JP5763504B2 - Copper alloy rolling materials and rolled products - Google Patents

Description

  The present invention relates to a rolling material and a rolled product obtained by rolling the material, and in particular, a rolled product made of a copper alloy in which the rolled part has excellent strength and corrosion resistance, and the same. The present invention relates to a material for rolling process made of copper alloy.

  The rolling process has features such as (a) high productivity, (b) stable processing accuracy, (c) improved surface roughness, and (d) high strength, and is used in various alloys. Specifically, (a) productivity increases the material, so that the material loss is not generated and the yield is improved. Further, since the processing time is short and the life of the roll as a tool is long, productivity is improved as compared with the cutting process. (B) Since the roll life is long, the processing accuracy is stable, and it is a process for medium mass production. (C) The surface condition is improved because of strong processing by the ground roll. (D) The metal structure is not divided as in the cutting process, but becomes a continuous metal structure like a forged product. Further, since the surface is work hardened, there is an advantage that the strength is improved. However, since it is strong processing by local stress, it is difficult to maintain the processing accuracy of the unconstrained product part.

  Rolling processing is also applied to various steel materials such as stainless steel, non-ferrous metals and plastic materials, shaft products such as steering shafts and motor shafts, worm gears used for door lock actuators, sunroof motors, power window motors, etc. It is also used in products such as involute spline shafts and involute serration shafts manufactured by rack die method.

  In brass, the rolling process is used for products such as screws and worm gears, and many products are produced. In addition, insert nuts are used for fastening various substrates such as automobiles and industrial machines and resin-molded covers. Because it is a precision instrument, there is a risk of short-circuiting during use if chips during cutting flow out to the resin side during resin molding. For this reason, there are also products that specify the rolling process as the cutting process is not possible when processing the insert nut. Rolling is also frequently used for inexpensive and mass-produced products such as screws and products that do not require as much precision as cutting.

  Due to the recent tightening of lead regulations, lead-free materials are rapidly becoming free. Initially, it was mainly in the faucet field, and there was no movement toward lead-free in the rolling process field. However, due to the growing record of lead-free products in the faucet field and the growing interest in global environmental issues, the study and development of lead-free products in the electrical / electronics and automotive fields is also progressing. . At present, as lead-free copper alloys, materials in which Pb is replaced with Bi are beginning to be used.

  As the brass to be rolled, JIS C3604 and JIS C3602 whose copper amount is increased to 60% are often used (for example, refer to paragraph [0007] of Patent Document 1). Since rolling is a strong work in the cold, JIS C3602 is frequently used because the deformability in the cold is improved by increasing the amount of copper and decreasing the amount of β phase. Considering the rolling processability of the Pb-free copper alloy described above, Bi-based lead-free brass in which Pb is replaced with Bi may be considered equivalent to the conventional JIS C3604.

  Further, the rolling process is a strong process in the cold, and in the case of a screw, the residual compressive stress at the bottom of the screw is increased to improve the fastening force and improve the life. However, increasing the residual stress also increases the risk of stress corrosion cracking. In general brass, residual stress is removed by low-temperature annealing as a measure against stress corrosion cracking (see, for example, paragraph [0063] of Patent Document 2). Taking measures against stress corrosion cracking by removing residual stress by low-temperature annealing of rolled brass products not only creates extra costs, but also throws away the benefits of improving strength by rolling. Become.

  Due to recent trends in lead regulations, lead regulations are not only limited to the faucet field, but are being strengthened in all industrial fields such as electronics and automobiles. Even for copper alloys, there is a demand for alloys having not only machinability but also conflicting properties such as strength, corrosion resistance, and workability.

JP-A-2005-287204 JP 2006-274313 A

  The present invention has been made in view of the above points, and a rolling process product made of a copper alloy having at least a strength and corrosion resistance at a rolling process part and a rolling processability that can be obtained by the rolling process. An object of the present invention is to provide a material for rolling process made of a copper alloy excellent in the above.

  In order to achieve the above object, the present invention proposes the following copper alloy material for rolling process and rolled product.

  That is, according to the present invention, the part to be rolled is composed of Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, Zn: balance and inevitable impurities, and the condition (1 Is a Cu-Zn-Si alloy having a metal composition satisfying the condition (2) and having a hardness satisfying the condition (3). A material for rolling process made of copper alloy (hereinafter referred to as “first invention material”) is proposed.

  Moreover, as for this invention, a to-be-rolled part is Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, P: 0.015-0.2 mass%, Sb: One or more elements selected from 0.015 to 0.2 mass%, As: 0.015 to 0.15 mass%, Sn: 0.03 to 1.0 mass%, and Al: 0.03 to 1.5 mass% And Zn: the balance and inevitable impurities, and an alloy composition that satisfies the condition (1), a metal structure that includes at least the κ phase in the α phase matrix and satisfies the condition (2), and a condition (3 A material for rolling work made of a copper alloy (hereinafter referred to as “second invention material”), characterized in that it is a Cu—Zn—Si alloy having a hardness satisfying the above.

  Further, in the present invention, the rolled part is Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, Pb: 0.003-0.25 mass%, and / or An alloy composition comprising Bi: 0.003 to 0.30 mass%, Zn: balance and inevitable impurities and satisfying the condition (1), including an at least κ phase in the α phase matrix and satisfying the condition (2) A copper alloy rolling material (hereinafter referred to as “third invention material”), characterized in that it is a Cu—Zn—Si alloy having a hardness that satisfies the condition (3). suggest.

  Moreover, as for this invention, a to-be-rolled part is Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, P: 0.015-0.2 mass%, Sb: One or more elements selected from 0.015 to 0.2 mass%, As: 0.015 to 0.15 mass%, Sn: 0.03 to 1.0 mass%, and Al: 0.03 to 1.5 mass% And Pb: 0.003-0.25 mass% and / or Bi: 0.003-0.30 mass%, Zn: balance and inevitable impurities, and an alloy composition satisfying the condition (1) is satisfied, α A copper alloy made of a copper alloy, characterized in that it is a Cu—Zn—Si alloy having a metal structure containing at least a κ phase in the phase matrix and satisfying the condition (2) and having a hardness satisfying the condition (3). Materials for manufacturing (hereinafter referred to as “No. 4 invention material ").

Further, in the present invention, the part to be rolled is Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, Mn: 0.05-2.0 mass%, Ni: One or more selected from 0.05 to 2.0 mass%, Ti: 0.003 to 0.3 mass% , B: 0.001 to 0.1 mass%, and Zr: 0.0005 to 0.03 mass% An alloy composition comprising an element, Zn: balance and inevitable impurities and satisfying the condition (1), forming a metal structure containing at least a κ phase in the α phase matrix and satisfying the condition (2), A copper alloy rolling material (hereinafter referred to as “fifth invention material”) is proposed, which is a Cu—Zn—Si alloy having a hardness satisfying 3).

Moreover, as for this invention, a to-be-rolled part is Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, P: 0.015-0.2 mass%, Sb: One or more elements selected from 0.015 to 0.2 mass%, As: 0.015 to 0.15 mass%, Sn: 0.03 to 1.0 mass%, and Al: 0.03 to 1.5 mass% Mn: 0.05 to 2.0 mass%, Ni: 0.05 to 2.0 mass%, Ti: 0.003 to 0.3 mass%, B: 0.001 to 0.1 mass%, and Zr: 0.00. One or more elements selected from 0005 to 0.03 mass% , Zn: the balance and inevitable impurities, and an alloy composition satisfying the condition (1), the α phase matrix includes at least a κ phase, and Metal that satisfies condition (2) A copper alloy rolling material (hereinafter referred to as “sixth invention material”), characterized in that it is a Cu—Zn—Si alloy having a hardness that satisfies the condition (3) while being woven. .

