EP1559802B1

EP1559802B1 - Lead-free, free-cutting copper alloys

Info

Publication number: EP1559802B1
Application number: EP05075421.7A
Authority: EP
Inventors: Keiichiro Sambo Copper Alloy Co. Ltd OISHI
Original assignee: Mitsubishi Shindoh Co Ltd
Current assignee: Mitsubishi Shindoh Co Ltd
Priority date: 1998-10-12
Filing date: 1998-11-16
Publication date: 2014-01-15
Anticipated expiration: 2018-11-16
Also published as: EP1600517A3; KR100352213B1; EP1045041A1; DE69839830D1; DE69840585D1; EP1600517B1; EP1600515B1; EP1600516A2; CA2314144A1; KR20010033073A; WO2000022182A1; DE69838115T2; EP1600515A2; EP1600517A2; DE69832097T2; CA2314144C; AU744335B2; JP2000119775A; EP1559802A1; JP3734372B2

Description

Field of The Invention

The present invention relates to lead-free, free- cutting copper alloys.

Prior Art

Among the copper alloys with a good machinability are bronze alloys such as the one under JIS designation H5111 BC6 and brass alloys such as the ones under JIS designations H3250-C3604 and C3771. Those alloys are enhanced in machinability by the addition of 1.0 to 6.0 wt% of lead and provide an industrially satisfactory machinability. Because of their excellent machinability, those lead-contained copper alloys have been an important basic material for a variety of articles such as city water faucets, water supply/drainage metal fittings and valves.
However, the application of those lead-mixed alloys has been greatly limited in recent years, because lead contained therein is an environment pollutant harmful to humans. That is, the lead-containing alloys pose a threat to human health and environmental hygiene because lead is contained in metallic vapor that is generated in the steps of processing those alloys at high temperatures such as melting and casting and there is also concern that lead contained in the water system metal fittings, valves and others made of those alloys will dissolve out into drinking water.
On that ground, the United States and other advanced countries have been moving to tighten the standards for lead-contained copper alloys to drastically limit the permissible level of lead in copper alloys in recent years. In Japan, too, the use of lead-contained alloys has been increasingly restricted, and there has been a growing call for development of free-cutting copper alloys with a low lead content.
DE 1558470 discloses copper zinc alloys with 0.5 to 2.5% silicon which are suitable for forming guides for valves in combustion engines.
US 3,900,349 discloses corrosion-resistant silicon brasses which are quenched from a high annealing temperature to form an alpha plus zeta microstructure.

Summary or the invention

It is an object of the present invention to provide a lead-free copper alloy which does not contain the machinability-improving element lead yet is quite excellent in machinability and can be used as safe substitute for the conventional free cutting copper alloy with a large content of lead presenting environmental hygienic problems and which permits recycling of chips without problems, thus a timely answer to the mounting call for restriction of lead-contained products.
It is an another object of the present invention to provide a lead-free copper alloy which has a high corrosion resistance as well as an excellent machinability and Is suitable as basic material for cutting works, forgings, castings and others, thus having a very high practical value. The cutting works, forgings, castings and others include city water faucets, water supply/drainage metal fittings, valves, stems, hot water supply pipe fittings, shaft and heat exchanger parts.
It is yet another object of the present invention to provide a lead-free copper alloy with a high strength as well as machinability which is suitable as basic material for the manufacture of cutting works, forgings, castings and other uses requiring a high strength and wear resistance such as, for example, bearings, bolts, nuts, bushes, gears, sewing machine parts and hydraulic system parts, hence has a very high practical value.
It is a further object of the present invention to provide a lead-free copper alloy with an excellent high-temperature oxidation resistance as well as machinability which is suitable as basic material for the manufacture of cutting works, forgings, castings and other uses where a high thermal oxidation resistance is essential, e.g. nozzles for kerosene oil and gas heaters, burner heads and gas nozzles for hot-water dispensers, hence has a very high practical value.
According to this invention, there is provided lead-free copper alloys in accordance with claim 1. Silicon in an amount of 2.0 to 4.0 percent, is an additive to a lead-free copper alloy composition which comprises 69 to 79 wt% copper and the remaining wt% zinc, to improve the machinability of the alloy by producing in the metal structure γ (gamma) phase, as set out in claim 1 hereinafter. The invention is carried out in the manufacture of the following alloys:

