it is difficult to perform manual work. There were problems such as there were many dependent processes, and therefore productivity had to be low.

On the other hand, the manufacturing method of cladding material using the cast walnut method has the advantage of being highly productive on an industrial concavity scale because it is easy to automate for mass production and requires relatively few man-hours. There was a problem like this.

In other words, the method of producing clad material by the casting method is to use a material with a relatively melting point of 11, such as a ferrous material, as a core material, and then cast the core material with a non-ferrous metal material with a low melting point.
On the other hand, there are two main methods: casting a core material made of a non-ferrous metal material with a low melting point and encasing the core material in a ferrous material with a high melting point. Cast walnut materials made of metal do not blend well with the core material, which has a high melting point, resulting in poor fusion welding at the boundary, or slag adhering to the surface of the core material may cause bonding defects in that area. As a result, the bonding strength between the core material and the cast walnut material may become insufficient, and there is a risk that peeling may occur during the product stage.

On the other hand, in the latter method, which uses a non-ferrous core material with a low melting point, the cast material with a high melting point fully adapts to the core material during casting, and therefore there is little risk of defective fusion welding. When the core material is cast, it melts from the surface and the core material components and the cast walnut phase components mix, and if the degree of this becomes severe, the original characteristics of the clad material cannot be fully demonstrated, and harmful gold WEE compounds may be produced. In many cases, '51R' occurred where phases were formed and the entire cast walnut ingot had to be discarded.

As mentioned above, the cast walnut method is superior in terms of productivity and cost, and among the cast walnut methods, a non-ferrous metal material with a low melting point is particularly preferred in terms of bonding strength between the core material and the cast walnut material. Casting with high-melting-point iron-based materials is an excellent method, but it cannot be applied to materials where the difference in melting point between the core material and cast walnut material is too large due to the problem of melting of the core material during casting. Therefore, there was a problem in that the type of material used for the cladding material, particularly the type of non-ferrous metal material used as the core material, was restricted.

Means for Solving the Problems In order to solve the above-mentioned problems, the inventors used a non-ferrous metal material with a low melting point as the core material and a ferrous material with a high melting point as the cast walnut material. As a result of repeated experiments and studies on the phenomena that occur near the interface between the core material and the cast walnut material during walnut production in the production of clad ingots using the walnut method, the following facts were discovered.

In other words, when a core material made of a non-ferrous metal material is placed in a mold and molten cast walnut material with a high melting point is injected by under-pouring, the molten cast walnut material that is in contact with the surface of the core material is first rapidly cooled and its interface As the solidified shell of the walnut wood grows, the heat from the walnut crushing is transmitted to the core material, increasing the temperature of the core material, and as time passes, the core material melts from the surface, but the melting It has been found that the molten core material and the unsolidified molten walnut material are separated by the solidified shell of the walnut material that has already solidified. In that case, if the thickness of the solidified cast walnut shell is still thin at the time the core material is melted, the molten core material components will break through the solidified shell and leak into the unsolidified cast walnut material on the outside. It has been discovered that the cladding material cannot exhibit its original performance due to mixing of the material components and the cast walnut material components. Focusing on these newly discovered facts, the inventors of the present invention conducted further experiments and found that molten walnut material, which has a higher melting point than the core material, was poured into the mold in which the core material had been installed. At the time of casting, the melting point of the core material and the liquid phase of 11m degrees of the cast walnut material (the casting temperature of the molten material and the rising speed of the VI type internal surface of the molten walnut material, so-called rising speed) are controlled by VJ. By,
By increasing the thickness of the solidified shell of the cast walnut material at the start of core melting to an extent that does not cause leakage of the molten core material, mixing of the core material components and the cast walnut material components can be prevented. It was discovered that good quality clad ingots can be obtained even when the melting point difference between the walnut material and the cast walnut material is as large as 150°C or more.
This led to this invention.

Specifically, the first invention provides a non-ferrous clad ingot in which the core material is a non-ferrous metal material and the core material is cast with a cast walnut material made of a metal material different from the core material, the melting point of the core material being that of the cast walnut material. lower than the melting point of , and the difference in their melting points is 150℃
Provided is a non-ferrous clad ingot characterized by the above.

Further, a second invention is a method for manufacturing the non-ferrous clad ingot of the first invention, in which a core material made of a non-ferrous metal material is installed in a mold, and a cast walnut material having a higher melting point than the core material is placed in the mold. When pouring the molten metal by bottom pouring, the casting temperature of the molten walnut material and the rate of rise of the i-plane in the mold are set to vJ l according to the melting point of the core material and the liquidus temperature of the walnut material. It is.