Further, in the present invention, the rolled part is Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, Pb: 0.003-0.25 mass%, and / or Bi: 0.003-0.30 mass%, Mn: 0.05-2.0 mass%, Ni: 0.05-2.0 mass%, Ti: 0.003-0.3 mass%, B: 0.001 ~ 0.1 mass % and Zr: 0.0005 to 0.03 one or more elements selected from mass% , Zn: balance and inevitable impurities, and an alloy composition satisfying the condition (1), A Cu-Zn-Si alloy characterized in that it is a Cu-Zn-Si alloy having a metal structure that includes at least a κ phase in an α phase matrix and satisfies the condition (2) and has a hardness that satisfies the condition (3). Rolling material (below) To propose a) of the seventh aspect of the present invention material ".

Moreover, as for this invention, a to-be-rolled part is Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, P: 0.015-0.2 mass%, Sb: One or more elements selected from 0.015 to 0.2 mass%, As: 0.015 to 0.15 mass%, Sn: 0.03 to 1.0 mass%, and Al: 0.03 to 1.5 mass% And Pb: 0.003-0.25 mass% and / or Bi: 0.003-0.30 mass%, Mn: 0.05-2.0 mass%, Ni: 0.05-2.0 mass%, Ti : One or more elements selected from 0.003 to 0.3 mass %, B: 0.001 to 0.1 mass % and Zr: 0.0005 to 0.03 mass% , Zn: balance and inevitable impurities And satisfies condition (1) A Cu—Zn—Si alloy having a hardness that satisfies the condition (3) and has a metal structure that includes at least the κ phase in the α phase matrix and satisfies the condition (2). A material for rolling process (hereinafter referred to as “eighth invention material”) made of copper alloy is proposed.

  Condition (1): 63.0 ≦ [Cu] −3.6 × [Si] −3 × [P] −0.3 × [Sb] + 0.5 × [As] −1 between the constituent element contents * [Sn] -1.9 * [Al] + 0.5 * [Pb] + 0.5 * [Bi] + 2 * [Mn] + 1.7 * [Ni] + 1 * [Ti] + 2 * [B] + 2 * An alloy composition having a relationship of [Zr] ≦ 67.5.

  In the condition (1), the content of the constituent element x is [x] mass% (the same applies to the following description). For example, the Cu content is [Cu] mass%. For the element x not contained, [x] = 0. For example, in the first invention material, [P] = [Sb] = [As] = [Sn] = [Al] = [Pb] = [Bi] = [Mn] = [Ni] = [Ti] = [ Since B] = [Zr] = 0, the condition (1) is 63.0 ≦ [Cu] −3.6 × [Si] ≦ 67.5.

  Condition (2): 60 ≦ [α] ≦ 84, 15 ≦ [κ] ≦ 40, [α] + [κ] ≧ 96, 0.2 ≦ [κ] / [α] ≦ between the area ratios of the contained phases 0.65, [β] ≦ 2, [μ] ≦ 2, [β] + [μ] ≦ 2, [γ] ≦ 2, [β] + [μ] + [γ] ≦ 4 Make an organization.

  In the condition (2), the area ratio of the contained phase y is [y]% (the same applies to the following description). For example, the area ratio of the α phase is [α]%. For the phase y not contained, [y] = 0. For example, when [beta] phase is not contained, [[beta]] = 0, so [[beta]] + [[mu]] + [[gamma]] ≤4 is [[mu] + [[gamma]] ≤4. However, this formula is applied when at least two phases are included among β phase, μ phase and γ phase, and when one phase of β phase, μ phase or γ phase is included. , [Β] ≦ 2, [μ] ≦ 2, or [γ] ≦ 2.

  Further, the area ratio (%) of each phase is measured by image analysis. Specifically, an optical microscope structure of 200 times or 500 times is obtained with image processing software “WinROOF” (manufactured by Techjam Co., Ltd.). It is obtained by binarization and is an average value measured in three fields of view.

  Condition (3): Hardness (Vickers hardness) of the part to be rolled is HV1: 125 to 165.

  In the first to eighth invention materials, when the γ phase (and κ phase) is contained in the metal structure of the processed part to be rolled, the metal structure is in condition (4) in addition to condition (2). Is preferably satisfied.

  Condition (4): The metal structure of the part to be rolled has a relationship of 23 ≦ [γ] + [κ] ≦ 33.

  In addition, the first to eighth invention materials are generally provided as a cast material, an extruded material, a drawn material, or a forged material, but the metal structure and / or hardness of the processed part to be rolled does not satisfy the above-described conditions. In order to satisfy these conditions, a heat treatment such as annealing is performed. The heat treatment is held at 500 to 600 ° C. for 0.5 to 8.0 hours, and the cooling rate at 400 ° C. or less is 0.3 ° C./min. It is preferable to carry out under the above conditions. When the first to eighth invention materials are any of a cast material, an extruded material, a drawn material, and a forged material, it is preferable that at least the drawn material is subjected to the heat treatment.

  Furthermore, the present invention is a rolled product obtained by rolling a rolled processed portion of the first to eighth invention materials, and the hardness (Vickers hardness) of the rolled processed portion is HV1: 220 to 270. A copper alloy rolled processed product (hereinafter referred to as “processed product of the present invention”) is proposed. If the cross-sectional hardness of the rolled portion is less than HV1: 220, the strength as a practical rolled product is not sufficient, and excellent wear resistance cannot be ensured. On the contrary, when HV1: 270 is exceeded, the processing limit of the copper alloy material (Cu—Zn—Si alloy) is exceeded, and the rolling process portion is crushed during the rolling process. There is a possibility that the rolling process part is damaged during use. From these points, the hardness of the rolled processed portion of the processed product of the present invention needs to be HV1: 220-270, and preferably HV1: 230-260.

  In addition, in this invention processed product which rolled the 1st-8th invention raw material and its rolling process part, parts other than a rolling process part or parts other than a rolling process part are the above-mentioned alloy compositions, Needless to say, it does not prevent having a metal structure or hardness. In addition, in the first to eighth invention materials and the processed product of the present invention, in addition to a case where a part thereof is a rolled part or a rolled part, the whole is a rolled part or a rolled part. Includes cases.

  Thus, in the first to eighth invention materials and the processed products of the present invention obtained by rolling this material, Cu is a main element constituting the material and has a relationship with the Si content. In order to prevent the β phase that adversely affects the corrosion resistance of the processed part from appearing or to suppress the appearance of the β phase to a minimum, a content of a certain amount or more is required. Further, by containing a certain amount or more of Cu, it is possible to reduce the stress corrosion cracking susceptibility of the rolled portion, and to ensure high strength, wear resistance, ductility and impact characteristics of the rolled portion. From these points, the content of Cu needs to be 73.5 mass% or more, and preferably 74.0 mass% or more.

  On the other hand, even if Cu is contained in excess of 79.5 mass%, there is also a relationship with the Si content, but the corrosion resistance of the rolled portion is saturated, and on the contrary, the castability at the manufacturing stage of the rolling material. As a result, problems arise in forgeability, and sufficient machinability cannot be ensured, and cutting cannot be performed satisfactorily in the production stage of the material and the rolled product. From these points, the Cu content needs to be 79.5 mass% or less, and is preferably 79.0 mass% or less.

  In the first to eighth invention materials and the processed products of the present invention obtained by rolling these, Si is a main element constituting the material together with Cu and Zn, but the Si content is less than 2.5 mass%. Then, solid solution hardening by Si occurs, or the formation of the κ phase becomes insufficient, and the strength of the rolled portion may be insufficient. In addition, sufficient machinability cannot be ensured, and the cutting process cannot be performed satisfactorily in the case where the cutting process is performed in the manufacturing stage of the material or the manufacturing process of the rolled product. From these points, the Si content needs to be 2.5 mass% or more, and is preferably 2.7 mass% or more.