1. A lead-free, free-cutting copper alloy with excellent machinability is composed of 69 to 79 wt% of copper, 2.0 to 4.0 wt% of silicon, and the remaining wt% of zinc. For purpose of simplicity, this copper alloy will be hereinafter called the "first alloy."
Lead forms no solid solution in the matrix but disperses in a granular form to improve the machinability. Silicon raises the easy-to-cut property by producing a gamma phase (in some cases, a kappa phase) in the structure of metal. That way, both are common in that they are effective in improving the machinability, though they are quite different in contribution to the properties of the alloy. On the basis of that recognition, silicon is added to the first alloy in place of lead so as to bring about a high level of machinability meeting the industrial requirements. That is, the first alloy is improved in machinability through formation of a gamma phase, with the addition of silicon.
The addition of less than 2.0 percent, by weight, of silicon cannot form a gamma phase sufficient to secure an industrially satisfactory machinability. With the increase in the addition of silicon, the machinability improves. But with the addition of more than 4.0 wt% of silicon, the machinability will not go up in proportion. The problem is, however, that silicon has a high melting point and a low specific gravity and is also liable to oxidize. If silicon alone is fed in the form of a simple substance into a furnace in the alloy melting step, then silicon will float on the molten metal and is oxidized into oxides of silicon or silicon oxide, hampering production of a silicon-contained copper alloy. In making an ingot of silicon-containing copper alloy, therefore, silicon Is usually added In the form of a Cu-Si alloy, which boosts the production cost. In the light of the cost of making the alloy, too, it is not desirable to add silicon in a quantity exceeding the saturation point where machinability improvement levels off - 4.0 wt%wt%. An experiment showed that when silicon is added in an amount of 2.0 to 4.0 wt%, it is desirable to hold the content of copper at 69 to 79 wt% in consideration of its relation to the content of zinc in order to maintain the intrinsic properties of the Cu-Zn alloy. For this reason, the first alloy Is composed of 69 to 79 wt%, of copper and 2.0 to 4.0 wt% of silicon. The addition of silicon improves not only the machinability but also the flow of the molten metal in casting, strength, wear resistance, resistance to stress corrosion cracking, high-temperature oxidation resistance. Also, the ductility and dezincification resistance will be improved to some extent.
2. Another lead-free, free-cutting copper alloy also with an excellent machinability feature is composed of 69 to 79 wt% of copper; 2.0 to 4.0 wt% of silicon; at least one element selected from among 0.02 to 0.4 wt% of bismuth, 0.02 to 0.4 wt% of tellurium, and 0.02 to 0.4 wt% of selenium; and the remaining wt% of zinc. This second copper alloy will be hereinafter called the "second alloy."
That is, the second alloy is composed of the first alloy and at least one element selected from among 0.02 to 0.4 wt% of bismuth, 0.02 to 0.4 wt% of tellurium, and 0.02 to 0.4 wt% of selenium.
Bismuth, tellurium and selenium as well as lead do not form a solid solution in the matrix but disperse in granular form to enhance the machinability and that through a mechanism different from that of silicon. Hence, the addition of those elements along with silicon could further improve the machinability beyond the level obtained by the addition of silicon alone. From this finding, the second alloy Is provided In which at least one element selected from bismuth, tellurium and selenium is mixed to Improve further the machinability obtained by the first alloy. The addition of bismuth, tellurium or selenium in addition to silicon produces a high machinability such that complicated forms could be freely cut at a high speed. But no improvement in machinability can be realized from the addition of bismuth, tellurium or selenium In an amount less than 0.02 percent, by weight. Meanwhile, those elements are expensive as compared with copper. Even if the addition exceeds 0.4 wt%, the proportional improvement in machinability is so small that the addition beyond that does not pay economically. What is more, if the addition is more than 0.4 wt%, the alloy will deteriorate in hot workability such as forgeability and cold workability such as ductility. While it might be feared that heavy metals like bismuth would cause problems similar to those of lead, an addition in a very small amount of less than 0.4 wt% is negligible and would present no particular problems. From those considerations, the second alloy is prepared with the addition of bismuth, tellurium or selenium kept to 0.02 to 0.4 wt%. The addition of those elements, which work on the machinability of the copper alloy though a mechanism different from that of silicon as mentioned above, would not affect the proper contents of copper and silicon. On this ground, the contents of copper and silicon in the second alloy are set at the same level as those in the first alloy.
5. A further lead-free, free-cutting copper alloy with an excellent machinability and with a high corrosion resistance which is composed of 69 to 79 wt% of copper; 2.0 to 4.0 wt% of silicon; at least one element selected from among 0.02 to 0.25 wt% of phosphorus, 0.02 to 0.15 wt% of antimony, and 0.02 to 0.15 wt% of arsenic, and the remaining wt% of zinc. This fifth copper alloy will be hereinafter called the "fifth alloy".
The fifth alloy thus contains at least one element selected from among 0.02 to 0.25 wt% of phosphorus, 0.02 to 0.15 wt% of antimony, and 0.02 to 0.15 wt% of arsenic in addition to the first alloy. The fifth alloy is thus improved in machinability mainly by adding silicon. Therefore, the contents of silicon and copper in this alloy are set at the same as those in the first alloy.
As described above, phosphorus disperses the gamma phase uniformly and at the same time refines the crystal grains in the alpha phase in the matrix, thereby improving the machinability and also the corrosion resistance properties (dezincification resistance and erosion corrosion resistance), forgeability, stress corrosion cracking resistance and mechanical strength. The fifth alloy is thus improved in corrosion resistance and others by such properties of phosphorus and In machinability mainly by adding silicon. The addition of phosphorus in a very small quantity, that is, 0.02 or more wt% could produce results. But the addition in an amount of more than 0.25 wt% would not produce proportional results. Instead, that would reduce the hot forgeability and extrudability.
Just as with phosphorus, antimony and arsenic In a very small quantity - 0.02 or more wt% - are effective in improving the dezincification resistance and other properties. But the addition exceeding 0.15 wt% would not produce results in proportion to the quantity mixed. Instead, it would lower the hot forgeability and extrudability as phosphorus applied in excessive amounts.
Those observations indicate that the fifth alloy is improved in machinability and also corrosion resistance and other properties by adding at least one element selected from among phosphorus, antimony and arsenic in quantities within the aforesaid limits in addition to the same quantities of copper and silicon as in the first invention copper alloy. In the fifth alloy, the additions of copper and silicon are set at 69 to 79 wt% and 2.0 to 4.0 wt% respectively - the same level as In the first alloy in which any other machinability improverthan silicon is not added - because phosphorus works mainly as a corrosion resistance improver like antimony and arsenic.
6. A still further lead-free free-cutting copper alloy also with an excellent machinability and with a high corrosion resistance is composed of 69 to 79 wt% of copper; 2.0 to 4.0 wt% of silicon; at least one element selected from among 0.3 to 3.5 wt% of tin, 0.02 to 0.25 wt% of phosphorus, 0.02 to 0.15 percent, by weight, of antimony, and 0.02 to 0.15 percent, by weight, of arsenic; at least one element selected from among 0.02 to 0.4 wt% of bismuth, 0.02 to 0.4 wt% of tellurium, and 0.02 to 0.4 wt% of selenium; and the remaining wt% of zinc. This sixth copper alloy will be hereinafter called the "sixth alloy".
The sixth alloy thus contains at least one element selected from among 0.02 to 0.4 percent, by weight, of bismuth, 0.02 to 0.4 wt% of tellurium, and 0.02 to 0.4 wt% of selenium in addition to the components in the fifth alloy. The machinability is improved by adding silicon and at least one element selected from among bismuth, tellurium and selenium as in the second alloy and the corrosion resistance and other properties are raised by using at least one selected from among tin, phosphorus, antimony and arsenic as in the fifth alloy. Therefore, the additions of copper, silicon, bismuth, tellurium and selenium are set at the same levels as those in the second alloy, while the contents of tin, phosphorus, antimony and arsenic are adjusted to those in the fifth alloy.
9. A yet further lead-free, free-cutting copper alloy also with excellent machinability coupled with a good high-temperature oxidation resistance is composed of 69 to 79 wt% of copper; 2.0 to 4.0 wt% of silicon; 0.1 to 1.5 wt% of aluminum; 0.02 to 0.25 wt% of phosphorus; and the remaining wt% of zinc. The ninth copper alloy will be hereinafter called the "ninth alloy".
Aluminum is an element which improves the strength, machinability, wear resistance and also high-temperature oxidation resistance. Silicon, too, has a property of enhancing the machinability, strength, wear resistance, resistance to stress corrosion cracking and also high-temperature oxidation resistance, as mentioned above. Aluminum works to raise the high-temperature oxidation resistance when aluminium is added in an amount not less than 0.1 wt% together with silicon. But even if the addition of aluminum Increases beyond 1.5 wt%, no proportional results can be expected. For this reason, the addition of aluminum is set at 0.1 to 1.5 wt%.
Phosphorus is added to enhance the flow of molten metal in casting. Phosphorus also works for improvement of the aforesaid machinability, dezincification resistance and also high-temperature oxidation resistance in addition to the flow of molten metal. Those effects are exhibited when phosphorus is added in an amount not less than 0.02 wt%. But even if phosphorus is used in more than 0.25 wt%, it will not result in a proportional increase in effect. For this consideration, the addition of phosphorus settles down on 0.02 to 0.25 wt%.
While silicon is added to improve the machinability as mentioned above, it is also capable of increasing the flow of molten metal like phosphorus. The effect of silicon in raising the flow of molten metal is exhibited when it is added in an amount not less than 2.0 wt%. The range of the addition of silicon for improving the flow of molten metal overlaps that for improvement of the machinability. These taken Into consideration, the addition of silicon Is set to 2.0 to 4.0 wt%.
10. Another further lead-free, free-cutting copper alloy also with excellent machinability and a good high-temperature oxidation resistance is composed of 69 to 79 wt% of copper; 2.0 to 4.0 percent, by weight, of silicon; 0.1 to 1.5 wt% of aluminum; 0.02 to 0.25 wt% of phosphorus; at least one element selected from among 0.02 to 0.4 wt% of chromium and 0.02 to 0.4 wt% of titanium; and the remaining wt% of zinc. The tenth copper alloy will be hereinafter called the "tenth alloy".
Chromium and titanium are added for improving the high-temperature oxidation resistance. Good results can be expected especially when they are added together with aluminum to produce a synergistic effect. Those effects are exhibited when the addition is 0.02 percent or more by weight, whether they are used alone or in combination. The saturation point is 0.4 wt%. In consideration of such observations, the tenth alloy contains at least one element selected from among 0.02 to 0.4 wt% of chromium and 0.02 to 0.4 wt% of titanium in addition to the components of the ninth alloy and is an improvement over the ninth alloy with regard to the high-temperature oxidation resistance.
11. A yet still further lead-free, free-cutting copper alloy also with excellent machinability and a good high-temperature oxidation resistance is composed of 69 to 79 wt% of copper, 2.0 to 4.0 wt% of silicon; 0.1 to 1.5 wt% of aluminum; 0.02 to 0.25 wt% of phosphorus; at least one element selected from among 0.02 to 0.4 wt% of bismuth, 0.02 to 0.4 wt% of tellurium and 0.02 to 0.4 wt% of selenium; and the remaining wt% of zinc. The eleventh copper alloy will be hereinafter called the "eleventh alloy".
The eleventh alloy contains at least one element selected from among 0.02 to 0.4 wt% of bismuth, 0.02 to 0.4 wt% of tellurium an 0.02 to 0.4 wt% of selenium in addition to the components of the ninth alloy. While as high a high-temperature oxidation resistance as in the ninth alloy is secured, the eleventh alloy is further improved in machinability by adding at least one element selected from among bismuth and other elements which are effective in raising the machinability through a mechanism other than that exhibited by silicon.
12. In An additional further lead-free, free-cutting copper alloy also with excellent machinability and a good high-temperature oxidation resistance is composed of 69 to 79 wt% of copper; 2.0 to 4.0 wt% of silicon; 0.1 to 1.5 wt% of aluminum; 0.02 to 0.25 wt% of phosphorus; at least one element selected from among 0.02 to 0.4 wt% of chromium, and 0.02 to 0.4 wt% of titanium; at least one element selected from among 0.02 to 0.4 wt% of bismuth, 0.02 to 0.4 wt% of tellurium and 0.02 to 0.4 wt% of selenium; and the remaining wt% of zinc. The twelfth copper alloy will be hereinafter called the "twelfth alloy".
The twelfth alloy contains at least one element selected from among 0.02 to 0.4 percent, by weight, of bismuth, 0.02 to 0.4 wt% of tellurium and 0.02 to 0.4 wt% of selenium in addition to the components of the tenth alloy. While as high a high-temperature oxidation resistance as in the tenth alloy is secured, the twelfth alloy is further improved in machinability by adding at least one element selected from among bismuth and other elements which are effective in raising the machinability through a mechanism other than that exhibited by silicon.
13. Yet another further lead-free, free-cutting copper alloy also with further improved machinability Is obtained by subjecting any one of the preceding alloys to a heat treatment for 30 minutes to 5 hours at 400°C to 600° C. The thirteenth copper alloy will be hereinafter called the "thirteenth alloy".

