Component for drinking water pipe and method for manufacturing same

Abstract

A Cu-Zn-Si alloy having a low lead content and components such as plumbing fittings suitable for drinking water pipes and methods for making the same are described.

Description

[Technical field]

[0001] Field

[0001] Components suitable for plumbing fixtures, such as drinking water pipes, and methods for manufacturing the same are provided. Such components include, for example, coupling components, angle components, elbow components, tee components, distribution components, fittings and valves. These components may also find utility in other plumbing applications, such as central heating, ventilation or air conditioning systems. [Background technology]

[0002] background

[0002] The use of small amounts of lead in copper alloys such as brass and bronze used to form plumbing components provides beneficial properties to the resulting alloys, such as improved machining properties, thereby enabling the manufacture of complex parts.

[0003]

[0003] Materials from which components for plumbing installations, particularly those carrying media such as drinking water, are manufactured must be corrosion resistant for many years. In addition, to enable the manufacture of such components, the alloys from which said components are manufactured must be easily and economically processed and have good machinability. The alloys must be able to withstand the mechanical strains to which the components may be subjected during manufacture, storage, transportation, installation, and the service life of the installation.

[0004]

[0004] The presence of heavy metals such as lead and tin in alloys used in plumbing components can pose health risks and therefore there are regulatory limits on the amounts of certain metals present in alloys for use in the manufacture of plumbing components for drinking water.

[0005]

[0005] Copper-tin alloys such as CC499K (EN designation for casting is CuSn5Zn5Pb2-C), containing 84%-88% Cu, 4%-6% Sn, 4%-6% Zn, 3% Pb and 0.10% Sb, are widely used to form piping components. The alloy has good mechanical and machining properties. CC499K is suitable for sand casting, die casting, centrifugal casting and continuous casting. CC499K has a tensile strength of about 220 MPa and an elongation of about 13% according to BE EN 1982. The 0.2% proof stress is 110 MPa. CC499K is approved for contact with drinking water under the 4MS initiative.

[0006]

[0006] EP 1446510 discloses the use of a non-corrosive copper-zinc alloy for molded parts for drinking water. EP 1446510 describes a corrosion-resistant copper-zinc alloy for molded parts for drinking water, which is composed of the following alloy components: a) 23-32% by weight of zinc, b) 0.01-0.3% by weight of at least one of tin, iron, nickel, aluminum and silicon, c) 0.7-1.5% by weight of lead, and d) the remaining copper, which contains manufacturing-related impurities as a manufacturing material (the remaining copper content is based on the total content of each mixed component of a)-c).

[0007]

[0007] The migration of elements such as lead and tin into the media being transported through plumbing components is undesirable, especially when said media is intended for human consumption. The European Drinking Water Directive requires drinking water to contain a maximum of 10 micrograms of lead per liter, and this lead limit must be reduced to a maximum of 5 micrograms by 2036. To meet these limits, replacement of lead-containing plumbing components in homes and buildings is required.

[0008]

[0008] US Patent Application Publication No. 2007158004 relates to a method for producing components such as fittings, valves and pipes suitable for conveying media or drinking water, which components are said to exhibit low migration of metal ions into the media. The method comprises continuous casting of ingots or rods from a copper alloy having the following composition in weight percent: 2%≦Si≦4.5%≦Zn≦17%≦0.05%≦Mn≦0.6% with unavoidable incidental elements totaling up to 0.5% by weight, preferably totaling up to 0.3% by weight, the remainder being copper, and the ingots or rods for producing the components are subjected to at least one cold and / or hot forming process. US Patent Publication No. 2007158004 includes a single example composition containing 3.5 wt% Si, 1.6 wt% Zn, and 0.5 wt% Mn, with up to 0.5 wt% unavoidable incidental elements, the balance being copper. The example composition released less lead, nickel, copper, and zinc than a brass alloy containing 5.5 wt% Zn, 4.5 wt% Sn, 3 wt% Pb, 0.5 wt% Ni, the balance being copper. The tensile strength of such a copper alloy is about 300 MPa, and the elongation is about 16%. This alloy does not have good machinability and cannot be used for forming.

[0009]

[0009] EP 1045041 discloses and claims a lead-free, free-cutting copper alloy comprising 69-79 weight percent copper; 2.0-4.0 weight percent silicon; 0.02-0.4 weight percent bismuth, 0.02-0.4 weight percent tellurium, and 0.02-0.4 weight percent selenium; and the remaining weight percent zinc. Thus, EP 1045041 discloses a copper alloy comprising about 16% to about 29% by weight zinc. The copper alloy of EP 1045041 is criticized for its corrosion resistance, and in addition, the alloy contains elements that make it unsuitable for drinking water pipes.

[0010]

[0010] U.S. Patent Application Publication No. 2009 / 0214380 discloses and claims the use of a copper alloy for manufacturing medium carrying gas or water pipes, particularly drinking water pipes, and components of fittings and valves thereof, the copper alloy having, in weight percent, 2.8≦Si≦4.5, 1≦Zn≦15, 0.05≦Mn≦2, 80≦Cu≦96.95, and optionally further containing 0.05≦Al≦0.5, 0.05≦Sn≦2, 0.0005≦Zr≦0.05, 0.01≦P≦0.2 and unavoidable impurities.

[0011]

[0011] U.S. Patent Application Publication No. 2008 / 0318079 discloses plumbing valves, fittings and other water handling devices made from silicon bronze having a lead content of less than 0.2%. The silicon bronze alloy C87800 described therein consists of the following components by weight:

[0012] [Table 1]

[0013] The preferred C87800 alloy contained about 82% copper, 4% silicon and 14% zinc by weight. Alternatively, silicon bronze alloy C87610 may be used.

[0014] [Table 2]

[0015] The preferred C87610 alloy contains about 92% copper, about 4% silicon, and about 4% zinc by weight. C87800 has an elongation of up to about 25% and C87610 has an elongation of up to about 20%. Summary of the Invention [Problem to be solved by the invention]

[0016]

[0012] It would be desirable to provide an alloy having reduced lead content, low ionic migration into media such as drinking water, suitable for both molding and casting, good machinability, and suitable for soldering. In particular, it would be desirable to provide an alloy having the above-mentioned properties and increased tensile strength and elongation properties. These and other needs are provided by the present invention. [Means for solving the problem]

[0017] overview In one aspect, the present invention provides a composition comprising, in weight percent, the following components: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2 A Cu-Zn-Si alloy comprising, consisting essentially of, or consisting of: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦48, The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, suitably 82.0≦Cu≦86.0, for example 82.0≦Cu≦85.8, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or more, preferably 400 MPa or more; and The alloy provides a Cu-Zn-Si alloy having an elongation at break, determined according to ISO 6892-1:2009, of 25% or more, preferably 30% or more, and more preferably 40% or more.

