CN108885067B

CN108885067B - Method for manufacturing steam cavity

Info

Publication number: CN108885067B
Application number: CN201780018564.XA
Authority: CN
Inventors: 桥本大辅; 西村昌泰
Original assignee: Kobe Steel Ltd
Current assignee: Kobe Steel Ltd
Priority date: 2016-03-23
Filing date: 2017-03-14
Publication date: 2020-08-04
Anticipated expiration: 2037-03-14
Also published as: JP2017172871A; CN108885067A; WO2017164013A1; TWI658146B; TW201802249A; KR20180122001A; JP6151813B1

Abstract

The method for manufacturing a steam chamber by assembling a steam chamber from a plurality of parts and then joining the parts to each other by heating to 650 ℃ or higher, wherein the parts (2) and (3) constituting the frame of the steam chamber are made of a precipitation hardening copper alloy, and the precipitation hardening copper alloy is subjected to an aging treatment to cause precipitation hardening without applying plastic working to the frame of the joined steam chamber.

Description

Method for manufacturing steam cavity

Technical Field

The present invention relates to a method of manufacturing a vapor chamber (flat plate heat pipe) by joining a plurality of parts.

Background

The operating speed and density of CPUs mounted in desktop PCs, notebook PCs, tablet terminals, mobile phones represented by smartphones, and the like have rapidly increased, and the amount of heat generated from these CPUs per unit area has further increased. When the temperature of the CPU rises to a high temperature to some extent, it becomes a cause of malfunction, thermal runaway, and the like, and therefore effective heat dissipation from a semiconductor device such as the CPU becomes a problem.

As a heat dissipating member for absorbing heat of the semiconductor device and dissipating the heat into the atmosphere, a heat sink is used. Since high thermal conductivity is required for the heat sink, copper, aluminum, or the like having high thermal conductivity is used as a raw material. A method used in a desktop PC is a method of discharging heat by a small fan provided in a desktop PC housing by transferring heat of a CPU to a heat sink or the like provided on a heat sink.

However, in notebook PCs, tablet terminals, and the like, which do not have a space for a fan, a vapor chamber (flat heat pipe) can be used as a heat dissipation component having a higher heat transfer capability in a limited area. The heat pipe cyclically evaporates (absorbs heat from the CPU) and condenses (releases absorbed heat) a refrigerant sealed inside, and thereby exhibits higher heat dissipation characteristics than a heat sink. It is also proposed to solve the problem of heat dissipation of the semiconductor device by combining a heat pipe with a heat sink and a heat dissipating component such as a fan.

The vapor chamber further improves the heat radiation performance of the tubular heat pipe (see patent documents 1 to 4). As the vapor chamber, in order to efficiently condense and evaporate the refrigerant, it has been proposed to perform surface roughening, grooving, fine hole formation by powder sintering, and the like on the inner surface, as in the case of the tubular heat pipe.

Further, a steam chamber has been proposed which is composed of an outer member (housing) and an inner member accommodated and fixed in the outer member. To facilitate condensation, evaporation, and transport of the refrigerant, the inner member is configured with one or more fins, protrusions, holes, slits, etc. in various shapes inside the outer member. The steam chamber of this type is manufactured by disposing the inner member inside the outer member and then integrally joining the outer members and the inner member to each other by brazing, diffusion bonding, or the like. After the refrigerant is charged into the inside, the vapor chamber is sealed by brazing or the like.

A method for manufacturing a steam chamber will be specifically described with reference to fig. 1, taking as an example a case where a plurality of patterns such as grooves and projections are formed on one side surface of a rectangular upper plate member and a rectangular lower plate member, and the upper plate member and the lower plate member are joined to each other with the pattern forming surface thereof being on the inside to manufacture a steam chamber. The upper plate member and the lower plate member are parts of a frame constituting a steam chamber, which does not contain internal members.

(1) As a material of the casing of the steam chamber, a pure copper-based strip material such as oxygen-free copper or phosphorus deoxidized copper is generally used. A plurality of patterns such as grooves and projections are formed on one surface of a rectangular plate material (an upper plate member and a lower plate member) cut out from a pure copper strip material. In fig. 1A, an upper plate member 2 (or a lower plate member 3) formed with a pattern 1 (diagonal line portion) is shown.

(2) As a means for forming the pattern 1, etching or pressing with a die is used. In the etching process, only the intended etching portion on one surface of the upper plate member 2 or/and the lower plate member 3 is exposed, and copper in the intended etching portion is dissolved in an etching solution containing an iron chloride solution to form a predetermined pattern. In the press working, the surface properties of the single-side transfer mold of the upper plate member 2 and/or the lower plate member 3 are formed into a pattern having a predetermined shape.

(3) The upper plate member 2 and the lower plate member 3 are joined in a state in which the pattern forming surfaces of the upper plate member 2 and/or the lower plate member 3 are positioned inside and the upper plate member 2 and the lower plate member 3 are superposed on each other (fig. 1B). The bonding is performed by diffusion bonding or brazing. A nozzle (small diameter pipe) 4 is inserted between the upper plate member 2 and the lower plate member 3, and the nozzle 4 is also joined.

(4) In the diffusion bonding, as shown in fig. 1C, a load of several N is applied between the upper plate member 2 and the lower plate member 3, and the resultant is pressed (see white arrows), heated to a temperature of 800 ℃ or higher in a vacuum or an inert atmosphere, and held at the temperature for 30 minutes or longer. Therefore, the material is softened, the crystal grains are coarsened, and dimensional change due to creep deformation by pressurization or the like occurs. In anticipation of the reduction in strength and dimensional change of this material, the thickness (both of the portion where the pattern 1 is formed and the other portion) before diffusion bonding needs to be set in advance. In the diffusion bonding, Cu atoms are solid-phase diffused among the respective members, and the respective members (the upper plate member 2, the lower plate member 3, and the nozzle 4) are integrated.

(5) In the case of joining by brazing, heating is performed in a reducing atmosphere or a non-oxidizing atmosphere, and brazing is performed with silver solder (BAg), phosphor copper solder (BCuP), or the like. In general, the solder is heated to 650 ℃ or higher when silver solder is used in the soldered portion, and to 750 ℃ or higher when phosphor-copper solder is used. As the brazing method, the existing brazing filler metal brazing (one of the manual brazing) or the brazing filler metal pre-brazing (one of the furnace brazing) can be applied, but in either of the brazing methods, it is necessary to control the brazing atmosphere so that the inside of the vapor chamber is not oxidized. In the manual brazing, although the time for heating to a high temperature is short, the steam chamber has a small mass and good thermal conductivity, and therefore the temperature rises to the brazing temperature and the entire material softens. When brazing in a furnace, although atmosphere control is facilitated, the time for holding the steam chamber at a high temperature is long, and the degree of softening of the entire material is greater than that of manual brazing.

(6) After the steam chamber is manufactured (after bonding), a working fluid (water or the like) is injected into the steam chamber through the nozzle 4 in a vacuum or reduced pressure atmosphere, and the nozzle 4 is sealed.

