CONTINUOUS CAST WIRE ROD OF Cu-Zn-Sn-BASED ALLOY
20240133011 ยท 2024-04-25
Assignee
Inventors
- Masahiro Kataoka (Iwaki-shi, JP)
- Keiichiro Oishi (Sakai-shi, JP)
- Shinobu Satou (Iwaki-shi, JP)
- Kanta Dairaku (Iwaki-shi, JP)
Cpc classification
International classification
B22D11/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
This continuous cast wire rod contains Cu: 62.0 mass % or greater and 70.0 mass % or less, Sn: 0.3 mass % or greater and 0.9 mass % or less, Zr: 0.0050 mass % or greater and 0.1000 mass % or less, and P: 0.0050 mass % or greater and 0.1000 mass % or less, with a balance being Zn and impurities, and a mass ratio Zr/P of Zr to P is 0.3 or greater.
Claims
1. A continuous cast wire rod of a CuZnSn-based alloy containing Cu, Zn, and Sn, comprising: Cu: 62.0 mass % or greater and 70.0 mass % or less; Sn: 0.3 mass % or greater and 0.9 mass % or less; Zr: 0.0050 mass % or greater and 0.1000 mass % or less; and P: 0.0050 mass % or greater and 0.1000 mass % or less, with a balance being Zn and impurities, wherein a mass ratio Zr/P of Zr to P is 0.3 or greater.
2. The continuous cast wire rod of a CuZnSn-based alloy according to claim 1, wherein a tensile strength is 370 N/mm.sup.2 or greater, and an elongation is 14% or greater.
3. The continuous cast wire rod of a CuZnSn-based alloy according to claim 1, wherein a worked material after a working process has a tensile strength of 420 N/mm.sup.2 or greater, an elongation of 22% or greater, and a 0.2% yield strength of 300 N/mm.sup.2 or greater and 350 N/mm.sup.2 or less, and the working process includes: a first heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a first cold working at a working ratio of 41%; a second heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a second cold working at a working ratio of 41%; a third heat treatment of holding at 450? C. for 2 hours and subsequently conducing air cooling; and a third cold working at a working ratio of 11%.
4. The continuous cast wire rod of a CuZnSn-based alloy according to claim 1, wherein a number density of ZrP compounds containing Zr and P is in a range of 50 pieces/mm.sup.2 or greater and 500 pieces/mm.sup.2 or less.
5. The continuous cast wire rod of a CuZnSn-based alloy according to claim 1, wherein Al is further contained in an amount of 0.20 mass % or greater and 0.80 mass % or less.
6. The continuous cast wire rod of a CuZnSn-based alloy according to claim 1, wherein Sb is further contained in an amount of 0.02 mass % or greater and 0.06 mass % or less.
7. The continuous cast wire rod of a CuZnSn-based alloy according to claim 1, which is an up-drawn continuous cast wire rod.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0032]
[0033]
[0034]
[0035]
[0036]
[0037]
[0038]
[0039]
DETAILED DESCRIPTION OF THE INVENTION
[0040] Hereinafter, a continuous cast wire rod of a CuZnSn-based alloy according to an embodiment of the present invention will be described.
[0041] A cross section of the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, which is orthogonal to a longitudinal direction, has a substantially circular shape, and its cross sectional area is in a range of 12 mm.sup.2 or greater and 227 mm.sup.2 or less.
[0042] As will be described later, the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment is preferably an up-drawn continuous cast wire rod produced by an up-drawing type continuous casting apparatus shown in
[0043] The continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment has a composition containing Cu: 62.0 mass % or greater and 70.0 mass % or less, Sn: 0.3 mass % or greater and 0.9 mass % or less, Zr: 0.0050 mass % or greater and 0.1000 mass % or less, and P: 0.0050 mass % or greater and 0.1000 mass % or less, with a balance being Zn and impurities.
[0044] In the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, a mass ratio Zr/P of Zr to P is 0.3 or greater.
[0045] In the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, in addition to Cu, Zr, and Sn, Al may be contained in an amount of 0.20 mass % or greater and 0.80 mass % or less.
[0046] In addition, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, Sb may be further contained in an amount of 0.02 mass % or greater and 0.06 mass % or less.
[0047] In addition, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, the number density of ZrP compounds containing Zr and P is preferably in a range of 50 pieces/mm.sup.2 or greater and 500 pieces/mm.sup.2 or less.
[0048] In addition, in the present embodiment, the tensile strength is preferably 370 N/mm.sup.2 or greater, and the elongation is preferably 14% or greater.
[0049] Furthermore, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, a worked material after a working process preferably has a tensile strength of 420 N/mm.sup.2 or greater, an elongation of 22% or greater, and a 0.2% yield strength of 300 N/mm.sup.2 or greater and 350 N/mm.sup.2 or less, and the working process includes: a first heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a first cold working at a working ratio of 41%; a second heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a second cold working at a working ratio of 41%; a third heat treatment of holding at 450? C. for 2 hours and subsequently conducing air cooling; and a third cold working at a working ratio of 11%.
[0050] Hereinafter, the reasons why the composition, the number density of the ZrP compounds, the mechanical properties of the continuous cast wire rod, and the mechanical properties of the worked material obtained by working the continuous cast wire rod under predetermined conditions are specified as described above will be described.