[0018]

[0014] Preferably, the Cu-Zn-Si alloy contains, in weight percent, 2.5≦Si≦3.5.

[0019]

[0015] Preferably, 38≦Q≦44.

[0020]

[0016] For example, a Cu-Zn-Si alloy may include, in weight percent, 2.5≦Si≦3.2 and 36≦Q≦47, preferably 38≦Q≦45, such as 38≦Q≦42. Such silicon contents and Q values ​​are particularly advantageous when the alloy is to be continuously cast.

[0021]

[0017] Suitably the Cu-Zn-Si alloy comprises, in weight percent, 2.5≦Si≦3.2 and 36≦Q≦47, preferably 38≦Q≦45, for example 38≦Q≦42, and said alloy is continuously cast.

[0022]

[0018] In another embodiment, the Cu-Zn-Si alloy comprises, in weight percent, 2.7≦Si≦3.5, where 37≦Q≦48, preferably 40≦Q≦46, such as 40≦Q≦44. Such silicon content and Q value are particularly advantageous when the alloy is gravity cast.

[0023]

[0019] Suitably the Cu-Zn-Si alloy comprises, in weight percent, 2.7≦Si≦3.5, where 37≦Q≦48, preferably 40≦Q≦46, for example 40≦Q≦44, and is gravity cast.

[0024]

[0020] Suitably, the Cu-Zn-Si alloy comprises a zinc content in the range 11.5≦Zn≦13.0, for example 12.0≦Zn≦13.0.

[0025]

[0021] The Cu-Zn-Si alloy may contain a manganese content in the range of 0.1≦Mn≦0.15, preferably in the range of 0.10≦Mn≦0.14.

[0026]

[0022] Preferably, the Cu-Zn-Si alloy does not contain As and / or Sb.

[0027]

[0023] The Cu-Zn-Si alloy may have a tensile strength, determined in accordance with ISO 6892-1:2009, of 350 MPa or more, preferably 380 MPa or more, even more preferably 400 MPa or more, such as 450 MPa or more.

[0028]

[0024] Preferably, the Cu-Zn-Si alloy has a melting point of 8.0 kg / m 3 ~8.29kg / m 3 , preferably 8.0 to 8.28 kg / m 3 , preferably 8.18 to 8.28 kg / m 3 True solid density may be measured in accordance with BS ISO 12154.

[0029] In another aspect, the present invention provides a composition comprising, in weight percent: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2, for example 0.1≦Mn≦0.15, preferably 0.10≦Mn≦0.14 and providing components for drinking water pipes, i.e. valves and fittings for drinking water pipes, made from the Cu-Zn-Si alloy described herein, comprising, consisting essentially of or consisting of: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦48, The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, suitably 82.0≦Cu≦86.0, for example 82.0≦Cu≦85.8, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or greater; and The alloy has an elongation at break, determined according to ISO 6892-1:2009, of greater than or equal to 25%, preferably greater than or equal to 30%, and more preferably greater than or equal to 40%.

[0030]

[0026] In a still further aspect, the present invention relates to a method for manufacturing components for drinking water pipes, namely valves and fittings for drinking water pipes, comprising the steps of: (i) the following, in weight percent: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2, for example 0.1≦Mn≦0.15, preferably 0.10≦Mn≦0.14 1. A Cu-Zn-Si alloy as described herein comprising, consisting essentially of, or consisting of: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦48, The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, suitably 82.0≦Cu≦86.0, for example 82.0≦Cu≦85.8, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or greater; and providing a Cu-Zn-Si alloy, the alloy having an elongation at break of 25% or more, preferably 30% or more, more preferably 40% or more, as determined according to ISO 6892-1:2009; (ii) processing the alloy to form the component; The present invention provides a method comprising:

[0031] Processing the alloy to form the components described herein may include continuous casting the alloy and / or one or more metal forming steps.

[0032]

[0028] Processing the alloy to form a component as described herein may include gravity casting the alloy, for example sand casting or die casting the alloy.

[0033]

[0029] Processing the alloy to form a part as described herein may include pressure die casting, such as high pressure die casting.

[0034] Processing the alloy to form a component as described herein may include one or more metal forming steps, such as forging or rolling the alloy.

[0035]

[0031] Processing the alloy to form the components described herein may include one or more machining steps.

[0036]

[0032] Processing of Cu-Zn-Si alloys may include heating the copper alloy in one or more processing steps to a temperature in the range of 800-1300°C, preferably 1000°C-1300°C. For example, in a continuous casting process, the Cu-Zn-Si alloy may be heated to a temperature in the range of 1000°C-1150°C. In a gravity casting process, the Cu-Zn-Si alloy may be heated to a temperature in the range of 1200°C-1300°C.

[0037]

[0033] Suitably, when the production of the components described in this specification involves continuous casting, the Cu-Zn-Si alloy comprises, in weight percent, 2.5≦Si≦3.2 and suitably 36≦Q≦47, preferably 38≦Q≦45, for example 38≦Q≦42.

[0038]

[0034] Preferably, when the production of the components described in this specification involves gravity casting, such as sand casting or die casting, the Cu-Zn-Si alloy comprises, in weight percent, 2.7≦Si≦3.5 and preferably 37≦Q≦48, preferably 40≦Q≦46, for example 40≦Q≦44.

[0039]

[0035] The Cu-Zn-Si alloy has a tensile strength, determined in accordance with ISO 6892-1:2009, of 350 MPa or more, preferably 380 MPa or more, even more preferably 400 MPa or more, such as 450 MPa or more.

[0040]

[0036] Cu-Zn-Si alloy has a strength of 8.0 kg / m 3 ~8.29kg / m 3 , preferably 8.0 to 8.28 kg / m 3, preferably 8.18 to 8.28 kg / m 3 The method according to any one of claims 10 to 15, wherein the composition has a true solid density in the range of 0.01 to 0.05. The true solid density may be measured according to BS ISO 12154.

[0041]

[0037] The present disclosure provides a composition comprising, in weight percent, the following components: 11.0≦Zn≦13.0, optionally 11.5≦Zn≦13.0, for example 12.0≦Zn≦13.0, 2.4≦Si≦4.1, 0.1≦Fe≦0.5, Optionally, 0.1≦Mn≦0.2 A Cu-Zn-Si alloy comprising, consisting essentially of, or consisting of: The weight percentage of Zn plus 10 times the weight percentage of Si is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 35≦Q≦52, The alloy contains unavoidable impurities in an amount not exceeding 0.53% by weight, There is also provided a Cu-Zn-Si alloy, wherein the impurities include 0.2 wt. % or less Sn and 0.06 wt. % or less Pb.

