KR20080057677A - Ni-fe-si alloys for low thermal coefficient materials and fabrication method - Google Patents

Abstract

A Ni-Fe-Si alloy for low thermal expansion and a fabrication method thereof are provided to improve continuous mold performance with less inflow of impurities in a solution/molding process by adding Si component to the alloy. A Ni-Fe-Si alloy for low thermal expansion includes, by weight%, C: less than 0.015%, Mn: less than 1.0%, P: less than 0.01%, S: less than 0.005%, Al: 0.01 to 0.02%, O: less than 0.006%, Si: 0.1 to 4.5%, Ni: 30 to 85%, and the remainder Fe, and other unavoidable impurities. The difference between a liquid temperature and a solid state temperature is 60 to 140°C. The alloy includes one of a group having Mo:1 to 15%, Cu:1 to 15%, and Nb: 1 to 15%.

Description

Ni-Fe-Si-based low thermal expansion alloy and manufacturing method thereof {Ni-Fe-Si Alloys for Low Thermal Coefficient Materials and Fabrication Method}

1 is a graph showing elongation characteristics according to the processing heat treatment conditions of 42Ni-Fe- (0.5,1.0) Si alloy.

2 is a graph showing the thermal expansion characteristics of the 42Ni-Fe-1Si alloy according to the processing heat treatment conditions.

Japanese Patent Publication No. 2002-161328

Japanese Patent Publication No. 2002-266017

Japanese Patent Publication No. 2002-173745

The present invention relates to a functional Ni-based alloy material and a manufacturing method thereof that can be widely used as a component material such as electromechanical by using low thermal expansion characteristics. More specifically, the present invention relates to an alloy material having excellent castability and punching process by adding Si to a Ni-Fe alloy system, and a method for producing the alloy material.

Ni-Fe-based alloys are widely used in the technical field requiring low thermal expansion characteristics. For example, an electron gun material of an electronic component, a semiconductor lead frame material, a gas storage container material for LNG ships, a material for measuring instruments, and the like. Ni-Fe alloys are alloys in which Ni and Fe are the main components, and the types of alloys are classified according to the Ni content. Fe-36Ni alloys and Fe-42Ni alloys are commercially available. Kovar alloys with Co element added to Ni-Fe alloys are also included in the low thermal expansion alloy.

Such low thermal expansion properties are known to be closely related to the soft magnetic properties of the material, more specifically the magnetostrictive properties. These properties are fundamentally determined by the alloying ratio in the alloy manufacturing process, but may be greatly affected by inevitable impurities (oxygen, sulfur, phosphorus, etc.) in the manufacturing process.

Therefore, in order to minimize the deterioration of characteristics due to impurities during the manufacturing process, a process of preventing melting from atmospheric gases by melting and casting in a vacuum has been conventionally adopted. In addition, in Japanese Patent Laid-Open No. 2002-161328, molten slag having a CaO-SiO ₂ -Al ₂ O ₃ -MgO-F component is formed on the surface of molten steel in a dissolution step to deoxidize and desulfurize the concentration of oxygen and sulfur in molten steel. A method of reducing the pressure has been proposed. Japanese Patent Laid-Open No. 2002-266017 proposes a method of reducing oxygen concentration by adding Si and Mn as a deoxidizer in Ni-Fe alloy molten steel. In Japanese Patent Laid-Open No. 2002-173745, Si and Mn are added to the Ni-Fe alloy as a trace element in an amount less than 1% by weight, and inevitable impurities such as C, S, P, and O are contained in an amount of 0.005 to 0.02% by weight. A method of improving soft magnetic properties by reducing the Ni segregation degree of the ingot or slab by maintaining the range is proposed. In addition, a method of adding Mn and S for the purpose of dispersing fine MnS of a certain size in an alloy base is known in order to adjust the ductility of the Ni-Fe alloy in an appropriate range in order to improve the punchability required in such a material.

However, these conventional techniques do not propose a method of improving the magnetic properties by controlling the microstructure in the expansion of the solid-liquid coexistence region and the processing heat treatment to improve the continuous casting performance of Ni-Fe alloy.