Here, in carrying out the method of the second invention, the specific control method is to control the melting point To ("C) of the core material, the difference ΔT (°C) between the casting temperature and the liquidus temperature of the cast walnut material, The relationship with the rate of rise of the mold surface level V (a/■) is as follows (i)
It is sufficient to perform control so as to satisfy the expression (ii) or the expression (ii).

When the temperature is 61640℃, ■≧0.15 ・
...When (+)ΔT>40℃.

■≧0.15 + (0,02395-1,65x10
` In this case, the walnut material first begins to melt and solidify from the part that contacts the core material to form a solidified shell, and then the thickness of the walnut material solidified shell that grows until the core material surface begins to melt is the thickness of the core material. Based on the knowledge that the core material components affect the occurrence of leakage when the core material components are crushed, the following conditions are necessary to generate a solidified shell of the initial cast walnut material with a thickness that prevents leakage of the core material components. This discovery was made based on the results of heat transfer calculations and actual in-depth experiments as described in .

In other words, in Figure 1, Nr-c with a melting point of 1340°C is used as the core material.
Using u-gold alloy, liquid phase I'11 152 as cast walnut material
When core material is cast using carbon steel at 0°C, casting factors that affect the solidified shell thickness of the molten cast walnut material that grows during the time until the core material surface starts to melt, especially the WJ thickness of the cast walnut material. Regarding the influence of the difference ΔT between the casting temperature and the liquid phase I temperature of the cast walnut material (that is, the so-called molten overripening degree) and the initial temperature of the core material surface on the solidified shell thickness of the cast walnut material, heat transfer is conducted. This shows the results of model calculations. Note that the initial temperature of the core material surface here corresponds to the core material surface temperature when it comes into contact with the molten cast walnut material, and therefore, as will be described later, the temperature varies depending on the position of the core material.

As can be seen from Figure 1, the larger the degree of overmaturity Δ, that is, the casting temperature of the cast walnut material is lower than the liquidus temperature of the cast walnut material, the thinner the solidified shell thickness becomes. The higher the initial temperature of the core material surface, the thinner the solidified shell thickness becomes. Here, the i degree of the core material surface is at room temperature until the beginning of pouring of the cast walnut material, but as soon as the casting of the cast walnut material starts, the radiant heat from the molten metal is also applied to the parts that are not yet immersed in the cast walnut compatible i. is added, and heat conduction starts from the part immersed in the molten metal in the height direction of the core material, and the I
As the surface rises, the temperature of the unimmersed portion increases, and the initial temperature of the surface of the core material increases.

The increase in the initial temperature on the surface of the core material is most noticeable at the head of the core material, which is affected by the above-mentioned radiant heat and heat conduction for the longest time.
The degree of this becomes larger as the rise of the hot water level is slower. In other words, it is thought that the rate of surface rise of the cast walnut compatibility in the mold has a great influence on the initial concentration on the surface of the core material.

Therefore, the present inventors used carbon steel with a liquidus temperature of 1520°C as the cast walnut material in the same way as described above, and N2 with a melting point of 1340°C.
i-Cu alloy core material is cast by bottom pouring method t < 8 G
m ′)
When we investigated the relationship between K `` `` `` `` '' in an actual casting experiment, we obtained the results shown in the second factor. Also, in this experiment, the ingot fractured in the longitudinal direction at the 1.72 width. The macro-O structure of the cross section was observed to check for melt leakage to the walnut material side of the surface layer of the core material.The ingots in which no melt leakage was observed were marked with a 0 mark, and the melted all The ingot for which this was determined is indicated with a mark.

As is clear from FIG. 2, it was observed that the initial surface temperature of the core head decreased parabolically as the interface velocity above the surface of the molten metal increased. It was also found that when the initial temperature of the surface of the core material was 300° C. or higher, the melted portion of the surface layer of the core material leaked to the walnut material side. From these results, it has become clear that the increase in initial concentration on the surface of the core material can be reduced as the critical velocity above the surface of the molten metal increases, and that melting of the core material and leakage can be prevented accordingly.

Based on the above results, the inventors further determined that the liquidus temperature 1
Using 520°C carbon steel as the casting material and varying the composition ratio of the Ni-Cu alloy as the core material to vary its melting point within the range of 1000 to 1300°C, actual skin pattern 5 was cast. A casting experiment was carried out using a bottom pouring mold for lump (height 1.5111) l. In this experiment, the casting temperature and the surface rising speed of the cast walnut compatible 1 were variously changed, and each of the obtained clad ingots was F! ! Cut the surface layer of the core material to show the melted R growth condition and the melted core material components of cast walnut material! We investigated whether there is a gate to 1. The results are expressed as m i3 superheating degree ΔT, that is, the difference between the casting temperature of the cast walnut material and the liquid phase η, and the correspondence () to the critical velocity above the surface of the molten metal (Figs. 3 and 4).
As shown in the figure. Here, Fig. 3 shows the case where the melting point of the core material is 1340°C, and Fig. 4 shows the 41st case where the melting point of the core material is 1005°C.
In addition, in these figures, O indicates a case where melting of the surface m of the core material was observed, but no leakage was observed in the 75-inch bar to be cast, and a cross indicates a case where a gate was observed. shows.