[0042]

[0038] As used herein, the following components are included in weight percent: 80≦Cu≦88, preferably 81.0≦Cu≦86.5, 11.0≦Zn≦13.0, optionally 11.5≦Zn≦13.0, for example 12.0≦Zn≦13.0, 2.4≦Si≦4.1, 0.1≦Fe≦0.5, Optionally, 0.1≦Mn≦0.2; Also disclosed are components for drinking water pipes, i.e. valves and fittings for drinking water pipes, made from a Cu-Zn-Si alloy comprising: The weight percentage of Zn plus 10 times the weight percentage of Si is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 35≦Q≦52, The alloy contains unavoidable impurities in an amount not exceeding 0.53% by weight, The impurities include up to 0.2 wt. % Sn and up to 0.06 wt. % Pb.

[0043]

[0039] In another aspect, the present disclosure provides a method for manufacturing components for drinking water pipes, i.e. valves and fittings for drinking water pipes, comprising: (i) The following components, in weight percent: 80≦Cu≦88, preferably 81.0≦Cu≦86.5, 11.0≦Zn≦13.0, optionally 11.5≦Zn≦13.0, for example 12.0≦Zn≦13.0, 2.4≦Si≦4.1, 0.1≦Fe≦0.5, Optionally, 0.1≦Mn≦0.2 A Cu-Zn-Si alloy comprising: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 35≦Q≦52, The alloy contains unavoidable impurities in an amount not exceeding 0.53% by weight, providing a Cu-Zn-Si alloy, the impurities including 0.2 wt. % Sn or less and 0.06 wt. % Pb or less; (ii) processing the alloy to form the component; The present invention provides a method comprising:

[0044]

[0040] The Cu-Zn-Si alloy of the present disclosure may include, in weight percent, 80.5≦Cu≦87, preferably 81.0≦Cu≦86.5, more preferably 81.5≦Cu≦86.3, even more preferably 82.0≦Cu≦86.0, such as 82.0≦Cu≦85.8, such as 82.0≦Cu≦85.0, such as 82.2≦Cu≦85.0.

[0045]

[0041] It is particularly preferred that the amount of copper in the Cu-Zn-Si alloy of the present invention is in the range 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5.

[0046]

[0042] The Cu-Zn-Si alloy may, for example, contain, in weight percent, 2.5≦Si≦3.7, preferably 2.5≦Si≦3.5.

[0047]

[0043] The Cu-Zn-Si alloy may have a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or more, preferably 350 MPa or more, even more preferably 380 MPa or more, even more preferably 400 MPa or more, such as 450 MPa or more. For example, the Cu-Zn-Si alloy may have a tensile strength, determined according to ISO 6892-1:2009, in the range of 300 MPa to 650 MPa, such as 350 MPa to 650 MPa, preferably 380 MPa to 600 MPa, such as 400 MPa to 600 MPa, such as 450 MPa to 600 MPa.

[0048]

[0044] The Cu-Zn-Si alloy suitably has an elongation to break of at least 15%, suitably at least 20%, preferably at least 25%, such as at least 30% or at least 35%, determined according to ISO 6892-1:2009. For example, the Cu-Zn-Si alloy may have an elongation to break in the range of 25% to 65%, such as at least 30% to 60% or at least 35% to 60%.

[0049]

[0045] Suitably, the Cu-Zn-Si alloy may have a tensile strength of 350 MPa or more and an elongation to break of 25% or more, determined according to ISO 6892-1:2009. In some embodiments, the Cu-Zn-Si alloy has a tensile strength of 380 MPa or more and an elongation to break in the range of 25% to 65%. In particularly preferred embodiments, the Cu-Zn-Si alloy (and parts made therefrom) has a tensile strength of 380 MPa to 650 MPa, e.g., 400 to 600 MPa or 450 MPa to 600 MPa, and an elongation to break of 25% to 65%, e.g., 30% to 60% or 35% to 60%, determined according to ISO 6892-1:2009.

[0050]

[0046] Preferably, the Cu-Zn-Si alloy contains not more than 0.1 wt. % Sn, more preferably not more than 0.06 wt. % Sn.

[0051]

[0047] The Cu-Zn-Si alloy contains 0.05% or less Ni by weight.

[0052]

[0048] The Cu-Zn-Si alloy may contain up to 0.2 wt. % Al, for example 0.001 wt. % to 0.2 wt. % Al.

[0053]

[0049] The Cu-Zn-Si alloy may contain up to 0.03 wt. % P, for example 0.001 wt. % to 0.03 wt. % P.

[0054]

[0050] Preferably, the Cu-Zn-Si alloy does not contain As.

[0055]

[0051] The Cu-Zn-Si alloy may alternatively or additionally be free of one or more of Sb, Bi, Te and Se. For example, the Cu-Zn-Si alloy may be free of As, Sb, Bi, Te and Se. [Brief description of the drawings]

[0056] [Figure 1] 1 shows a cross section of a continuous cast rod of Example 1. [Diagram 2] An enlarged view of FIG. [Diagram 3] 1 shows the end of a continuously cast Cu—Zn—Si alloy rod of Example 1 that has been elongated to break in an extensometer. [Figure 4] 1 shows a cross section of a continuous cast rod according to Example 2. [Diagram 5] 1 shows a cross section of a rod cast in Comparative Example 4. [Figure 6] 1 shows the end of a die-cast Cu—Zn—Si alloy rod of Comparative Example 4 that has been stretched to break in an extensometer. [Figure 7] 3 shows a rod cast in Comparative Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0057] Detailed Description

[0052] As outlined above, the following components are used herein in weight percent: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2, for example 0.1≦Mn≦0.15, preferably 0.10≦Mn≦0.14 A Cu-Zn-Si alloy comprising, consisting essentially of, or consisting of: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦48, The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or more, preferably 400 MPa or more; and The alloy is disclosed as a Cu-Zn-Si alloy having an elongation at break of 25% or more, preferably 30% or more, and more preferably 40% or more, as determined according to ISO 6892-1:2009.

[0058]

[0053] The Cu-Zn-Si alloys are particularly suitable for the manufacture of components such as plumbing fittings, for example components for drinking water pipes, i.e. pipes suitable for conveying drinking water or other media for human consumption, such as coupling parts, angle parts, elbow parts, T-pieces, distribution parts, fittings and valves. Naturally, these parts can also be used in other plumbing settings, for example in central heating, ventilation or air conditioning systems.

