JP2013544962A - Copper alloy - Google Patents

Abstract

  Copper and alloys with manganese and sulfur and / or calcium and associated element additives are shown. The copper alloy is tellurium-free and lead-free and features high electrical conductivity and good machinability.

Description

  The present invention relates to copper alloys, in particular lead-free and tellurium-free copper alloys, and semi-finished products from such copper alloys.

  In many industrial and scientific fields, copper is an essential raw material for its original quality. In particular, copper and copper alloys are very important when the material requires very high electrical and thermal conductivity. However, the use of pure copper is difficult when the part has to be cut and machined. The high toughness of copper, which is exceptionally evaluated during non-cutting shaping, in this case is an inconvenient material property. The problem with this is the formation of long chips that impede machining progress during drilling and rotation, and that significantly wear the tool blades. However, with CNC control, even with conventional automatic lathes, pure copper can usually not be machined or processed without expensive and expensive expenditures for time, workers and tools.

  Zerspanbare copper materials to which lead, bismuth, sulfur and tellurium are added are known. US Pat. No. 1,959,509A has already described the beneficial effect of bismuth alloying on the machinability of copper alloys. The advantageous properties of tellurium in a copper alloy are revealed from US Pat. No. 2,027,807A.

As a chip breaker, lead and bismuth act in the form of metals, and conversely, sulfur and tellurium are intermetallic phases in the form of copper sulfide (Cu ₂ S) or tellurium copper (Cu ₂ Te). Acts as However, the low melting point of lead and bismuth severely limits the hot formability by, for example, an extrusion press, so that it is not economical or is limited by conventional manufacturing equipment. Will be. Furthermore, there are concerns about health and environmental damage regarding lead in copper alloys.

  On the other hand, copper materials in the form of CuSP or CuTeP doped with sulfur or tellurium feature an advantageous combination of good machinability and very high electrical and thermal conductivity. However, just tellurium is relatively expensive because its availability is limited as a result of resource shortages. Therefore, alternatives are desired as tellurium is running out of resources.

US Pat. No. 1,959,509A US Patent No. 2,027,807A

  Thus, the present invention starts from the prior art and shows a copper alloy having at least the same or better machinability and cold formability and hot formability compared to the known copper alloys CuTeP and CuSP. It is based on the problem.

  According to the present invention, the first solution of the problem lies in the copper alloy according to claim 1.

  According to the present invention, the proposed copper alloy is based on copper with added manganese and sulfur and associated elements (Beglelitementen), which does not contain lead or tellurium, but has good machinability Have

  The copper alloy is composed of copper, 0.05 to 0.80 wt% manganese (Mn), 0.10 to 0.80 wt% sulfur (S), and optionally 0.002 to 0.05 wt% phosphorus (P), 0.01-0.5 wt% chromium (Cr), 0.01-0.5 wt% aluminum (Al), 0.01-0.5 wt% magnesium (Mg ) And one or more elements selected from the group consisting of:

As a chip breaker in the CuSMn alloy of the present invention, a mixed phase composed of copper sulfide (Cu ₂ S) and manganese sulfide (MnS) acts.

  Particularly preferably, the manganese ratio is 0.10 to 0.20% by weight. Likewise preferably, the sulfur proportion is 0.20 to 0.60% by weight.

  The problem on which the present invention is based is also solved by an alloy based on copper according to claim 4. This is 0.30 to 1.50 wt% calcium (Ca), and optionally 0.005 to 0.05 wt% manganese (Mn), 0.005 to 0.05 wt% sulfur (S), 0 0.002-0.05 wt% phosphorus (P), 0.01-0.5 wt% chromium (Cr), 0.01-0.5 wt% aluminum (Al), 0.01-0.5 wt% It is composed of one or more elements selected from the group consisting of magnesium (Mg), the remaining copper (Cu), and unavoidable impurities.

  Preferably, in the case of the above copper alloy, the calcium ratio is 0.5 to 1.0% by weight.

The resulting eutectic phase Cu ₅ Ca acts as a chip breaker in the CuCa alloy.

  Phosphorus acts as a deoxidizer, which combines with free oxygen dissolved in the melt, thus preventing alloy component bubbles (Wasseroffrankrankheit) and oxidation. In addition, phosphorus is added to improve the flow characteristics of the copper alloy during casting.

  Manganese refines the particles and improves machinability in combination with sulfur.