In the Ni-Fe alloy, the solid-liquid coexistence area does not change significantly depending on the Ni content when solidified from the molten state. In addition, since the T _L ~ T _S (liquid temperature ~ solid temperature) range is very narrow in the range of 2 ~ 5 ℃, it is difficult to apply this alloy to the thin plate manufacturing process by continuous casting. For example, the 42Ni-Fe low thermal expansion alloy has a large change in low thermal expansion characteristics due to homogenization heat treatment and processing / heat treatment process after casting. Influencing these changes requires the management of the addition of microaddition elements because they are influenced by the formation of microstructure by the microaddition elements. On the other hand, an antioxidant-based inclusion such as MnS used for the purpose of improving the punching workability of Ni-Fe alloy has a diameter of about 0.1 to several micrometers in diameter, and these sizes are almost the same as the thickness of the magnetic wall. Since it is particularly detrimental to movement, soft magnetic properties, which are the source of low thermal expansion properties, are lowered, and thus there are limitations in obtaining the desired properties.

The present invention for solving the above problems is to provide a low thermal expansion Ni-Fe alloy to improve the continuous casting performance by expanding the solid-liquid coexistence region in the solidification characteristics of Ni-Fe molten steel. Furthermore, the punchability is to be ensured even after the casting / heat treatment process of the cast steel. Also provided is a method for producing a Ni-Fe alloy.

Ni-Fe-based alloy for achieving the above object,

By weight%, C: 0.015% or less, Mn: 1.0% or less, P: 0.01% or less, S: 0.005% or less, Al: 0.01 to 0.02%, O: 0.006% or less, Si: 0.1-4.5%, Ni: It contains 30-85% and is composed of the remaining Fe and other unavoidable impurities.

According to one embodiment of the present invention, the Ni-Fe-based alloy, ΔT, which is the difference between the liquidus temperature (T _L ) and the solidus temperature (T _S ), satisfies 60-140 ° C. In the present invention, the Si is most preferably 1-4.5%. Ni-Fe-based alloy of the present invention may further include at least one selected from the group of Mo: 1-15%, Cu: 1-15%, Nb: 1-15%.

In addition, the method for producing a Ni-Fe-based alloy in the present invention,

By weight%, C: 0.015% or less, Mn: 1.0% or less, P: 0.01% or less, S: 0.005% or less, Al: 0.01 to 0.02%, O: 0.006% or less, Si: 0.1-4.5%, Ni: Casting a melt comprising 30-85% and composed of the remaining Fe and other unavoidable impurities,

The cast material is heat-treated to a temperature in the range of 950 ~ 1150 ℃ and rolled to constitute a rolled material.

According to one embodiment of the present invention, the casting step,

Dissolving and refining the Ni-Fe alloy material without the Si,

Maintaining the refined molten steel in the range of 1450 ~ 1550 ℃ while adding the silicon (Si) in the range of 0.1 ~ 4.5% in the molten steel and stirred for 5 to 30 minutes it can be configured as a continuous casting step.

The alloy obtained according to the present invention satisfies 60-140 ° C., which is the difference between the liquidus temperature T _L and the solidus temperature T _S. Si is most preferably 1-4.5%. The alloy may further include at least one selected from the group consisting of Mo: 1-15%, Cu: 1-15%, and Nb: 1-15%.

Hereinafter, the present invention will be described in detail.

The present invention was developed in the course of research for improving the continuous castability and punching processability of the Ni-Fe-based low thermal expansion alloy, and the thermal expansion characteristics, and is characterized by adding Si to the Ni-Fe-based alloy.

The present invention is characterized by adding Si to a Ni-Fe alloy. The target Ni-Fe alloy is an alloy containing Fe and Ni as main components, and the kind thereof is not particularly limited. Ni-Fe alloys typically contain 30-85% by weight of Ni. According to one embodiment of the present invention, the optimum Ni-Fe alloy for improving the continuous castability and punchability and thermal expansion characteristics of the alloy by applying Si is 42Ni-Fe alloy.