[0059]

[0054] Advantageously, the components are lead-free and have low ion migration into media, such as drinking water, that are transported through the components.

[0060]

[0055] A zinc content of 11.0 wt% to 13.0 wt% affects elongation and tensile strength. When the zinc content is less than about 11 wt%, elongation decreases. When the zinc content is more than about 13 wt%, tensile strength decreases. In some embodiments, the zinc content is in the range of 11.5 wt% to 13.0 wt%, for example, 12.0 wt% to 13.0 wt%.

[0061]

[0056] A silicon content of 2.5% to 3.7% by weight affects corrosion resistance, castability, and wear resistance. The corrosion rate can be 0.02 to 0.002 mm / year as determined according to ISO 16151:2018. If the silicon content is less than about 2.5% by weight, these properties are reduced. If the silicon content is more than about 3.7% by weight, these properties are reduced. In some embodiments, the silicon content is in the range of 2.5% to 3.5% by weight.

[0062]

[0057] Importantly, the relationship between zinc content and silicon content has a large effect on tensile strength and elongation when the alloy is processed under different processing conditions.

[0063]

[0058] For example, the alloy of the present invention, when processed by continuous casting or metal forming processes, has an optimal relationship between the amount of zinc and the amount of silicon, defined as Q, where Q = [Zn] + (10 x [Si]), 2.5 < Si < 3.5, for example 2.5 < Si < 3.2, and 36 < Q < 47, preferably 38 < Q < 42.

[0064]

[0059] In a continuous casting or metal forming process, a decrease in tensile strength is observed when Q is less than about 36, while a decrease in elongation is observed when Q is greater than about 47. Advantageously, optimal tensile strength and elongation are achieved for parts described in this invention when Q is in the range of about 38% to about 42% by weight.

[0065]

[0060] Thus, one aspect of the present invention is a composition comprising, in weight percent, the following components: 11.0≦Zn≦13.0 2.5≦Si≦3.5 0.1≦Fe≦0.5 0.1≦Mn≦0.2, for example, 0.1≦Mn≦0.15, preferably 0.10≦Mn≦0.14 The present invention provides components for drinking water pipes, i.e. valves and fittings for drinking water pipes, which are manufactured by continuous casting or metal forming of a Cu-Zn-Si alloy comprising The weight percentage of Zn plus 10 times the weight percentage of Si is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦47, preferably 38≦Q≦42; The alloy contains unavoidable impurities in an amount not exceeding 0.53% by weight, The impurities include 0.2 wt.% or less Sn and 0.06 wt.% or less Pb, preferably 0.05 wt.% or less Pb; The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or more, preferably 400 MPa or more; and The alloy has an elongation at break, determined according to ISO 6892-1:2009, of greater than or equal to 25%, preferably greater than or equal to 30%, and more preferably greater than or equal to 40%.

[0066]

[0061] When the alloy of the present invention is processed by a gravity casting process, the optimal relationship between the amount of zinc and the amount of silicon is defined by Q, where Q = [Zn] + (10 × [Si]), 2.7 ≦ Si ≦ 3.5, for example 2.8 ≦ Si ≦ 3.2, and 37 ≦ Q ≦ 48, preferably 40 ≦ Q ≦ 46.

[0067]

[0062] In gravity casting processes, such as sand casting or die casting processes, a loss in tensile strength is observed when Q is less than about 37, while a loss in elongation is observed when Q is greater than about 48. Advantageously, optimal elongation and tensile strength for gravity casting is achieved when Q is in the range of about 40% to about 46% by weight.

[0068]

[0063] Thus, another aspect of the present invention is a composition comprising, in weight percent, the following components: 11.0≦Zn≦13.0 2.7≦Si≦3.5 0.1≦Fe≦0.5 0.1≦Mn≦0.2, for example, 0.1≦Mn≦0.15, preferably 0.10≦Mn≦0.14 and (c) providing a component for a drinking water pipe, i.e. a valve and a fitting for a drinking water pipe, produced by gravity casting (e.g., sand casting or die casting) a Cu-Zn-Si alloy of the present invention comprising: The weight percentage of Zn plus 10 times the weight percentage of Si is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 37≦Q≦48, preferably 40≦Q≦46; The alloy contains unavoidable impurities in an amount not exceeding 0.53% by weight, The impurities include up to 0.2 wt. % Sn and up to 0.06 wt. % Pb.

[0069]

[0064] The Cu-Zn-Si alloy of the present invention contains iron in an amount of 0.1 wt% to 0.5 wt%. If the amount of iron is less than about 0.1 wt%, the tendency to crack when heated increases, the ductility decreases, and a fine-grained homogeneous structure is not observed. If the amount of iron is more than about 0.5 wt%, the tendency to crack when heated increases, the ductility decreases, and a fine-grained homogeneous structure is not observed.

[0070]

[0065] The Cu-Zn-Si alloy of the present invention contains manganese in an amount of 0.1% to 0.2% by weight.

[0071]

[0066] When the amount of manganese is less than about 0.1 wt%, a decrease in corrosion resistance is observed. When the amount of manganese is more than about 0.2 wt%, a decrease in corrosion resistance is observed. The amount of manganese is suitably in the range of 0.1 wt% to 0.15 wt%, preferably in the range of 0.1 wt% to 0.14 wt%. When the amount of manganese is within this range, advantageously, the breaking elongation is further improved.

[0072]

[0067] Preferably, for parts manufactured using continuous casting or metal forming, the content of the four main alloying elements other than copper, namely Zn, Si, Fe and Mn, is between 13.7 and 16.9 wt.%, for example between 13.7 and 16.6 wt.%.

[0073]

[0068] Preferably, for parts manufactured using gravity casting such as sand casting or die casting, the content of the four main alloying elements excluding copper, namely Zn, Si, Fe and Mn, is 13.9-17.3 wt.%, for example 14.1-17.3 wt.% or 13.9-17.2 wt.%.

[0074]

[0069] The part of the present invention is a Cu-Zn-Si alloy cast part such as a Cu-Zn-Si alloy: continuous casting, gravity casting, sand casting or die casting.

[0075]

[0070] Suitably, the methods described herein may include one or more annealing steps. Advantageously, such annealing may improve the ductility of the Cu-Zn-Si alloy and components manufactured therefrom. For example, the Cu-Zn-Si alloy may be annealed by heating to a temperature in the range of 700-900°C.

[0076]

[0071] For clarity and conciseness of description, features are described in this specification as part of the same or separate embodiments, but it will be recognized that the scope of the present invention may include embodiments having combinations of all or part of the described features.