The alloys listed above contain machinability improving elements such as silicon and have an excellent machinability because of the addition of such elements. Of those alloys, the alloys with a high copper content which have great amounts of other phases, mainly kappa phase, than alpha, beta, gamma and delta phases can further improve In machinability in a heat treatment. In the heat treatment, the kappa phase turns to a gamma phase. The gamma phase finely disperses and precipitates to further enhance the machinability. The alloys with a high content of copper are high in ductility of the matrix and low in absolute quantity of gamma phase, and therefore are excellent in cold workability. But in case cold working such as caulking and cutting are required, the aforesaid heat treatment is very useful. In other words, among the first to twelfth alloys, those which are high in copper content with gamma phase in small quantities and kappa phase in large quantities (hereinafter referred to as the "high copper content alloy") undergo a change in phase from the kappa phase to the gamma phase in a heat treatment. As a result, the gamma phase is finely dispersed and precipitated, and the machinability is improved. In the manufacturing process of castings, expanded metals and hot forgings in practice, the materials are often force-alr-cooled or water cooled depending on the forging conditions, productivity after hot working (hot extrusion, hot forging etc.), working environment and other factors. In such cases, among the first to twelfth alloys, those with a low content of copper (hereinafter called the low copper content alloy") are rather low in the content of the gamma phase and contain beta phase. In a heat treatment, the beta phase changes into gamma phase, and the gamma phase Is finely dispersed and precipitated, whereby the machinability is improved. Experiments showed that heat treatment is especially effective with high copper content alloys where mixing ratio of copper and silicon to other added elements (except for zinc) A is given as 67 ≤ Cu - 3Si + aA or low copper content alloys with such a composition with 64 ≥ Cu - 3Si + aA. It is noted that a is a coefficient. The coefficient is different depending on the added element A. For example, with tin a Is - 0.5; aluminum, -2; phosphorus, -3; antimony, 0; arsenic, 0; manganese, +2.5; and nickel, +2.5.
But a heat treatment temperature at less than 400°C is not economical and practical, because the aforesaid phase change will proceed slowly and much time will be needed. At temperatures over 600°C, on the other hand, the kappa phase will grow or the beta phase will appear, bringing about no improvement in machinability. From the practical viewpoint, therefore, it is desired to perform the heat treatment for 30 minutes to 5 hours at 400 to 600°C.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1 shows perspective views of cuttings formed in cutting a round bar of copper alloy by lathe.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Example 1