  On the other hand, when the Si content exceeds 3.7 mass%, the strength of the rolled portion is saturated and the proportion of the α phase is small, so that the rolling process becomes difficult, the ductility of the rolled portion, Problems arise in corrosion resistance and impact properties. In addition, since the proportion of the κ phase and / or γ phase increases and the proportion of the α phase decreases, sufficient machinability cannot be secured, and the production stage of the material and the production stage of the rolled product The cutting process cannot be performed well. Further, a β phase harmful to corrosion resistance or the like is easily formed, and the proportion of the μ phase and / or γ phase increases, and the corrosion resistance, ductility, and impact characteristics of the rolled portion may be deteriorated. From these points, the Si content needs to be 3.7 mass% or less, and is preferably 3.5 mass% or less.

  Zn is the main element constituting the alloy composition of the first to eighth invention materials and the processed product of the present invention obtained by rolling this together with Cu and Si, and the effect of improving machinability, corrosion resistance, and mechanical properties There is. Therefore, it is defined as the balance of each constituent element.

  In the second, fourth, sixth and eighth invention materials and the processed products of the present invention obtained by rolling these, P, Sb, As, Sn, and Al are 1 for improving the corrosion resistance of the rolled parts. More than seeds are contained.

  That is, P, Sb, and As all improve the corrosion resistance of the α phase, and the effect of improving the corrosion resistance due to the inclusion of As and / or P is particularly great. On the other hand, Sb improves the corrosion resistance of the κ phase and improves the corrosion resistance of the μ, γ and β phases. P and As also improve the corrosion resistance of the κ phase, but its effect is lower than that of Sb, and the effect of improving the corrosion resistance of the μ, γ and β phases is less than that of Sb. In general, when a large plastic deformation is applied to a copper alloy material as in the rolling process, the corrosion resistance of the deformed part (rolling process part) decreases, but sufficient corrosion resistance can be obtained by adding these elements. Can be secured. In addition, P refines the crystal grains of the hot forged material and refines the crystal grains of the casting by co-addition with Zr. However, P or As and Sb are co-added in terms of suppressing crystal grain growth. It is preferable to make it. Such an effect of improving corrosion resistance and strength cannot be expected so much for any of P, Sb, and As if the content is less than 0.015 mass%. However, even if the As content exceeds 0.15 mass% and the Sb content or the P content exceeds 0.2 mass%, the effect is saturated. From these points, the P content was 0.015 to 0.2 mass%, the Sb content was 0.015 to 0.2 mass%, and the As content was 0.015 to 0.15 mass%.

  Sn and Al are elements that improve the corrosion resistance like P, Sb, and As, and particularly under high-speed flowing water, particularly corrosion resistance under flowing water conditions where physical action occurs particularly, that is, erosion corrosion resistance and cavitation. The effect of improving the corrosion resistance in an environment with poor water quality is further exhibited. Furthermore, Sn and Al exhibit the effect of hardening the α phase and κ phase to improve the strength and wear resistance. About Sn, in order for the said effect to fully be exhibited, it is necessary to make the content 0.03 mass% or more, it is preferable that it is 0.2 mass% or more, 0.3 mass% or more More preferably. However, even if the Sn content exceeds 1.0 mass%, the effect is saturated, the amount of γ phase increases, and the elongation is damaged. On the contrary, the Sn content needs to be 1.0 mass% or less. Yes, it is preferably set to 0.8 mass% or less. Further, for Al, in order for the above effect to be sufficiently exerted, the content needs to be 0.03 mass% or more, preferably 0.25 mass% or more, and 0.45 mass%. More preferably. However, even if the Al content exceeds 1.5 mass%, the effect is saturated, and the castability and ductility are impaired. Therefore, the Al content needs to be 1.5 mass% or less. It is preferable to set it to 2 mass% or less, and it is more preferable to set it to 0.9 mass% or less.

  In the third, fourth, seventh and eighth invention materials and the processed products of the present invention obtained by rolling these, Pb and / or Bi needs to be cut at the manufacturing stage of the material or the member. In the case (for example, when cutting the ingot or cast material to manufacture the material, or cutting the portion other than the rolling portion of the member to manufacture the final rolled product) It is contained in order to exhibit machinability. In the Cu—Zn—Si alloy containing Cu, Si and Zn in the above-described range, Pb and Bi exhibit a machinability improving effect by setting each content to 0.003 mass% or more. However, Pb is harmful to the human body, and its content tends to be regulated. Further, if Pb is contained more than necessary, ductility and impact properties are impaired, so the content of Pb is 0.25 mass%. It is necessary to keep it below, and it is preferable to set it as 0.15 mass% or less, and it is more preferable to set it as 0.08 mass% or less. In addition, since Bi is a rare metal, and if it is contained more than necessary as in Pb, ductility and impact characteristics may be impaired, the Bi content must be 0.30 mass% or less. It is preferable to set it to 2 mass% or less, and it is more preferable to set it to 0.1 mass% or less. When Pb and Bi are co-added, the total content is preferably suppressed to 0.25 mass% or less, and more preferably 0.15 mass% or less. In addition, Pb and Bi are not dissolved in the matrix but are present in a granular form. However, when Pb and Bi are co-added, they coexist and the melting point of the coexisting particles is lowered, and the cutting process is in progress. Therefore, when 0.02 mass% or more of Pb and Bi are added together, the content ratio [Bi] / [Pb] is 7 or more ([Bi ] / [Pb] ≧ 7), and more preferably [Bi] / [Pb] ≧ 0.35. Even in this case, it is needless to say that the total content of Pb and Bi is preferably suppressed to 0.25 mass% or less (more preferably 0.15 mass%) or less as described above.

  In the fifth to eighth invention materials and the processed products of the present invention obtained by rolling these, Mn, Ni, Ti, B, and Zr are mainly included in order to improve the strength of the rolled portion. The

  That is, Mn and Ni have the effect of improving strength and wear resistance mainly by forming an intermetallic compound with Si. However, in order to exert such effects, the contents of Mn and Ni are 0 respectively. .05 mass% or more is necessary. However, even if Mn and Ni are added in excess of 2.0 mass%, the effect is almost saturated, and on the contrary, the rolling processability is deteriorated, and the machinability and the ductility and impact properties are also reduced. It will be. Therefore, the contents of Mn and Ni are 0.05 to 2.0 mass%, respectively.

  Ti and B are contained in order to improve the strength by adding a small amount. Such an improvement in strength is mainly due to the suppression of crystal grain growth by refining crystal grains at the forging or casting stage, but the effect is when the Ti content is 0.003 mass% or more, or This is exhibited when the B content is 0.001 mass% or more. However, even if the Ti content exceeds 0.3 mass%, or the B content exceeds 0.1 mass%, the effect is saturated, rather, if the content of Ti or B that is an active metal is large, There is an adverse effect that oxides are involved when dissolved in the atmosphere. Therefore, the Ti content is 0.003 to 0.3 mass%, and the B content is 0.001 to 0.1 mass%.

  Zr exhibits the effect of improving the strength by adding a small amount. Such an effect is mainly due to remarkably refining of the crystal grains at the casting stage, and the strength is improved by refining the crystal grains. The effect of improving the strength by such refinement of crystal grains is exhibited when the Zr content is 0.0005 mass% or more. However, even if Zr is added in excess of 0.03 mass%, the effect is saturated, and there is a possibility that the refinement of crystal grains may be hindered. Therefore, the Zr content is set to 0.0005 to 0.03 mass%. The effect of crystal grain refinement by Zr is further exhibited by co-addition with P. Such an effect is more prominent particularly when the co-addition ratio [P] / [Zr] of Zr and P is 1 ≦ [P] / [Zr] ≦ 80.