[ Prior art documents ]

[ patent document ]

[ patent document 1 ] Japanese patent laid-open No. 2004-238672

[ patent document 2 ] Japanese patent application laid-open No. 2007-315745

[ patent document 3 ] Japanese patent laid-open No. 2014-134347

[ patent document 4 ] Japanese patent laid-open No. 2015-121355

In the production (bonding) of the steam chamber, since the parts constituting the steam chamber are heated to a temperature of 650 ℃ or higher at the minimum, they are easily softened when they are made of a pure copper material having low heat resistance. When the components (the upper plate member 2 and the lower plate member 3 in the above example) constituting the housing of the vapor chamber are softened, the vapor chamber is easily deformed during transportation, handling, mounting to a semiconductor device, or the like. In this case, a gap is formed between the vapor chamber and the semiconductor device due to a change in the shape and size of the pattern formed inside the vapor chamber, a dent formed in the frame of the vapor chamber, or the like, and the expected heat transfer performance cannot be exhibited.

In the diffusion bonding step, the frame of the steam chamber is deformed by the pressure applied to the bonding portion. Specifically, as shown in fig. 2A and 2B, the joint between the upper plate member 2 and the lower plate member 3 is subjected to creep deformation by a pressing force (see white arrows), and the thickness is reduced (t)_s→t_f). Further, the upper plate member 2 and the lower plate member 3 expand due to heating and extend in the left-right direction, and the movement of the joint portion in the left-right direction is restrained by the pressing force, so that the thin-walled portions of the upper plate member 2 and the lower plate member 3 are bent inward. As a result, the dimensional accuracy of the steam chamber is also reduced, and the above-mentioned problem caused by softening becomes more serious.

Further, when a pure copper-based material is heated to a temperature of 650 ℃ or higher, crystal grains are easily coarsened, and the coarsening of crystal grains progresses as the thickness of the material passes through the plate (is larger than the diameter of the crystal grains in the plate). In this case, the solder wetting and spreading is inhibited, or grain boundary cracks are generated by a fatigue phenomenon accompanied by repeated internal pressure fluctuations (stress is added to the frame) due to evaporation and condensation when the vapor chamber is used, and as a result, it is pointed out that leakage occurs or corrosion resistance at the grain boundary is lowered.

Disclosure of Invention

The present invention has been made to solve the above-described problems in the production of a steam chamber, and a main object thereof is to provide a method for producing a steam chamber having sufficient strength and heat transfer performance, in which dimensional changes due to softening, creep deformation, and the like of a frame are less likely to occur even after a joining step. Another object of the present invention is to prevent the crystal grains from being excessively coarsened in the frame even after the bonding step.

A method of manufacturing a steam chamber according to an embodiment of the present invention is a method of manufacturing a steam chamber by assembling a steam chamber from a plurality of parts, and then joining the parts to each other through a process of heating to 650 ℃ or higher, wherein the parts constituting a frame of the steam chamber are made of a precipitation hardening copper alloy, and the precipitation hardening copper alloy is precipitation hardened by aging without applying plastic working to the frame of the joined steam chamber. In the embodiments of the present invention, the components may be constituted by only the components constituting the housing of the steam chamber, or may include other components (the internal member).

Examples of the precipitation hardening copper alloy include Cu-Ni-Si alloys, Cu-Fe-P alloys, Cu-Fe-Ni-P alloys, Cu-Cr-Zr alloys, and the like known per se.

According to the embodiment of the present invention, by using the precipitation hardening copper alloy as a material of the frame body, dimensional changes due to softening, creep deformation, and the like of the frame body are less likely to occur even after the bonding step, as compared with the conventional vapor chamber using a pure copper material. Further, although the strength and the electric conductivity of the frame body decrease after the joining step, the strength and the electric conductivity (thermal conductivity) of the frame body are restored (improved) by performing an aging treatment (precipitation hardening treatment) next. Therefore, a steam chamber having a higher strength can be manufactured while suppressing the decrease in heat transfer performance, and the material can be further thinned.

Further, according to the embodiment of the present invention, by using the precipitation hardening copper alloy as a material of the frame body, the coarsening of crystal grains of the frame body can be suppressed as compared with the conventional vapor chamber using a pure copper-based material. Therefore, the vapor chamber is improved in leakage resistance and corrosion resistance in use, and solder wet spread is also improved.

Drawings

Fig. 1 is a diagram for explaining a manufacturing method (bonding method) of a vapor chamber, and is a perspective view (1A) of a frame part (upper plate member or lower plate member) formed with a pattern, a sectional view (1B) of the upper plate member and lower plate member overlapped for bonding, and a sectional view (1C) at the time of diffusion bonding of the vapor chamber.

Fig. 2 is a view for explaining the deformation of the upper plate member and the lower plate member at the time of diffusion bonding of the vapor chamber, and is a sectional view (2A) at the start of diffusion bonding and a sectional view (2B) at the end of diffusion bonding.

Fig. 3 is a graph showing ranges of Fe and Sn contents of a typical precipitation hardening copper alloy.

Detailed Description

Hereinafter, a method of manufacturing the steam chamber according to the embodiment of the present invention will be described in more detail.

As a preferable precipitation hardening copper alloy to be applied to the casing of the steam chamber, Cu-Fe-P system, Cu- (Ni, Co) -Si system, Cu- (Ni, Co) -P system, Cu-Cr system and Cu-Cr-Zr system copper alloys known per se are listed. These precipitation hardening copper alloys are softened to a lesser extent than conventional pure copper under high-temperature heating (a bonding step in a steam chamber), and coarsening of crystal grains after high-temperature heating is suppressed as compared with conventional pure copper. Further, even when these precipitation hardening copper alloys are subjected to aging treatment after high-temperature heating without plastic working (without introducing plastic strain as a precipitation point into the material), the strength and electric conductivity are restored (improved). Although plastic working is not applied to the frame of the steam chamber after the joining step, the use of these precipitation hardening copper alloys enables the frame to have high strength (50MPa or more) and high electrical conductivity (25% IACS or more) after aging treatment even if plastic working is not applied after the joining step.

The aging treatment (precipitation hardening treatment) after the bonding step (after high-temperature heating) can be performed by, for example, the following method. The conditions for the aging treatment (precipitation temperature range, holding time), the respective alloy systems, and the like will be described later.

(1) After cooling the joined vapor chamber, the entire vapor chamber is reheated to the precipitation temperature range of the precipitation hardening type copper alloy, and kept in the same temperature range for a certain period of time to be subjected to precipitation hardening. In this case, it is preferable to perform rapid cooling by water cooling or the like while the vapor chamber after joining is still at a high temperature, or to perform rapid cooling after the vapor chamber after joining is heated again to a solutionizing temperature, and thereby to solutionize the precipitation hardening copper alloy in advance.