As the first series of examples of the present invention, cylindrical ingots with compositions given in Tables 1 to 35, each 100 mm in outside diameter and 150 mm in length, were hot extruded into a round bar 15 mm in outside diameter at 750°C to produce the following test pieces: first alloys Nos. 1001 to 1008, second alloys Nos. 2001 to 2011, fifth alloys Nos. 5001 to 5020, sixth alloys Nos. 6001 to 6105, ninth alloys Nos. 9001 to 9005, tenth alloys Nos. 10001 to 10008, eleventh alloys Nos. 11001 to 11007, and twelfth alloys Nos. 12001 to 12021. Also, cylindrical ingots with the compositions given in Table 36, each 100 mm in outside diameter and 150 mm in length, were hot extruded into a round bar 15 mm in outside diameter at 750°C to produce the following test pieces: thirteenth alloys Nos. 13001 to 13006. That is, No. 13001 is an alloy test piece obtained by heat-treating an extruded test piece with the same composition as first alloy No. 1005 for 30 minutes at 580°C. No. 13002 is an alloy test piece obtained by heat-treating an extruded test piece with the same composition as No. 13001 for two hours at 450°C. No. 13003 is an alloy test piece obtained by heat-treating an extruded test piece with the same composition as first alloy No. 1007 under the same conditions as for No. 13001 - for 30 minutes at 580°C. No. 13004 is an alloy test piece obtained by heat-treating an extruded test piece with the same composition as No. 13007 under the same conditions as for 13002 - for two hours at 450°C. No. 13005 is an alloy test piece obtained by heat-treating an extruded test piece with the same composition as first alloy No. 1008 under the same conditions as for No. 13001 - for 30 minutes at 580°C. No. 13006 is an alloy test piece obtained by heat-treating an extruded test piece with the same composition as No. 1008 and heat-treated under the same conditions as for 13002 - for two hours at 450°C.
As comparative examples, cylindrical ingots with the compositions as shown in Table 37, each 100 mm in outside diameter and 150 mm In length, were hot extruded into a round bar 15 mm in outside diameter at 750°C to obtain the following round extruded test pieces: Nos. 14001 to 14006 (hereinafter referred to as the "conventional alloys"). No. 14001 corresponds to the alloy "JIS C 3604," No. 14002 to the alloy "CDA C 36000," No. 14003 to the alloy "JIS C 3771" and No. 14004 to the alloy "CDA C 69800." No. 14005 corresponds to the alloy "JIS C 6191." This aluminum bronze is the most excellent of the expanded copper alloys under the JIS designations with regard to strength and wear resistance. No. 14006 corresponds to the naval brass alloy "JIS C 4622" and is the most excellent of the expanded copper alloys under the JIS designations with regard to corrosion resistance. To study the machinability of the first to thirteenth alloys in comparison with the conventional alloys, cutting tests were carried out. In the tests, evaluations were made on the basis of cutting force, condition of chips cut surface condition.
The tests were conducted this way: The extruded test pieces obtained, as mentioned above, were cut on the circumferential surface by a lathe mounted with a point noise straight tool at a rake angle of - 8 degrees and at a cutting rate of 50 meters/minute, a cutting depth of 1.5 mm, a feed of 0.11 mm/rev. Signals from a three-component dynamometer mounted on the tool were converted into electric voltage signals and recorded on a recorder. From the signals were then calculated the cutting resistance. It Is noted that while, to be perfectly exact, an amount of the cutting resistance should be judged by three component forces - cutting force, feed force and thrust force, the judgement was made on the basis of the cutting force (N) of the three component forces in the present example. The results are shown in Table 38 to Table 66.
Furthermore, the chips from the cutting work were examined and classified into four forms (A) to (D) as shown in Fig. 1. The results are enumerated in Table 38 to Table 66. in this regard, the chips in the form of a spiral with three or more windings as (D) in Fig. 1 are difficult to process, that is, recover or recycle, and could cause trouble in cutting work as, for example, getting tangled with the tool and damaging the cut metal surface. Chips In the form of an arc with a half winding to a spiral with two about windings as shown in (C), Fig. 1 do not cause such serous trouble as the chips in the form of a spiral with three or more windings yet are not easy to remove and could get tangled with the tool or damage the cut metal surface. In contrast, chips in the form of a fine needle as (A) in Fig. 1 or in the form of an arc as (B) will not present such problems as mentioned above and are not bulky as the chips in (C) and (D) and easy to process. But fine chips as (A) still could creep into the sliding surfaces of a machine tool such as a lathe and cause mechanical trouble, or could be dangerous because they could stick into the worker's finger, eye or other body parts. Those taken into account, it is appropriate to consider that the chips in (B) are the best, and the second best are the chips in (A). Those in (C) and (D) are not good. In Table 38 to Table 66, the chips judged to be shown in (B), (A), (C) and (D) are indicated by the symbols "
", "○", '_" and "x" respectively.
In addition, the surface condition of the cut metal surface was checked after cutting work. The results are shown in Table 38 to Table 66. In this regard, the commonly used basis for indication of the surface roughness is the maximum roughness (Rmax). While requirements are different depending on the application field of brass articles, the alloys with Rmax < 10 microns are generally considered excellent in machinability. The alloys with 10 microns ≤Rmax < 15 microns are judged as industrially acceptable, while those with Rmax ≥ 15 microns are taken as poor in machinability. In Table 38 to Table 65, the alloys with Rmax < 10 microns are marked "o", those with 10 microns ≤ Rmax < 15 microns are indicated as "_" and those with Rmax ≥ 15 microns are represented by a symbol "x".
As is evident from the results of the cutting tests shown in Table 38 to Table 66, the following alloys are all equal to the conventional lead- contained alloys Nos. 14001 to 14003 in machinability: first alloys Nos. 1001 to 1008, second alloys Nos. 2001 to 2011, fifth alloys Nos. 5001 to 5020, sixth alloys Nos. 6001 to 6105, ninth alloys Nos. 9001 to 9005, tenth alloys Nos. 10001 to 10008, eleventh alloys Nos. 11001 to 11007, twelfth alloys Nos. 12001 to 12021. Especially with regard to formation of the chips, those alloys are favourably compared not only with the conventional alloys Nos. 14004 to 14006 with a lead content of not higher than 0.1 wt% but also Nos. 14001 to 14003 which contain large quantities of lead.
Also to be noted is that as is clear from Tables Nos. 38 to 65, thirteenth alloys Nos. 13001 to 13006 are improved over first alloy No. 1005, No. 1007 and No. 1008 with the same composition as the thirteenth alloys in machinability. It is thus confirmed that a proper heat treatment could further enhance the machinability.
In another series of tests, the first to thirteenth alloys were examined in comparison with the conventional alloys In hot workability and mechanical properties. For the purpose, hot compression and tensile tests were conducted the following way.
First, two test pieces, first and second test pieces, in the same shape 15 mm in outside diameter and 25 mm in length were cut out of each extruded test piece obtained as described above. In the hot compression tests, the first test piece was held for 30 minutes at 700°C, and then compressed 70 percent in the direction of axis to reduce the length from 25 mm to 7.5 mm. The surface condition after the compression (700°C deformability) was visually evaluated. The results are given in Table 38 to Table 66. The evaluation of deformability was made by visually checking for cracks on the side of the test piece. In Table 38 to Table 66, the test pieces with no cracks found are marked "o", those with small cracks are indicated in "_" and those with large cracks are represented by a symbol "x".
The second test pieces were put to a tensile test by the commonly practised test method to determine the tensile strength, N/mm² and elongation, %.
As the test results of the hot compression and tensile tests in Table 38 to Table 66 indicate, it was confirmed that the first to thirteenth alloys are equal to or superior to the conventional alloys Nos. 14001 to 14004 and No. 14006 in hot workability and mechanical properties and are suitable for industrial use. The seventh and eighth alloys in particular have the same level of mechanical properties as the conventional alloy No. 14005, the aluminum bronze which is the most excellent in strength of the expanded copper alloys under the JIS designations, and thus have understandably a prominent high strength feature.
Furthermore, the first second, fifth, six and ninth to thirteenth alloys were put to dezincification and stress corrosion cracking tests in accordance with the test methods specified under "ISO 6509" and "JIS H 3250" respectively to examine the corrosion resistance and resistance to stress corrosion cracking in comparison with the conventional alloys.
In the dezincification test by the "ISO 6509" method, a sample taken from each extruded test piece was imbedded in a phenolic resin material in such a way that part of the side surface of the sample is exposed, the exposed surface perpendicular to the extrusion direction of the extruded test piece. The surface of the example was polished with emery paper No. 1200, and then ultrasonic-washed in pure water and dried. The sample thus prepared was dipped in a 12.7 g/l aqueous solution of cupric chloride dihydrate (CuCl₂.2H₂O) 1.0% and left standing for 24 hours at 75°C. The sample was taken out of the aqueous solution and the maximum depth of dezincification was determined. The measurements of the maximum dezincification depth are given in Table 38 to Table 50 and Table 61 to Table 66.
As is clear from the results of dezincification tests shown in Table 38 to Table 50 and Table 61 to Table 66, the first and second alloys and the ninth to thirteenth alloys are excellent in corrosion resistance and favourablycomparable with the conventional alloys Nos.14001 to 14003 containing great amounts of lead. And it was confirmed that especially the fifth and sixth alloys which seek improvement in both machinability and corrosion resistance are very high in corrosion resistance and superior in corrosion resistance to the conventional alloy No. 14006, a naval brass which is the most resistant to corrosion of all the expanded alloys under the JIS designations.
In the stress corrosion cracking tests in accordance with the test method described in "JIS H 3250," a 150-mm-long sample was cut out from each extruded test piece. The sample was bent with its centre placed on an arc-shaped tester with a radius of 40 mm in such a way that one end and the other end subtend an angle of 45 degrees. The test sample thus subjected to a tensile residual stress was degreased and dried, and then placed in an ammonia environment in the desiccator with a 2.5% aqueous ammonia (ammonia diluted in the equivalent of pure water). To be exact, the test sample was held some 80 mm above the surface of aqueous ammonia in the desiccator. After the test sample was left standing in the ammonia environment for two hours, 8 hours and 24 hours, the test sample was taken out from the desiccator, washed in sulfuric acid solution 10% and examined for cracks under a magnifier of 10 magnifications. The results are given in Table 38 to Table 50 and Table 61 to Table 66. In those tables, the alloys which have developed clear cracks when held in the ammonia environment for two hours are marked "xx." The test samples which had no cracks at passage of two hours but were found to have clear cracks at 8 hours are indicated by "x." The test samples which had no cracks at 8 hours, but were found to have clear cracks at 24 hours were indicated by "_". The test samples which were found to have no cracks at all at 24 hours are given a symbol "o."
As is indicated by the results of the stress corrosion cracking test given in Table 38 to Table 50 and Table 61 to Table 66, it was confirmed that not only the fifth and sixth alloys which seek improvement in both machinability and corrosion resistance but also the first and second alloys and the ninth and thirteenth alloys In which nothing particular was done to improve corrosion resistance were both equal to the conventional alloy No. 14005, an aluminum bronze containing no zinc, in stress corrosion cracking resistance and were superior in stress corrosion cracking resistance to the conventional naval brass alloy No. 14006, the one which has a highest corrosion resistance of all the expanded copper alloys under the JIS designations.
In addition, oxidation tests were carried out to study the high-temperature oxidation resistance of the ninth to twelfth alloys in comparison with the conventional alloys.
A test piece in the shape of a round bar with the surface cut to a outside diameter of 14 mm and the length cut to 30 mm was prepared from each of the following extruded test pieces: No. 9001 to No. 9005, No. 10001 to No. 10008, No. 11001 to No. 11007, No. 12001 to No. 12021 and No. 14001 to No. 14006. Each test piece was then weighed to measure the weight before oxidation. After that, the test piece was placed In a porcelain crucible and held in an electric furnace maintained at 500°C. At passage of 100 hours, the test piece was taken out of the electric furnace and weighed to measure the weight after oxidation. From the measurements before and after oxidation was calculated the increase In weight by oxidation. It is understood that the increase by oxidation is an amount, mg, of increase in weight by oxidation per 10cm² of the surface area of the test piece and is calculated by the equation: increase In weight by oxidation, mg/10cm² = (weight, mg, after oxidation - weight, mg, before oxidation) x (10cm² / surface area, cm², of test piece). The weight of each test piece increased after oxidation. The increase was brought about by high-temperature oxidation. Subjected to a high temperature, oxygen combines with copper, zinc and silicon to form Cu₂O, ZnO, SiO₂. That Is, oxygen increase contributes to the weight gain. It can be said, therefore, that the alloys which are the smaller in weight increase by oxidation are the more excellent in high-temperature oxidation resistance. The results obtained are shown In Table 61 to Table 64 and Table 66.

As is evident from the test results shown in Table 61 to Table 64 and Table 66, the ninth to twelfth alloys are equal to the conventional alloy No. 14005, an aluminum bronze ranking high in resistance to high-temperature oxidation among the expanded copper alloys under the JIS designations and are far smaller than any other conventional copper alloy. Thus, it was confirmed that the ninth to twelfth alloys are very excellent in machinability and resistance to high-temperature oxidation as well.