  By the way, copper alloys such as Cu—Zn—Si alloys are excellent in recyclability, and are collected and recycled at a high recycling rate. On the other hand, Fe may be inevitably mixed due to mixing of other copper alloys during recycling, for example, due to tool wear during cutting. Therefore, even in the first to eighth invention materials, the inclusion of those standardized as inevitable impurities in various standards such as JIS is allowed. For example, in the free-cutting copper alloy rod C3601 described in JIS H3250 copper and copper alloy rod, 0.3 mass% or less of Fe is defined as an impurity, and such Fe is the first to eighth invention materials. Are treated as inevitable impurities.

  In addition, in order to obtain a good metal structure that greatly affects these properties in order that the rolling processed portion has high strength and excellent impact properties and ductility, and the first to eighth inventions. The content of the elements constituting the alloy composition of the material is not enough to be determined individually within the above range, and the first invention material is determined in consideration of the mutual relationship between the contents of Cu and Si. In addition, in the second to eighth invention materials, the contents of Cu and Si and elements contained selectively (P, Sb, As, Sn, Al, Pb, Bi, Mn , Ni, Ti, B, and Zr must be determined in consideration of the interrelation with the content of the element, and the alloy composition of the first to eighth invention materials is a condition ( It is necessary to satisfy 1).

  That is, the content formula f (= [Cu] −3.6 × [Si] −3 × [P] −0.3 × [Sb] + 0.5 × [As] −1 × [Sn) in the condition (1) ] -1.9 × [Al] + 0.5 × [Pb] + 0.5 × [Bi] + 2 × [Mn] + 1.7 × [Ni] + 1 × [Ti] + 2 × [B] + 2 × [Zr] ) Was devised by accumulating many experiments and trials and errors. When f <63.0, macrocrystal grains coarsen during high-temperature heating, particularly impact properties and ductility are reduced. Corrosion resistance and tensile strength are also reduced. In addition, when f> 67.5, the proportion of the α phase becomes too large, α phase crystal grains grow during high temperature heating, and the tensile strength and proof stress decrease. From these points, the alloy composition of the first to eighth invention materials must be such that the content of the constituent elements is 63 ≦ f ≦ 67.5 within the above-described range, and the lower limit value of f is 63.5 is preferable, and 64.0 is more preferable. The upper limit value of f is preferably 67.0, and more preferably 66.5. In addition, in the 3rd, 4th, 7th and 8th invention materials and the processed products of the present invention formed by rolling these, when Pb and Bi are co-added, the total content is 0.003 mass% If it exceeds C, impact properties, ductility, and tensile strength begin to decrease, so that 63.0 + 2 ([Pb] + [Bi] −0.003) ≦ f ≦ 67.5-2 ([Pb] + [ Bi] −0.003) is preferable (63.5 + 2 ([Pb] + [Bi] −0.003) ≦ f ≦ 67.0-2 ([Pb] + [Bi] −0.003) In the case where cutting is performed in the manufacturing stage of the rolling material and / or the rolled product, f <63.0 + 2 ([Pb] + [Bi] −0.003). ) Or f> 67.5-2 ([Pb] + [Bi] −0.003) Sex can not be obtained, hardly make good cutting. In addition, in the first to eighth invention materials and the processed products of the present invention formed by rolling these, if the total content of inevitable impurities such as Fe is 0.7 mass% or less, the adverse effects due to the impurities are not However, if the influence of the impurity is taken into consideration, it is preferable to set the condition (1) to 63.7 ≦ f ≦ 66.8. Moreover, when the total content of inevitable impurities exceeds 0.7 mass%, when the total content is [X] mass%, the condition (1) is 63.0 + ([X] −0.7) ≦ It is preferable that f ≦ 67.5 − ([X] −0.7), that is, 62.3+ [X] ≦ f ≦ 68.2− [X], and 63.0+ [X] ≦ f ≦ 67.5. -[X] is more preferable.

  In addition, in the case of a rolling material, since it is generally manufactured through various heating processes (for example, hot extrusion, annealing, etc.), in addition to the α phase of the matrix, the β phase, κ Various phases such as γ phase, γ phase, μ phase, and in some cases δ phase, ζ phase, χ phase, etc. may appear, and the types of phases appearing depending on extrusion conditions, annealing conditions, etc. The ratio of the occupancy varies greatly. In the first to eighth invention materials and the processed products of the present invention formed by rolling these, in addition to the above-described alloy composition, the α phase matrix It is necessary to form a metal structure that includes at least the κ phase and satisfies the condition (2) (in the case where the γ phase is included, it is preferable that the metal structure further satisfies the condition (4)).

  That is, when the total area ratio of the α phase and the κ phase in the metal structure is less than 96%, it is difficult to perform a good rolling process, and high strength, ductility and impact properties cannot be ensured, and the corrosion resistance. Will be insufficient. Basically, the α phase is a matrix and is rich in ductility and corrosion resistance. In the metal structure after the rolling process, the κ phase surrounds the α phase, or the α phase and the κ phase are uniformly mixed, so that the growth of crystal grains of the α phase and the κ phase is suppressed and high. At the same time as obtaining strength, excellent rolling processability is ensured, and high ductility, impact properties and excellent corrosion resistance are obtained. Therefore, in order to make these characteristics more excellent, it is necessary that [α] + [κ] ≧ 96, and it is preferable that [α] + [κ] ≧ 97, and [α] ] + [Κ] ≧ 98 is more preferable.

  In addition, in order to obtain high strength, high ductility, impact properties, and excellent corrosion resistance, a metal structure in which the κ phase surrounds the α phase, or a metal in which the α phase and κ phase are uniformly mixed is used. Although it is preferable to form a structure, an α phase and a κ phase are necessary to form such a metal structure, and the area ratio relationship between both phases is extremely important. That is, if [κ] / [α] <0.2, the α phase becomes excessive and the ductility, corrosion resistance and impact resistance are excellent, but the strength and wear resistance are reduced. [Α] ≧ 0.2 is required, [κ] / [α] ≧ 0.3 is preferable, and [κ] / [α] ≧ 0.4 is more preferable. On the other hand, if [κ] / [α]> 0.65, on the other hand, the κ phase is excessive, particularly a problem occurs in ductility, the rolling difficulty and impact properties are deteriorated, and the strength improvement is saturated. Therefore, it is necessary that [κ] / [α] ≦ 0.65, preferably [κ] / [α] ≦ 0.6, and [κ] / [α] ≦ 0.5. More preferably.

  In addition to the above-described relationship between the area ratios of the α phase and the κ phase, the individual area ratios of the α phase and the κ phase are within a certain range in order that the rolled part has high strength, ductility, impact characteristics, and corrosion resistance. It is necessary to become. That is, it is necessary that 60 ≦ [α] ≦ 84 and 15 ≦ [κ] ≦ 40, 63 ≦ [α] ≦ 81 and 20 ≦ [κ] ≦ 35, and 66 ≦ [α ] ≦ 78 and 25 ≦ [κ] ≦ 30 are more preferable.

  Further, both the β phase and the μ phase deteriorate the rolling processability, and hinder the strength, ductility, corrosion resistance, and impact characteristics of the copper alloy of the rolled product. Alone, if the β phase exceeds 2%, the corrosion resistance is adversely affected, and the ductility and impact properties are also adversely affected. Therefore, [β] ≦ 2 is required, [β] ≦ 1.5% is preferable, and [β] ≦ 0.5% is preferable. On the other hand, if the μ phase exceeds 2%, the corrosion resistance, ductility, strength and impact properties are adversely affected. Therefore, it is necessary that [μ] ≦ 2, and [μ] ≦ 1.5. Is preferable, and [μ] ≦ 0.5 is more preferable. Furthermore, when the β phase and the μ phase are included in the metal structure, it is necessary to set [β] + [μ] ≦ 2 in consideration of the influence on the corrosion resistance, ductility, and the like. β] + [μ] ≦ 1 is preferable, and [β] + [μ] ≦ 0.5 is more preferable.