[0051] (Zr)
[0052] By adding Zr together with P, ZrP compounds containing Zr and P are produced. A primary crystal ?-phase is formed with the ZrP compound particles acting as inoculant nuclei; and thereby, fine dendrite formation and granular crystallization of the ?-phase crystallized during solidification are achieved.
[0053] Due to the fine dendrite formation and granular crystallization of the ?-phase as described above, the workability of the continuous cast wire rod is significantly improved, and it is possible to prevent defects such as cracking from occurring during hot working and cold working. Furthermore, the fluidity of the molten metal during casting is improved, the occurrence of large shrinkage cavities is suppressed, and it is possible to significantly improve the yield during casting.
[0054] However, since Zr has a strong affinity for oxygen, Zr oxide and the like are likely to be generated. As a result, the viscosity of the molten metal increases, and entrainment defects such as oxides are likely to occur during casting. In addition, blow holes and microporosities are likely to occur. In addition, since Zr is an element which is likely to react with a carbon mold, there is a concern that surface defects may be likely to occur and the castability may decrease in a case where a large amount of Zr is contained.
[0055] Therefore, in the present embodiment, the amount of Zr is set to be in a range of 0.0050 mass % or greater and 0.1000 mass % or less.
[0056] In order to reliably produce the ZrP compounds, the lower limit of the amount of Zr is preferably 0.0200 mass % or greater, and more preferably 0.0380 mass % or greater. Meanwhile, in order to suppress the production of Zr oxide, the upper limit of the amount of Zr is preferably 0.0840 mass % or less, and more preferably 0.0680 mass % or less.
[0057] (P)
[0058] As described above, P is added together with Zr to produce ZrP compounds containing Zr and P, and a primary crystal ?-phase is formed with the ZrP compound particles acting as inoculant nuclei. As a result, fine dendrite formation and granular crystallization can be achieved.
[0059] However, in a case where a large amount of P is contained, cracking is likely to occur on a surface or in the inside of an ingot during the formation of the ingot, and wire break is likely to occur during working. In addition, since P is an element which is likely to react with a carbon mold, there is a concern that surface defects may be likely to occur and the castability may decrease in a case where a large amount of P is contained.
[0060] Therefore, in the present embodiment, the amount of P is set to be in a range of 0.0050 mass % or greater and 0.1000 mass % or less.
[0061] In order to reliably produce the ZrP compound, the lower limit of the amount of P is preferably 0.0200 mass % or greater, and more preferably 0.0360 mass % or greater. Meanwhile, in order to suppress the occurrence of cracking, the upper limit of the amount of P is preferably 0.0800 mass % or less, and more preferably 0.0680 mass % or less.
[0062] (Cu)
[0063] As described above, a primary crystal ?-phase is formed with the ZrP compound particles acting as inoculant nuclei; and thereby, fine dendrite formation and granular crystallization of the ?-phase crystallized are achieved.
[0064] By setting the amount of Cu to be 62.0 mass % or greater, a region of the primary crystal ?-phase is easily obtained, and it becomes possible to achieve fine dendrite formation and granular crystallization by the above-described actions and effects of Zr and P.
[0065] Meanwhile, in a case where the amount of Cu is greater than 70.0 mass %, the primary crystal ?-phases (granular crystal grains) are bonded to each other, and the resulting ?-phases become the same as the grown dendrite arms. Furthermore, due to the bonding between the crystal grains, problems occur on a casting surface, such as the occurrence of large numbers and large sizes of blow holes and shrinkage cavities. Furthermore, there is also a concern that the strength may decrease as the amount of Cu increases.
[0066] Therefore, in the present embodiment, the amount of Cu is set to be in a range of 62.0 mass % or greater and 70.0 mass % or less.
[0067] In order to reliably produce the primary crystal ?-phase, the lower limit of the amount of Cu is preferably 64 mass % or greater, and more preferably 65 mass % or greater. Meanwhile, in order to suppress the bonding between the primary crystal ?-phases (granular crystal grains), the upper limit of the amount of Cu is preferably 68 mass % or less, and more preferably 67 mass % or less.
[0068] (Sn)
[0069] Sn is an element acting to improve the corrosion resistance, erosion resistance, wear resistance, and strength.
[0070] However, in a case where the amount of Sn is too large, the solidification temperature range is widened, and casting defects such as cracking, shrinkage cavities, and porous shrinkage cavities are likely to occur. In addition, there is a concern that the Sn segregation may become remarkable during casting; and as a result, hot ductility deteriorates, and this may lead to a decrease in cold workability and a decrease in ductility.
[0071] Meanwhile, although depending on the blending ratio with Cu, Zn, and the like, the ?-phase, which is a hard phase having a higher Sn concentration than that of the matrix (?-phase), is remarkably generated, so that breaking is easy to occur during wire drawing. In addition, due to the selective corrosion of they-phase, and there is a concern that the seawater resistance may decrease.
[0072] Therefore, in the present embodiment, the amount of Sn is set to be in a range of 0.3 mass % or greater and 0.9 mass % or less.
[0073] In order to further improve the corrosion resistance, erosion resistance, wear resistance, and strength, the lower limit of the amount of Sn is preferably 0.60 mass % or greater, and more preferably 0.62 mass % or greater. Meanwhile, in order to further improve the castability, hot workability, and cold workability, the upper limit of the amount of Sn is preferably 0.68 mass % or less, and more preferably 0.66 mass % or less.