(2) The joined vapor chamber is kept in the precipitation temperature range for a certain period of time while being cooled from a high temperature, and the precipitation hardening copper alloy is precipitation hardened. The vapor chamber may be maintained at a fixed temperature within the precipitation temperature range or may continue to cool within the precipitation temperature range.

(3) After the step (2), the step (1) is further reheated to cause precipitation hardening of the precipitation hardening copper alloy.

Next, each alloy system will be described.

(Cu-Fe-P series)

(1) Examples of the Cu — Fe — P-based copper alloy include a copper alloy containing Fe: 0.07 to 0.7 mass%, P: 0.2 mass% or less of a copper alloy. The basic composition of the copper alloy is composed of Cu and inevitable impurities in addition to Fe and P, and contains alloying elements described later as necessary.

In the case of this copper alloy, the alloy can be heated at a high temperature (a bonding step in a steam chamber) and then subjected to aging treatment, whereby a 0.2% proof stress value of 100MPa or more and an electrical conductivity of 50% IACS or more (45% IACS or more when Sn is contained as an alloy element) can be achieved. Further, by setting the Fe content to 0.25 mass% or more, the average crystal grain size after high-temperature heating (the bonding step in the vapor chamber) can be suppressed to 50 μm or less. The aging treatment may be performed at a temperature of 350 to 600 ℃ for 5 minutes to 10 hours.

In this copper alloy, Fe is precipitated as a simple substance of Fe or as an Fe — P compound, and has an effect of improving the strength and conductivity of the copper alloy sheet after aging treatment. Fe that is not precipitated as an Fe — P compound precipitates as a simple substance of Fe, and particularly, if the Fe content is 0.4 mass% or more, the amount of Fe precipitated as a simple substance of Fe increases. If the Fe content is less than 0.07 mass%, the 0.2% yield strength after the high-temperature heating and aging treatment is insufficient, and if the Fe content is more than 0.7 mass%, the electric conductivity after the high-temperature heating and aging treatment cannot be improved. Therefore, the Fe content is 0.07 to 0.7 mass%. The lower limit of the Fe content is preferably 0.15 mass%, and the upper limit is preferably 0.65 mass%.

P reduces the amount of oxygen contained in the copper alloy by deoxidation, and has the effect of preventing hydrogen embrittlement when the steam chamber is heated in a reducing atmosphere containing hydrogen. In addition, the dissolved P is heated to a precipitation temperature to form an Fe-P compound, thereby improving the strength, heat resistance and electrical conductivity of the copper alloy. The P content needs to be 0.005 mass% or more for the Fe-P compound to precipitate. However, if the content of P is more than 0.2 mass%, cracks occur during hot rolling of the ingot, and subsequent processing cannot be performed, so the upper limit of the content of P is 0.2 mass%.

For the above-mentioned action, the content of P needs to be as small as possible, but on the other hand, the content of P which does not contribute to the precipitation of Fe-P compounds is preferably as small as possible within a range by preventing hydrogen embrittlement. From this point of view, the ratio [ Fe ]/[ P ] of the content (mass%) of Fe to the content (mass%) of P is preferably in the range of 2 to 5. The lower limit of [ Fe ]/[ P ] is more preferably 2.5, still more preferably 3.0, and the upper limit of [ Fe ]/[ P ] is more preferably 4.5, still more preferably 4.0.

The copper alloy contains one or more of the following alloying elements (or alloying element groups) as required within a range that does not impair the electric conductivity after high-temperature heating and aging treatment. (a) Sn: 0.006-1.1 mass%, (b) Zn: 1.5% by mass or less of (c) Mn: 0.1 mass% or less, Mg: 0.2 mass% or less, Si: 0.2 mass% or less, Al: 0.2 mass% or less, Cr: 0.2 mass% or less, Ti: 0.1 mass% or less, Zr: 0.05 mass% or less, and 0.5 mass% or less in total.

Sn has an effect of improving the strength of the copper alloy. When the copper alloy contains Sn, the contents of Fe and Sn fall within the range (including the boundary line) surrounded by the point a (0.1, 0.006), the point B (0.5, 0.006), the point C (0.05, 1.1) and the point D (0.05 ) shown in fig. 3. The lower limit of the Fe content in this case is preferably 0.07 mass%, more preferably 0.15 mass%. The lower limit of the Sn content is preferably 0.01 mass%, more preferably 0.02 mass%, and the upper limit is preferably 0.5 mass%, more preferably 0.4 mass%.

Zn has an effect of improving solder hot-peeling resistance and Sn-plating hot-peeling resistance of the copper alloy. However, if the content of Zn is more than 1.5 mass%, the solder wettability is lowered and the conductivity is also lowered, so that the content of Zn is 1.5 mass% or less. The upper limit of the Zn content is preferably 0.7 mass%, and more preferably 0.5 mass%. On the other hand, the lower limit of the Zn content is preferably 0.01 mass%, more preferably 0.05 mass%, and still more preferably 0.1 mass% in order to improve the thermal peeling resistance.

Mn, Mg, Si, Al, Cr, Ti, Zr have an effect of improving the strength and heat resistance of the copper alloy. Since the conductivity of the copper alloy is lowered even when Mn, Mg, Si, and Al are contained in small amounts, the upper limit values are Mn: 0.1 mass%, Mg: 0.2 mass%, Si: 0.2 mass%, Al: 0.2% by mass. Cr, Ti, and Zr tend to form oxide-based or sulfide-based inclusions of several μm to 10 μm or so, and a gap can be formed between the inclusions and the base material by cold rolling, and when the inclusions exist on the surface, the corrosion resistance of the copper alloy is lowered. Therefore, the upper limit of Cr, Ti and Zr is, Cr: 0.2 mass%, Ti: 0.1 mass%, Zr: 0.05% by mass. Further, if a plurality of elements among Mn, Mg, Si, Al, Cr, Ti, and Zr are contained in the copper alloy and the total content thereof is more than 0.5 mass%, the electrical conductivity of the copper alloy decreases. Therefore, the total content of these elements is 0.5% by mass or less. On the other hand, the lower limit of the total content of one or two or more of these elements is preferably 0.01% by mass, more preferably 0.02% by mass, and still more preferably 0.03% by mass.

A copper alloy (strip) having the above composition is produced, for example, by hot rolling an ingot and then repeating one or two or more times of cold rolling and heat treatment (aging treatment). The copper alloy produced under the following conditions has a 0.2% yield strength of 150MPa or more and an elongation of 5% or more, and has excellent bending workability, and has a 0.2% yield strength of 40MPa or more after high-temperature heating (850 ℃ × 30 minutes), a 0.2% yield strength of 100MPa or more and an electric conductivity of 50% IACS or more (45% IACS or more when Sn is contained) after aging treatment, and further, coarsening of crystal grains by high-temperature heating (850 ℃ × 30 minutes) is suppressed, and the average crystal grain diameter after high-temperature heating can be suppressed to 50 μm or less.