[0077]

[0072] It will be appreciated that the weights of the components of the alloy of the present invention add up to 100% by weight, and thus, for example, if a composition is specified to have a balance of copper, this means that the balance of the composition is copper to make up 100% by weight, i.e. the balance is copper up to 100% by weight.

[0078]

[0073] The invention will be more readily appreciated by consideration of the following examples, which are not intended to limit the scope of the invention as defined in the claims.

[0079] Embodiment 1. The following components, in weight percent: 80≦Cu≦88, preferably 81.0≦Cu≦86.5 11.0≦Zn≦13.0 2.4≦Si≦4.1 0.1≦Fe≦0.5 Optionally, 0.1≦Mn≦0.2 Parts for drinking water pipes, namely valves and fittings for drinking water pipes, made from a Cu-Zn-Si alloy comprising The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 35≦Q≦52, The alloy contains unavoidable impurities in an amount not exceeding 0.53% by weight, Parts for drinking water pipes, namely valves and fittings for drinking water pipes, the impurities containing not more than 0.2% by weight of Sn and not more than 0.06% by weight of Pb.

[0080] 2. A method for manufacturing components for drinking water pipes, namely valves and fittings for drinking water pipes, comprising the steps of: (i) The following components, in weight percent: 80≦Cu≦88, preferably 81.0≦Cu≦86.5, 11.0≦Zn≦13.0 2.4≦Si≦4.1 0.1≦Fe≦0.5 Optionally, 0.1≦Mn≦0.2 A Cu-Zn-Si alloy comprising: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 35≦Q≦52, The alloy contains unavoidable impurities in an amount not exceeding 0.53% by weight, providing a Cu-Zn-Si alloy, the impurities including 0.2 wt. % Sn or less and 0.06 wt. % Pb or less; (ii) processing the alloy to form the component; The method includes:

[0081] 3. The method of embodiment 2, wherein step (ii) comprises continuous casting the alloy, and / or step (ii) comprises one or more metal forming steps.

[0082] 4. The method of embodiment 2, wherein step (ii) comprises gravity casting the alloy, e.g., sand casting or die casting the alloy.

[0083] 5. The method of embodiment 2, wherein step (ii) comprises one or more metal forming steps, such as forging or rolling the alloy.

[0084] 6. The method of any one of embodiments 2-5, wherein step (ii) further comprises one or more machining steps.

[0085] 7. Cu-Zn-Si alloy contains, in weight percent: 80.5≦Cu≦87, Preferably, 81.0≦Cu≦86.5; More preferably, 81.5≦Cu≦86.3; Even more preferably, 82.0≦Cu≦86.0, for example 82.0≦Cu≦85.0 The method of any one of embodiments 2 to 6, comprising:

[0086] 8. Cu-Zn-Si alloy contains, in weight percent: 2.5≦Si≦3.7, preferably 2.5≦Si≦3.5 The method of any one of embodiments 2 to 7, comprising:

[0087] 9. The method of any one of embodiments 2-8, wherein step (ii) comprises heating the Cu-Zn-Si alloy to a temperature in the range of 800-1300 °C in one or more processing steps.

[0088] 10. The Cu-Zn-Si alloy contains, in weight percent: 2.5≦Si≦3.5, for example 2.5≦Si≦3.2 4. The method of embodiment 3, comprising:

[0089] 11. The Cu-Zn-Si alloy contains, in weight percent: 2.5≦Si≦3.7, for example 2.7≦Si≦3.5 5. The method of embodiment 4, comprising:

[0090] 12. The method of any one of embodiments 2-11, wherein the Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or more, preferably 350 MPa or more, even more preferably 380 MPa or more, even more preferably 400 MPa or more, such as 450 MPa or more.

[0091] 13. The method of any one of embodiments 2-12, wherein the Cu-Zn-Si alloy has an elongation of 25% or greater, determined according to ISO 6892-1:2009.

[0092] 14. The method of any one of embodiments 2-13, wherein the Cu-Zn-Si alloy contains, by weight percent, 0.05% or less Ni.

[0093] 15. The method of any one of embodiments 2-14, wherein the Cu-Zn-Si alloy contains up to 0.2 wt.% Al.

[0094] 16. The method of any one of embodiments 2-15, wherein the Cu-Zn-Si alloy contains up to 0.03 wt.% P.

[0095] 17. The method of any one of embodiments 2 to 16, wherein the Cu-Zn-Si alloy does not contain As or Sb.

[0096] 18. In weight percent, the following components: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2, for example, 0.1≦Mn≦0.15, preferably 0.10≦Mn≦0.14 A Cu-Zn-Si alloy comprising, consisting essentially of, or consisting of: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦48, The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, suitably 82.0≦Cu≦86.0, for example 82.0≦Cu≦85.8, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or more, preferably 400 MPa or more; and The alloy is a Cu-Zn-Si alloy having an elongation at break of 25% or more, preferably 30% or more, more preferably 40% or more, as determined according to ISO 6892-1:2009.

[0097] 19. The Cu-Zn-Si alloy contains, in weight percent: 2.5≦Si≦3.5 20. The Cu-Zn-Si alloy of claim 18, comprising:

[0098] 20.2.5≦Si≦3.2, A Cu-Zn-Si alloy according to claim 19, wherein 36≦Q≦47, preferably 38≦Q≦45, for example 38≦Q≦42.

[0099] 21.2.7≦Si≦3.5; A Cu-Zn-Si alloy according to claim 19, wherein 37≦Q≦48, preferably 40≦Q≦46, for example 40≦Q≦44.

[0100] 22. A Cu-Zn-Si alloy according to any one of embodiments 18-21, wherein 11.5≦Zn≦13.0, such as 12.0≦Zn≦13.0.

[0101] 23. A Cu-Zn-Si alloy according to any one of embodiments 18 to 22, which does not contain As and / or Sb.

[0102] 24. In weight percent, the following: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2, for example 0.1≦Mn≦0.15, preferably 0.10≦Mn≦0.14 Components for drinking water pipes, namely valves and fittings for drinking water pipes, made from a Cu-Zn-Si alloy comprising, consisting essentially of or consisting of: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦48, The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, suitably 82.0≦Cu≦86.0, for example 82.0≦Cu≦85.8, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or greater; and The alloy has an elongation at break determined according to ISO 6892-1:2009 of at least 25%, preferably at least 30%, more preferably at least 40%.

[0103] 25. A part for a drinking water pipe according to embodiment 24, made from a Cu-Zn-Si alloy according to any one of claims 2 to 6.