In the present invention, the silicon (Si) is 0.1-4.5 wt% in the Ni-Fe alloy. When the addition of the Si component is less than 0.1%, the addition effect is weak, and when added in excess of 4.5% there is a problem that the casting strip is hardened and broken after casting or cold rolling is difficult. Si addition amount becomes like this. Preferably it is 0.1-3.5 weight%, 1.0-4.5%, More preferably, it is 1.0-3.5 weight%.

In the case where Si is added to the Ni-Fe alloy according to the present invention, the Ni-Fe alloy is most preferably formed as follows. That is, the Ni-Fe-based alloy is 0.015% or less of carbon (C), 1.0% or less of manganese (Mn), 0.01% or less of phosphorus (P), 0.005% or less of sulfur (S), and 0.01 Aluminum (Al) in the range of 0.02%, oxygen (O) of 0.0060% or less, and silicon (Si) of 0.1-4.5%, Ni: 30-85%, and the remaining Fe. Most preferably, the content of Ni is 42%. Of course, additionally, 1 to 15% molybdenum (Mo), 1 to 15% copper (Cu), and 1 to 15% niobium (Nb) may be included.

Hereinafter, the reason for limitation of the chemical composition of the Ni-Fe alloy of the present invention will be described.

Carbon (C) is preferably at most 0.015%.

When the carbon content exceeds 0.015%, carbides are formed and the growth of crystal grains is suppressed, so the soft magnetic properties are deteriorated.

The content of manganese (Mn) is preferably 1.0% or less.

If the manganese content exceeds 1.0%, it promotes the production of MnS like silicon and lowers the soft magnetic properties. Manganese content is preferably in the range of 0.01% to 1.0% because it has a function of controlling the generation of regular lattice in terms of soft magnetic properties. In the punching workability of the material, a fine MnS dispersion effect may be used.

The phosphorus (P) is preferably 0.01% or less.

When phosphorus is excessively added, phosphorus compounds precipitate in grain boundaries and in the mouth, thereby deteriorating soft magnetic properties.

Sulfur (S) is preferably 0.005% or less.

When sulfur exceeds 0.005%, an sulfide-based inclusion is produced and dispersed in MnS and CaS. These sulfide diameters range from about 0.1 to a few micrometers, and since these sizes are almost the same as the thickness of the magnetic walls, they are particularly harmful to the movement of the magnetic walls, thereby reducing soft magnetic properties, but have a useful function in punching workability of the material.

As for aluminum (Al), 0.01 to 0.02% is preferable.

Aluminum acts as an important deoxidizer, but if the addition amount is less than 0.01%, deoxidation is insufficient. Therefore, molten oxide should be added even if the non-metallic inclusions increase due to aluminum addition. The influence of Mn and Si suppresses the formation of sulfide into MnS. However, when the content exceeds 0.02%, the magnetostriction constant or magnetic anisotropy index is increased, and thus the soft magnetic characteristics are deteriorated.

Oxygen (O) is preferably 0.0060% or less.

Oxygen is removed by deoxidation and finally remains in the steel to be dissolved, but can be divided into residual oxygen and residual oxygen as oxides such as nonmetallic inclusions. If the amount of oxygen exceeds 0.006%, the amount of non-metallic inclusions increases and the soft magnetic properties deteriorate. At the same time, it can affect the presence of sulfur. When there is much oxygen remaining, deoxidation is insufficient, so sulfide is present as MnS, which inhibits the movement of the wall or grain growth.

Molybdenum (Mo) is preferably in the range of 1 to 15%.

Molybdenum is an effective ingredient in order to effectively obtain the magnetic properties of PC-grade materials, it is preferable to add more than 1%. Molybdenum also acts to control the conditions for the generation of regular lattice that affects crystal anisotropy and magnetostriction. Regular lattice is affected by the cooling conditions after self-heat treatment. Alloys without molybdenum require a high cooling rate in order to suppress the formation of harmful regular lattice. Cooling conditions) can suppress the formation of regular lattice and obtain optimum soft magnetic properties. In view of this aspect, the content of molybdenum is preferably in the range of 1-15%.

Copper (Cu) is preferably in the range of 1 to 15%.