Melting and casting can be performed by a usual method such as continuous casting and semi-continuous casting. In addition, As the copper smelting raw material, it is preferable to use one with a small content of S, Pb, Bi, Se, and As. Note that red heat treatment (moisture removal) of charcoal coated on the copper alloy molten metal, drying of the matrix metal, scrap, launder, mold, and oxygen removal of the molten metal are preferably reduced by O, H. The ingot is preferably homogenized, and in the homogenization treatment, the temperature inside the ingot is preferably maintained at 800 ℃ for 30 minutes or more. The holding time for the homogenization treatment is more preferably 1 hour or more, and still more preferably 2 hours or more.

After the homogenization treatment, hot rolling is started at a temperature of 800 ℃ or higher. Preferably, the hot rolling is completed at a temperature of 600 ℃ or higher, and the hot rolled material is quenched from this temperature by a method such as water cooling so that coarse Fe or Fe — P precipitates are not formed in the hot rolled material. When the quenching start temperature after hot rolling is lower than 600 ℃, coarse Fe — P precipitates are formed, the microstructure tends to become nonuniform, and the strength of the copper alloy sheet (product sheet) tends to decrease.

After hot rolling, (a) the hot rolled material is cold rolled to the product thickness and subjected to aging treatment, (b) the hot rolled material is cold rolled and aged and then cold rolled to the product thickness, or (c) low temperature annealing (recovery of ductility) is performed after the (b).

The aging treatment (precipitation treatment) is carried out at a heating temperature of about 300 to 600 ℃ for 0.5 to 10 hours. When the heating temperature is lower than 300 ℃, the amount of precipitates is small, and when the temperature is higher than 600 ℃, the precipitates are easily coarsened. The lower limit of the heating temperature is preferably 350 ℃ and the upper limit thereof is preferably 580 ℃. The retention time of the aging treatment is appropriately selected according to the heating temperature, and is within the range of 0.5 to 10 hours. When the holding time is 0.5 hours or less, the deposition is insufficient, and the deposition amount is saturated even when the holding time exceeds 10 hours, and the productivity is lowered. The lower limit of the holding time is preferably 1 hour, more preferably 2 hours.

(2) Other examples of the Cu-Fe-P system include a Cu-Fe-P system containing Fe: 1.0 to 2.4 mass%, P: 0.005 to 0.1 mass% or less of a copper alloy. The basic composition of the copper alloy is composed of Cu and inevitable impurities in addition to Fe and P, and contains alloying elements described later as necessary.

In the case of this copper alloy, the aging treatment is performed after the high-temperature heating (the bonding step in the steam chamber), and the alloy can achieve a 0.2% proof stress value of 110MPa or more and an electrical conductivity of 50% IACS or more. Further, the average crystal grain size after high-temperature heating (the bonding step in the vapor chamber) can be suppressed to 50 μm or less. The aging treatment may be performed at a temperature of 350 to 600 ℃ for 5 minutes to 10 hours.

In this copper alloy, Fe precipitates as a simple substance of Fe or as a compound with P, and has an effect of improving the strength and conductivity of the copper alloy sheet after aging treatment. However, if the Fe content is less than 1.0 mass%, the 0.2% yield strength after the high-temperature heating and aging treatment is insufficient. On the other hand, if the Fe content is more than 2.4 mass%, the ratio of strength improvement after high-temperature heating and aging treatment is saturated, and coarse Fe crystals are formed in the melting and casting step and are hard to disappear in the subsequent working step. Coarse Fe crystals reduce corrosion resistance, bending workability, plating properties, and the like. Therefore, the Fe content is 1.0 to 2.4 mass%. The lower limit of the Fe content is preferably 1.2 mass%, and the upper limit is preferably 2.2 mass%.

P has a function of reducing the amount of oxygen contained in the copper alloy by a deoxidizing function, and preventing hydrogen embrittlement when the heat-dissipating component is heated in a reducing atmosphere containing hydrogen. The P content required for preventing hydrogen embrittlement is 0.005 mass% or more. In addition, the solid-dissolved P lowers the electrical conductivity of the copper alloy, but by heating to the precipitation temperature, an Fe — P compound is formed, thereby improving the strength, heat resistance, and electrical conductivity of the copper alloy. However, if the content of P is more than 0.1 mass%, the amount of P dissolved in the solution increases, and the conductivity decreases. Therefore, the content of P is 0.005 to 0.1 mass%.

The copper alloy contains one or more of the following alloying elements (or alloying element groups) as required within a range that does not impair the electric conductivity after high-temperature heating and aging treatment. (a) Zn: 2.0 mass% or less, (b) Sn: 0.005-0.5 mass%, (c) one or more of Mn, Mg, Si, Al, Cr, Ti, Zr, Ni, and Co, and 0.5 mass% or less in total.

Zn is added as needed for the same reason as Zn in the copper alloy described in the above (1). The upper limit of the Zn content is preferably 0.7 mass%, and more preferably 0.5 mass%. On the other hand, the lower limit of the Zn content is preferably 0.01 mass%, more preferably 0.05 mass%, and still more preferably 0.1 mass%.

Sn is solid-dissolved in the copper alloy matrix, and has an effect of improving the strength of the copper alloy. In addition, addition of Sn is also effective for improving the stress relaxation resistance. When the use environment of the steam chamber reaches 80 ℃ or higher, the frame is deformed by creep deformation, the contact surface with a heat source such as a CPU is reduced, and the heat radiation performance is reduced. In order to obtain the effect of improving the strength and the stress relaxation resistance, the Sn content is 0.005 mass% or more, preferably 0.01 mass% or more, more preferably 0.02 mass% or more, and further preferably 0.05 mass% or more. On the other hand, if the content of Sn is more than 0.5 mass%, the electrical conductivity of the copper alloy sheet after high-temperature heating and aging treatment is lowered. Accordingly, the content of Sn is 0.5 mass% or less.

Mn, Mg, Si, Al, Cr, Ti, Zr, Ni, and Co have an effect of improving the strength and heat resistance of the copper alloy, and therefore, one or more of them may be added as necessary. However, if the total content of one or two or more of these elements is higher than 0.5 mass%, the conductivity is lowered. The lower limit of the total content of one or two or more of these elements is preferably 0.01% by mass, more preferably 0.02% by mass, and still more preferably 0.03% by mass.

The copper alloy (strip) having the above composition can be produced, for example, by the same production method as the copper alloy (1) and has a 0.2% proof stress of 150MPa or more, an elongation of 5% or more and excellent bending workability, and further has a 0.2% proof stress of 40MPa or more after high-temperature heating (850 ℃ × 30 minutes), a 0.2% proof stress of 110MPa or more after aging treatment and an electric conductivity of 50% IACS or more after high-temperature heating (850 ℃ × 30 minutes), and further, the coarsening of crystal grains due to high-temperature heating is suppressed and the average crystal grain size after high-temperature heating can be suppressed to 50 μm or less.