[Table 1]

No.	alloy composition (wt%)
No.	Cu	Si	Zn
1001	70.2	2.1	remainder
1002	74.1	2.9	remainder
1003	74.8	3.1	remainder
1004	77.6	3.7	remainder
1005	78.5	3.2	remainder
1006	73.3	2.4	remainder
1007	77.0	2.9	remainder
1008	69.9	2.3	remainder

[Table 2]

No.	alloy composition (wt%)
No.	Cu	Si	Bi	Te	Se	Zn
2001	74.5	2.9	0.05			remainder
2002	74.8	2.8		0.25		remainder
2003	75.0	2.9			0.13	remainder
2004	69.9	2.1	0.32	0.03		remainder
2005	72.4	2.3	0.11		0.31	remainder
2006	78.2	3.4		0.14	0.03	remainder
2007	76.2	2.9	0.03	0.05	0.12	remainder
2008	78.2	3.7	0.33			remainder
2009	73.0	2.4	0.16			remainder
2010	74.7	2.8	0.04	0.30		remainder
2011	76.3	3.0	0.18	0.12		remainder

[Table 7]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	P	Sb	As	Zn
5001	69.9	2.1	3.3				remainder
5002	74.1	2.7		0.21			remainder
5003	75.8	2.4			0.14		remainder
5004	77.3	3.4				0.05	remainder
5005	73.4	2.4	2.1	0.04			remainder
5006	75.3	2.7	0.4		0.04		remainder
5007	70.9	2.2	2.4			0.07	remainder
5008	71.2	2.6	1.1	0.03	0.03		remainder
5009	77.3	2.9	0.7	0.19		0.03	remainder
5010	78.2	3.1	0.4		0.09	0.15	remainder
5011	72.5	2.1	2.8	0.02	0.10	0.03	remainder
5012	79.0	3.3		0.24	0.02		remainder
5013	75.6	2.9		0.07		0.14	remainder
5014	74.8	3.0			0.11	0.02	remainder
5015	74.3	2.8		0.06	0.02	0.03	remainder
5016	72.9	2.5		0.03			remainder
5017	77.0	3.4		0.14			remainder
5018	76.8	3.2	0.7	0.12			remainder
5019	74.5	2.8	1.8				remainder
5020	74.9	3.0		0.20	0.05		remainder

[Table 8]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	Bi	Te	P	Sb	As	Zn
6001	69.6	2.1	3.2	0.15					remainder
6002	77.3	3.7	0.5	0.02		0.23			remainder
6003	75.2	2.4	1.1	0.33			0.12		remainder
6004	70.9	2.3	3.1	0.11				0.03	remainder
6005	78.1	2.7	0.6	0.14		0.02	0.07		remainder
6006	74.5	2.6	1.5	0.21		0.10		0.04	remainder
6007	74.7	3.2	2.1	0.05			0.02	0.12	remainder
6008	73.8	2.5	0.7	0.31		0.03	0.02	0.10	remainder
6009	74.5	2.9		0.05		0.19			remainder
6010	78.1	3.1		0.11			0.15		remainder
6011	74.6	3.3		0.02				0.22	remainder
6012	69.9	2.3		0.35		0.08	0.02		remainder
6013	73.2	2.6		0.21		0.03		0.07	remainder
6014	76.3	2.9		0.07			0.09	0.02	remainder
6015	74.4	2.8		0.19		0.13	0.03	0.02	remainder
6016	70.5	2.3	2.9	0.10	0.02				remainder
6017	74.7	2.4	0.9	0.31	0.04	0.05			remainder
6018	78.1	3.8	0.6	0.02	0.33		0.07		remainder
6019	69.4	2.0	3.4	0.11	0.03			0.03	remainder
6020	77.8	2.8	0.5	0.06	0.11	0.21	0.02		remainder

[Table 9]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	Bi	Te	Se	P	Sb	As	Zn
6021	74.2	2.6	0.6	0.20	0.03		0.02		0.14	remainder
6022	75.8	3.3	1.8	0.03	0.06			0.11	0.02	remainder
6023	74.4	2.6	1.5	0.09	0.12		0.03	0.02	0.06	remainder
6024	77.3	3.1		0.02	0.25		0.08			remainder
6025	70.5	2.4		0.12	0.04		0.06	0.03		remainder
6026	74.3	2.9		0.24	0.02		0.13		0.11	remainder
6027	69.8	2.3		0.34	0.03		0.21	0.02	0.02	remainder

[Table 8]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	Bi	Te	P	Sb	As	Zn
6001	69.6	2.1	3.2	0.15					remainder
6002	77.3	3.7	0.5	0.02		0.23			remainder
6003	75.2	2.4	1.1	0.33			0.12		remainder
6004	70.9	2.3	3.1	0.11				0.03	remainder
6005	78.1	2.7	0.6	0.14		0.02	0.07		remainder
6006	74.5	2.6	1.5	0.21		0.10		0.04	remainder
6007	74.7	3.2	2.1	0.05			0.02	0.12	remainder
6008	73.8	2.5	0.7	0.31		0.03	0.02	0.10	remainder
6009	74.5	2.9		0.05		0.19			remainder
6010	78.1	3.1		0.11			0.15		remainder
6011	74.6	3.3		0.02				0.22	remainder
6012	69.9	2.3		0.35		0.08	0.02		remainder
6013	73.2	2.6		0.21		0.03	0.07	0.07	remainder
6014	76.3	2.9		0.07			0.09	0.02	remainder
6015	74.4	2.8		0.19		0.13	0.03	0.02	remainder
6016	70.5	2.3	2.9	0.10	0.02				remainder
6017	74.7	2.4	0.9	0.31	0.04	0.05			remainder
6018	78.1	3.8	0.6	0.02	0.33		0.07		remainder
6019	69.4	2.0	3.4	0.11	0.03			0.03	remainder
6020	77.8	2.8	0.5	0.06	0.11	0.21	0.02		remainder

[Table 9]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	Bi	Te	Se	P	Sb	As	Zn
6021	74.2	2.6	0.6	0.20	0.03		0.02		0.14	remainder
6022	75.8	3.3	1.8	0.03	0.06			0.11	0.02	remainder
6023	74.4	2.6	1.5	0.09	0.12		0.03	0.02	0.06	remainder
6024	77.3	3.1		0.02	0.25		0.08			remainder
6025	70.5	2.4		0.12	0.04		0.06	0.03		remainder
6026	74.3	2.9		0.24	0.02		0.13		0.11	remainder
6027	69.8	2.3		0.34	0.03		0.21	0.02	0.02	remainder
6028	74.5	2.9		0.03	0.11			0.13		remainder
6029	78.4	3.2		0.02	0.08			0.04	0.05	remainder
6030	73.8	3.0		0.08	0.31				0.23	remainder
6031	72.8	2.5	1.6	0.11		0.36				remainder
6032	78.1	3.7	0.5	0.03		0.02	0.05			remainder
6033	77.2	2.8	0.6	0.09		0.04		0.07		remainder
6034	76.9	3.8	0.4	0.03		0.06			0.07	remainder
6035	74.1	2.3	3.3	0.06		0.03	0.02	0.05		remainder
6036	69. 8	2.0	2.5	0.31		0.12	0.03		0.06	remainder
6037	74.9	3.0	1.1	0.07		0.21		0.12	0.02	remainder
6038	72.6	2.8	0.6	0.20		0.05	0.21	0.07	0.03	remainder
6039	69.7	2.3		0.23		0.06	0.10			remainder
6040	75.4	3.0		0.02		0.09	0.11	0.03		remainder