[0074] (Zr/P)
[0075] Zr and P are added together for the purpose of forming fine dendrites of copper alloy crystal grains. Each of Zr and P can only slightly refine copper alloy crystal grains in the same manner as other general additive elements. However, in a case where Zr and P coexist in an appropriate range, fine dendrites can be effectively formed. However, in a case where the ratio of Zr to P is small, it is difficult to achieve fine dendrite formation.
[0076] Therefore, in the present embodiment, the mass ratio Zr/P of Zr to P is set to be 0.3 or greater.
[0077] The lower limit of the mass ratio Zr/P of Zr to P is preferably 0.5 or greater, and more preferably 0.6 or greater. Meanwhile, the upper limit of the mass ratio Zr/P is preferably 4 or less, and more preferably 2 or less.
[0078] (Al)
[0079] Al is an element acting to improve the strength and yield strength by strengthening the matrix. In addition, Al acts to improve the molten metal flowability. Meanwhile, in a case where a large amount of Al is contained, there is a concern that the elongation may decrease.
[0080] Therefore, in the present embodiment, Al may be contained in an amount of 0.20 mass % or greater and 0.80 mass % or less in order to improve the strength, yield strength, and molten metal flowability.
[0081] The lower limit of the amount of Al is more preferably 0.30 mass % or greater, and even more preferably 0.40 mass % or greater. Meanwhile, the upper limit of the amount of Al is more preferably 0.70 mass % or less, and even more preferably 0.60 mass % or less.
[0082] (Sb)
[0083] Sb is an element acting to improve the corrosion resistance. Meanwhile, in a case where a large amount of Sb is contained, there is a concern that the workability may decrease.
[0084] Therefore, in the present embodiment, Sb may be contained in an amount of 0.02 mass % or greater and 0.06 mass % or less in order to improve the corrosion resistance.
[0085] The lower limit of the amount of Sb is more preferably 0.027 mass % or greater, and even more preferably 0.034 mass % or greater. Meanwhile, the upper limit of the amount of Sb is more preferably 0.054 mass % or less, and even more preferably 0.047 mass % or less.
[0086] (Number Density of ZrP Compounds)
[0087] As described above, a primary crystal ?-phase is formed with the ZrP compound acting as an inoculant nucleus; and thereby, fine dendrite formation and granular crystallization of the ?-phase crystallized during solidification are achieved.
[0088] However, in a case where the amount of the ZrP compounds is too large, the primary crystal ?-phases (granular crystal grains) are bonded to each other, and the resulting ?-phases become the same as coarse dendrites obtained by growing dendrite arms. In addition, in a case where the primary crystal ?-phases are not bonded to each other, there is a concern that the crystal grains may become too fine and the elongation may decrease.
[0089] Therefore, in the present embodiment, the number density of the ZrP compounds is set to be in a range of 50 pieces/mm.sup.2 or greater and 500 pieces/mm.sup.2 or less.
[0090] In order to ensure the effects of the fine dendrite formation and the granular crystallization, the lower limit of the number density of the ZrP compounds is preferably 60 pieces/mm.sup.2 or greater, and more preferably 90 pieces/mm.sup.2 or greater. Meanwhile, in order to further suppress the bonding between the primary crystal ?-phases (granular crystal grains), the upper limit of the number density of the ZrP compounds is preferably 400 pieces/mm.sup.2 or less, and more preferably 300 pieces/mm.sup.2 or less.
[0091] (Tensile Strength and Elongation)
[0092] In the continuous cast wire rod of a CuZnSn-based alloy, a balance between strength and elongation is important for cold drawability.
[0093] Therefore, in the present embodiment, the tensile strength is preferably 370 N/mm.sup.2 or greater, and the elongation is preferably 14% or greater.
[0094] The lower limit of the tensile strength is more preferably 380 N/mm.sup.2 or greater, and even more preferably 390 N/mm.sup.2 or greater. Meanwhile, the upper limit of the tensile strength is preferably 420 N/mm.sup.2 or less, and more preferably 410 N/mm.sup.2 or less.
[0095] In addition, the lower limit of the elongation is more preferably 16% or greater, and even more preferably 18% or greater. Meanwhile, the upper limit of the elongation is preferably 29% or less, and more preferably 27% or less.
[0096] (Mechanical Properties of Worked Material)
[0097] With regard to the continuous cast wire rod of a CuZnSn-based alloy, a wire material (worked material) worked into a predetermined wire diameter is subjected to bending, and thus becomes, for example, a member constituting a net-like structure for seawater. Therefore, with regard to the continuous cast wire rod of a CuZnSn-based alloy, the mechanical properties of the worked material after working under predetermined conditions are particularly important.
[0098] Therefore, in the present embodiment, a worked material after a working process preferably has a tensile strength of 420 N/mm.sup.2 or greater, an elongation of 22% or greater, and a 0.2% yield strength of 300 N/mm.sup.2 or greater and 350 N/mm.sup.2 or less, and the working process include: a first heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a first cold working at a working ratio of 41%; a second heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a second cold working at a working ratio of 41%; a third heat treatment of holding at 450? C. for 2 hours and subsequently conducing air cooling; and a third cold working at a working ratio of 11%.
[0099] The lower limit of the tensile strength of the above-described worked material is preferably 430 N/mm.sup.2 or greater, and more preferably 435 N/mm.sup.2 or greater. Meanwhile, the upper limit of the tensile strength of the above-described worked material is preferably 460 N/mm.sup.2 or less, and more preferably 450 N/mm.sup.2 or less.