(Cu- (Ni, Co) -Si system)

Examples of the Cu- (Ni, Co) -Si-based copper alloy include a copper alloy containing 1.0 to 4.0 mass% of one or both of Ni and Co, 0.2 to 1.2 mass% of Si, and a ratio of the total content of Ni and Co to the content of Si [ Ni + Co ]/[ Si ] in a range of 3.5 to 5. The basic composition of the copper alloy is composed of Cu and inevitable impurities in addition to Ni or/and Co and Si, and contains alloying elements described later as necessary.

In the case of such a copper alloy, the alloy can be heated at a high temperature (a step of joining in a steam chamber) and then subjected to aging treatment, whereby a 0.2% proof stress value of 300MPa or more and an electric conductivity of 25% IACS or more can be achieved. The aging treatment may be performed by keeping the temperature at 350 to 600 ℃ for 5 minutes to 10 hours.

In the copper alloy, Ni and SiFormation of Ni₂Si precipitates improve the strength of the copper alloy. However, when the Ni content is less than 1.0 mass% or the Si content is less than 0.2 mass%, the effect is small. On the other hand, if the Ni content is more than 4.0 mass% or the Si content is more than 1.2 mass%, Ni or Si is crystallized or precipitated during casting, and hot workability is lowered. Therefore, the Ni content is 1.0 to 4.0 mass%, and the Si content is 0.2 to 1.2 mass%. The lower limit of the Ni content is preferably 1.1 mass%, and the upper limit thereof is preferably 3.9 mass%.

In this copper alloy, a part or all of Ni can be replaced with Co.

In short, when the ratio [ Ni + Co ]/[ Si ] of the total content [ Ni + Co ] of Ni and Co to the content [ Si ] of Si is less than 3.5 or more than 5, excessive Ni (and/or Co) or Si is dissolved in a solid solution, resulting in a decrease in conductivity. Therefore, the content ratio [ Ni + Co ]/[ Si ] is 3.5 to 5.

The copper alloy contains one or more of the following alloying elements (or alloying element groups) as required within a range that does not impair the electric conductivity after high-temperature heating and aging treatment. (a) Sn: 0.005-1.0 mass% or/and Mg: 0.005-0.2 mass%, (b) Zn: 2.0 mass%, and (c) one or more of Al, Mn, Cr, Ti, Zr, Fe, P and Ag, in total, 0.5 mass% or less.

Sn is solid-dissolved in the copper alloy matrix and acts to improve the strength of the copper alloy. In addition, addition of Sn is also effective for improving the stress relaxation resistance. When the use environment of the steam chamber reaches 80 ℃ or higher, the frame is deformed by creep deformation, the contact surface with a heat source such as a CPU is reduced, and the heat radiation performance is reduced. In order to obtain the effect of improving the strength and the stress relaxation resistance, the Sn content is 0.005 mass% or more, preferably 0.01 mass% or more, and more preferably 0.02 mass% or more. On the other hand, if the Sn content is more than 1.0 mass%, the bending workability of the copper alloy sheet is lowered, and the electrical conductivity after the aging treatment is lowered. Accordingly, the Sn content is 1.0 mass% or less, preferably 0.6 mass% or less, and more preferably 0.3 mass% or less.

Mg, like Sn, is solid-dissolved in the copper alloy matrix, and has an effect of improving the strength and stress relaxation resistance of the copper alloy. The content of Mg is 0.005 mass% or more for obtaining the effect of improving the strength and the stress relaxation resistance. On the other hand, if the Mg content is more than 0.2 mass%, the bending workability of the copper alloy is lowered, and the electric conductivity after the aging treatment is lowered. Therefore, the Mg content is 0.2 mass% or less, preferably 0.15 mass% or less, and more preferably 0.05 mass% or less.

Zn has an effect of improving solder hot-peeling resistance and Sn-plating hot-peeling resistance of the copper alloy. However, if the content of Zn is higher than 2.0 mass%, the solder wettability is lowered, so the content of Zn is 2.0 mass% or less. The upper limit of the Zn content is preferably 0.7 mass% or less, and more preferably 0.5 mass% or less. On the other hand, if the Zn content is less than 0.01 mass%, the improvement of the thermal peeling resistance is insufficient, and the Zn content is preferably 0.01 mass% or more. The lower limit of the Zn content is more preferably 0.05 mass%, and still more preferably 0.1 mass%.

Al, Mn, Cr, Ti, Zr, Fe, P, Ag have an effect of improving the strength and heat resistance of the copper alloy. However, if the total content of one or two or more of these elements is higher than 0.5 mass%, the conductivity is lowered. The lower limit of the total content of one or two or more of these elements is preferably 0.01% by mass, more preferably 0.02% by mass, and still more preferably 0.03% by mass.

A copper alloy (strip) having the above composition is produced by a standard production method comprising soaking an ingot, hot rolling, cold rolling, recrystallization treatment accompanied by solutionizing, cold rolling, and precipitation treatment, and has a 0.2% proof stress of 300MPa or more and excellent bending workability, and further has an electrical conductivity of 25% IACS or more by aging treatment after heating at a high temperature (850 ℃ C. × 30 minutes).

Melting, casting and homogenization treatment were carried out in the same manner as for the Cu-Fe-P based copper alloy.

After the homogenization treatment, hot rolling is started at a temperature of 800 ℃ or higher. Preferably, the hot rolling is completed at a temperature of 600 ℃ or higher, and the hot rolled material is rapidly cooled from this temperature by a method such as water cooling so that coarse (Ni, Co) -Si precipitates are not formed. When the quenching start temperature after hot rolling is lower than 600 ℃, coarse (Ni, Co) -Si precipitates are formed, the structure is likely to become uneven, and the strength of the copper alloy sheet (product sheet) is reduced.

By cold rolling after hot rolling, a certain strain is applied to the copper alloy, and after the recrystallization treatment is continued, a copper alloy having a desired recrystallized structure (fine recrystallized structure) can be obtained. The cold rolling reduction ratio is preferably 5 to 35%.

The recrystallization treatment with solutionizing is carried out under conditions of 650 to 950 ℃, preferably 670 to 900 ℃ for 3 minutes or less. When the contents of Ni, Co, and Si in the copper alloy are small, the operation is preferably performed in a relatively low temperature region within the above temperature range, and when the contents of Ni, Co, and Si are large, the operation is preferably performed in a relatively high temperature region within the above temperature range. By this recrystallization treatment, Ni, Co, and Si can be dissolved in the copper alloy base metal to form a recrystallized structure (grain size of 1 to 20 μm) with good bending workability. When the temperature of the recrystallization treatment is lower than 650 ℃, the amount of solid solution of Ni, Co, and Si decreases, and the strength decreases. On the other hand, when the temperature of the recrystallization treatment is higher than 950 ℃ or the treatment time exceeds 3 minutes, recrystallized grains become coarse.

After the recrystallization treatment accompanied by solutionizing, (a) cold rolling and aging treatment are performed, (b) after the cold rolling and aging treatment, cold rolling is performed to the thickness of the product, or (c) after the (b) low-temperature annealing (recovery of ductility) is performed. The aging treatment (precipitation treatment) may be performed under the same conditions as those for the Cu-Fe-P based copper alloy.