[0104] 26. The alloy has a strength of 8.0 kg / m 3 ~8.29kg / m 3 , preferably 8.0 to 8.28 kg / m 3 , preferably 8.18 to 8.28 kg / m 326. A part for a drinking water pipe according to embodiment 24 or 25, having a true solid density in the range of

[0105] 27. A method for manufacturing components for drinking water pipes, namely valves and fittings for drinking water pipes, comprising the steps of: (i) the following, in weight percent: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2, for example 0.1≦Mn≦0.15, preferably 0.1≦Mn≦0.14 A Cu-Zn-Si alloy comprising, consisting essentially of, or consisting of: The weight percentage of Zn ([Zn]) plus 10 times the weight percentage of Si ([Si]) is the total weight percentage Q, Here, Q = [Zn] + (10 × [Si]), 36≦Q≦48, The Cu-Zn-Si alloy contains, by weight percent, 0.05% or less of Ni; The Cu-Zn-Si alloy contains up to 0.2% by weight of Al; The Cu-Zn-Si alloy contains not more than 0.03 wt. % P; The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, said impurities including not more than 0.2% by weight Sn and not more than 0.06% by weight Pb; the remainder being copper, for example 82.0≦Cu≦86.3, suitably 82.0≦Cu≦86.0, for example 82.0≦Cu≦85.8, preferably 82.0≦Cu≦85.0, for example 82.2≦Cu≦85.0 or 82.5≦Cu≦84.5, for example 83.0≦Cu≦84.5; The Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or greater; and providing a Cu-Zn-Si alloy, the alloy having an elongation at break of 25% or more, preferably 30% or more, more preferably 40% or more, as determined according to ISO 6892-1:2009; (ii) processing the alloy to form the component; The method includes:

[0106] 28. The method of embodiment 27, wherein step (ii) comprises continuous casting the alloy, and / or step (ii) comprises one or more metal forming steps.

[0107] 29. The method of embodiment 27, wherein step (ii) comprises gravity casting the alloy, e.g., sand casting or die casting the alloy.

[0108] 30. The method of embodiment 27, wherein step (ii) comprises one or more metal forming steps, such as forging or rolling the alloy.

[0109] 31. The method of any one of embodiments 27-30, wherein step (ii) further comprises one or more machining steps.

[0110] 32. The method of any one of embodiments 27-31, wherein the Cu-Zn-Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 350 MPa or more, preferably 380 MPa or more, even more preferably 400 MPa or more, for example 450 MPa or more.

[0111] 33. Cu-Zn-Si alloy has a strength of 8.0 kg / m, determined in accordance with BS ISO 12154. 3 ~8.29kg / m 3 , preferably 8.0 to 8.28 kg / m 3 , preferably 8.18 to 8.28 kg / m 3 33. The method of any one of claims 27 to 32, wherein the composition has a true solid density in the range of EXAMPLES

[0112] Working Example Example 1

[0074] 81.0≦Cu≦86.5 11.5≦Zn≦13.0 2.9≦Si≦3.4 0.1≦Fe≦0.5 0.1≦Mn≦0.2 The Cu-Zn-Si alloy of the present invention comprises: 42≦Q≦47, The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, The impurities include 0.06 wt.% or less of Sn and 0.06 wt.% or less of Pb. Rods were continuously cast from the Cu-Zn-Si alloy. The composition of Example 1 contained 0.010≦Ni≦0.025. The composition of Example 1 did not contain Bi, Ag, Te, or As. The amount of copper ranged from 82.0 to 85.0 wt %, based on the total weight of the alloy.

[0113]

[0075] An ingot having the above alloy composition is placed in a furnace capable of smelting and casting. The alloy is heated to a temperature in the range of 1000-1200°C and the smelt is cast through a graphite die equipped with a copper cooler. The liquid metal is cooled and drawn off as a continuous rod or tube. The tube is cut to size and transported to a stamping station and / or machining station.

[0114]

[0076] For the stamping process, the continuous cast rod is cut into billets of a particular size (the size depends on the amount of material required to produce the final component). The billets may then be heated and forged. After forging, the stamped article is cooled and trimmed. The stamped article may optionally be annealed, for example, by heating to a temperature in the range of 700-900°C. The stamped article is cleaned and then sent to a machining station.

[0115]

[0077] The continuous cast Cu-Zn-Si alloy of Example 1 was used to manufacture components for drinking water pipes in a process including stamping and machining steps.

[0116]

[0078] The tensile strength and elongation of the Cu-Zn-Si alloys were evaluated in a Hounsfield tensiometer according to ISO 6892-1:2009. Measurement parameters: Extensometer Type: Extensometer Extensometer measuring length (Le): 50 mm Force measurement range: 50kN Environmental Monitoring: Humidity: 50.0% Temperature: 22.0℃ Sample data: Sample initial dimensions - D0: 9.50mm S0: 70.88mm 2 Initial measurement length (L0): 50.00 mm Length of parallel section (Lc): 55.00mm Sample results: Tensile strength Rm: 488.2MPa Breaking elongation % (Agt): 51.214%

[0117]

[0079] A cross section of the continuous cast rod of Example 1 is shown in FIG.

[0118]

[0080] Figure 2 shows an enlarged view of Figure 1. Using a 5XJP-6A metallurgical microscope with a 20x lens microscope camera DLT-Cam PRO, an acid mixture: HCl (20%):H 2 NO 3 (20%):H 2 SO 4 Samples were taken from φ26 rods in (20%) 1:2.

[0119]

[0081] Figure 3 shows the end of a continuously cast Cu-Zn-Si alloy rod of Example 1 that was elongated to break in an extensometer.

[0120] Example 2

[0082] Composition of: 82≦Cu≦86.5 12.0≦Zn≦13.0 2.7≦Si≦3.1 0.1≦Fe≦0.5 0.1≦Mn≦0.2 The Cu-Zn-Si alloy of the present invention has the following structure: 38≦Q≦44, The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, The impurities include 0.06 wt.% or less of Sn and 0.05 wt.% or less of Pb. Rods were continuously cast from the Cu-Zn-Si alloy. The composition of Example 2 contained 0.010≦Ni≦0.025. The composition of Example 2 did not contain Bi, Ag, Te, or As. The amount of copper ranged from 82.0 to 85.0 wt %, based on the total weight of the alloy.

[0121]

[0083] Continuously cast rods were processed as described in Example 1.