  In addition, the γ phase is a phase that improves machinability, but worsens the rolling processability, and when the area ratio of the γ phase in the metal structure exceeds 2%, the ductility, corrosion resistance, Adversely affects impact properties. Preferably, it is 1.5% or less, and optimally 1.0% or less. However, the strength is improved when a small amount of γ phase is dispersed. The effect is such that the γ phase exceeds 0.05% and the effect is exhibited. If the γ phase is dispersed in a small amount and distributed, the ductility and corrosion resistance are not adversely affected. Therefore, 0 ≦ [γ] ≦ 2, preferably 0 ≦ [γ] ≦ 1.5, and most preferably 0.05 ≦ [γ] ≦ 1.0. However, when rolling a cold-worked material, the amount of γ phase is more limited, and 0 ≦ [γ] ≦ 1.5, 23 ≦ [κ] + [γ] ≦ 33, preferably 0 ≦ γ ≦ 0.5, and optimally 0 ≦ γ ≦ 0.2. Furthermore, the proportion of β, μ, and γ phases must be evaluated by the total amount. That is, if the total amount of β, μ and γ phases exceeds 4%, ductility after rolling, corrosion resistance, impact properties, and strength deteriorate. Preferably, it is 3% or less, and optimally 2% or less. That is, when expressed by a mathematical expression, 0 ≦ [β] + [μ] + [γ] ≦ 4, preferably 0 ≦ [β] + [μ] + [γ] ≦ 3, and optimally 0.05 ≦ [β] + [μ] + [γ] ≦ 2.

The α, κ, γ, β, and μ phases can be defined as follows in the Cu—Zn—Si alloy that is the basis of the present invention, based on the quantitative analysis results using an X-ray microanalyzer.
The α phase of the matrix is Cu: 73 to 80 mass%, Si: 1.7 mass% to 3.1 mass%, and the balance is Zn and other additive elements. A typical composition is 76Cu-2.4Si-residual Zn.
The κ phase, which is an essential phase, is Cu: 73 to 79 mass%, Si: 3.2 mass% to 4.7 mass%, and the balance is Zn and other additive elements. A typical composition is 76Cu-3.9Si-residual Zn.
The γ phase is Cu: 66 to 75 mass%, Si: 4.8 mass% to 7.2 mass%, and the balance is Zn and other additive elements. A typical composition is 72Cu-6.0Si-residual Zn.
The β phase is Cu: 63 to 72 mass%, Si: 1.8 mass% to 4.0 mass%, and the balance is Zn and other additive elements. A typical composition is 69Cu-2.4Si-residual Zn.
The μ phase is Cu: 76 to 89 mass%, Si: 7.3 mass% to 11 mass%, and the balance is Zn and other additive elements. A typical composition is 83Cu-9.0Si-residual Zn.
Thus, the μ phase can be distinguished from the α, κ, γ, β phase and the Si concentration, and the γ phase can be distinguished from the α, κ, β, μ phase and the Si concentration. The μ phase and the γ phase are close to each other in Si content, but are distinguished at a Cu concentration of 76%. The β phase can be distinguished from the γ phase by the Si concentration, and the α, κ, and μ phases can be distinguished from the Cu concentration. The α phase and the κ phase are close to each other, but are distinguished on the basis of the Si concentration of 3.15 mass% or 3.1 to 3.2 mass%. Further, when the crystal structure was examined by EBSD (electron backscatter diffraction), the α phase was fcc, the β phase was bcc, the γ phase was bcc, and the κ phase was hcp, which are distinguished from each other. be able to. Note that the β phase has a CuZn type, that is, a W type bcc structure, and the γ phase has a Cu ₅ Zn ₈ type bcc structure, which can be distinguished from each other. Originally, the crystal structure of the κ phase: hcp is poor in ductility, but it is satisfactory if it satisfies 0.2 ≦ [κ] / [α] ≦ 0.65 in the presence of the α phase. And ductility. In addition, the ratio of the phase in a metal structure is shown, and the compound of a nonmetallic inclusion, Pb particle | grains, Bi particle | grains, Ni and Si, Mn and Si is not contained.

  By the way, in the case of a rolling process material, when the manufacturing process includes an extrusion process, multiple types of phases appear in addition to the main constituent phases (α phase, κ phase, γ phase) due to the influence of the extrusion temperature. Therefore, it is necessary to optimize the extrusion temperature so that the rolling process is possible and various characteristics are optimized. The optimum extrusion temperature is 650-750 ° C. When extrusion is performed at a temperature lower than this range, a lot of γ phase is precipitated, the rolling processability is lowered, and the γ phase remains even after annealing. Moreover, deformation resistance becomes high and extrusion with a small diameter cannot be performed. When extruded at a temperature higher than this range, the κ phase and β phase increase, and even after annealing, the β phase and κ phase remain, and the corrosion resistance and the like deteriorate.

  Further, in the case of a rolling process material, when the manufacturing process includes a drawing process or a drawing process, the workability is hardened by such cold processing and the rolling processability is lowered. Therefore, in order to obtain a high-quality rolled product, it is necessary to make the material soft by annealing. In order to ensure good rolling processability, as described above, it is necessary to form a metal structure containing at least the κ phase in the α phase matrix and satisfying the condition (2). In order to achieve this improvement, the metal structure after heat treatment (annealing) preferably has [γ] ≦ 1.5, more preferably [γ] ≦ 0.5, and [γ] ≦ 0. 2 is optimal. However, although the kind of phase constituting the metal structure and the proportion of the phase are changed by heating, when heat treatment is performed at a low temperature of less than 500 ° C., the influence of the metal structure before annealing remains, particularly at a high temperature. It may be difficult to eliminate the β phase and reduce the γ phase to a predetermined amount, and it may be difficult to reduce the hardness to HV1: 165 or less. On the other hand, when the heat treatment temperature exceeds 600 ° C., in many cases, the hardness becomes HV1: 165 or less, but the proportion of the γ phase and κ phase increases, and the rolling processability decreases. Therefore, since the heat treatment time (annealing time) depends on the type of processing furnace such as batch type or continuous annealing, it is desirable to hold for 0.5 to 8 hours after the material temperature reaches 500 to 600 ° C. . Further, the cooling rate after the heat treatment is such that the μ phase is precipitated at a cooling rate of 0.1 ° C./min corresponding to furnace cooling in the temperature region of 400 ° C. or lower, and the rolling workability and corrosion resistance are lowered. It is necessary to cool at 400 ° C. or lower at a cooling rate of 0.3 ° C./min or higher.

In addition, wear resistance is an important characteristic required for rolled products, but this depends on hardness, and by controlling the hardness within a certain range, strength is not impaired without impairing ductility and impact characteristics. In addition, it is possible to obtain a rolled product having excellent wear resistance. Therefore, the hardness of the work material for rolling needs to be HV1: 125-165 like condition (3). That is, HV1: 165 (corresponding to 620 N / mm ² in tensile strength) is the upper limit hardness for enabling rolling, and HV1: 125 (corresponding to 550 N / mm ² in tensile strength) is This is the lower limit hardness for setting the material strength after the rolling process to the target strength level.

  Further, if the hardness of the rolled product (cross section hardness of the rolled product) is less than HV1: 220, the strength of the rolled product is insufficient and the wear resistance may be reduced. . On the other hand, if the hardness of the rolled product exceeds HV1: 270, there is a possibility that the rolling process part may be crushed during the rolling process exceeding the processing limit of the material. There is a risk that the rolled part may be damaged during use of the product. Accordingly, the hardness of the rolled product is required to be HV1: 220 to 270, and preferably 230 to 260.