(Cu- (Ni, Co) -P series)

Examples of Cu- (Ni, Co) -P-based copper alloys include alloys containing Ni: 0.2 to 1.0 mass% or/and Co: 0.05 to 1.0 mass%, and P: 0.03 to 0.2 mass% of a copper alloy. The basic composition of the copper alloy is composed of Cu and inevitable impurities in addition to Ni and/or Co and P, and if necessary, contains Fe and other alloy elements described later. In the copper alloy, the total content [ Ni + Co + Fe ] of Ni, Co and Fe is in the range of 0.3-1.0 mass%, and the ratio [ Ni + Co + Fe ]/[ P ] of the total content of Ni, Co and Fe to the content of P is in the range of 2-10.

In the case of such a copper alloy, the copper alloy can be heated at a high temperature (a step of joining in a steam chamber) and then subjected to aging treatment, and can achieve a 0.2% proof stress value of 120MPa or more and an electric conductivity of 40% IACS or more. The aging treatment may be performed by keeping the temperature at 350 to 600 ℃ for 5 minutes to 10 hours.

A P compound ((Ni, Co, Fe) -P compound) is formed between Ni, Co, Fe and P, and the strength and the stress relaxation resistance of the copper alloy are improved. The (Ni, Co, Fe) -P compound includes Ni-P, Co-P, Fe-P and M-P compound containing two or more of Fe, Ni and Co.

When the total content [ Ni + Co + Fe ] of Ni, Co and Fe is less than 0.3 mass%, or the content of P is less than 0.03 mass%, the amount of P compound deposited is small, and the effect of improving the strength and stress relaxation resistance of the copper alloy is small. On the other hand, if [ Ni + Co + Fe ] is more than 1.0 mass% or the P content [ P ] is more than 0.2 mass%, coarse oxides, crystallized substances, precipitates, and the like are generated, and hot workability is degraded, and the strength, stress relaxation resistance, and bending workability of the copper alloy are degraded. Further, the amount of solid solutions of Ni, Co, Fe, and P increases, and the conductivity of the copper alloy decreases. Therefore, [ Ni + Co + Fe ] is 0.3 to 1.0 mass%, and the P content is 0.03 to 0.2 mass%

When the respective contents of Ni, Co, and Fe are less than 0.2 mass%, less than 0.05 mass%, and less than 0.05 mass%, the effect of improving the strength and the stress relaxation resistance of the copper alloy sheet is small. Therefore, the lower limit values of the contents of Ni, Co, and Fe are 0.2 mass%, 0.05 mass%, and 0.05 mass%, respectively.

When the ratio of the total content of Ni, Co and Fe to the content of P [ Ni + Co + Fe ]/[ P ] is less than 2 or more than 10, excessive Ni, Co, Fe or P is dissolved in solid solution, resulting in a decrease in conductivity. Therefore, the content ratio [ Ni + Co + Fe ]/[ P ] is 2 to 10. The lower limit of [ Ni + Co + Fe ]/[ P ] is preferably 2.2, and the upper limit thereof is preferably 9.5.

The copper alloy contains one or more of the following alloying elements (or alloying element groups) as required within a range that does not impair the electric conductivity after high-temperature heating and aging treatment. (a) Sn: 0.005-1.0 mass% or/and Mg: 0.005-0.2 mass%, (b) Zn: 1.0 mass% or less, and (c) one or more of Si, Al, Mn, Cr, Ti, Zr and Ag, the total amount of which is 0.5 mass% or less.

Sn is solid-dissolved in the copper alloy matrix, and has an effect of improving the strength of the copper alloy. In addition, addition of Sn is also effective for improving the stress relaxation resistance. When the use environment of the steam chamber reaches 80 ℃ or higher, the frame is deformed by creep deformation, the contact surface with a heat source such as a CPU is reduced, and the heat radiation performance is reduced. In order to obtain the effect of improving the strength and the stress relaxation resistance, the Sn content is 0.005 mass% or more, preferably 0.01 mass% or more, and more preferably 0.02 mass% or more. On the other hand, if the Sn content is more than 1.0 mass%, the bending workability of the copper alloy sheet is lowered, and the electrical conductivity after the aging treatment is lowered. Accordingly, the Sn content is 1.0 mass% or less, preferably 0.6 mass% or less, and more preferably 0.3 mass% or less.

Mg is solid-dissolved in the copper alloy matrix, similarly to Sn, and has an effect of improving the strength and stress relaxation resistance of the copper alloy. The Mg content is 0.005 mass% or more in order to obtain the effect of improving the strength and the stress relaxation resistance. On the other hand, if the Mg content is more than 0.2 mass%, the bending workability of the copper alloy sheet is lowered, and the electric conductivity after the aging treatment is lowered. Therefore, the Mg content is 0.2 mass% or less, preferably 0.15 mass% or less, and more preferably 0.05 mass% or less.

Zn has an effect of improving solder hot-peeling resistance and Sn-plating hot-peeling resistance of the copper alloy. However, if the content of Zn is more than 1.0 mass%, the solder wettability is lowered, and therefore the content of Zn is 1.0 mass% or less. The Zn content is preferably 0.7 mass% or less, and more preferably 0.5 mass% or less. On the other hand, if the Zn content is less than 0.01 mass%, the improvement of the thermal peeling resistance is insufficient, and the Zn content is preferably 0.01 mass% or more. The Zn content is more preferably 0.05 mass% or more, and still more preferably 0.1 mass% or more.

Si, Al, Mn, Cr, Ti, Zr, and Ag have an effect of improving the strength and heat resistance of the copper alloy. However, since the conductivity of the copper alloy decreases when the content of these elements is large, the total content of one or two or more of these elements is limited to 0.5 mass% or less. The lower limit of the total content of one or two or more of these elements is preferably 0.01% by mass, more preferably 0.02% by mass, and still more preferably 0.03% by mass.

A copper alloy (strip) having the above composition is produced by a standard production method comprising soaking an ingot, hot rolling the ingot, and then cold rolling, recrystallization treatment accompanied by solutionizing, cold rolling, and precipitation treatment, wherein the conditions of the respective steps are the same as those of a Cu- (Ni, Co) -Si-based copper alloy, and the copper alloy produced under the conditions has a 0.2% proof stress of 300MPa or more and excellent bending workability, and further has an aging treatment after heating at a high temperature (850 ℃ C. × 30 minutes), whereby the copper alloy (strip) has a 0.2% proof stress of 120MPa or more and an electric conductivity of 40% IACS or more.

(Cu-Cr series)

Examples of the Cu — Cr-based copper alloy include a Cu — Cr-based copper alloy containing Cr: 0.15 to 0.6 mass%, Si: 0.005-0.15 mass% and Ti: 0.005 to 0.15 mass% of one or two kinds, and 0.01 to 0.3 mass% in total. The basic composition of the copper alloy is composed of Cu and unavoidable impurities in addition to Cr, Si and/or Ti, and contains alloying elements described later as necessary.