[0122]

[0084] The tensile strength and elongation of the continuously cast Cu-Zn-Si alloy from Example 2 were evaluated in a Hounsfield tensiometer according to ISO 6892-1:2009. Measurement parameters: Extensometer Type: Extensometer Extensometer measuring length (Le): 50 mm Force measurement range: 50kN Environmental Monitoring: Humidity: 50.0% Temperature: 20.0℃ Sample data Initial dimensions of sample - D0: 9.48m S0: 70.58mm2 Initial measurement length (L0): 50.00 mm Length of parallel section (Lc): 55.00mm Sample results: Tensile strength (Rm): 454.0MPa Breaking elongation% (Agt): 43.036%

[0123] FIG. 4 shows a cross section of a continuously cast rod according to Example 2.

[0124]

[0086] Surprisingly, it has been found that the Cu-Zn-Si alloy of the present invention, when continuously cast, has significantly better tensile strength and elongation at break properties compared to the continuous cast products of the prior art. For example, the continuous cast products have a tensile strength of 380 MPa or more, preferably 400 MPa or more, even more preferably 450 MPa or more, as determined according to ISO 6892-1:2009. In addition, the continuous cast products of the present invention have a breaking elongation of 25% or more, preferably 30% or more, even more preferably 40% or more, as determined according to ISO 6892-1:2009. For example, the continuous cast products have a breaking elongation in the range of 25% to 65%, for example 35% to 60%, as determined according to ISO 6892-1:2009. Suitably, the Cu-Zn-Si alloy of the present invention and continuous cast products produced therefrom have a tensile strength of at least 380 MPa and an elongation to break in the range of 25% to 65%, preferably the tensile strength is in the range of 380 MPa to 650 MPa, preferably 400 MPa to 600, for example 450 MPa to 600 MPa, and the elongation to break is 25% to 65%, for example 35% to 60%, determined according to ISO 6892-1:2009.

[0125] Example 3

[0087] Composition of: 82.5≦Cu≦84.5 11.5≦Zn≦12.3 3.3≦Si≦3.5 0.1≦Fe≦0.5 0.1≦Mn≦0.2 The Cu-Zn-Si alloy of the present invention has the following structure: 40≦Q≦44, The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, The impurities include 0.06 wt.% or less of Sn and 0.06 wt.% or less of Pb. Rods were gravity die cast from a Cu-Zn-Si alloy. The composition of Example 3 contained 0.010≦Ni≦0.025. The composition of Example 3 did not contain Bi, Ag, or As.

[0126]

[0088] An ingot having the above alloy composition was placed in a furnace capable of smelting and casting. The alloy was heated to a temperature in the range of 1000-1300°C, preferably 1150-1300°C.

[0127]

[0089] In this step, the chemical composition may be monitored and controlled to ensure that the composition is maintained. For example, if some elements (e.g., Zn and P) evaporate or become slag, they must be replaced to maintain the required composition of the present invention. The smelted metal is transported and poured into a holding furnace, and then cast into a die casting. The liquid metal is cooled (e.g., air-cooled or water-cooled) in the die, and upon solidification, the die is opened and the rod is ejected. Advantageously, the Cu-Zn-Si alloy of the present invention has improved tensile strength and elongation properties compared to the Cu-Zn-Si alloys of the prior art. The improved properties increase the ease of processing of the alloy.

[0128]

[0090] The properties of the die castings were evaluated in accordance with ISO 6892-1:2009 on a Hounsfield tensiometer as outlined above for Examples 1 and 2.

[0129]

[0091] The castings had a tensile strength of greater than 380 MPa and an elongation at break of greater than 25%, determined in accordance with ISO 6892-1:2009.

[0130]

[0092] Advantageously, the Cu-Zn-Si alloys of the examples had manganese contents in the range 0.10 < Mn < 0.14. When the amount of manganese is within this preferred range, the alloys of the present invention advantageously have even more improved elongation.

[0131] Advantageously, the Cu-Zn-Si alloy of the examples described herein has a true solid density of 8.18-8.28 Kg / m, measured in accordance with BS ISO 12154. 3BS ISO 12154 defines true solid density as the ratio of the mass of a sample to the volume of the dense solid skeleton of the sample, excluding the volume of open and closed pores or internal voids and also the volume of interparticle voids, as in the case of granular or highly dispersed samples.

[0132] Comparative Example

[0094] Rods were cast from a Cu-Zn-Si alloy having the following composition:

[0133] [Table 3]

[0134]

[0095] CE1 has low tensile strength, even though it contains more than 13 wt% Zn and 0.136 wt% Pb.

[0135]

[0096] CE2 contained less than 11 wt% Zn, more than 4.1 wt% Si and had good tensile strength. However, the alloy was very brittle (see FIG. 7). Therefore, preferably, the CE2 alloy did not have adequate elongation properties.

[0136] CE3 contains more than 4.1 wt% Si and has more than 52 wt% Q. The tensile strength was excellent, but the elongation was not favorable.

[0137] Comparative Example 4 (CE4)

[0098] Composition of: 82≦Cu≦86.5 11.5≦Zn≦12.3 3.6≦Si≦4.1 0.1≦Fe≦0.5 0.1≦Mn≦0.2 The Cu-Zn-Si alloy of the present invention has the following structure: 48≦Q≦51, The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, The impurities include 0.06 wt.% or less of Sn and 0.06 wt.% or less of Pb. Rods were gravity die cast from a Cu-Zn-Si alloy. The composition of Example 3 contained 0.010≦Ni≦0.025. The composition of Example 3 did not contain Bi, Ag, or As.

[0138]

[0099] The properties of the die castings were evaluated in accordance with ISO 6892-1:2009 on a Hounsfield tensiometer as outlined above for Examples 1 and 2.

[0139]

[0100] The Cu-Zn-Si alloy of Comparative Example 4 had a tensile strength of 363.6 MPa and a fracture elongation of 16%. The Cu-Zn-Si alloy of Comparative Example 4 had a Q of about 50.

[0140]

[0101] Figure 5 shows a cross section of the rod cast in Comparative Example 4. Advantageously, the grain is uniform / homogeneous, but the elongation of the rod cast in Comparative Example 4 was 16%. Figure 6 shows the end of the die cast Cu-Zn-Si alloy rod of Comparative Example 4 that was elongated to break in the extensometer.

[0141]

[0102] Thus, the alloy of Comparative Example 4 had good tensile strength, but the elongation to break was less than 25%. Advantageously, Cu-Zn-Si alloys according to the invention having Q in the range of 36 < Q < 48 (preferably 40 < Q < 46 for gravity cast Cu-Zn-Si alloys of the invention, and preferably 38 < Q < 45 for continuously cast Cu-Zn-Si alloys of the invention) have an elongation to break of 25% or more, determined according to ISO 6892-1:2009.

