MX2012011929A

MX2012011929A - Copper alloy.

Info

Publication number: MX2012011929A
Application number: MX2012011929A
Authority: MX
Inventors: Dirk Rode; Thomas Helmenkamp; Hark Schulze; Uwe Quadfasel
Original assignee: Kme Germany Gmbh & Co Kg
Priority date: 2010-10-08
Filing date: 2011-08-16
Publication date: 2013-02-07
Also published as: EP2625300B1; WO2012062248A8; US20130183194A1; JP2013544962A; BR112013008521A2; EP2625300A2; WO2012062248A2; DE102010038060A1; WO2012062248A3; PL2625300T3

Abstract

The invention relates to alloys based on copper, which comprise additives of manganese and sulfur and/or calcium and tramp elements. The copper alloys are free of tellurium and lead and are characterized by high electrical conductivity and good machinability.

Description

COPPER ALLOY Description of the invention The present invention relates to a copper alloy, in particular a copper alloy free of lead and tellurium, as well as semi-finished parts of a copper alloy thereof.

In many fields of industry and technology copper is a material that can not be dispensed with by virtue of its natural qualities. Particularly where copper and copper alloys are required, materials with the highest electrical and thermal conductivity are required. However, the use of pure copper causes difficulties if it is necessary to machine parts with chip removal. The high tenacity of the copper that is particularly appreciated in the deformation without chip removal, in this case turns out to be a property of unfavorable material. In this respect, the formation of long shavings is essential, which inhibits the development of the work when drilling and turning and causes a strong wear of the tool blades. In automatic lathes controlled by CNC, but also in conventional lathes, pure copper can only be processed and worked in the normal case with an uneconomic expenditure of time, personnel and tools.

Useful copper materials are known for Ref.236153 machining with chip removal that have additions of lead, bismuth, sulfur and tellurium. Already in US-A-1,959,509 the favorable influence of the bismuth alloy on the usefulness for machining with copper alloy chip was explained. The favorable properties of tellurium in copper alloys are apparent from US-A-2, 027, 807.

As chip breakers, lead and bismuth act in metallic form, while sulfur and tellurium act as an intermetallic phase in the form of copper sulphide (Cu2S) or copper telluride (Cu2Te). However, the low melting points of lead and bismuth considerably limit the usefulness for hot deformation, for example by extrusion and impact pressing, so that an economical processing capacity in conventional production devices is not possible or only in a limited way. Additionally, with respect to lead in copper alloys, there are reservations about health and damage to the environment.

In contrast, copper materials with additions of sulfur or tellurium in the form of CuSP or CuTeP are characterized by a favorable combination of utility for machining with chip removal and very high electrical and thermal conductivity. However, just tellurium is only available in a limited way as a result of its scarcity and is comparatively expensive. Therefore, due to the increase in the scarcity of tellurium resources, an alternative is desirable.

Therefore the invention has as its object, from the state of the art, to specify a copper alloy which has utility for machining with chip removal and usefulness for cold and hot deformation which are at least equal or better in Comparison with known CuTeP and CuSP copper alloys.

According to the invention, a first solution to this problem consists of a copper alloy according to claim 1.

According to the invention, a copper alloy based on copper with additions of manganese and sulfur as well as secondary elements is proposed, which does not require lead or tellurium but nevertheless has a good use for machining with chip removal. .

The copper alloy consists of copper which as components of the alloy comprises 0.05 to 0.80% by weight of manganese (Mn), 0.10 to 0.80% by weight of sulfur (S), optionally one or several elements that are selected from the group consisting of from 0.002 to 0.05% by weight of phosphorus (P), 0.01 to 0.5% by weight of chromium (Cr), 0.01 to 0.5% by weight of aluminum (Al), 0.01 to 0.5% by weight of magnesium (Mg), of the inevitable impurities.

As a chip breaker in the CuSMn alloy according to the invention, a mixed phase consists of copper sulphide (Cu2S) and manganese sulphide (MnS).

A manganese content of 0.10 to 0.20% by weight is particularly preferred. A proportion of sulfur which is between 0.20 to 0.60% by weight is likewise preferred.

The problem on which the invention is based is also solved by means of an alloy based on copper according to claim 4. It consists of 0.30 to 1.50% by weight of calcium (Ca), optionally one or several elements that are selected of the group consisting of 0.005 to 0.05% by weight of manganese (Mn), 0.005 to 0.05% by weight of sulfur (S), 0.002 to 0.05% by weight of phosphorus (P), 0.01 to 0.5% by weight of chromium ( Cr), 0.01 to 0.5% by weight of aluminum (Al), 0.01 to 0.5% by weight of magnesium (Mg) as well as the remainder copper (Cu) and unavoidable impurities.

In the aforementioned copper alloy the proportion of calcium is preferably between 0.5 to 1.0% by weight.

In the CuCa alloy, the eutectic phase (Cu5Ca) acts as a chipbreaker.