  Aluminum increases hardness and yield strength without reducing toughness. Aluminum is an element that improves strength at high temperatures, workability, wear resistance, and oxidation resistance.

  Chromium and magnesium are used to improve oxidation resistance at high temperatures. Here, particularly good results are achieved when they are mixed with aluminum in order to obtain a synergistic effect.

  The two copper materials CuSMn and CuCa proposed by the present invention have the same or better machinability than CuSP. In the experiment, a machinability index of 90% for CuSMn, 86% for CuCa and 76 or 79% for the control materials CuTeP and CuSP was measured.

  The material has an electrical conductivity of 35 to 55 MS / m, in particular in the range of 48 to 53 MS / m. Furthermore, the copper alloy proposed by the present invention is economically advantageous because it does not contain toxic alloy elements and the alloy elements are available at low cost. Furthermore, it should be strongly emphasized that scrap can be reused. In particular, the proposed standard for these two copper alloys is that they can be processed on conventional manufacturing and processing machines, and in particular, the alloys are also very cold formable. It also has good hot formability.

  From this, it is possible to provide semi-finished products in the form of rolled products, press- / draw-out products (Press- / Zieh product), forged products or cast products from the copper alloys proposed according to the invention.

FIG. 1 is a diagram showing drilling chips from a machinability survey.

Embodiment and comparative considerations:
Based on the two examples, the advantageous properties according to the invention of the new lead-free and tellurium-free alloys are shown by the known standardized material CuTeP (= EN-material CW118C, ASTM-material C14500). And CuSP (= EN-material CW114C, ASTM-material C14700).

  In a crucible induction furnace, CuSMn, CuCa and control materials CuTeP and CuSP, respectively, were melted and round billets were cast in a continuous casting process. The composition of the materials is shown in Table 1. The composition of CuSMn corresponds to claims 1, 2 and 3, and the composition of CuCa satisfies claims 4 and 5. The composition of the control material corresponds to the EN and ASTM standards for the materials CuTeP and CuSP. Continuously cast round billets (Rundbolzen) are pressed into a press rod without problems by a continuous pressing method at a heating temperature of ≧ 850 ° C. and subsequently drawn to a final dimension of φ35 mm with a cross-section reduction of 10-15% It was. The supply state R250 according to EN standard 12164 or the supply state H02 according to ASTM standard B301, which is frequently used for machinable copper, is adjusted by reducing the cross section by 10-15%. Table 2 shows the mechanical-technical characteristic values, the Brinell hardness and the conductivity of the rod thus completed and cast. As the test results show, the new material according to the invention has mechanical property values comparable to the standard materials CuTeP or CuSP and also has a good conductivity. The material CuSMn is based on a more advantageous strength / break elongation combination and has better cold formability (eg for the production of “stretched” burner nozzles, etc.) compared to the standard material CuSP. ) Providing further advantages.

Machinability investigation:
The rods listed in Table 2 were subjected to a comparative machinability test in the form of a drilling test. Punching was prioritized over rotation or threading. This is because the production of small perforations (such as in a burner nozzle) is the most difficult cutting form. Therefore, here, if the material shows favorable results, it means that machining by rotation or threading is equally problematic.

For drilling tests, the following conventional parameters were used on modern CNC machines.
Drilling tool: 2mmφ carbide drill with internal cooling, tip coated with AlTiN, type Guehring WRRN15XD

Drilling strategy: Drill the front 45 holes on the rod piece:
Cutting speed: 100m / min
Feed: 0.04mm / rotation
Drilling depth: 33mm
Internal cooling drill: 40 bar emulsion

Evaluated as follows:
・ Cut shape based on steel test sheet 1178-90 (Spanform)
Average weight of each chip by weighing 100 chips, 270 tool wear as free surface wear after drilling, required average feed force, drill quality based on the following criteria-cylindricity of drill over length ( Conicity)
-Roundness of perforation at the periphery-Dimensional difference in diameter over length-Roughness Rz of the perforated surface

  In order to be able to evaluate a quantitative comparison between the material and the control material, the individual measurement results are evaluated in a 0-10 point scoring system, with 0 being very bad and 10 being optimal. = Indicates very good.