[Table 10]

	alloy composition (wt%)
No. Cu		Si	Sn	Bi	Te	Se	P	Sb	As	Zn
6041	73.2	2.5		0.11		0.36	0.05		0.02	remainder
6042	78.2	3.7		0.03		0.04	0.03	0.04	0.10	remainder
6043	77.8	2.8		0.09		0.02		0.04		remainder
6044	73.4	2.6		0.16		0.06		0.03	0.02	remainder
6045	71.2	2.4		0.35		0.14			0.08	remainder
6046	70.3	2.5	1.9	0.09	0.05	0.03				remainder
6047	74.5	3.6	2.2	0.02	0.20	0.04	0.04			remainder
6048	73.8	2.9	1.2	0.03	0.10	0.05		0.12		remainder
6049	69.8	2.1	3.1	0.32	0.03	0.05			0.13	remainder
6050	74.2	2.2	0.6	0.19	0.11	0.02	0.02	0.03		remainder
6051	74.8	3.2	0.5	0.03	0.07	0.03	0.05		0.02	remainder
6052	78.0	2.8	0.6	0.06	0.04	0.11		0.11	0.03	remainder
6053	76.3	2.4	0.8	0.05	0.03	0.22	0.03	0.04	0.03	remainder
6054	74.2	2.6		0.21	0.02	0.04	0.05			remainder
6055	78.2	2.9		0.16	0.08	0.03	0.21	0.03		remainder
6056	72.3	2.5		0.08	0.36	0.02	0.10		0.04	remainder
6057	69.8	2.4		0.36	0.04	0.04	0.06	0.07	0.02	remainder
6058	74.6	3.1		0.05	0.09	0.04		0.14		remainder
6059	73.8	2.5		0.08	0.05	0.03		0.02	0.04	remainder
6060	74.9	2.7		0.03	0.16	0.02			0.03	remainder

[Table 11]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	Te	Se	P	Sb	As	Zn
6061	69.7	2.6	3.1	0.26					remainder
6062	74.2	3.2	0.6	0.03		0.04			remainder
6063	74.9	2.6	0.7	0.14			0.14		remainder
6064	73.8	3.0	0.4	0.07				0.13	remainder
6065	78.1	3.3	0.8	0.02		0.12	0.02		remainder
6066	72.8	2.4	1.2	0.32		0.03		0.05	remainder
6067	73.6	2.7	2.1	0.03			0.07	0.02	remainder
6068	72.3	2.6	0.5	0.16		0.02	0.04	0.03	remainder
6069	70.6	2.3		0.33		0.09			remainder
6070	76.5	3.2		0.14		0.21	0.03		remainder
6071	74.5	3.1		0.05		0.03		0.03	remainder
6072	72.8	2.7		0.08			0.13		remainder
6073	78.0	3.8		0.04			0.02	0.12	remainder
6074	73.8	2.9		0.20				0.10	remainder
6075	74.5	2.9		0.07		0.04	0.10	0.02	remainder
6076	73.6	3.2	2.1	0.04	0.07				remainder
6077	74.1	2.5	0.8	0.21	0.18	0.05			remainder
6078	77.8	2.9	0.6	0.11	0.05		0.07		remainder
6079	71.5	2.1	1.1	0.06	0.03			0.06	remainder
6080	72.6	2.3	0.5	0.15	0.23	0.11	0.02		remainder

[Table 12]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	Te	Se	P	Sb	As	Zn
6081	74.2	3.0	0.5	0.03	0.03	0.20		0.02	remainder
6082	70.6	2.2	2.6	0.32	0.05		0.13	0.03	remainder
6083	73.7	2.6	0.8	0.14	0.16	0.06	0.02	0.03	remainder
6084	74.5	3.1		0.04	0.04	0.05			remainder
6085	72.8	2.7		0.09	0.21	0.04	0.02		remainder
6086	76.2	3.3		0.03	0.04	0.11		0.04	remainder
6087	73.8	2.7		0.11	0.03	0.02	0.04	0.03	remainder
6088	74.9	2.9		0.05	0.31		0.05		remainder
6089	75.8	2.8		0.08	0.04		0.03	0.14	remainder
6090	73.6	2.4		0.27	0.10			0.06	remainder
6091	72.4	2.2	3.2		0.33				remainder
6092	75.0	3.2	0.6		0.05	0.10			remainder
6093	76.8	3.1	0.5		0.04		0.11		remainder
6094	74.5	2.9	0.7		0.08			0.15	remainder
6095	73.2	2.7	1.2		0.12	0.06	0.03		remainder
6096	69.6	2.4	2.3		0.14	0.04		0.02	remainder
6097	74.2	2.8	0.8		0.07		0.02	0.03	remainder
6098	74.4	2.9	0.8		0.06	0.03	0.03	0.03	remainder
6099	74.8	3.1			0.09	0.04			remainder
6100	73.9	2.8			0.05	0.10	0.04		remainder

[Table 13]

No.	alloy composition (wt%)
No.	Cu	Si	Se	P	Sb	As	Zn
6101	76.1	3.0	0.04	0.05		0.02	remainder
6102	74.5	2.8	0.03	0.04	0.02	0.03	remainder
6103	74.3	2.6	0.31		0.04		remainder
6104	75.0	3.3	0.06		0.02	0.05	remainder
6105	73.9	2.9	0.10			0.11	remainder

[Table 32]

No.	alloy composition (wt%)
No.	Cu	Si	Al	P	Zn
9001	72.6	2.3	0.8	0.03	remainder
9002	74.8	2.8	1.3	0.09	remainder
9003	77.2	3.6	0.2	0.21	remainder
9004	75.7	3.0	1.1	0.07	remainder
9005	78.0	3.8	0.7	0.12	remainder

[Table 33]

No.	alloy composition (wt%)
No.	Cu	Si	Al	P	Cr	Ti	Zn
10001	74.3	2.9	0.6	0.05		0.03	remainder
10002	74.8	3.0	0.2	0.12		0.32	remainder
10003	74.9	2.8	0.9	0.08	0.33		remainder
10004	77.8	3.6	1.2	0.22	0.08		remainder
10005	71.9	2.3	1.4	0.07	0.02	0.24	remainder
10006	76.0	2.8	1.2	0.03		0.15	remainder
10007	75.5	3.0	0.3	0.06	0.20		remainder
10008	71.5	2.2	0.7	0.12	0.14	0.05	remainder

[Table 34]

No.	alloy composition (wt%)
No.	Cu	Si	Al	P	Bi	Te	Se	Zn
11001	74.8	2.8	1.4	0.10	0.03			remainder
11002	76.1	3.0	0.6	0.06		0.21		remainder
11003	78.3	3.5	1.3	0.19			0.18	remainder
11004	71.7	2.4	0.8	0.04	0.21	0.03		remainder
11005	73.9	2.8	0.3	0.09	0.33		0.03	remainder
11006	74.8	2.8	0.7	0.11		0.16	0.02	remainder
11007	78.3	3.8	1.1	0.05	0.22	0.05	0.04	remainder

[Table 35]

No.	alloy composition (wt%)
No.	Cu	Si	Al	Bi	Te	Se	P	Cr	T	Zn
12001	73.8	2.6	0.5	0.21			0.05	0.11		remainder
12002	76.5	3.2	0.9		0.03		0.11	0.03		remainder
12003	78.1	3.4	1.3			0.09	0.20	0.05		remainder
12004	70.8	2.1	0.6	0.22	0.06		0.08	0.32		remainder
12005	77.8	3.8	0.2	0.02		0.03	0.03	0.26		reminder
12006	74.6	2.9	0.7		0.15	0.02	0.10	0.06		remainder
12007	73.9	2.8	0.3	0.04	0.05	0.16	0.03	0.18		remainder
12008	75.7	2.9	1.2	0.03			0.12		0.05	remainder
12009	72.9	2.6	0.5		0.33		0.04		0.12	remainder
12010	76.5	3.2	0.3			0.32	0.03		0.35	remainder
12011	71.9	2.5	0.8	0.19	0.03		0.03		0.03	remainder
12012	74.7	2.9	0.6	0.07		0.05	0.21		0.06	remainder
12013	74.8	2.8	1.3		0.04	0.21	0.06		0.26	remainder
12014	78.2	3.8	1.1	0.22	0.05	0.03	0.04		0.24	remainder
12015	74.6	2.7	1.0	0.15			0.03	0.02	0.10	remainder
12016	75.5	2.9	0.7		0.22		0.05	0.34	0.02	remainder
12017	76.2	3.4	0.3			0.05	0.12	0.08	0.31	remainder
12018	77.0	3.3	1.1	0.03	0.14		0.03	0.05	0.03	remainder
12019	73.7	2.8	0.3	0.32		0.03	0.10	0.03	0.19	remainder
12020	74.8	2.8	1.2		0.02	0.14	0.05	0.14	0.05	remainder
12021	74.0	2.9	0.4	0.07	0.05	0.05	0.08	0.11	0.26	remainder

[Table 36]

No.	alloy composition (wt%)			heat treatment
No.	Cu	Si	Z	temperature	time
13001	78.5	3.2	remainder	580°C	30min.
13002	78.5	3.2	remainder	450°C	2hr.
13003	77.0	2.9	remainder	580°C	30min.
13004	77.0	2.9	remainder	450°C	2hr.
13005	69.9	2.3	remainder	580°C	30min.
13006	69.9	2.3	remainder	450°C	2hr.