Phosphorus serves as a deoxidizing agent that binds dissolved free oxygen in the foundry and thus avoids gas bubbles (hydrogen disease) and oxidations of the alloy components. In addition, phosphorus is added to improve the flow properties of the copper alloy when melting.

The manganese provides fineness to the grain and in the combination with sulfur improves the usefulness for machining with chip removal.

Aluminum increases the hardness and the elongation limit without reducing the tenacity. Aluminum is an element that improves hardness, usefulness for processing and resistance to wear as well as resistance to oxidation at high temperatures.

Chromium and magnesium serve to improve the resistance to oxidation at elevated temperatures. Particularly good results are obtained if these are mixed with aluminum to obtain a synergistic effect.

The two CuSMn and CuCa copper materials proposed in accordance with the invention have utility for machining with chip removal that is equal to or better than that of CuSP. In tests, a useful index for machining with chip removal of 90% for CuSMn, 86% for CuCa and 76 and 79% for reference materials CuTeP and CuSP was determined.

The materials have an electrical conductivity that is between 35 to 55 MS / m, in particular in a range of 48 to 53 MS / m. In addition, the copper alloys proposed in accordance with the invention are free of toxic alloying elements and are economical in that the alloying elements are economically available. Additionally, it is important to highlight the importance that scrap can be reused. The particular criterion of the two copper alloys proposed is that it is possible to machine with conventional manufacturing and machining machines, in particular that the alloys have both a sufficient usefulness for cold deformation as well as a very good utility for hot deformation. .

Therefore, of the copper alloys which are proposed according to the invention semi-finished parts can be manufactured in the form of rolled products, pressed products, forged products or cast products.

Exemplary modalities and comparative considerations: By means of 2 exemplary embodiments the favorable properties of the new alloys free of lead and tellurium according to the invention will be explained in comparison with the known and standardized materials CuTeP (= material EN C 118C, material ASTM C14500) and CuSP (= material EN CW114C, material ASTM C14700).

In a crucible induction furnace, CuSMn, CuCa and the reference materials CuTeP and CuSP are melted respectively, and in a continuous casting process, they are melted to obtain pressed bolts. The composition of the materials is reproduced in table 1. The CuSMn composition corresponds to claim 1, 2 and 3, CuCa satisfies claims 4 and 5. The composition of the reference materials corresponds to the provisions of the EN and ASTM standards for the CuTeP and CuSP materials. The round bolts of the continuous casting were pressed without problems in the process of extrusion and impact pressing with a heating temperature >; 850 ° C to obtain pressed bars and then drawn with a reduction of the cross section of 10 to 15% to the final dimension of 35 mm of 0. With the decrease of the cross section of 10 to 15% the commercial state is adjusted R250 according to EN 12164 and H02 according to ASTM B301 used more frequently for copper useful for machining with chip removal. Table 2 reproduces the mechanical-technological nominal values, Brinell hardness and the specific direct conductivity of the terminated wire rod. As evidenced by the test results, the new materials according to the invention have mechanical rated values comparable to the standard CuTeP and CuSP materials, and an equally good electrical conductivity. By virtue of the combination of hardness / elongation at break even more favorable compared to the standard CuSP material, the CuSMn material also has the advantage of a better use for cold deformation (for example for the manufacture of burner nozzles). hammered ").

Investigations on the utility for machining with chip removal: In the rods listed in Table 2, useful comparative tests were carried out for machining with chip removal in the form of drill tests. When machining by drill, preference was given to the machining by lathe and tap, because the manufacture of small holes (eg burner nozzles) is the form of machining with more difficult chip removal. If the material shows positive results here, then the machining by lathe or tap is also not a problem.

For the drill tests, the following usual parameters were used in modern CNC machining machines: * Drill tool: Solid metal drill with internal cooling 2 mm of 0, coated tip AlTiN, type Gühring WRN15XD * Drilling strategy: Directly insert 45 holes in rod sections: Cutting speed: 100 m / min Advance: 0.04 mm / revolution Drill depth: 33 mm Internal drilling coolant: Emulsion 40 bar The following were qualified: * The shape of chip according to the steel iron test sheet 1178-90 * The average chip mass by measuring the weight of 100 chips respectively * The block of the tool as blockade of free surface after 270 perforations * The average advance force required * The quality of the drill using the criteria: * Cylindrical perfection (taper) of the drill over the length * Roundness of the drill on the circumference * Deviation of diameter over length * Rz roughness of the drill surface To allow a comparative quantitative qualification of the materials with the reference materials, the individual measurement results were graded with a point system from 0 to 10 points, with 0 points representing extremely bad and 10 points representing very good = optimal.