The individual evaluations are summed up and can reach up to 80 points. In this case, the overall evaluation of the machinability should be defined as the machinability index, so that 80 points here corresponds to 100% of the maximum achievable machinability index. The new inventive materials CuCa and CuSMn achieve the following machinability index compared to the control material.
CuSMn: 90%
CuCa: 86%
CuTeP: 76%
CuSP: 79%

  In order to show the good short cut machinability of all materials, in FIG. 1 the drilling chips from the machinability investigation are shown. Somewhat longer spiral cuts (Wendelspanstucke) appear rarely. Due to very elaborate and time-consuming machinability studies, in machinability, the material of the present invention is at least comparable or even slightly advantageous in the previously available control materials CuSP and CuTeP. It was shown that there is.

The inventors have accomplished a copper material in a careful investigation that complements the current supply range by CuTeP and CuSP and has the following quality features.
Same or better machinability than CuTeP / CuSP;
Conductivity ≧ 35 MS / m;
Non-toxic alloying elements;
Cost-effective availability of alloying elements;
Scrap reusability;
Processability with conventional manufacturing processes and machines

  In the survey, alloy elements such as aluminum (Al), calcium (Ca), cobalt (Co), chromium (Cr), iron (Fe), magnesium (Mg), manganese (in combination with sulfur (S) and calcium (Ca) Mn), molybdenum (Mo), nickel (Ni), tin (Sn) and zinc (Zn) were each tested as the only additive to copper for reachable conductivity and machinability. Proven materials CuSP and CUTeP were used as comparative samples for machinability testing. What was evaluated in terms of quality was the shape of the cutting waste when a 3 mm hole was drilled, and the appearance of drill breakage.

  The targeted material properties, or combinations of material properties, are manganese, specifically 0.05 to 0.80 wt%, preferably 0.10 to 0.30 wt%, in particular 0.10 to 0.00. This was achieved by alloying manganese up to a proportion of 20% by weight and sulfur in a proportion of 0.10-0.80% by weight, in particular 0.20-0.60% by weight.

  Furthermore, the targeted material properties are achieved in the case of copper-based alloys containing calcium in a proportion of 0.30 to 1.50% by weight, preferably 0.5 to 1.0% by weight as alloy components. I was able to prove that.

In essence of the present invention, the two indicated copper materials CuSMn and CuCa are found to have the unique chip breaker phase described above, ie a mixed phase consisting of Cu ₂ S and MnS, or a eutectic phase Cu ₅ Ca. It was.

  In the processing and testing of the copper alloy material samples of the present invention, among other things, the hot and cold formability of the copper alloy CuSMn is comparable or even slightly better than the copper alloy CuSP or copper alloy CuTeP. It was shown to have.

Claims (12)

0.05-0.80 wt% manganese (Mn),
0.10 to 0.80 wt% sulfur (S),
Optionally, one or more elements,
0.002 to 0.05 wt% phosphorus (P),
0.01 to 0.5 wt% chromium (Cr),
0.01 to 0.5 wt% aluminum (Al),
0.01-0.5 wt% magnesium (Mg),
The element selected from the group consisting of:
And a copper-based alloy consisting of the balance copper (Cu) and inevitable impurities.   The copper-based alloy according to claim 1, wherein the manganese proportion is adjusted to 0.10 to 0.30% by weight, in particular 0.10 to 0.20% by weight.   The copper-based alloy according to claim 1 or 2, wherein the sulfur proportion is adjusted to 0.20 to 0.60 wt%. 0.30 to 1.50 wt% calcium (Ca),
Optionally, one or more elements,
0.005 to 0.05 wt% manganese (Mn),
0.005 to 0.05 wt% sulfur (S),
0.002 to 0.05 wt% phosphorus (P),
0.01 to 0.5 wt% chromium (Cr),
0.01-0.5 wt% aluminum (Al),
0.01-0.5 wt% magnesium (Mg),
The element selected from the group consisting of:
And a copper-based alloy consisting of the balance copper (Cu) and inevitable impurities.   The copper-based alloy of claim 4, wherein the calcium percentage is adjusted to 0.5-1.0 wt%.   The copper-based alloy according to any one of claims 1 to 5, wherein the conductivity is 35 to 55 MS / m.   The copper-based alloy according to claim 6, wherein the electrical conductivity is 48-53 MS / m.   Copper-based alloy according to any one of the preceding claims, wherein the machinability index is 80% to 95%.   A semi-finished product in the form of a rolled product, comprising the alloy according to any one of claims 1-8.   Semi-finished product in the form of a press / draw-out product (Press- / Zieh) made of the alloy according to claim 1.   Semi-finished product in the form of a forged product, comprising the alloy according to any one of claims 1-8.   A semi-finished product in the form of a cast product, comprising the alloy according to claim 1.

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