  The material for rolling process (the first to eighth invention materials) of the present invention is excellent in rolling processability, and can easily and appropriately perform the rolling process of the part to be rolled. In addition, a rolled product can be obtained in which a rolled part (a part formed by rolling a part to be rolled) is excellent in strength, wear resistance, stress corrosion cracking resistance and corrosion resistance. For example, shaft products such as steering shafts and motor shafts, worm gears used for door lock actuators, sunroof motors, power window motors, etc., and rolled products such as involute spline shafts and involute serration shafts manufactured by the rack die method. It can be suitably used as a constituent material. In particular, according to the second, fourth, sixth and eighth invention materials, it is possible to obtain a rolled product that is extremely excellent in corrosion resistance and stress corrosion cracking resistance. The materials of the third, fourth, seventh and eighth inventions are extremely excellent in machinability, and even when cutting is required in the manufacturing stage of the material or its rolled product, the processing is further performed. It can be performed well. Moreover, according to the 5th-8th invention material, the rolling processed goods excellent in intensity | strength and abrasion resistance can be obtained.

  In addition, the rolled product of the present invention is formed by rolling the processed parts of the materials of the first to eighth inventions, and is excellent in strength, wear resistance, stress corrosion cracking resistance and corrosion resistance. Therefore, the application can be expanded to fields that have been difficult or impossible to use with conventional rolled products made of copper alloys, and are extremely practical. For example, the rolled processed product of the present invention is a rolled processed material, a rolled processed part, a rolled processed member, in which the rolled processed portion has a continuous uneven shape such as a male screw, a female screw, a spline, a gear, or a knurling. And rolling products (shaft products such as steering shafts and motor shafts, worm gears used in door lock actuators, sunroof motors, power window motors, etc., involute spline shafts and involute serration shafts manufactured by rack dies) It can be used suitably. In particular, the rolled product of the present invention formed by rolling the materials of the second, fourth, sixth, and eighth inventions is extremely excellent in corrosion resistance and stress corrosion cracking resistance, and has high corrosion resistance. It can be suitably used for required applications. In addition, the rolled products of the present invention formed by rolling the materials of the third, fourth, seventh and eighth inventions are extremely excellent in machinability, and are also included in products that include cutting in the manufacturing process. It can be preferably used. In addition, the rolled product of the present invention formed by rolling the materials of the fifth to eighth inventions is extremely excellent in strength and wear resistance, and in a field where high strength or durability is strongly required. Can also be suitably used.

  Thus, according to the present invention, the use of the copper alloy material in the rolling process field can be greatly expanded.

FIG. 1 is a front view showing an example of a rolled product manufactured using a copper alloy rolling material according to the present invention. FIG. 2 is a longitudinal front view showing a microstructure in a rolling process portion of the rolled product.

  As an example, a rolling material (hereinafter referred to as “Example material”) No. 1 having the alloy composition shown in Table 1 and the metal structure and hardness (Vickers hardness HV1) shown in Table 2 according to the present invention. 1-No. 23 was obtained. In addition, Example material No. 1 is the first invention material, Example material No. 2-No. No. 8 is the material of the second invention, the example material No. No. 9 is the third invention material, Example material No. 10-No. 13, no. 18, no. 19 and No. No. 23 is the fourth invention material, Example material No. No. 14 is the material of the fifth invention, the example material No. 21 and no. No. 22 is the sixth invention material. 15 is the seventh invention material, and the example material No. 16, no. 17 and no. 20 corresponds to each of the eighth invention materials.

  That is, Example material No. 1-No. Reference numeral 17 denotes an extruded material, and cylindrical ingots having an alloy composition shown in Table 1 (outer diameter 100 mm, length 150 mm) were extruded at 670 ° C. to obtain a round bar with an outer diameter of 20 mm. Above, this round bar material is a general correction.

  In addition, Example Material No. 18 and no. 19 is a drawing material, and each of the cylindrical ingots (outer diameter 100 mm, length 150 mm) having the alloy composition shown in Table 1 is extruded into a round bar shape having an outer diameter of 20 mm under the condition of 670 ° C. Is drawn into a round bar shape having an outer diameter of 19 mm, and the drawn material is heat-treated (annealed) in a muffle furnace. Annealing is performed in Example Material No. No. 18 was held at 520 ° C. for 1 hour and the cooling rate at 400 ° C. or lower was set to 1 ° C./min. No. 19 is maintained at 580 ° C. for 1 hour and the cooling rate at 400 ° C. or lower is 1 ° C./min. In addition, Example material No. 18 and no. No. 19 has the same alloy composition, and differs only in heat treatment conditions (annealing temperature).

  In addition, Example Material No. 20-No. Reference numeral 22 denotes a cast material, in which a molten metal was cast into a mold (diameter 35 mm, depth 200 mm) to obtain a cylindrical ingot having an alloy composition shown in Table 1, and this was turned by a lathe. It was cut into a 17 mm round bar.

  In addition, Example Material No. 23 is a forging material, and a cylindrical ingot having an alloy composition shown in Table 1 (outer diameter 100 mm, length 150 mm) was extruded at 670 ° C. to obtain a round bar with an outer diameter of 40 mm. This was forged into a flat plate shape at a suitable forging temperature of 700 ° C. to a thickness of 20 mm, and then cut into a round bar shape with an outer diameter of 20 mm.

  And Example material No. 1-No. When the metal structure and hardness (Vickers hardness: HV1) of No. 23 were measured, they were as shown in Table 2 and all satisfied the conditions (2) to (4). In addition, about the metal structure, the cross section of the sample was grind | polished and it was set as the mirror surface, this was etched with the liquid mixture of hydrogen peroxide and ammonia water, and the area ratio (%) of each phase was measured by image analysis. That is, the area ratio of each phase was determined by binarizing a 200-fold or 500-fold optical microscope structure with image processing software [WinROOF] (manufactured by Techjam Corporation). The area ratio was measured in three fields, and the average value was used as the phase ratio of each phase. When it was difficult to specify the phase, the phase was specified by the FE-SEM-EBSP (Electron Back Scattering Diffraction Pattern) method, and the area ratio of each phase was obtained. FE-SEM is JSM-7000F manufactured by JEOL Ltd., and OIM-Ver. 5.1 was used, and it was obtained from a phase map (Phase map) with an analysis magnification of 500 times and 2000 times.

  Further, as a comparative example, a rolling process material (hereinafter referred to as “comparative material”) No. 1 having the alloy composition shown in Table 4 and the metal structure and hardness (Vickers hardness: HV1) shown in Table 5 was used. 101-No. 112 was obtained.

  That is, the comparative material No. 101-No. 108 is an extruded material, and each of the cylindrical ingots (outer diameter 100 mm, length 150 mm) having the alloy composition shown in Table 4 is extruded under the conditions of 620 ° C., 670 ° C. or 780 ° C., and the outer diameter is 20 mm. In addition to obtaining a round bar, this round bar was subjected to general correction. Extrusion temperature is comparative example material No. 101-No. No. 106 was set to 670 ° C., and comparative material No. No. 107 was set to 780 ° C., and comparative material No. About 108, it was set as 620 degreeC.

  Comparative material No. 109-No. 112 is a drawing material, and each of the cylindrical ingots (outer diameter 100 mm, length 150 mm) having the alloy composition shown in Table 4 is extruded into a round bar shape having an outer diameter of 20 mm under the condition of 670 ° C. Is drawn into a round bar shape having an outer diameter of 19 mm, and the drawn material is heat-treated (annealed) in a muffle furnace. The heat treatment was performed in Comparative Example Material No. No comparison is made for Comparative Example Material No. 109. About 110, it hold | maintained at 480 degreeC for 1 hour, and also annealed by making the cooling rate in 400 degrees C or less into 1 degree-C / min. No. 111 was held at 620 ° C. for 1 hour and annealed at a cooling rate of 400 ° C. or lower at 1 ° C./min. About 112, it hold | maintained at 580 degreeC for 1 hour, and also annealed by making the cooling rate in 400 degrees C or less into 0.1 degrees C / min. In addition, comparative example material No. 107-No. 112, Example material No. 18 and no. 19 has the same alloy composition.