[Table 37]

No.	alloy composition (wt%)
No.	Cu	Si	Sn	Al	Mn	Pb	Fe	Ni	Zn
14001	58.8		0.2			3.1	0.2		remainder
14001a
14002	61.4		0.2			3.0	0.2		remainder
14002a
14003	59.1		0.2			2.0	0.2		remainder
14003a
14004	69.2	1.2				0.1			remainder
14004a
14005	remainder			9.8	1.1		3.9	1.2
14005a
14006	61.8		1.0			0.1			remainder
14006a

[Table 381

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
1001	Δ	Δ	146	290	○	470	32	Δ
1002	⊚	○	122	210	○	524	36	○
1003	⊚	○	119	190	○	543	34	○
1004	⊚	○	126	170	Δ	590	37	○
1005	Δ	○	134	150	Δ	532	42	○
1006	⊚	Δ	129	230	○	490	34	○
1007	Δ	○	132	170	Δ	512	41	○
1008	Δ	Δ	137	270	○	501	31	Δ

[Table 39]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
2001	○	○	116	190	○	523	34	○
2002	⊚	○	117	190	○	508	36	○
2003	⊚	○	118	180	○	525	36	○
2004	⊚	○	119	280	Δ	463	28	Δ
2005	⊚	○	119	240	Δ	481	30	○
2006	⊚	○	119	170	Δ	552	36	○
2007	⊚	○	116	180	○	520	41	○
2008	⊚	○	115	140	Δ	570	34	○
2009	⊚	○	117	200	Δ	485	31	○
2010	⊚	○	114	180	○	507	34	○
2011	⊚	○	115	170	Δ	522	33	○

[Table 44]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
5001	⊚	Δ	127	30	○	501	25	○
5002	⊚	○	119	<5	○	524	37	○
5003	⊚	Δ	135	10	○	488	41	○
5004	⊚	○	126	20	Δ	552	38	○
5005	⊚	○	123	<5	○	518	29	○
5006	⊚	○	122	<5	○	520	34	○
5007	⊚	Δ	125	<5	○	507	23	○
5008	⊚	○	122	<5	○	515	30	○
5009	⊚	○	124	<5	○	544	35	○
5010	⊚	○	123	<5	Δ	536	36	○
5011	⊚	Δ	126	<5	○	511	27	○
5012	⊚	○	124	<5	○	596	36	○
5013	⊚	○	119	<5	○	519	39	○
5014	⊚	○	122	<5	○	523	37	○
5015	⊚	○	123	<5	○	510	40	○
5016	⊚	○	120	20	○	490	35	Δ
5017	⊚	○	121	<5	○	573	40	○
5018	⊚	○	120	<5	○	549	39	○
5019	⊚	○	122	50	○	537	30	○
5020	⊚	○	118	<5	○	521	37	○

[Table 45]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
6001	⊚	○	121	30	○	512	24	○
6002	⊚	○	122	<5	○	574	31	○
6003	⊚	○	117	<5	Δ	501	32	○
6004	⊚	○	120	<5	○	514	26	○
6005	⊚	○	121	<5	Δ	525	42	○
6006	⊚	○	115	<5	○	514	32	○
6007	⊚	○	120	<5	○	548	27	○
6008	⊚	○	119	<5	○	503	30	○
6009	⊚	○	117	<5	○	522	38	○
6010	⊚	○	122	<5	Δ	527	41	○
6011	⊚	○	119	<5	○	536	32	○
6012	⊚	○	123	20	○	478	27	Δ
6013	⊚	○	118	<5	○	506	30	○
6014	⊚	○	118	<5	○	525	39	○
6015	○	○	114	<5	○	503	35	○
6016	⊚	○	122	40	○	526	27	○
6017	⊚	○	119	<5	Δ	507	30	○
6018	⊚	○	121	<5	○	589	31	○
6019	⊚	○	120	<5	○	508	25	○
6020	⊚	○	121	<5	Δ	504	43	○

[Table 46]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700 °C deformability	tensile strength (N/mm²)	elongation (%)
6021	⊚	○	116	<5	○	501	33	○
6022	⊚	○	120	<5	○	547	29	○
6023	○	○	119	<5	○	523	30	○
6024	⊚	○	120	<5	Δ	525	40	○
6025	⊚	○	120	<5	○	496	30	○
6026	○	○	114	<5	○	518	34	○
6027	⊚	○	119	<5	○	487	28	Δ
6028	⊚	○	118	<5	○	524	35	○
6029	⊚	○	122	<5	Δ	540	41	○
6030	⊚	○	118	<5	○	511	29	○
6031	⊚	○	119	40	○	519	28	○
6032	⊚	○	120	<5	○	572	32	○
6033	⊚	○	123	<5	Δ	515	36	○
6034	⊚	○	122	<5	○	580	35	○
6035	⊚	○	123	<5	○	517	27	○
6036	⊚	○	121	< 5	○	503	26	○
6037	○	○	117	<5	○	536	30	○
6038	⊚	○	116	<5	○	506	30	○
6039	⊚	○	120	<5	○	485	28	Δ
6040	○	○	116	<5	○	528	36	○

[Table 47]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700 °C deformability	tensile strength (N/mm²)	elongation (%)
6041	⊚	○	117	<5	○	496	30	○
6042	⊚	○	120	<5	Δ	574	34	○

	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
6043	⊚	○	123	10	Δ	506	43	○
6044	⊚	○	115	10	○	500	30	○
6045	⊚	○	119	20	Δ	485	27	Δ
6046	⊚	○	121	40	○	512	24	○
6047	⊚	○	123	<5	○	557	25	○
6048	⊚	○	120	<5	○	526	30	○
6049	⊚	○	120	<5	○	502	24	○
6050	⊚	○	124	<5	○	480	31	○
6051	○	○	117	<5	○	534	32	○
6052	⊚	○	123	<5	Δ	523	38	○
6053	⊚	○	123	<5	○	506	39	○
6054	⊚	○	115	<5	○	485	31	○
6055	⊚	○	122	<5	Δ	512	44	○
6056	⊚	○	120	<5	○	480	33	Δ
6057	⊚	○	121	<5	○	479	25	Δ
6058	○	○	116	<5	○	525	34	○
6059	⊚	○	119	20	○	482	35	○
6060	○	○	118	30	○	513	38	○

[Table 48]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
6061	⊚	○	123	30	○	530	22	○
6062	⊚	○	119	10	○	538	33	○
6063	⊚	○	118	<5	○	504	37	○
6064	⊚	○	121	<5	○	526	30	○
6065	⊚	○	123	<5	○	565	35	○

No.	machinability			corrosion resistance	hot workabllity	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformabllity	tensile strength (N/mm²)	elongation (%)
6066	⊚	○	120	<5	○	501	25	○
6067	⊚	○	119	<5	○	526	26	○
6068	⊚	○	122	<5	○	502	30	○
6069	⊚	○	124	<5	○	484	28	Δ
6070	○	○	115	<5	○	548	37	○
6071	⊚	○	118	<5	○	530	34	○
6072	⊚	○	119	<5	○	515	30	○
6073	⊚	○	121	<5	Δ	579	35	○
6074	⊚	○	117	<5	○	517	32	○
6075	⊚	○	117	<5	○	513	38	○
6076	⊚	○	122	40	○	535	28	○
6077	○	○	119	<5	○	490	30	○
6078	⊚	○	122	<5	Δ	513	40	○
6079	⊚	○	118	<5	○	524	30	○
6080	⊚	○	123	<5	○	482	35	○

[Table 49]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
6081	⊚	○	118	<5	○	536	34	○
6082	⊚	○	123	<5	○	510	25	○
6083	⊚	○	119	<5	○	504	32	○
6084	⊚	○	117	<5	○	533	34	○
6085	○	○	118	10	○	501	30	○
6086	⊚	○	117	<5	○	545	37	○
6087	⊚	○	119	<5	○	503	34	○
6088	○	○	115	<5	○	526	36	○