[0100] The lower limit of the elongation of the above-described worked material is preferably 26% or greater, and more preferably 30% or greater. Meanwhile, the upper limit of the elongation of the above-described worked material is preferably 41% or less, and more preferably 37% or less.
[0101] The lower limit of the 0.2% yield strength of the above-described worked material is preferably 310 N/mm.sup.2 or greater, and more preferably 315 N/mm.sup.2 or greater. Meanwhile, the upper limit of the 0.2% yield strength of the above-described worked material is preferably 340 N/mm.sup.2 or less, and more preferably 330 N/mm.sup.2 or less.
[0102] Next, an up-drawing type continuous casting apparatus 10 used in the production of the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment will be described with reference to
[0103] The continuous casting apparatus 10 includes a casting furnace 11, a continuous casting mold 20 connected to the casting furnace 11, and pinch rolls 17 which draw a cast wire material 1 produced from the continuous casting mold 20.
[0104] The casting furnace 11 heats and melts a melting raw material to produce and store a molten copper having a predetermined composition, and the casting furnace 11 includes a crucible 12 which stores the melting raw material and the molten copper, and a heating apparatus (not shown) for heating the crucible 12.
[0105] The cast wire material 1 produced from the continuous casting mold 20 is interposed between the pinch rolls 17 which draw the cast wire material 1 out in a drawing direction F. In the present embodiment, the cast wire material 1 is intermittently drawn out.
[0106] The continuous casting mold 20 includes a cylindrical mold 21 into which the supplied molten copper is injected, and a cooling portion 28 which cools the mold 21.
[0107] In the present embodiment, as shown in
[0108] The mold 21 has a substantially cylindrical shape, and the mold 21 has a casting hole 24 penetrating from one side to the other side.
[0109] The cooling portion 28 is a water-cooling jacket disposed on the outer peripheral side of the mold 21, and is configured to circulate cooling water to cool the mold 21.
[0110] Next, a method of producing the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment by using the above-described continuous casting apparatus 10 will be described.
[0111] First, a melting raw material is charged into the crucible 12 from a raw material input port of the casting furnace 11. As the raw material, a Cu single element, a Zn single element, a Sn single element, a CuZn base alloy, a CuSn base alloy, and the like can be used. In addition, a raw material containing Zn and Sn may be melted together with a copper raw material. Furthermore, a recycled material and a scrap material of the present alloy may be used.
[0112] Next, the melting raw material charged into the crucible 12 is heated and melted by the heating apparatus to produce a molten copper prepared to have the above-described component composition.
[0113] The molten copper is heated to a predetermined casting temperature and held in the crucible 12. Then, the molten copper is supplied to the continuous casting mold 20.
[0114] The molten copper supplied into the continuous casting mold 20 is cooled in the mold 21, solidified, and becomes the cast wire material 1. The cast wire material 1 is continuously produced by being intermittently drawn out by the pinch rolls 17.
[0115] In a case where the casting temperature is low, misrun occurs due to a decrease in fluidity of the molten metal, and deep oscillation marks, internal defects, and altered layers are formed. Meanwhile, in a case where the casting temperature is high, there is a concern that seizure to the mold may occur.
[0116] Therefore, in the present embodiment, the casting temperature is preferably in a range of 980? C. or higher and 1,100? C. or lower.
[0117] In addition, in a case where the casting speed is low and the cooling rate during solidification is low, crystal growth or coalescence of crystal grains is promoted even with the ZrP compound particles acting as inoculant nuclei. Therefore, there is a concern that the crystal grains may not be sufficiently refined. Meanwhile, in a case where the casting speed is high, the molten metal is not sufficiently supplied during drawing-out, and there is a concern that deep oscillation marks, internal defects, and altered layers may be formed. In addition, the frictional force between the mold and the solidified shell during drawing-out also increases, and there is a concern that the solidified shell may break during drawing-out, and deep oscillation marks may be formed.
[0118] Therefore, in the present embodiment, the casting speed is preferably in a range of 0.8 m/min or higher and 3.3 m/min or less.
[0119] In addition, in a case where the cooling rate is low during casting, the degree of undercooling becomes low, and only a part of the ZrP compounds acts as the inoculant nucleus. Therefore, the refining effect is not sufficient. In addition, since crystal grain growth or coalescence of crystal grains is promoted, there is a concern that it may be difficult to refine the crystal grains. Meanwhile, in a case where the cooling rate is high during casting, the molten metal temperature decreases and the molten metal solidifies before the ZrP compounds act as the inoculant nucleus, so that there is a concern that the refining effect may not be obtained.
[0120] Therefore, in the present embodiment, the cooling rate during casting is preferably in a range of 22? C./sec or higher and 75? C./sec or lower.
[0121] In addition, in a case where the continuous cast wire rod has a small cross sectional area, the cooling rate during casting increases, and there is a concern that a sufficient refining effect may not be obtained. Meanwhile, in a case where the continuous cast wire rod has a large cross sectional area, the cooling rate during casting decreases, and there is a concern that a sufficient refining effect may not be obtained. In addition, there is a concern that a sufficient solidified shell strength may not be obtained, and due to the drawing stress applied during casting, the oscillation marks may become large, or breaking may be likely to occur.