  These comparative material No. 101-No. The alloy composition, metal structure, and hardness (Vickers hardness: HV1) of No. 112 are as shown in Tables 4 and 5, all of which relate to the alloy composition, metal structure, and hardness specified in the first to eighth invention materials. It does not satisfy at least some of the conditions.

  Thus, each example material No. 1-No. 23 and each comparative example material No. 101-No. 112 (five each) are rolled to form five types of metric coarse screws, M5, M7, M10, M12 and M14, on the outer periphery of each of the obtained rolled products. Appearance evaluation, hardness measurement, dezincification corrosion test (ISO 6509) and the like were performed on the processed portion (screw portion). In the following description, each rolled product is given the same number as its material number, and the example material No. A rolled product obtained by rolling m is referred to as “Example processed product No. m”. A rolled product obtained by rolling n is referred to as a “comparative example processed product No. n”. Note that FIG. Example processed product No. 10 formed by rolling and processing No. 10 10 is a front view showing the external appearance of No. 10, and FIG. It is a vertical front view which shows the microstructure in 10 rolling process parts (screw part).

In rolling processing, each material No. 1-No. 23 and no. 101-No. The outer diameter of 112 is cut into a round bar (outer diameter: d) having a dimension (tolerance is ± 0.02) reduced by 10% with respect to the predetermined outer diameter dimension of each metric coarse screw, This round bar is passed between the round dies in the cold state, and the processed product of the example in which metric coarse screws M5, M7, M10, M12 and M14 are formed on the outer peripheral portion of the round bar (the processed product of the present invention) No. 1-No. 23 and comparative example processed product No. 101-No. 112 (5 types each) were obtained. In addition, each Example processed product No. 1-No. 22 and comparative processed product No. 101-No. The outer diameter dimension (outer diameter dimension of the round bar) d and the “hanging height” H ₁ before thread rolling in 112 are M5: d = 4.5 mm, H ₁ = 0.433 m, respectively. _{M7: d = 6.3mm, H 1} = 0.541mm, M10: d = 9.0mm, H 1 = 0.812mm, M12: d = 10.8mm, H 1 = 0.947mm and M14: d = 12 0.6 mm, H ₁ = 1.083 mm.

  The processed product No. of each Example obtained in this way. 1-No. No. 23 and each comparative example processed product No. 101-No. About 112 thread part (rolling processed part), the external appearance was magnified 25 times and 200 times with the objective microscope, and the external appearance evaluation was performed. The results were as shown in Tables 3 and 4. In Tables 3 and 6, those that were not cracked even at 200 times were evaluated as good rolling and indicated by “O”, and cracks were found at 200 times that were not seen at 25 times. The rolls were evaluated as slightly good by rolling and indicated by “Δ”, and those with cracks observed at 25 times were evaluated as poor rolling and indicated by “x”.

  And based on the result of this external appearance evaluation, the rolling workability of each raw material was evaluated. The results were as shown in Tables 3 and 6. In Tables 3 and 6, the appearance evaluations of all five types of screws (M5, M7, M10, M12 and M14) were “◯” or “Δ” Is evaluated as “excellent in rolling processability” and indicated by “A”, and at least M5, M7 and M10 were evaluated as “○” or “△” in appearance evaluation as “practical” It was evaluated as “rollable” and displayed as “B”, and the appearance evaluation of “M” for M10 was evaluated as “impossible to roll in practice” and displayed as “C”.

  In addition, each processed product No. 1-No. No. 23 and each comparative example processed product No. 101-No. The hardness (Vickers hardness HV1) of the rolling processed part (screw part) of 112 (excluding comparative example processed product No. 109) was measured. This hardness measurement was performed at a location 0.3 mm away from the top of the screw thread in the valley direction. The results were as shown in Tables 3 and 6. In addition, comparative example processed goods No. No. 109 is a comparative material No. Since the hardness of 109 is extremely high (HV1: 188), the processing limit was reached in the rolling process, and any kind of screw part was crushed. Therefore, the hardness measurement of the screw part and the stress corrosion cracking test and removal described later were performed. No zinc corrosion test was conducted.

  Further, each processed product No. 1-No. No. 23 and each comparative example processed product No. 105-No. A stress corrosion cracking test and a dezincification corrosion test were conducted on 112 (excluding the comparative example processed product No. 109).

  That is, the stress corrosion cracking test was conducted for each rolled product No. 1-No. 23 and no. 101-No. For 112, the ammonia test method defined in “JIS K8085” and “ASTM B858”, which is a milder test method closer to the actual environment, were used.

  In the ammonia test method “JIS K8085”, a sample collected from each rolled product is held at room temperature for 2 hours in an aqueous solution atmosphere in which 900 ml of water is added to 900 ml of 28% ammonia water. The presence or absence of cracking under a microscope 20 times was confirmed. The results were as shown in Tables 3 and 6. In Table 3 and Table 6, those in which no cracks were observed were indicated by “◯”, and those in which cracks were confirmed were indicated by “x”.

In the test by “ASTM B858”, a sample collected from each rolled product in an aqueous solution atmosphere prepared by adding 30 to 35% NaOH aqueous solution to 107 g / 500 ml NH ₄ OH aqueous solution and adjusting the pH to 10.1 at room temperature for 24 hours. After the exposure, the presence or absence of cracking with an objective microscope 10 times was confirmed. The results were as shown in Tables 3 and 6. In Table 3 and Table 6, those in which no cracks were observed were indicated by “◯”, and those in which cracks were confirmed were indicated by “x”.

In addition, the dezincification corrosion test is based on “ISO 6509”. First, a sample taken from each rolled product is exposed to the extrusion direction of the rolling material or the longitudinal direction of the cast material. The sample was embedded in a phenol resin material so as to form a right angle, and the surface of the sample was polished with No. 1200 emery paper, and then ultrasonically washed in pure water and dried. Each sample thus obtained was immersed in a 12.7 g / L aqueous solution of 1.0% cupric chloride dihydrate CuCl ₂ .2H ₂ O, kept at 75 ° C. for 24 hours, and then out of the aqueous solution. The maximum depth of removal and dezincification corrosion was measured as follows. That is, the exposed surface of the sample taken out from the aqueous solution is re-embedded in the phenolic resin material so that the exposed surface of the sample is perpendicular to the extrusion direction of the rolling material or the longitudinal direction of the cast material, and then the longest cut portion is obtained. The sample was cut so as to obtain Subsequently, the sample was polished, and the corrosion depth was measured at 10 points of view of the microscope using a metal microscope of 100 to 500 times, and the deepest corrosion point was recorded as the maximum dezincification corrosion depth (μm). . The results were as shown in Table 3 and Table 6. In Tables 3 and 6, if the maximum corrosion depth is 50 μm or less, it is evaluated as “Excellent corrosion resistance” and indicated by “◯”, and if the maximum corrosion depth is 200 μm or less, it is used in practical use. It was evaluated as “possible” and indicated by “Δ”, and when the maximum corrosion depth exceeded 200 μm, it was indicated by “x” as [practical corrosion resistance has a problem].

  Thus, the example material No. 1-No. As for No. 23, regardless of whether it is an extruded material, a drawn material, a forged material, or a cast material, as shown in Tables 1 and 2, the alloy composition satisfying the condition (1) and the conditions (2) and (4) are satisfied. As shown in Table 3, a high-quality rolled processed product (Example processed product) No. 1 having excellent strength, corrosion resistance, etc. is satisfied. 1-No. 22 was obtained.

  On the other hand, comparative material No. 101-No. As shown in Table 4 and Table 5, 106 does not satisfy the alloy composition and metallographic conditions specified in the present invention, and as shown in Table 6, most of them are inferior in rolling workability (rolling). The workability is C evaluation), and a high-quality rolled product cannot be obtained. Comparative example material No. whose rolling processability is A evaluation 105 and comparative material No. whose rolling processability is B evaluation. As for Table 106, as shown in Table 6, the corrosion resistance of the rolled processed products (Comparative Example processed products No. 105, No. 106) is very poor.