This copper alloy can recover strength and electric conductivity when subjected to aging treatment without plastic working after high-temperature heating (a step of joining in a steam chamber), but the recovery amount thereof is smaller than that of the precipitation hardening copper alloy. Even in this case, a 0.2% proof stress value of 60MPa or more and a conductivity of 45% IACS or more can be achieved. On the other hand, precipitated particles containing Cr, Si, Ti, and the like remain during high-temperature heating, and this suppresses coarsening of crystal grains due to secondary recrystallization, and thus suppresses coarsening of crystal grains. Therefore, the average grain size of the copper alloy after high-temperature heating (the bonding step in the vapor chamber) can be suppressed to 50 μm or less. Further, it is preferable to heat the mixture at a high temperature and then quench the mixture (e.g., by water cooling). The aging treatment may be performed at a temperature of 350 to 550 ℃ for 5 minutes to 10 hours.

In this copper alloy, Cr is precipitated as Cr, a Cr-Si compound or a Cr-Ti-Si compound in the copper alloy matrix, and the strength and conductivity of the copper alloy after aging treatment are improved. Further, Cr has a small amount of solid solution in Cu even at a temperature of 700 ℃ or higher, and can prevent coarsening of crystal grains in high-temperature heating (a bonding step in a steam chamber). However, if the Cr content is less than 0.15 mass%, the effect is insufficient. On the other hand, if the Cr content is more than 0.6 mass%, coarse Cr and Cr compounds are generated, and the bending workability of the copper alloy is lowered. Therefore, the Cr content is 0.15 to 0.6 mass%. The lower limit of Cr is preferably 0.2 mass%, more preferably 0.25 mass%. The upper limit of Cr is preferably 0.5%, and more preferably 0.45% by mass. In order to effectively prevent coarsening of crystal grains at a high temperature of 850 ℃ or higher, the Cr content is preferably 0.25 mass% or higher.

Si and Ti are precipitated as Cr-Si compounds or Cr-Ti-Si compounds in the copper alloy matrix phase, and the strength and the electric conductivity of the copper alloy are improved. In addition, the heat resistance of the copper alloy is improved, and coarsening of crystal grains during high-temperature heating (a bonding step in a steam chamber) can be prevented. However, when the Si content is less than 0.005 mass%, the Ti content is less than 0.005 mass%, or the total content of Si and Ti is less than 0.01 mass%, the effect is small. On the other hand, if the content of Si or Ti is more than 0.15 mass%, or the total content of Si and Ti is more than 0.3 mass%, coarse Cr — Si compounds or Cr — Ti — Si compounds in the copper alloy base material increase, and the bending workability is deteriorated. Therefore, the Si content is 0.005-0.15 mass%, the Ti content is 0.005-0.15 mass%, and the total content of Si and Ti is 0.01-0.3 mass%. The lower limit of the Si content and the Ti content is preferably 0.01% and the upper limit thereof is preferably 0.1% by mass, respectively.

The copper alloy contains one or more of Zn, Mg, Mn, Al, Ag, Ni, Fe, Co and P in an amount of 0.01 to 0.3 mass% as required. These elements improve the strength of the copper alloy, but if the total content is less than 0.01 mass%, the effect is insufficient, and if it is more than 0.3 mass%, the electrical conductivity is lowered. Therefore, the total content of one or two or more of these elements is 0.01 to 0.3% by mass.

A copper alloy (strip) having the above composition is produced by homogenizing an ingot, hot rolling the ingot, cold rolling the ingot, and aging the ingot, wherein the copper alloy has a 0.2% proof stress of 300MPa or more, an elongation of 5% or more, and excellent bending workability, and further has a 0.2% proof stress of 40MPa or more after high-temperature heating (850 ℃ × 30 minutes), and further has a 0.2% proof stress of 60MPa or more and an electric conductivity of 45% IACS or more after aging treatment, and further wherein coarsening of crystal grains due to high-temperature heating (850 ℃ × 30 minutes) is suppressed, and an average crystal grain size after high-temperature heating is suppressed to 50 [ mu ] m or less.

The homogenization treatment is performed under a condition of maintaining the temperature of 800 to 1000 ℃ for 1 to 10 hours.

After the homogenization treatment, hot rolling is started at a temperature of 800 ℃ or higher, the reduction ratio is about 50 to 90%, and the steel sheet is rapidly cooled from 700 ℃ or higher by a method such as water cooling.

The cold rolling after the hot rolling is performed at a reduction ratio of 50 to 99%.

The aging treatment is performed under the condition of keeping the temperature of 350-550 ℃ for 30 minutes-10 hours.

After the aging treatment, cold rolling at a reduction ratio of 5 to 30% may be performed, if necessary, and then stress relief annealing may be performed.

In addition, a solution treatment and a cold rolling may be carried out as necessary between the cold rolling and the aging treatment after the hot rolling in the above steps. In this case, it is preferable that the cold rolling after the hot rolling is performed at a reduction ratio of 50 to 95%, the solutionizing is performed under conditions of holding at a temperature of 700 to 900 ℃ for 5 seconds to 3 minutes, and then the cold rolling is performed at a reduction ratio of 50 to 95%.

(Cu-Cr-Zr series)

Examples of the Cu — Cr — Zr-based copper alloy include a copper alloy containing Cr: 0.15 to 0.6 mass% and Zr: 0.005-0.15 mass% of a copper alloy. The basic composition of the copper alloy is composed of Cu and unavoidable impurities in addition to Cr and Zr, and contains alloying elements described later as necessary.

This copper alloy can recover strength and electric conductivity without performing plastic working after high-temperature heating (a step of joining in a steam chamber) and aging treatment, as in the case of the Cu — Cr-based copper alloy described above, but the recovery amount is smaller than that of the other precipitation hardening copper alloys. Even in this case, a 0.2% proof stress value of 60MPa or more and a conductivity of 45% IACS or more can be achieved. On the other hand, precipitated particles containing Cr, Zr, or the like remain during high-temperature heating, and this suppresses coarsening of crystal grains due to secondary recrystallization, and thus suppresses coarsening of crystal grains. Therefore, the average grain size of the copper alloy after high-temperature heating (the bonding step in the vapor chamber) can be suppressed to 50 μm or less. Further, it is preferable to heat the mixture at a high temperature and then quench the mixture (e.g., by water cooling). The aging treatment may be performed by keeping the temperature at 350 to 550 ℃ for 5 minutes to 10 hours.

The reason why Cr is added to this copper alloy is the same as that of the Cu-Cr-based copper alloy described above.