[0122] Therefore, in the present embodiment, the cross sectional area of the continuous cast wire rod is preferably in a range of 28 mm.sup.2 or greater and 226 mm.sup.2 or less.
[0123] In the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment having the above-described configuration, the amount of Zr is in a range of 0.0050 mass % or greater and 0.1000 mass % or less, the amount of P is in a range of 0.0050 mass % or greater and 0.1000 mass % or less, and the mass ratio Zr/P of Zr to P is 0.3 or greater. Accordingly, the ZrP compounds are sufficiently dispersed. Thus, fine dendrite formation and granular crystallization of the ?-phase crystallized during solidification are achieved, and it is possible to appropriately refine the crystal grain diameter of the cast structure. Therefore, the continuous cast wire rod has excellent mechanical properties and workability, and is particularly suitable as a material for a CuZnSn-based alloy wire material constituting a net-like structure for seawater or the like.
[0124] In addition, since the amount of Cu is in a range of 62.0 mass % or greater and 70.0 mass % or less, an effect of preventing adhesion of marine organisms and a sterilization effect, which are generated by Cu ions, can be obtained.
[0125] Furthermore, since the amount of Sn is in a range of 0.3 mass % or greater and 0.9 mass % or less, it is possible to ensure corrosion resistance (seawater resistance) and to suppress a decrease in castability.
[0126] In addition, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, in a case where the number density of the ZrP compounds containing Zr and P is in a range of 50 pieces/mm.sup.2 or greater and 500 pieces/mm.sup.2 or less, it is possible to reliably refine the crystal grain diameter of the cast structure, and to further improve the mechanical properties and workability.
[0127] Furthermore, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, in a case where the tensile strength is 370 N/mm.sup.2 or greater and the elongation is 14% or greater, the mechanical properties are sufficiently excellent, and subsequent cold working can be favorably performed. Therefore, the continuous cast wire rod is particularly suitable as a material for a CuZnSn-based alloy wire material constituting a net-like structure for seawater or the like.
[0128] In addition, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, in a case where a worked material after a working process has a tensile strength of 420 N/mm.sup.2 or greater, an elongation of 22% or greater, and a 0.2% yield strength of 300 N/mm.sup.2 or greater and 350 N/mm.sup.2 or less, it is possible to obtain a worked material (wire material) having excellent mechanical properties. The working process includes: a first heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a first cold working at a working ratio of 41%; a second heat treatment of holding at 550? C. for 2 hours and subsequently conducing air cooling; a second cold working at a working ratio of 41%; a third heat treatment of holding at 450? C. for 2 hours and subsequently conducing air cooling; and a third cold working at a working ratio of 11%.
[0129] Furthermore, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, in a case where Al is further contained in an amount of 0.20 mass % or greater and 0.80 mass % or less, it is possible to further improve the strength and yield strength. In addition, the molten metal flowability is improved, and casting can thus be more favorably performed.
[0130] In addition, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, in a case where Sb is contained in an amount of 0.02 mass % or greater and 0.06 mass % or less, it is possible to further improve the corrosion resistance, and to sufficiently ensure the workability.
[0131] In addition, in the continuous cast wire rod of a CuZnSn-based alloy according to the present embodiment, in a case where the continuous cast wire rod is an up-drawn continuous cast wire rod produced by an up-drawing type continuous casting apparatus, the influence of gravity can be suppressed, and thus the continuous cast wire rod has a uniform and fine cast structure in a cross section orthogonal to the drawing direction, and is particularly excellent in workability.
[0132] The continuous cast wire rod of a CuZnSn-based alloy according to the embodiment of the present invention has been described as above, but the present invention is not limited thereto, and can be appropriately modified without departing from the technical features of the invention.
[0133] For example, in the present embodiment, an up-drawn continuous cast wire rod produced using the up-drawing type continuous casting apparatus shown in
[0134] In addition, in the present embodiment, the production of a continuous cast wire rod having a circular cross section and having a cross sectional area of 12 mm.sup.2 or greater and 227 mm.sup.2 or less has been described, but the present invention is not limited thereto, and the continuous cast wire rod may have a polygonal cross section or a tubular cross section. In addition, the continuous cast wire rod may have an irregular shape with a cross section having a protruding portion and a recessed portion. In addition, the cross sectional area of the cross section orthogonal to the longitudinal direction thereof is not particularly limited.
Examples
[0135] A description will be given below of the results of confirmatory experiments performed to confirm the effects of the present invention.
[0136] Melting raw materials were prepared so that the compositions shown in Tables 1 and 2 were obtained. 500 kg of the prepared melting raw material was charged into a crucible 12 of a casting furnace 11 shown in
[0137] As a mold, a mold for producing a cast wire rod having a circular cross section and an outer diameter of 6 mm (cross sectional area of the cross section orthogonal to a drawing direction: 28.26 mm.sup.2) was prepared.
[0138] Then, cast wire rods were drawn out under the casting conditions shown in Tables 3 and 4; and thereby, 300 kg of the melting raw material was cast.
[0139] The obtained cast wire material was cut along a center line parallel to the drawing direction to prepare a sample for microstructure observation, which was for observing oscillation and internal defects, and a sample for EPMA measurement. In addition, the cast wire material was cut in a direction orthogonal to the drawing direction to prepare a sample for microstructure observation.
