Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C9/00—Alloys based on copper
  • C22C9/04—Alloys based on copper with zinc as the next major constituent
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
  • F16C33/02—Parts of sliding-contact bearings
  • F16C33/04—Brasses; Bushes; Linings
  • F16C33/06—Sliding surface mainly made of metal
  • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
  • F16C33/121—Use of special materials
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2204/00—Metallic materials; Alloys
  • F16C2204/10—Alloys based on copper
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C2204/00—Metallic materials; Alloys
  • F16C2204/10—Alloys based on copper
  • F16C2204/14—Alloys based on copper with zinc as the next major constituent

Definitions

• the invention relates to a copper-zinc alloy, to methods for producing tubes or rods from the copper-zinc alloy and to its use.
• Documents DE 10 2004 058 318 B4 and DE 10 2005 015 467 A1 disclose the application possibilities of a copper-zinc alloy for use as a valve guide and friction bearing with high thermal and wear stability.
• the alloy consists of 59-73 wt % copper, 2.7-8.5 wt % manganese, 1.5-6.3 wt % aluminum, 0.2-4 wt % silicon, 0.2-3 wt % iron, 0-2 wt % lead, 0-2 wt % nickel, 0-0.4 wt % tin and the remainder zinc.
• DE 29 19 478 C2 discloses the use of a similar alloy for synchronous rings. In respect of this use, it is regarded as advantageous that there is an improved wear-resistance and at the same time a significantly increased coefficient of friction.
• the semifinished products made from the alloy furthermore have good processability; they can readily be cold-formed owing to the relatively high aluminum content, although an increase in hardness at room temperature is to be noted compared with the previously conventional special brasses.
• the aluminum content lies in the range of from 4 to 6 wt %.
• the further document OS 21 45 710 discloses a copper-based alloy which is wear-resistant at high temperature for a valve seat in combustion engines, which likewise has a comparatively high aluminum content of from 5 to 12 wt %.
• the aluminum content in the specified range improves the corrosion resistance in addition to the effect of reinforcing the matrix.
• a further increase in the wear resistance occurs through the formation of an intermetallic phase of manganese and silicon.
• the patent application published for opposition 1 194 592 discloses a method for producing synchronous rings, which are distinguished by a high and constant coefficient of friction, a high wear resistance and good machining processability.
• annealing treatments of the alloy consisting substantially of ⁇ -phase at between 200 and 500° C., are proposed in order to achieve from 5 to 50% ⁇ -precipitation.
• a certain lead content is usually provided in said documents for better machining processability.
• the invention is defined in respect of the alloy by the features of claim 1 and in respect of the method for producing tubes or rods made of the alloy by the features of claims 8 and 9 , and in respect of the use of the alloy by claim 11 .
• the other dependent claims define advantageous embodiments and refinements of the invention.
• the invention includes the technical teaching that a copper-zinc alloy consists of (in wt %):
• the invention is based on the idea of providing a copper-zinc alloy which has incorporated mixed silicides of iron-nickel-manganese and can be produced with the aid of the continuous or semicontinuous extrusion casting method.
• the copper-zinc alloy Owing to the mixed silicide formation, the copper-zinc alloy has a high hard phase content which contributes to improving the material resistance against abrasive wear. Owing to their low susceptibility to seizure, the high content of silicides furthermore entails a better resistance against adhesive wear.
• the alloy thus has high hardness and strength values but a requisite degree of ductility is nevertheless ensured, as expressed by an elongation at break value in a tensile test.
• the subject of the invention is particularly suitable for Pb-free friction bearing elements in engines, for example piston bore liners, and in transmissions.
• the particular advantage of the alloy according to the invention is due to a combination of properties, optimized for an application purpose, in the form of increasing the strength, the heat resistance of the structure and the complex wear resistance while simultaneously having sufficient ductility properties. Furthermore, the alloy has good performance in the event of lubrication supply failure for friction bearing applications, which avoids seizure of the bearing partners. Owing to the substituted lead content compared with conventional alloys, the claimed material solution also accommodates the need for an environmentally friendly lead-free alloy alternative.
• This material is furthermore intended for particular applications in which a requisite degree of plasticizability is important, despite stringent requirements for the hardness and strength. This is the case for example in the field of hydraulic equipment, the sliding pad of which is partly produced by pressing together the respective connection partners. Particularly in this field of hydraulic mechanical engineering, for example for axial piston machines, future developments are likely to entail increasing operating pressures which place greater demands on the strength properties of the materials being used.
• the alloy according to the invention may contain
• the iron-nickel-manganese mixed silicide formation can be specially oriented toward an optimized combination of properties, particularly in relation to the requisite degree of ductility.
• the alloy according to the invention may contain
• the ratio Mn/Ni of the elementary contents of the elements manganese and nickel may preferably lie between 0.7 and 1.3. With a higher silicon content, particularly in conjunction with the preferred Mn/Ni ratio, this material has good plasticizability. This is important particularly for friction bearing elements which need to receive their bearing partners by producing a press-fit connection just before operation.
• the structure comprises a ⁇ -phase content of up to 50 vol. % in the cast state. This is regarded as a necessary prerequisite for sufficiently good hot formability of the copper alloy by extrusion.
• the structure comprises a ⁇ -phase content of up to 45 vol. %, the mixed silicides of Fe—Ni—Mn up to 20 vol. % and a remainder of ⁇ -phase.
• this alloy ensures advantageous heat resistance of the structure with sufficient ductility properties as well as a suitable complex wear resistance of the components.
• the high silicide content contributes to improving the frictional and lubricant-failure properties in bearing elements, so that the omission of the Pb content can be compensated for.
• the demand for improved environmental compatibility of these machine and system components has therefore likewise been accommodated.
• the ratio R p0.2 /R m of the values for the yield point and tensile strength of the alloy may advantageously lie between 0.5 and 0.95.
• Another aspect of the invention relates to a method for producing tubes or rods made of the copper-zinc alloy according the invention, wherein a post-processing of the alloy comprises the following steps:
• tubes and rods may be used as starting material for the machining manufacture of friction bearing elements.
• Another alternative aspect of the invention relates to a method for producing tubes or rods made of the copper-zinc alloy according the invention, wherein a post-processing of the alloy comprises the following steps:
• the forming may be followed by a stress-relieving anneal in a temperature range of from 250 to 450° C.
• the copper-zinc alloy according to the invention may be used for friction bearing elements in combustion engines, transmissions or hydraulic equipment.
• Cast bolts made of the copper-zinc alloy according to the invention were produced by ingot casting.
• the chemical composition of the castings is shown in Tab. 1.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Sliding-Contact Bearings (AREA)
• Forging (AREA)

Applications Claiming Priority (3)

Publications (1)

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Family Applications (1)

Country Status (2)

Cited By (25)

Families Citing this family (9)

Citations (6)

Family Cites Families (7)

• 2007
  • 2007-06-28 DE DE102007029991A patent/DE102007029991B4/de active Active
  • 2007-06-28 DE DE102007063643A patent/DE102007063643B4/de active Active
• 2008
  • 2008-06-25 US US12/215,191 patent/US20090022620A1/en not_active Abandoned

Patent Citations (6)

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