Like molybdenum, copper acts to control the regular lattice formation of Ni-Fe alloy materials, but it acts to reduce the effect of cooling rate compared to the molybdenum effect and stabilizes soft magnetic properties. In consideration of this aspect, the copper content is preferably in the range of 1-15%.

Niobium (Nb) is preferably in the range of 1 to 15%.

Niobium has little effect on magnetic properties, but it is a necessary component in materials for use such as magnetic heads because it increases the hardness of the alloy and increases the wear resistance. It is also effective in reducing the degree of soft magnetic deterioration that may occur in mold molding and the like. In consideration of this aspect, the content of niobium is preferably in the range of 1-15%.

According to the present invention, an example of a method for producing a Ni-Fe-based alloy containing Si is as follows. The cast material is obtained by casting molten steel that satisfies the above component system of the present invention. Casting is preferred for continuous casting in terms of productivity. According to one embodiment of the present invention, the casting step is a step of dissolving and refining the Ni-Fe alloy material without the addition of Si and maintaining the refined molten steel in the range of 1450 ~ 1550 ℃ silicon (Si) in the molten steel It may be composed of a step of continuous casting by adding to the 0.1 to 4.5% range and stirring for 5 to 30 minutes. Dissolution of the Ni-Fe-based alloy may be carried out ladle refining after electric melting and induction dissolution in a vacuum atmosphere, inert gas atmosphere or air.

The cast material obtained is made into a strip of desired thickness by a rolling process after homogenizing heat treatment. The homogenization heat treatment is preferably 950-1150 ℃, the crack time is preferably 1-12 hours. Homogenization atmosphere is carried out in a vacuum or reducing component atmosphere. The thickness of the strip through rolling is preferably 0.05-0.5 mm. Rolling can be performed simultaneously with hot rolling and cold rolling, or by selecting one rolling. The rolled sheet material may be subjected to annealing for 1 to 2 hours in a temperature range of 950 to 1150 ° C. The obtained product can be used as component materials such as electron gun materials and semiconductor lead frame materials.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

Based on the 42% Ni-Fe alloy, 0.1 to 3.0% by weight of the Si component was added to replace the Fe component to prepare an alloy by dissolving in air. Oxygen concentration, castability, processability, mechanical properties, etc. were evaluated for the prepared alloy, and the results are shown in Table 1.

The molten steel concentration of the alloy measures the oxygen concentration in the state of solidifying the molten steel sample. Castability evaluates the strip forming ability of the continuous sheet forming castability of the alloy by the continuous single roll casting method (melt-draw casting casting method). Rolling processability of the cast alloy was evaluated based on 0.3mm thickness sheet formability by applying a rolling reduction ratio of 50% or more through cold rolling of the cast strip. Also subjected to standard mechanical properties and the punching workability is each cold plate material by the use of the processed 0.3mm thickness in the test of 950 ^o C 30 bungan was evaluated on the basis subjected to hydrogen atmosphere, the heat treatment the low thermal expansion property is 1050 minutes at 30 ^o C the hydrogen atmosphere thermal treatment As a result, the thermal expansion characteristics up to about 350 ^° C. at room temperature were evaluated.

Si concentration (wt.%) △ T ( ^o C) Castability O ₂ concentration (ppm) Rollability Punching workability Tensile Strength (kgf / mm ² ) Elongation (%) Thermal expansion (ppm) 0.1 4 ↓ 700 ◎ △ 40 41 7.5 0.5 18 △ 68 ◎ ○ 43 36 6 1.0 60 ◎ 60 ◎ ◎ 47 32 4.5 1.5 115 ◎ 55 ◎ ◎ 51 29 5.0 2.0 140 ◎ 53 ○ ◎ 56 25 5.5 3.0 120 ◎ 50 △ ○ 60 20 5.6 3.5 110 ◎ 48 ↓ △ 65 16 6.0 4.0 105 ○ 46 × ↓ 60 10 6.6 4.5 95 ○ 45 × × 50 4 7.1 Excellent: ◎,: Good: ○, Normal: △, Under: ↓, Poor: ×

In Table 1, when the Si component is added to the Ni-Fe alloy system, the oxygen concentration decreases rapidly and the castability is improved. It is believed that this is due to the addition of the Si component in an appropriate range to react with oxygen in the molten steel to deoxidize and to improve the castability by expanding the solid-liquid coexistence region in the solidification process of the molten steel. In particular, when the Si component is added in the range of 1.0 to 3.5% by weight, it can be seen that the castability is excellent. In addition, the punchability is shown to be good even if the amount of Si added is increased to more than 1%. As the Si content increases, workability may be weak, but it shows a good level by controlling the microstructure in the heat treatment process. As described above, it can be seen that as Si is added to the Ni-Fe alloy, low thermal expansion characteristics and punching workability can be secured simultaneously.