[0140] The above-described various samples were polished using emery paper in the order of #240, #400, #800, and #1500 under conditions of a pressure of 100 N and a speed of 100 r/min for 1000 s in each case. Next, buffing was performed using a polishing agent in the order of 9 ?m-particles, 3 ?m-particles, and 1 ?m-particles under conditions of a pressure of 30 N and a speed of 100 r/min for 1000 s in each case.
[0141] After that, the resulting materials were immersed in an etching liquid (a mixture of a hydrogen peroxide solution and ammonia water) at a temperature of 30? C. to 40? C. and subjected to ultrasonic cleaning for 30 to 60 s. Next, the resulting materials were immersed in water at room temperature, subjected to ultrasonic cleaning for 30 to 60 s, and dried.
[0142] (Microstructure of Cross Section Orthogonal to Drawing Direction)
[0143] The cross section orthogonal to the drawing direction of the cast wire rod was observed by an optical microscope.
[0144] As shown in
[0145] In contrast, in Invention Example 14, as shown in
[0146] In addition, in Comparative Example 11, the amount of Zr and the amount of P were less than the ranges of the present embodiment, but as shown in
[0147] In contrast, in invention Example 14, as shown in
[0148] (ZrP Compound)
[0149] EPMA measurement was performed using the sample for EPMA measurement obtained as described above, and a dispersion status of the ZrP compounds was observed. The observation visual field was set to 69 ?m?49 ?m, and the measurement was performed once at a substantially center position of the sample for EPMA measurement. Various conditions for the EPMA measurement were set as follows. [0150] Acceleration Voltage: 15 kV [0151] Irradiation Current: 3.016?10.sup.?8 A [0152] Beam Shape: SPOT [0153] Beam Diameter: 0 ?m [0154] Time: 10 ms
[0155] A granular compound in which a detection intensity of each of Zr and P was level 3 or higher and a diameter was 1 ?m was recognized as the ZrP compound.
[0156] (Oscillation Depth)
[0157] The obtained cast wire material was cut into 10 mm along the center line parallel to the drawing direction. Polishing was performed thereon using emery paper in the order of #240, #400, #800, and #1500 under conditions of a pressure of 100 N and a speed of 100 r/min for 1,000 s in each case. Next, buffing was performed using a polishing agent in the order of 9 ?m-particles, 3 ?m-particles, and 1 ?m-particles under conditions of a pressure of 30 N and a speed of 100 r/min for 1000 s in each case.
[0158] After that, the resulting materials were immersed in an etching liquid (a mixture of a hydrogen peroxide solution and ammonia water) at a temperature of 30? C. to 40? C. and subjected to ultrasonic cleaning for 30 to 60 s. Next, the resulting materials were immersed in water at room temperature, subjected to ultrasonic cleaning for 30 to 60 s, and dried.
[0159] The structure was observed by an optical microscope at a100-fold magnification.
[0160] As shown in
[0161] A sample having an oscillation depth of less than 0.05 mm was evaluated as A, a sample having an oscillation depth of 0.05 mm or greater and less than 0.1 mm was evaluated as B, and a sample having an oscillation depth of 0.1 mm or greater was evaluated as C.
[0162] (Internal Defect)
[0163] The obtained cast wire material was cut into 100 mm along the center line parallel to the drawing direction. The cut material was divided into 10 equal pieces of 10 mm, and polished using emery paper in the order of #240, #400, #800, and #1500 under conditions of a pressure of 100 N and a speed of 100 r/min for 1000 s in each case. Next, buffing was performed using a polishing agent in the order of 9 ?m-particles, 3 ?m-particles, and 1 ?m-particles under conditions of a pressure of 30 N and a speed of 100 r/min for 1000 s in each case.
[0164] After that, the resulting materials were immersed in an etching liquid (a mixture of a hydrogen peroxide solution and ammonia water) at a temperature of 30? C. to 40? C. and subjected to ultrasonic cleaning for 30 to 60 s. Next, the resulting materials were immersed in water at room temperature, subjected to ultrasonic cleaning for 30 to 60 s, and dried.
[0165] The structure was observed by an optical microscope at a 100-fold magnification, and a circular or elliptical hole or fracture in a region of a depth of 20 ?m or greater was defined as an internal defect.
[0166] A sample in which no internal defects were observed was evaluated as O, and a sample in which internal defects were observed was evaluated as X.
[0167] (Mechanical Properties of Cast Wire Rod)
[0168] The obtained cast wire material was cut into a length of 150 mm, and a tensile test was performed thereon using a tensile tester AG-100kNX under conditions where an inter-grip distance was 70 mm, an inter-gauge point distance was 50 mm, and a tensile speed was 15 MPa/sec to evaluate the tensile strength, 0.2% yield strength, and elongation. The evaluation results are shown in Tables 5 and 6.
[0169] (Mechanical Properties of Worked Material)
[0170] The surface layer of the obtained cast wire material was peeled off, and the following working process was performed.
[0171] The material was held at 550? C. for 2 hours, and then air-cooled (first heat treatment). Next, first cold working was performed at a working ratio of 41%. Next, the material was held at 550? C. for 2 hours, and then air-cooled (second heat treatment). Next, second cold working was performed at a working ratio of 41%. Next, the material was held at 450? C. for 2 hours, and then air-cooled (third heat treatment). Next, third cold working was performed at a working ratio of 11%.
[0172] The obtained worked material was cut into a length of 150 mm, and a tensile test was performed thereon under the above-described conditions to evaluate the tensile strength, 0.2% yield strength, and elongation. The evaluation results are shown in Tables 5 and 6.
