Valve seat ring

Abstract

The invention relates to a highly heat conductive valve seat ring (1) comprising a carrier layer (2) and a functional layer (3), wherein the carrier layer (2) consists of a solidified copper matrix containing 0.10 to 20% w/w of a solidifying component and the functional layer (3) consists of a solidified copper matrix which further contains, based on the copper matrix, 5 to 35% w/w of one or more hard phases.

Claims

1. A valve seat ring (1) consisting of a carrier layer (2) and a functional layer (3), wherein: the carrier layer (2) forming a base and being superimposed with the functional layer (3), the carrier layer (2) and the functional layer (3) having a contact zone between them having a pressure and temperature formed transition area; the carrier layer (2) consists of a first solidified copper matrix containing 0.10 to 20% w/w of a solidifying component selected from: aluminum oxide (Al.sub.2O.sub.3), yttrium oxide (Y.sub.2O.sub.3), silicon dioxide (SiO.sub.2), rare earth metal oxides, and titanium dioxide (TiO.sub.2); and the functional layer (3) consists of a second solidified copper matrix containing, 5 to 35% w/w of one or more hard phases selected from: iron-based HS 6-5-4, iron-based FeMo29Cr9.5Si2.6, cobalt-based 28Mo-9Cr-2.6Si-0.04C, cobalt-based 28Mo-17Cr-3.4Si-0.04C, cobalt-based 23Mo-17Cr-16Ni-2.7Si-0.04C, tungsten carbide (WC), silicon carbide (SiC), titanium carbide (TiC) and chromium carbide (CrC), titanium nitride (TiN), chromium nitride (CrN) and cubic boron nitride (CBN).

2. The valve seat ring according to claim 1, characterized in that the solidifying component is aluminum oxide (Al.sub.2O.sub.3).

3. The valve seat ring according to claim 1, characterized in that the functional layer contains 0.1 to 5% w/w of a solid lubricant selected from: MnS, MoS.sub.2, WS.sub.2, CaF.sub.2 or hexagonal BN.

4. The valve seat ring according to claim 1, characterized in that a dividing line between carrier layer (2) and functional layer (3) extends at an angle of 0° to 65°, with the carrier layer (2) widening towards the outside thereby determining the slope of the dividing line.

5. The valve seat ring according to claim 1, characterized in that a thermal conductivity of the carrier layer (2) is ≥ (greater than or equal to) 120 W/mK at 500° C.

6. The valve seat ring according to claim 1, characterized in that a thermal conductivity of the functional layer (3) is ≥ (greater than or equal to) 70 W/mK at 500° C.

7. The valve seat ring according to claim 1, characterized in that the valve seat rind is manufactured by powder metallurgy.

8. The valve seat ring according to claim 1, characterized in that the valve seat ring is provided with a coating.

9. The valve seat ring according to claim 4, characterized in that the dividing line extends at an angle of between 35° and 65°.

10. The valve seat ring according to claim 5, characterized in that the thermal conductivity of the carrier layer (2) is ≥ (greater than or equal to) 220 W/mK at 500° C.

11. A method of manufacturing the valve seat ring according to claim 1, characterized by the following steps: Providing respective powders for the carrier layer and the functional layer, Mixing the respective powders for the carrier layer and the functional layer, Filling the powder of the carrier layer (2) into a molding die, Optionally pre-compacting the powder of the carrier layer (2), Filling the powder of the functional layer (3) into the molding die, Compacting the respective powders in the molding die, Forming the carrier layer and functional layer by simultaneously sintering and optionally subjecting the respective powders to hot isostatic process in the molding die to form a sintered ring with the contact zone between the carrier layer and the functional layer, the contact zone having the pressure and temperature formed transition area, and Thermally or mechanically after-treating the sintered ring.

12. The method according to claim 11, characterized in that the respective powders are post-compacted and/or post-sintered after the forming step.

13. The method according to claim 11, characterized in that the simultaneous sintering is carried out at a temperature of ≥ (greater than or equal to) 850° C.

14. The method according to claim 11, characterized in that the compacting the respective powders is carried out by means of cold isostatic pressing.

Description

(1) The invention is explained in more detail by way of the enclosed figures.

(2) FIG. 1 shows a valve seat ring 1 as proposed by the invention in cross sectional representation with a lower carrier layer 2 and a functional layer 3 arranged on it. The dividing line between the two layers is essentially horizontal.

(3) FIG. 2 is a cross-sectional view through a valve seat ring 1 according to the invention with an inclined dividing line existing between the carrier layer 2 and the functional layer 3. The carrier layer 2 thus expands towards the outer edge and in this manner increases the contact surface with the surrounding cylinder head. This results in an improved heat flow to be achieved into the cooled cylinder head. Between the layers there is a transition area 4, in which the dividing line runs between the carrier layer 2 and the functional layer 3.

(4) In FIG. 3 the thermal conductivity values of different materials within the scope of the invention are shown at different temperatures. The materials are as follows:

(5) 1. A carrier material consisting of oxide-reinforced copper; 2. A functional material with 20% of a hard phase; 3. A functional material with 30% of a hard phase; 4. A functional material with 40% of a hard phase.

(6) For all functional materials, the carrier matrix is the same as in the carrier material.

(7) TABLE-US-00001 TABLE 1 Base material for the carrier layer Thermal conductivity [W/mk] Chemical composition [% w/w] Designation Strength due to 20° C. 400° C. Cu Al.sub.2O.sub.3 Cr Zr Nb Ag Ni Si Cu + Al.sub.2O.sub.3 Al.sub.2O.sub.3 322-344 280-320 Base 0.1-1.1 Cu + Cr.sub.2Nb Cr.sub.2Nb 280-345 290-350 Base 1.5-6.5 3.6-5.5 up to 4.9 Cu + CrZr Cu.sub.5Zr/Cr.sub.2Zr/Cr 280-380 300-370 Base up to 0.08-0.5 up to 3 0.8 Cu + NiSi Ni.sub.2Si/Ni.sub.3Si/Ni.sub.31Si.sub.12 180 225 Base 0.5 2.4 0.7

(8) TABLE-US-00002 TABLE 2 Hard phase for the functional layer a) Alloying powder forming intermetallic phases Chemical composition [% w/w] Designation Fe Co C Mo V Si Cr Ni HS 6-5-4 Base max. 1.0 1.15-1.40 4.25-5.25 3.75-4.75 FeMo29Cr9.5Si2.6 Base max. 0.03 28.0-30.0 2.20-3.20 8.50-10.50 28Mo—9Cr—2.6Si—0.04C Base max. 0.15 27.0-29.0 2.50-3.50 7.0-9.0 max. 3 28Mo—17Cr—3.4Si—0.04C Base max. 0.15 27.0-29.0 3.4 17.5 max. 3 23Mo—17Cr—16Ni—2.7Si—0.04C Base 23 2.7 18   18 b) Carbidic ceramics c) Oxidic Ceramics d) Nitridic Ceramics Designation Designation Designation WC Tungsten carbide Al.sub.2O.sub.3 Aluminum oxide CBN Cubic boron nitride SIC Silicon carbide Y.sub.2O.sub.3 Yttrium oxide TIN Titanium nitride TIC Titanium carbide CrN Chromium nitride CrC Chromium carbide