	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700 °C deformability	tensile strength (N/mm²)	elongation (%)
6089	⊚	○	119	<5	○	514	39	○
6090	⊚	○	121	20	Δ	480	35	○
6091	⊚	○	122	30	○	516	24	○
6092	⊚	○	118	<5	○	532	30	○
6093	⊚	○	119	<5	○	539	34	○
6094	○	○	117	<5	○	528	32	○
6095	⊚	○	119	<5	○	507	30	○
6096	⊚	○	122	<5	○	508	22	○
6097	⊚	○	117	<5	○	510	31	○
6098	⊚	○	117	<5	○	527	32	○
6099	⊚	○	116	<5	○	529	34	○
6100	⊚	○	119	<5	○	515	32	○

[Table 50]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
6101	○	○	115	<5	○	530	38	○
6102	⊚	○	118	<5	○	512	36	○
6103	⊚	○	119	<5	○	501	35	○
6104	⊚	○	117	<5	○	535	32	○
6105	⊚	○	117	<5	○	517	37	○

[Table 61]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance	high-temperature oxidation
No.	form of chippings	condition of cut surface	cutting force	maximum depth of corrosion	700°C deformability	tensile strength	elongation		increase in weight by oxidation
	form of chippings	condition of cut surface	(N)	(µm)		(N/mm²)	(%)		(mg/10cm²)
9001	⊚	Δ	132	20	○	500	37	○	0.3
9002	⊚	○	122	<5	○	564	35	○	0.2
9003	⊚	○	123	<5	○	585	39	○	0.5
9004	⊚	○	118	<5	○	558	34	○	0.2
9005	Δ	○	132	<5	Δ	593	37	○	0.3

[Table 62]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance	high-temperature oxidation
No.	form of chippings	condition of cut surface	cutting force	maximum depth of corrosion	700°C deformability	tensile strength	elongation		increase in weight by oxidation
	form of chippings	condition of cut surface	(N)	(µm)		(N/mm²)	(%)		(mg/10cm²)
10001	⊚	○	124	<5	○	534	35	○	0.3
10002	⊚	○	120	<5	○	540	33	○	0.2
10003	⊚	○	122	<5	○	539	38	○	0.2
10004	⊚	○	124	<5	○	575	40	○	0.1
10005	⊚	Δ	128	<5	○	512	33	○	0.1
10006	⊚	○	120	20	○	560	35	○	0.1
10007	⊚	○	119	<5	○	536	36	○	0.3
10008	Δ	○	132	<5	○	501	31	Δ	0.1

[Table 63]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance	high-temperature oxidation
No.	form of chippings	condition of cut surface	cutting force	maximum depth of corrosion	700°C deformability	tensile strength	elongation		increase in weight by oxidation
	form of chippings	condition of cut surface	(N)	(µm)		(N/mm² )	(%)		(mg/10cm²)
11001	⊚	○	117	<5	○	540	36	○	0.2
11002	⊚	○	117	<5	○	537	34	○	0.3
11003	⊚	○	121	<5	Δ	573	38	○	0.2
11004	⊚	○	119	30	○	512	30	○	0.3
11005	○	○	114	<5	Δ	518	30	○	0.4
11006	⊚	○	118	<5	○	535	32	○	0.3
11007	⊚	○	119	<5	Δ	586	37	○	0.2

[Table 64]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance	high-temperature oxidation
No.	form of chippings	condition of cut surface	cutting force	maximum depth of corrosion	700°C deformability	tensile strength	elongation	stress resistance corrosion cracking resistance	increase in weight by oxidation
	form of chippings	condition of cut surface	(N)	(µm)		(N/mm²)	(%)		(mg/10cm²)
12001	⊚	○	121	<5	○	512	32	○	0.2
12002	⊚	○	119	<5	○	544	36	○	0.2
12003	⊚	○	123	<5	○	570	38	○	0.1
12004	⊚	○	124	<5	Δ	495	31	Δ	0.2
12005	⊚	○	123	30	Δ	583	32	○	0.3
12006	⊚	○	118	<5	○	537	33	○	0.2
12007	⊚	○	118	20	○	516	30	○	0.2
12008	⊚	○	117	<5	○	543	38	○	0.1
12009	⊚	○	122	20	○	501	32	○	0.2
12010	⊚	○	119	30	○	546	35	○	0.2
12011	⊚	○	121	20	○	516	31	○	0.1
12012	⊚	○	117	<5	○	539	33	○	0.2
12012	⊚	○	121	<5	○	544	33	○	<0.1
12014	⊚	○	121	<5	Δ	590	37	○	<0.1
12015	⊚	○	120	20	○	528	32	○	0.1
12016	⊚	○	117	<5	○	535	33	○	0.1
12017	⊚	○	121	<5	○	577	35	○	0.2
12018	⊚	○	120	<5	Δ	586	37	○	0.1
12019	⊚	○	115	<5	○	520	31	○	0.2
12020	⊚	○	118	<5	○	549	34	○	0.1
12021	⊚	○	116	<5	○	533	34	○	0.1

[Table 65]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance
	form of chippings	condition of cut surface	cutting force (N)	maximum depth of corrosion (µm)	700°C deformability	tensile strength (N/mm²)	elongation (%)
13001	⊚	○	128	140	Δ	521	39	○
13002	⊚	○	126	130	Δ	524	41	○
13003	⊚	○	127	150	Δ	500	38	○
13004	⊚	○	127	160	Δ	508	38	○
13005	⊚	○	128	180	○	483	35	○
13006	⊚	○	129	170	○	488	37	○

[Table 66]

No.	machinability			corrosion resistance	hot workability	mechanical properties		stress resistance corrosion cracking resistance	high-temperature oxidation
No.	form of chippings	condition of cut surface	cutting force	maximum depth of corrosion	700°C deformability	tensile strength	elongation	stress resistance corrosion cracking resistance	increase in weight by oxidation
	form of chippings	condition of cut surface	(N)	(µm)		(N/mm²)	(%)		(mg/10cm²)
14001	○	○	103	1100	Δ	408	37	××	1.8
14002	○	○	101	1000	×	387	39	××	1.7
14003	○	Δ	112	1050	○	414	38	××	1.7
14004	×	○	223	900	○	438	38	×	1.2
14005	×	○	178	350	Δ	735	28	○	0.2
14006	×	○	217	600	○	425	39	×	1.8

Claims

A lead-free copper alloy comprising 2.0 to 4.0 wt % silicon, 69 to 79 wt% copper, the remaining wt% being zinc, having a gamma phase in the alloy, and wherein the alloy optionally includes:
a) at least one element selected from among 0.02 to 0.4 wt% bismuth, 0.02 to 0.4 wt% tellurium, and 0.02 to 0.4 wt% selenium; or

b) at least one element selected from among 0.02 to 0.25 wt% phosphorus, 0.02 to 0.15 wt% antinomy, and 0.02 to 0.15 wt% arsenic; or

c) at least one element selected from among 0.3 to 3.5 wt% tin, 0.02 to 0.25 wt% phosphorus, 0.02 to 0.15 wt% antimony, and 0.02 to 0.15 wt% arsenic; at least one element selected from among 0.02 to 0.4 wt% bismuth, 0.02 to 0.4 wt% tellurium, and 0.02 to 0.4 wt% selenium; or

d) 0.1 to 1.5 wt% aluminium; and 0.02 to 0.25 wt% phosphorus; or

e) 0.1 to 1.5 wt% aluminium; 0.02 to 0.25 wt% phosphorus; at least one element selected from among 0.02 to 0.4 wt% chromium and 0.02 to 0.4 wt% titanium; or

f) 0.1 to 1.5 wt% aluminium; 0.02 to 0.25 wt% phosphorus; at least one element selected from among 0.02 to 0.4 wt% bismuth, 0.02 to 0.4 wt% tellurium and 0.02 to 0.4 wt% selenium; or

g) 0.1 to 1.5 wt% aluminium; 0.02 to 0.25 wt% phosphorus; at least one element selected from among 0.02 to 0.4 wt% chromium, and 0.02 to 0.4 wt% of titanium; at least one element selected from among 0.02 to 0.4% bismuth, 0.02 to 0.4 wt% of titanium; at least one element selected from among 0.02 to 0.4% bismuth, 0.02 to 0.4 wt% tellurium and 0.02 to 0.4 wt% selenium.