The individual grades were added, with a maximum of 80 points. This total rating of the utility for machining with chip removal should be defined here as an index of utility for machining with chip removal, being that then 80 points correspond to the maximum rate of 100% useful for machining with chip removal what can be obtained. In comparison with the reference materials, the new CuCa and CuSMn materials according to the invention achieve the following useful indexes for machining with chip removal: CuSMn: 90% CuCa: 86% CuTeP: 76% CuSP: 79% To clarify the good utility for the machining with chip breaking with short breakage of all materials, in figure 1 drill shavings of the investigations on utility for machining with chip removal are represented. Chunks of scrap chip a little longer only appear sporadically. The investigations on utility for machining with very large and costly chip removal showed that as regards the utility for machining with chip removal, the materials according to the invention are at least equivalent to the reference materials CuSP and CuTeP until now available, and even have slight advantages.

The inventors created in meticulous research a copper material that complements the current offer range with CuTeP and CuSP and that has the following quality characteristics: * Utility for machining with chip removal equal to or better than CuTeP / CuSP; * Electrical conductivity > 35 MS / m; * Free of toxic alloying elements; * Economic availability of alloy elements, - * Reuse of scrap; * Possibility of machining with the steps and conventional machining machines.

In investigations regarding the electrical conductivity obtainable and the usefulness for machining with chip removal, the aluminum alloy element (Al) was tested in each case, calcium (Ca), cobalt (Co), chromium (Cr), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), tin (Sn) and zinc (Zn) in combination with sulfur (S) and calcium (Ca) as the only addition to copper. The accredited CuSP and CuTeP materials were used as comparative tests for the useful tests for machining with chip removal. The chip form was qualitatively scored when drilling holes of 3 mm and the appearance of drill breaks.

The properties or combinations of material properties that were desired were obtained by the manganese alloy, and specifically in a proportion of 0.05 to 0.80% by weight, preferably 0.10 to 0.30% by weight, in particular 0.10 to 0.20% by weight, as well as sulfur in a proportion of 0.10 to 0.80% by weight, in particular 0.20 to 0.60% by weight.

Furthermore, it was found that the desired material properties are obtained with an alloy having copper as the base which as a component of the alloy contains calcium in a proportion of 0.30 to 1.50% by weight, preferably between 0.5 and 1.0% by weight.

It was recognized that it is essential to the invention that both CuSMn and CuCa specified copper materials have the above independent chip breaking phases, specifically the mixed phase consisting of Cu2S and MnS and the Cu5Ca eutectic phase.

In the machining and examination of the material tests of the copper alloys according to the invention it was found that in particular the CuSMn copper alloy has a utility for hot and cold deformation comparable or even slightly better than the copper alloy CuSP or CuTeP copper alloy.

Table 1 Composition of CuSMn, CuCa materials in accordance with the invention and CuTeP and CuSP reference materials Table 2 Mechanical-technological nominal values of the CuSMn, CuCa materials according to the invention and of the reference materials CuTeP and CuSP in the semi-hard drawn state (R250 according to EN and 12164 H02 according to ASTM B301) Table 3 Results of research on the utility for machining with chip removal (including qualification) - no breakage occurred in any material It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. Alloy based on copper, characterized in that it consists of: 0.05 to 0.80% by weight of manganese, 0.10 to 0.80% by weight of sulfur, optionally one or several elements that are selected from the group consisting of 0.002 to 0.05% by weight of phosphorus, 0.01 to 0.5% by weight of chromium, 0.01 to 0.5% by weight of aluminum, 0.01 to 0.5% by weight of magnesium, as well as the rest copper and the inevitable impurities.

2. Alloy based on copper according to claim 1, characterized in that the manganese content is adjusted between 0.10 to 0.30% by weight, in particular between 0.10 to 0.20% by weight.

3. Alloy based on copper according to any of claims 1 or 2, characterized in that the sulfur content is adjusted between 0.20 to 0.60% by weight.

4. Alloy based on copper, characterized in that it consists of: 0.30 to 1.50% by weight of calcium, optionally one or several elements that are selected from the group consisting of 0.005 to 0.05% by weight of manganese, 0.005 to 0.05% by weight of sulfur, 0.002 to 0.05% by weight of phosphorus, 0.01 to 0.5% by weight of chromium, 0.01 to 0.5% by weight of aluminum, 0.01 to 0.5% by weight of magnesium as well as the rest copper and unavoidable impurities.

5. Alloy based on copper according to claim 4, characterized in that the calcium content is adjusted between 0.5 and 1.0% by weight.

6. Alloy based on copper according to any of claims 1 to 5, characterized in that the electrical conductivity is from 35 to 55 MS / m.

7. Alloy based on copper according to claim 6, characterized in that the electrical conductivity is 48 to 53 MS / m.

8. Alloy based on copper according to any of claims 1 to 7, characterized in that the useful index for machining with chip removal is between 80% and 95%.

9. Semi-finished material characterized in that it consists of an alloy according to any of claims 1 to 8, in the form of a drawn product.

10. Semi-finished material characterized in that it consists of an alloy according to any of claims 1 to 8, in the form of a pressed / stretched product.

11. Semi-finished material characterized in that it consists of an alloy according to any of claims 1 to 8, in the form of a forged product.

12. Semi-finished material characterized in that it consists of an alloy according to any of claims 1 to 8, in the form of a molten product.