Zr precipitates as a Zr-Cu compound in the copper alloy matrix phase, and improves the strength and conductivity of the copper alloy. Further, since the amount of Zr dissolved in Cu is extremely small, coarsening of crystal grains during high-temperature heating (the step of bonding in a steam chamber) can be prevented. However, when the Zr content is less than 0.005 mass%, the effect is small. On the other hand, if the Zr content is higher than 0.15 mass%, coarse Zr compounds are generated, and the bending workability is deteriorated. Therefore, the Zr content is 0.005-0.15 mass%. The lower limit of Zr is preferably 0.01 mass%, more preferably 0.015 mass%. The upper limit value of Zr is preferably 0.1 mass%, more preferably 0.08 mass%. In order to effectively prevent coarsening of crystal grains at a temperature of 850 ℃ or higher, the content of Zr is preferably 0.015 mass% or higher.

The copper alloy contains one or more of the following alloying elements (or alloying element groups) as required within a range that does not impair the electric conductivity after high-temperature heating and aging treatment. (a) Si: 0.005-0.15 mass% and Ti: 0.005-0.15 mass% of one or two kinds, 0.01-0.3 mass% in total, and (b) 0.01-0.3 mass% in total of one or more kinds of elements selected from Zn, Mg, Mn, Al, Ag, Ni, Fe, Co, Si, and P.

The copper alloy (strip) having the above composition can be produced by the same steps and conditions as those of the above-mentioned Cu-Cr-based copper alloy, has a 0.2% proof stress of 300MPa or more, an elongation of 5% or more, and excellent bending workability, has a 0.2% proof stress of 40MPa or more after high-temperature heating (850 ℃ C. × 30 minutes), has a 0.2% proof stress of 60MPa or more after aging treatment, and has an electric conductivity of 45% IACS or more, and further, can suppress coarsening of crystal grains due to high-temperature heating (850 ℃ C. × 30 minutes), and can suppress the average crystal grain size after high-temperature heating to 50 μm or less.

[ example 1 ]

Copper alloy strips having a thickness of 0.40mm were produced by casting the copper alloys shown in Table 1 and by the production methods described above. In Table 1, Nos. 1 and 2 are Cu-Fe-P systems, Nos. 3 to 5 are Cu- (Ni, Co) -Si systems, No.6 is Cu- (Ni, Co) -P system, No.7 is Cu-Cr system, No.8 is Cu-Cr-Zr system, and No.9 is OFC (Oxygen-Free Copper) of the conventional example.

Each of the produced copper alloy strips was used as a test material, and the 0.2% yield strength, elongation and electric conductivity were measured in the following manner.

The sheet extracted from each produced copper alloy strip was subjected to heating at 850 ℃ for × 30 minutes corresponding to heating in the joining step in the steam chamber, and then water-cooled, and the water-cooled sheet was used as a test material to measure 0.2% yield strength and electrical conductivity in the same manner.

Further, the plate extracted from each of the produced copper alloy strips was subjected to heating at 850 ℃ for × 30 minutes corresponding to the heating in the joining step in the steam chamber, followed by water cooling, and then subjected to aging treatment (precipitation hardening treatment) at 500 ℃ for × 2 hours.

The above results are shown in table 2.

(measurement of 0.2% yield Strength and elongation)

From each test piece, a tensile test piece No. JIS5 was cut out with the longitudinal direction being the rolling parallel direction, and a tensile test was carried out in accordance with JIS-Z2241 to measure the yield strength and elongation. The yield strength is a tensile strength corresponding to 0.2% of permanent elongation.

(measurement of conductivity)

The measurement of the electric conductivity was carried out by a four-terminal method using a two-bridge, according to the method for measuring the electric conductivity of a nonferrous metal material specified in JIS-H0505.

(measurement of average Crystal grain diameter)

The surface of the test piece was observed, and a photograph of the structure was taken with an optical microscope. The average grain size was measured by cutting the wire segments parallel to the rolling direction, drawing 4 wire segments on the texture photograph, each having a length of 250 μm, and taking the arithmetic average of the grain sizes determined for the respective wire segments as the average grain size.

[ TABLE 1 ]

[ TABLE 2 ]

When tables 1 and 2 are seen, as in the OFC of the conventional example, No.9, the 0.2% yield strength after heating at 850 ℃ for × 30 minutes corresponding to the bonding step in the steam chamber was 38MPa, and softening was severe, and the 0.2% yield strength after heating at 500 ℃ for × 2 hours corresponding to the aging treatment was 38MPa, and the 0.2% yield strength was not recovered.

In contrast, in the case of the precipitation hardening copper alloys of nos. 1 to 8, although they were softened by heating at 850 ℃ for × 30 minutes, the 0.2% yield strength was higher than 50mpa, and the 0.2% yield strength and the electric conductivity were recovered by heating at 500 ℃ for × 2 hours, and in particular, the 0.2% yield strength showed a value 2 times or more as large as that of No.9, the coarsening of crystal grains was suppressed, and the average crystal grain diameters were smaller than those of No.9, in particular, nos. 1, 2, 7 and 8, and were significantly smaller.

[ example 2 ]

Copper alloys having compositions shown in Nos. 1, 3, 6 and 9 of Table 1 were cast, and copper alloy strips having a thickness of 1.0mm were produced by the production methods described above. The produced copper alloy strip was used as a test material, and the 0.2% yield strength at high temperature was measured in the following manner. The results are shown in Table 3. In addition, Nos. 1A, 3A, 6A and 9A in Table 3 mean copper alloy strips having a thickness of 1.0mm and having alloy compositions corresponding to the compositions of Nos. 1, 3, 6 and 9 in Table 1, respectively.

(measurement of 0.2% yield Strength at high temperature)

From the test pieces, tensile test pieces of JIS5 were cut out so that the longitudinal direction was parallel to the rolling direction, and after holding at each temperature shown in table 3 for 30 minutes, tensile tests were carried out at the same temperature according to the regulations of JISZ2241, and the 0.2% proof stress was measured. The test atmosphere was in an Ar gas flow to prevent oxidation of the test piece.

[ TABLE 3 ]

When Table 3 is seen, the 0.2% yield strength of conventional example No.9A is very low at 700 ℃ or higher. On the other hand, the 0.2% yield strength of the precipitation hardening copper alloys Nos. 1A, 3A, and 6A was 5 times or more as high as No.9 at 700 ℃ and 2 times or more as high as No.9 at 800 ℃ and greater than No.9 at 900 ℃, and the strength was relatively high at high temperature, and it was found that the alloys were hardly deformed by heating in the bonding step in the steam chamber.

This application is accompanied by the claims of priority based on the application of the Japanese patent application with the application date of 2016, 3, 23 and the application No. 2016-. Patent application no 2016-.

[ description of symbols ]

2 Upper plate Member

3 lower plate member

Claims

1. A method for manufacturing a steam chamber, characterized in that the steam chamber is manufactured by assembling a plurality of parts into the steam chamber and then joining the parts to each other through a process of heating to 650 ℃ or higher, wherein the parts constituting the frame of the steam chamber among the parts are made of a precipitation hardening copper alloy, and the precipitation hardening copper alloy is subjected to an aging treatment to be precipitation hardened without applying plastic working to the frame of the joined steam chamber.