  From this point, having the alloy composition and metal structure specified in the first to eighth invention materials and having the hardness of the condition (3) has excellent rolling processability and excellent strength, corrosion resistance, etc. It is confirmed that it is necessary to obtain a good quality rolled product.

  Comparative material No. 107-No. 112, as shown in Tables 1 and 3, Example material No. 18 and no. 19 having the same alloy composition as that of Comparative Example Material No. Except for 109, as shown in Table 5, the extrusion temperature, the annealing temperature, or the cooling rate at the time of annealing is not appropriate, so that an appropriate metal structure is not formed. As a result, the comparative material No. 107, no. 108, no. 110 and No. As shown in Table 6, No. 112 has poor rolling processability (C evaluation) and cannot be used as a rolling process material. Comparative material No. About 111, although rolling workability is good (A evaluation), as shown in Table 6, when the degree of rolling work is low (M5, M7, M10), a rolled product with high hardness cannot be obtained ( HV1: less than 220), a rolled product excellent in strength and wear resistance cannot be obtained. Comparative material No. No. 109 has an appropriate alloy composition and metal structure as shown in Tables 4 and 5. However, since the heat treatment (annealing) after drawing is not performed, the material hardness is high and the condition (3) is satisfied. Not done. As a result, the rolling processability is extremely poor, and as described above, a processing defect such as the rolling process portion (screw portion) being crushed is caused.

  From this point, in the rolling process, the extrusion temperature of the raw material for rolling process, the annealing temperature, and the cooling rate at the time of annealing are appropriately controlled to be the metal structure specified in the present invention, or the metal structure ( It is understood that it is extremely important to adjust the hardness to satisfy the condition (3) by heat treatment for the material for rolling processing that has undergone work hardening by drawing or the like even if the alloy composition is appropriate. Is done.

Claims (10)

  The part to be rolled is made of Cu: 73.5-79.5 mass%, Si: 2.5-3.7 mass%, Zn: remainder and inevitable impurities, and the content of constituent elements is 63.0 ≦ [ Cu] -3.6 × [Si] ≦ 67.5 (the content of the constituent element x is set to [x] mass%), and the α-phase matrix contains and contains at least a κ phase. 60 ≦ [α] ≦ 84, 15 ≦ [κ] ≦ 40, [α] + [κ] ≧ 96, 0.2 ≦ [κ] / [α] ≦ 0.65, [β ] ≦ 2, [μ] ≦ 2, [β] + [μ] ≦ 2, [γ] ≦ 2, [β] + [μ] + [γ] ≦ 4 (the area ratio of the contained phase y is [ y]%, and the phase y not contained is [y] = 0) and is a Cu—Zn—Si alloy having a hardness of HV1: 125 to 165. A material for rolling processing made of copper alloy.   The rolled part is P: 0.015-0.2 mass%, Sb: 0.015-0.2 mass%, As: 0.015-0.15 mass%, Sn: 0.03-1.0 mass%. And Al: one or more elements selected from 0.03 to 1.5 mass%, and 63.0 ≦ [Cu] −3.6 × [Si] −3 × between the constituent element contents [P] −0.3 × [Sb] + 0.5 × [As] −1 × [Sn] −1.9 × [Al] ≦ 67.5 (the content of the constituent element x is [x] mass %, And the element x not contained is [x] = 0), the α phase matrix contains at least the κ phase, and the area ratio of the contained phase is 60 ≦ [α] ≦ 84, 15 ≦ [κ] ≦ 40, [α] + [κ] ≧ 96, 0.2 ≦ [κ] / [α] ≦ 0.65, [β] ≦ 2, [μ] 2, [β] + [μ] ≦ 2, [γ] ≦ 2, [β] + [μ] + [γ] ≦ 4 (the phase ratio of the containing phase y is [y]%, and the phase not containing 2. The copper alloy according to claim 1, wherein y is a Cu—Zn—Si alloy having a metal composition having [y] = 0) and a hardness of HV1: 125 to 165. 3. Rolling material made of steel.   The rolled part further contains Pb: 0.003 to 0.25 mass% and / or Bi: 0.003 to 0.30 mass%, and 63.0 ≦ [Cu] − between the constituent element contents. 3.6 * [Si] -3 * [P] -0.3 * [Sb] + 0.5 * [As] -1 * [Sn] -1.9 * [Al] + 0.5 * [Pb] +0 .5 × [Bi] ≦ 67.5 (although the composition of the constituent element x is [x] mass%, and the element x not contained is [x] = 0), the α phase The matrix contains at least the κ phase and the area ratio of the contained phase is 60 ≦ [α] ≦ 84, 15 ≦ [κ] ≦ 40, [α] + [κ] ≧ 96, 0.2 ≦ [κ] / [ α] ≦ 0.65, [β] ≦ 2, [μ] ≦ 2, [β] + [μ] ≦ 2, [γ] ≦ 2, [β] + [μ] + [γ] ≦ 4 (The area ratio of the contained phase y is [ %, And the phase y not contained is [y] = 0), and is a Cu—Zn—Si alloy having a hardness of HV1: 125 to 165. Item 5. A copper alloy rolling material according to item 1 or item 2. The part to be rolled is Mn: 0.05 to 2.0 mass%, Ni: 0.05 to 2.0 mass%, Ti: 0.003 to 0.3 mass%, B: 0.001 to 0.1 mass% And Zr: one or more elements selected from 0.0005 to 0.03 mass%, and the content of constituent elements is 63.0 ≦ [Cu] −3.6 × [Si] −3 * [P] -0.3 * [Sb] + 0.5 * [As] -1 * [Sn] -1.9 * [Al] + 0.5 * [Pb] + 0.5 * [Bi] + 2 * [ Mn] + 1.7 × [Ni] + 1 × [Ti] + 2 × [B] + 2 × [Zr] ≦ 67.5 (the content of the constituent element x is [x] mass%, and the element x is not contained) [X] = 0), the α phase matrix contains at least the κ phase, and the area ratio of the contained phase is 60 ≦ [α] ≦ 84, 15 ≦ [κ] ≦ 40, [α] + [κ] ≧ 96, 0.2 ≦ [κ] / [α] ≦ 0.65, [β] ≦ 2, [μ] ≦ 2, [β] + [μ] ≦ 2, [γ] ≦ 2, [β] + [μ] + [γ] ≦ 4 (the area ratio of the contained phase y is [y]%, not contained) The phase y is a Cu-Zn-Si alloy having a metal composition having [y] = 0) and a hardness of HV1: 125-165. Raw material for rolling process made of copper alloy. 23 ≦ between the rolling part of the metal structure is Tsu der those containing gamma phase and kappa phase, the area ratio of the gamma [gamma]% and kappa phase area ratio of [κ]% [γ] The material for rolling processing made of a copper alloy according to claim 1, wherein the material has a relationship of + [κ] ≦ 33.   The material for a rolling process made of a copper alloy according to any one of claims 1 to 5, wherein the material is a cast material, an extruded material, a drawn material, or a forged material. Wherein the heat treatment is performed, the copper alloy of the rolling material for processing according to claim 6.   The heat treatment is held at 500 to 600 ° C. for 0.5 to 8.0 hours, and the cooling rate at 400 ° C. or less is 0.3 ° C./min. The copper alloy rolling material according to claim 7, wherein the material is formed under the above conditions.     A rolled product obtained by rolling a portion to be rolled of the material for rolling according to any one of claims 1 to 8, wherein the hardness of the portion to be rolled is HV1: 220 to 270. A rolled processed product made of copper alloy, characterized by being.   The rolled processed product made of copper alloy according to claim 9, wherein the rolled processed portion is formed by rolling into a male screw, a female screw, a spline, a gear, or a knurl.