From Fig. 3 and Fig. 4, in order to prevent the core material components from flowing to the casting walnut material side, it is necessary to
It is clear that there is an appropriate 1 penalty for each combination of surface rising speed \l, and that range is the I of the core material! ! ! You can see that it is sulcus by the dots. In other words, f5 is overcast! ′! degree ΔT
When is below 40℃, the critical velocity above the hot water surface is 0.15 m,
If it is above 40°C, it is possible to prevent the core material component from shifting regardless of the temperature, but in order to prevent the core material component from leaking if the casting overmaturity ΔT exceeds 40℃. To achieve this, the higher the degree of superheating ΔT of the molten metal, the higher the rate of rise in the level of the molten metal.
The surface rise of 31 degrees■ must be increased. By sorting out these relationships, a relational expression between the degree of superheating of the molten metal Δd and the rate of rise of the molten metal V (i/m), which is necessary to prevent core material components from leaking to the walnut material side, can be calculated. If it is determined as a function of the melting point To (° C.) of the material, the following equations (i) and (ii) can be obtained.

When ΔT≦40℃, ■≧0.15 ・
...(i) When ΔT>40°C.

V≧0.15 + (0,02395-1,65xlO
' XTo ) (ΔT-40) - (ii) Here, the pouring overripe degree ΔT is given by the difference between the casting temperature of the induced walnut compatible metal and the liquidus temperature of the cast walnut material, as described above. Therefore, depending on the melting point TO of the core material and the liquidus temperature of the cast walnut material, the casting temperature of the cast walnut material 1 and the rate of rise in the melt level Vwoi! 1IJtlDtLukotoniJ:TST
Equations (i) and (it) can be satisfied, and by burial in this way, it is possible to prevent the core material components from leaking into the falling walnuts and to obtain a clad ingot of good quality. In particular, the melting point of the core material is significantly lower than the liquidus line of cast walnut material, and the difference in melting point is 150°C.
Even in the above cases, it is possible to prevent core material components from leaking into the walnut and to exhibit the original properties of the cladding material.

Here, regarding the walnut clad ingot using a core material with a lower melting point than the cast walnut material, we will compare the ingot made by the conventionally proposed method, the nil material made by the method of this invention, and the cast walnut material. The melting point differences are shown in Table 1.

As shown in Table 1, conventional methods (1) and (2) use a core material made of stainless steel and cast clad steel, and conventional method (3) uses a core material of high carbon steel. It is a clad steel cast with 4g of low carbon, and the difference in melting point between the core material and the walnut material is less than 150°C. On the other hand, Example 1
．． The melting point difference of the product made by the present Komei method shown in No. 2 is as large as 150°C, and the present invention has a low melting point difference of 150°C or more. They established a method of casting a non-ferrous core material with high melting point walnut material.

However, the non-ferrous core material is not limited to the above-mentioned Ni-Cu alloy, but any material can be used depending on the final properties required, and the cast walnut material can be used in the carbon term, : Mr. Alloy', 1 Usually, iron-based materials such as high-alloy metals are used, but of course the material is not limited thereto.

Practical Example 1 1st a L Indication Point B 13 ll 0°C (
') A clad ingot was manufactured as follows using a 70%N+-30%CIJ alloy as a core material and a 0.12% carbon steel with a liquidus zero temperature of 1520°C as a casting material.

That is, the thickness 110 made of the j'Ji-CLI alloy
m+q, width 11050r, length 1510a, the core material is suspended in the center between the thickness center of the bottom pouring mold and the inner wall of the mold, and the layer temperature of the cast walnut material is adjusted to the superheat degree ΔT of two pouring melts.
-60', the rate of rise per plane is 0.151tl/cJlO,
The ingots were cast in three steps at 30 m/s/-10 and 45 m/s by the bottom pouring method, and each ingot was bloomed into a slab. Samples were taken from the slabs corresponding to the top, middle, and bottom in the height direction of the lump, and after cutting and polishing the C cross section, the macrostructure was detected, and the interface properties between the core material and the cast walnut material and the core material components were investigated. We investigated the occurrence of leaks in cast walnuts. The results are also shown in Table 2. Here, the melting surface rising speed at ΔT=60°C is 0.15 m/
Condition y) is a comparison that does not satisfy the above formula (i;),
Shoulder surface rising speed 0,3f) e/- condition and 0.454
The conditions +/mtn are examples of the present invention that satisfy the above formula (it).