Figure 1 shows the elongation characteristics of the 42Ni-Fe low thermal expansion alloy based on the processing heat treatment conditions of the alloy added 0.5% 1.0% Si component. FIG. 2 is a graph showing thermal expansion characteristics of 42Ni-Fe-1Si alloys according to heating and heat treatment conditions. FIG.

The present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims, and various forms of substitution, modification, and within the scope not departing from the technical spirit of the present invention described in the claims. It will be apparent to those skilled in the art that changes are possible. For example, in the embodiment of the present invention, 42% Ni-Fe alloy used as a Ni-Fe alloy is exemplified, but the application is also applicable to other Ni-Fe alloys.

According to the present invention described above, by adding an appropriate amount of the Si component to the Ni-Fe-based low heat-changing alloy, it is possible to reduce the inflow of impurities in the dissolution / casting process and to improve the continuous castability. The Ni-Fe-based alloy obtained according to the present invention has a low thermal expansion property at the same time as the excellent punching property and excellent punching property compared to the alloy in the case of casting by the atmospheric melting of the existing alloy or the alloy which improved the punchability by the dispersion effect of the existing MnS inclusions. There is a useful effect to ensure the thermal expansion characteristics.

Claims (9)

By weight%, C: 0.015% or less, Mn: 1.0% or less, P: 0.01% or less, S: 0.005% or less, Al: 0.01 to 0.02%, O: 0.006% or less, Si: 0.1-4.5%, Ni: A low thermal expansion Ni-Fe alloy containing 30-85% and composed of the remaining Fe and other unavoidable impurities. The method of claim 1, Low thermal expansion Ni-Fe-based alloy, characterized in that the difference between the liquidus temperature (T _L ) and the solidus temperature (T _S ) of the alloy is ΔT 60-140 ℃. The method of claim 1, The Si is low thermal expansion Ni-Fe-based alloy, characterized in that 1-4.5%. The method according to any one of claims 1 to 3, The alloy is a low thermal expansion Ni-Fe-based alloy further comprises at least one selected from the group of Mo: 1-15%, Cu: 1-15%, Nb: 1-15%. By weight%, C: 0.015% or less, Mn: 1.0% or less, P: 0.01% or less, S: 0.005% or less, Al: 0.01 to 0.02%, O: 0.006% or less, Si: 0.1-4.5%, Ni: Casting a melt comprising 30-85% and composed of the remaining Fe and other unavoidable impurities, A method for producing a low thermal expansion Ni-Fe-based alloy comprising the step of heat-treating and rolling the cast material at a temperature in the range of 950 ~ 1150 ℃. The method of claim 5, A method for producing a low thermal expansion Ni-Fe alloy, characterized in that the difference between the liquidus temperature (T _L ) and the solidus temperature (T _S ) of the alloy is ΔT is 60-140 ℃. The method of claim 5, The Si is a method of producing a low thermal expansion Ni-Fe-based alloy, characterized in that 1-4.5%. The method of claim 5, The alloy is a method of producing a low thermal expansion Ni-Fe-based alloy further comprises at least one selected from the group of Mo: 1-15%, Cu: 1-15%, Nb: 1-15%. The method of claim 1, The casting step is a step of melting and refining the Ni-Fe alloy material without the addition of Si, Low thermally expandable Ni-Fe-based system comprising the continuous molten steel, which is added to the molten steel in the range of 1450 ~ 1550 ℃ while adding silicon (Si) in the range of 0.1 ~ 4.5%, and then stirred for 5 to 30 minutes Method of producing an alloy.

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