TABLE-US-00001 TABLE 1 Component Composition (mass %) Zn and Cu Sn Zr P Al Sb Impurities Zr/P Invention 1 69.10 0.590 0.0194 0.0310 0.527 0.046 Balance 0.63 Examples 2 66.70 0.674 0.0183 0.0350 0.521 0.048 Balance 0.52 3 66.72 0.699 0.0253 0.0240 0.516 0.049 Balance 1.05 4 67.70 0.587 0.0220 0.0160 0.440 0.048 Balance 1.38 5 67.63 0.585 0.0480 0.0400 0.530 0.046 Balance 1.20 6 69.10 0.590 0.0097 0.0310 0.451 0.038 Balance 0.31 7 66.80 0.616 0.0360 0.0710 0.465 0.036 Balance 0.51 8 66.70 0.666 0.0170 0.0120 0.500 0.041 Balance 1.42 9 66.90 0.612 0.0150 0.0490 0.475 0.050 Balance 0.30 10 66.80 0.621 0.0190 0.0160 0.736 0.045 Balance 1.19 11 66.90 0.638 0.0172 0.0200 0.333 0.051 Balance 0.86 12 67.20 0.651 0.0102 0.0190 0.569 0.058 Balance 0.54 13 66.90 0.611 0.0177 0.0201 0.612 0.024 Balance 0.89 14 67.49 0.590 0.0210 0.0320 0.517 0.041 Balance 0.66 15 68.50 0.623 0.0480 0.0120 0.600 0.042 Balance 4.00 16 67.41 0.624 0.0229 0.0285 0.000 0.000 Balance 0.80 17 67.24 0.638 0.0238 0.0292 0.000 0.044 Balance 0.82 18 67.51 0.621 0.0158 0.0199 0.499 0.000 Balance 0.79
TABLE-US-00002 TABLE 2 Component Composition (mass %) Zn and Cu Sn Zr P Al Sb Impurities Zr/P Comparative 1 60.30 0.692 0.0070 0.0143 0.465 0.041 Balance 0.49 Examples 2 72.40 0.591 0.0147 0.0290 0.475 0.040 Balance 0.51 3 68.60 0.210 0.0120 0.0090 0.514 0.038 Balance 1.33 4 69.20 1.360 0.0658 0.0721 0.508 0.038 Balance 0.91 5 67.70 0.602 0.0037 0.0150 0.499 0.036 Balance 0.25 6 66.70 0.611 0.1230 0.1000 0.487 0.037 Balance 1.23 7 68.60 0.613 0.0233 0.0040 0.622 0.030 Balance 5.83 8 66.60 0.620 0.0950 0.1740 0.519 0.049 Balance 0.55 9 66.40 0.632 0.0090 0.0490 0.474 0.053 Balance 0.18 10 66.60 0.595 0.4410 0.2020 0.520 0.046 Balance 2.18 11 66.70 0.643 0.0000 0.0000 0.475 0.047 Balance
TABLE-US-00003 TABLE 3 Casting Conditions Maximum Average Molten Metal Cooling Speed Drawing Speed Temperature Time* Step (mm/s) (m/min) (? C.) (sec) Invention 1 Drawing 100.0 1.98 1000 35 Examples Pushing-back ?14.3 2 Drawing 139.1 2.98 1000 23 Pushing-back ?14.3 3 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 4 Drawing 46.7 0.89 1000 75 Pushing-back ?14.3 5 Drawing 46.7 0.89 1000 75 Pushing-back ?14.3 6 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 7 Drawing 56.7 1.09 1000 61 Pushing-back ?14.3 8 Drawing 139.1 3.21 1000 22 Pushing-back ?14.3 9 Drawing 50.0 0.95 1000 70 Pushing-back ?14.3 10 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 11 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 12 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 13 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 14 Drawing 46.7 0.89 1000 75 Pushing-back ?14.3 15 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 16 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 17 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 18 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 *A time required until the temperature was lowered from 1,000? C. to 25? C.
TABLE-US-00004 TABLE 4 Casting Conditions Maximum Average Molten Metal Cooling Speed Drawing Speed Temperature Time* Step (mm/s) (m/min) (? C.) (sec) Comparative 1 Drawing 100.0 1.98 1000 35 Examples Pushing-back ?14.3 2 Drawing 100.0 2.18 1000 32 Pushing-back ?14.3 3 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 4 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 5 Drawing 100.0 2.18 1000 32 Pushing-back ?14.3 6 Drawing 56.7 1.09 1000 62 Pushing-back ?14.3 7 Drawing 133.3 1.88 1000 36 Pushing-back ?22.2 8 Drawing 100.0 1.98 1000 35 Pushing-back ?14.3 9 Drawing 86.7 1.70 1000 40 Pushing-back ?14.3 10 Drawing 46.7 0.89 1000 75 Pushing-back ?14.3 11 Drawing 46.7 0.89 1000 75 Pushing-back ?14.3 *A time required until the temperature was lowered from 1,000? C. to 25? C.