As is clear from Table 2, when the method of the present invention was used, no leakage of core material components into the opening of the walnut was observed.

Example 2 As shown in Table 1, 10%\1-9 with a melting point of 1085°C
The core material is 0% Cu alloy, and the liquidus temperature is 1520°C.
The cladding material is made of 12% carbon steel as the core material.
iBAt was manufactured. That is, as in the case of Example 1, a core material plate with the same dimensions as the bottom pouring mold is poured.The center of the mold is held at the center between the center of the thickness of the mold and the inner wall of the mold. Shoulder surface rising speed is 0 at melt superheat degree ΔT = 50℃
,15a+,'6.0.3001ri,0.0.45m/
The ingots were cast using the bottom pouring method with varying three-stage weights, and each ingot was made into a slab using the blooming rolling method. Then, as in Example 1, samples were taken from the slag corresponding to the top, middle, and bottom of the ingot height, and the macrostructure of the C cross section was observed. We investigated the occurrence of leakage of core material components into the cast walnut. The F8 results of the investigation were almost the same as in Example 1, and it was confirmed that the method of the present invention did not show any δ deviation of the core material components to the cracking of the cast walnut.

Effects of the Invention As is clear from the above explanation, according to the present invention, a core material made of a low melting point non-ferrous metal is cast with a walnut material such as a high melting point ferrous material having a melting point of 150° C. or higher. In this process, cracking of the cast walnut with a low support point of 0 is effectively prevented from occurring, and therefore a defective ingot in which the core material component and the reduced walnut material component are combined is not produced, and the melting point difference is 1.
Low melting point non-ferrous core material of 50°C or higher - high fd p g9 <Producing quality non-ferrous clad ingots using solid wood steadily and stably 1! I can do roto. And also according to this invention,
As mentioned above, it is possible to produce non-ferrous clad ingots with a large difference in melting point in a really cool way, so the composition of the material,! 4) You can also obtain the effect of being able to defeat various floods depending on the purpose without having to control ÷ risa 4. The effect of cast walnut oil on the thickness of the solidified shell of walnut wood growing from the surface of the core material until the time of lining.
Filled stone, uY degree (ΔT) and core material surface? Noaki, A degree of Akira; Two, heat transfer model calculation result (check diagram shown next, ': f42 figure is the first temperature of the core material surface): Jζ long melting; Rino: A correlation diagram showing the relationship between the influence of 4 degrees of confusion on the first surface and the J deviation situation of 14 < Rumi j3 pH j\ of core material formation a. 7th hand
5 Clearance degree (ΔT), scene rising speed and core material component 13
Figure 4 is a correlation diagram showing the flash protection with the wetting condition to break through the melting process. Figure 4 shows the overripeness of casting melting (ΔT) and τ curve when the melting point of the core material is 10856) as the surface rise rate. FIG. 2 is a correlation diagram showing the relationship between 1SrI and the state of leakage of core material components into the cast walnut breakthrough.

Figure 1 @Δ〃Water) Desirability ΔT (°C) Figure 2 A 00.2 0.40.6 0.8 1.0 Uzuichi J: Noboru Satomo''/m1n)

Claims (3)

[Claims] (1) In a non-ferrous clad ingot in which a non-ferrous metal material is used as a core material and the core material is cast with a cast walnut material made of a metal material different from the core material, the melting point of the core material is the melting point of the cast walnut material. A non-ferrous clad ingot characterized by having a melting point difference of 150°C or more. (2) A core material made of a non-ferrous metal material is placed in a mold, and when molten walnut material made of a different metal material with a higher melting point than the core material is poured into the mold by under-pouring, the core material is 1. A method for producing a non-ferrous clad ingot, comprising controlling the casting temperature of molten walnut material and the rate of rise in the level of the molten metal in the mold according to the melting point of the molten walnut material and the liquidus temperature of the walnut material. (3) When casting the molten walnut material, the melting point difference between the core material and the walnut material should be 150°C or more, and the melting point T_o (°C) of the core material, the casting temperature and liquid phase of the molten walnut material The difference ΔT (℃) from the linear temperature and the rate of rise in the mold level V (m
3. The method for producing a non-ferrous clad ingot according to claim 2, wherein: /mm) is controlled so that it satisfies the following formula (i) or (ii). When ΔT≦40℃, V≧0.15...(i) ΔT
When >40℃, V≧0.15+(0.02395-1.65×10^-
＾5×T_o)(ΔT-40)...(ii)