[0142] Example 4

[0103] Rods were continuously cast from the Cu-Zn-Si alloys of the present invention as described in Examples 1 and 2. The Cu-Zn-Si alloy of Example 4 had the following composition: 82.5≦Cu≦84.5 12.5≦Zn≦13.0 2.6≦Si≦2.9 0.1≦Fe≦0.5 0.1≦Mn≦0.15 having 38.5≦Q≦42, The alloy contains unavoidable impurities in an amount of not more than 0.53% by weight, The impurities include up to 0.06 wt. % Sn and up to 0.06 wt. % Pb. The composition of Example 4 contained 0.010≦Ni≦0.025. The composition of Example 1 did not contain Bi, Ag, Te, or As.

[0143]

[0104] A comparison of the mechanical properties of the Cu-Zn-Si alloy of the present invention (Example 4) and C87800 is provided in Table 1.

[0144] [Table 4]

[0145]

[0105] Advantageously, the Cu-Zn-Si alloys of the present invention have greater ductility, in particular greater elongation to break as determined in accordance with ISO 6892-1:2009.

[0146] A comparison of the physical properties of the Cu-Zn-Si of the present invention and C87800 is provided in Table 2.

[0147] [Table 5]

[0148] Advantageously, the alloy of the present invention has a lower density than the prior art alloys. Thus, the alloy of the present invention is a lighter alloy than the prior art alloys, but has similar tensile strength performance and greater elongation properties. Furthermore, the alloy of the present invention is a lighter material, which results in lower distribution costs per cubic meter and is more economical to transport per meter from an environmental standpoint. The alloy of the present invention has a density of 8.0 kg / m 3 ~8.29kg / m 3 , preferably 8.0 to 8.28 kg / m 3 , preferably 8.18 to 8.28 kg / m 3 It is particularly desirable to have a true solid density in the range of 8.30 kg / m. In contrast, the comparative alloys have a true solid density in the range of 8.30 kg / m. 3 It has a true solid density of 1000 or more.

[0149]

[0108] A comparison of the performance of the Cu-Zn-Si of the present invention and C87800 in various manufacturing processes is provided in Table 3.

[0150] [Table 6]

[0151]

[0109] Advantageously, the alloy of the present invention can be processed by each of the above manufacturing processes, whereas the prior art C87800 alloy is not suitable for the sand casting, continuous casting, hot forging and air cooling processes or the hot forging and quenching processes.

[0152]

[0110] When used in this specification with respect to the present invention, the words "comprise" and "have" are used to specify the presence of stated features, integers, steps or components, but do not exclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0153] It will be appreciated that certain features of the invention, which are for clarity described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are for brevity described in the context of a single embodiment, may also be provided separately or in any suitable subcombination.

Claims

1. The following ingredients in weight percent: 11.0≦Zn≦13.0, 2.5≦Si≦3.7, 0.1≦Fe≦0.5, 0.1≦Mn≦0.2 A Cu-Zn-Si alloy consisting of The sum of the weight percentage of Zn [Zn] and 10 times the weight percentage of Si [Si] is the total weight percentage Q, where Q = [Zn] + (10 × [Si]), 36≦Q≦48, the Cu—Zn—Si alloy contains, by weight percent, 0.05% or less of Ni; the Cu—Zn—Si alloy contains 0.2 wt % or less of Al; the Cu—Zn—Si alloy contains 0.03 wt % or less of P; the alloy contains unavoidable impurities in an amount of not more than 0.53 wt.%, the impurities including not more than 0.2 wt.% Sn and not more than 0.06 wt.% Pb; The remainder is copper, The Cu—Zn—Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 300 MPa or greater; and The alloy is a Cu—Zn—Si alloy having an elongation at break of 30% or greater, determined in accordance with ISO 6892-1:2009.

2. The Cu—Zn—Si alloy contains, in weight percent: 2.5≦Si≦3.5 The Cu—Zn—Si alloy of claim 1 , comprising:

3. 3. The Cu—Zn—Si alloy of claim 2, wherein 2.5≦Si≦3.2 and 36≦Q≦47.

4. The Cu-Zn-Si alloy of claim 2, wherein 2.5≦Si≦3.2 and 38≦Q≦45.

5. 3. The Cu—Zn—Si alloy of claim 2, wherein 2.7≦Si≦3.5 and 37≦Q≦48.

6. The Cu-Zn-Si alloy of claim 2, wherein 2.7≦Si≦3.5 and 40≦Q≦46.

7. 2. The Cu—Zn—Si alloy of claim 1, wherein 11.5≦Zn≦13.

0.

8. The Cu-Zn-Si alloy of claim 1, wherein 12.0≦Zn≦13.

0.

9. The Cu—Zn—Si alloy according to claim 1, wherein the Cu—Zn—Si alloy does not contain As and / or Sb.

10. The Cu-Zn-Si alloy of claim 1, wherein the Cu-Zn-Si alloy has a tensile strength of 400 MPa or greater, determined in accordance with ISO 6892-1:2009.

11. Use of the Cu-Zn-Si alloy according to claim 1 in the manufacture of components for drinking water pipes.

12. The alloy has a compressive strength of 8.0 kg / m, measured in accordance with BS ISO 12154. ３ ~8.29 kg / m ３ 12. The use according to claim 11, having a density in the range of 13. The use of claim 11, wherein the alloy has a density in the range of 8.18 to 8.28 kg / m 3 , measured in accordance with BS ISO 12154.

14. 1. A method for manufacturing components for drinking water pipes, namely valves and fittings for drinking water pipes, comprising the steps of: (i) providing a Cu—Zn—Si alloy according to claim 1; (ii) processing the alloy to form the component; A method comprising:

15. 15. The method of claim 14, wherein step (ii) comprises continuous casting the alloy, and / or step (ii) comprises one or more metal forming steps.

16. 15. The method of claim 14, wherein step (ii) comprises gravity casting the alloy.

17. The method of claim 16, wherein step (ii) comprises sand casting or die casting the alloy.

18. The method of claim 14 , wherein step (ii) comprises one or more metal forming steps.

19. The method of claim 18, wherein step (ii) comprises forging or rolling the alloy.

20. The method of claim 14 , wherein step (ii) further comprises one or more machining steps.

21. 15. The method of claim 14, wherein the Cu—Zn—Si alloy has a tensile strength, determined according to ISO 6892-1:2009, of 350 MPa or greater.

22. The Cu—Zn—Si alloy has a compressive strength of 8.0 kg / m as measured in accordance with BS ISO 12154. ３ ~8.29 kg / m ３ The method of claim 14, having a density in the range of 23. A plumbing fixture comprising the Cu-Zn-Si alloy of claim 1.

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