TABLE-US-00005 TABLE 5 Number Mechanical Properties Density of Cast Wire Rod Worked Material ZrP Yield Yield Evaluation Compounds Strength Strength Elongation Strength Strength Elongation Internal Oscillation (pieces/mm.sup.2) (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) Defects Depth Invention 1 98 372 197 21 421 324 33 ? A Examples 2 69 381 197 17 423 330 26 ? B 3 76 391 202 23 431 329 27 ? A 4 80 389 207 16 428 329 25 ? A 5 145 399 206 15 445 336 25 ? A 6 51 373 211 15 422 331 29 ? A 7 137 390 198 14 440 341 23 ? B 8 51 383 207 15 425 330 25 ? B 9 52 375 203 23 424 331 37 ? B 10 99 373 195 26 420 310 40 ? B 11 131 380 209 22 428 322 37 ? B 12 79 394 209 19 444 331 25 ? B 13 72 379 196 22 435 326 29 ? B 14 91 393 199 27 438 313 45 ? A 15 159 396 208 14 448 329 23 ? B 16 85 370 184 27 420 309 32 ? B 17 90 371 185 26 420 310 35 ? B 18 81 371 187 26 422 315 34 ? B
TABLE-US-00006 TABLE 6 Number Mechanical Properties Density of Cast Wire Rod Worked Material ZrP Yield Yield Evaluation Compounds Strength Strength Elongation Strength Strength Elongation Internal Oscillation (pieces/mm.sup.2) (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) Defects Depth Comparative 1 21 309 210 10 342 224 16 ? A Examples 2 43 283 164 22 309 189 35 X C 3 60 274 150 21 299 181 34 ? A 4 149 388 145 7 431 328 10 X C 5 9 371 206 13 409 330 29 ? A 6 578 373 197 5 425 330 8 ? C 7 31 372 198 13 413 301 20 ? C 8 522 359 197 6 405 315 10 X C 9 23 352 190 18 397 221 29 ? C 10 609 317 187 12 386 210 19 X C 11 0 353 168 21 402 213 32 ? A
[0173] In Comparative Example 1, the amount of Cu was 60.3 mass %, which was less than the range of the present embodiment, and the composition was out of the region of the primary crystal ?-phase; and therefore, fine dendrite formation and granular crystallization by the actions and effects of Zr and P could not be achieved, and the cast wire rod and the worked material were low in strength and 0.2% yield strength.
[0174] In Comparative Example 2, the amount of Cu was 72.4 mass %, which was greater than the range of the present embodiment. Internal defects such as blow holes occurred, the oscillation depth was deep, and the cast wire rod was low in internal quality and surface quality. In addition, the cast wire rod and the worked material were low in strength and 0.2% yield strength.
[0175] In Comparative Example 3, the amount of Sn was 0.21 mass %, which was less than the range of the present embodiment, and the cast wire rod and the worked material were low in strength and 0.2% yield strength.
[0176] In Comparative Example 4, the amount of Sn was 1.36 mass %, which was greater than the range of the present embodiment, casting defects occurred, and the cast wire rod was low in internal quality and surface quality. In addition, the cast wire rod and the worked material were low in elongation.
[0177] In Comparative Example 5, the amount of Zr was 0.0037 mass %, which was less than the range of the present embodiment, the mass ratio Zr/P of Zr to P was 0.25, which was outside the range of the present invention, and the worked material was low in strength.
[0178] In Comparative Example 6, the amount of Zr was 0.1230 mass %, which was greater than the range of the present embodiment, the oscillation depth was deep, and the cast wire rod was low in surface quality.
[0179] In Comparative Example 7, the amount of P was 0.0037 mass %, which was less than the range of the present embodiment, the oscillation depth was deep, and the cast wire rod was low in surface quality. In addition, the worked material was low in strength.
[0180] In Comparative Example 8, the amount of P was 0.1740 mass %, which was greater than the range of the present embodiment, casting defects occurred, and the cast wire rod was low in internal quality and surface quality. In addition, the cast wire rod and the worked material were low in strength, 0.2% yield strength, and elongation.
[0181] In Comparative Example 9: the mass ratio Zr/P of Zr to P was 0.18, which was outside the range of the present embodiment, and the worked material was low in strength and 0.2% yield strength. In addition, the cast wire rod was low in internal quality and surface quality.
[0182] In Comparative Example 10, the amount of Zr was 0.4410 mass %, which was greater than the range of the present embodiment, the amount of P was 0.2020 mass %, which was greater than the range of the present invention, casting defects occurred, and the cast wire rod was low in internal quality and surface quality. In addition, the cast wire rod and the worked material were low in strength and 0.2% yield strength.
[0183] In Comparative Example 11, neither Zr nor P contained, and the cast wire rod and the worked material were low in strength and 0.2% yield strength.
[0184] In contrast, in Invention Examples 1 to 18 in which the composition was within the range of the present embodiment, the occurrence of internal defects in the cast wire rod was suppressed, and the cast wire rod and the worked material were excellent in strength, 0.2% yield strength, and elongation.
[0185] In Inventive Examples 2, 7 to 13, and 15, the oscillation depth was slightly deeper, but it could be removed by peeling, and no problems occurred in the production of the worked material.
[0186] As a result of the above confirmatory experiments, it was confirmed that according to Invention Examples, it is possible to provide a continuous cast wire rod of a CuZnSn-based alloy having few casting defects and excellent cold workability.
[0187] While preferred embodiments of the invention have been described and illustrated above, it should be understood that these are exemplary of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the scope of the invention. Accordingly, the invention is not to be considered as being limited by the foregoing description and is only limited by the scope of the appended claims.