Process for producing a protective coating on a brake side of a brake disk main element and process for producing a brake disk

Abstract

A process for producing a protective coating on a brake side of a brake disk main element includes using a laser powder build-up welding process. An NbC metal matrix powder or a Cr.sub.3C.sub.2 metal matrix powder is produced by agglomeration and sintering of NbC particles or Cr.sub.3C.sub.2 particles with particles of a metallic matrix composed of a stainless steel. During the laser powder build-up welding process, the NbC metal matrix powder or the Cr.sub.3C.sub.2 metal matrix powder and an aluminum alloy powder is supplied simultaneously to a molten surface region of the brake disk main element which has been melted by a laser.

Claims

1. A process for producing a protective coating at least on a brake side of a brake disk main element, the process comprising: producing at least one of an NbC metal matrix powder and a Cr.sub.3C.sub.2 metal matrix powder by agglomeration and sintering at least one of NbC particles and Cr.sub.3C.sub.2 particles, respectively, with particles of a metallic matrix composed of a stainless steel; and producing a protective coating using a laser powder build-up welding process, wherein during the laser powder build-up welding process the at least one of the NbC metal matrix powder and the Cr.sub.3C.sub.2 metal matrix powder is supplied simultaneously with an aluminum alloy powder to a molten surface region of the brake disk main element melted by a laser.

2. The process according to claim 1, wherein the NbC metal matrix powder is NbC—FeCr powder and the Cr.sub.3C.sub.2 metal matrix powder is Cr.sub.2C.sub.2—FeCr powder.

3. The process according to claim 1, wherein the aluminum alloy powder is an aluminum-silicon alloy powder.

4. The process according to claim 1, wherein a proportion of silicon in the aluminum alloy powder is between 12% by weight and 50% by weight.

5. The process according to claim 1, wherein the NbC metal matrix powder and the Cr.sub.3C.sub.2 metal matrix powder have a particle size in a range from 10 μm to 125 μm.

6. The process according to claim 1, wherein the NbC metal matrix powder and the Cr.sub.3C.sub.2 metal matrix powder have a particle size in a range from 15 μm to 45 μm.

7. The process according to claim 1, wherein a proportion of NbC in the NbC metal matrix powder and a proportion of Cr.sub.3C.sub.2 in the Cr.sub.3C.sub.2 metal matrix powder is in the range from 50% by weight to 90% by weight.

8. The process according to claim 1, wherein a proportion of NbC in the NbC metal matrix powder is in a range of 75% by weight to 85% by weight and a proportion of Cr.sub.3C.sub.2 in the Cr.sub.3C.sub.2 metal matrix powder is in a range from 70% by weight to 80% by weight.

9. The process according to claim 1, wherein the laser powder build-up welding process is carried out using a multijet nozzle with at least four jets.

10. The process according to claim 1, wherein the laser powder build-up welding process is carried out using a multijet nozzle with six jets.

11. The process according to claim 1, wherein at least one of copper, iron, chromium and nickel are supplied simultaneously to the molten surface region of the brake disk main element during the laser powder build-up welding process.

12. The process according to claim 1, wherein the brake side of the brake disk main element is composed of a gray cast iron and an aluminum alloy spray layer is applied to the brake side of the brake disk main element before carrying out the laser powder build-up welding process.

13. The process according to claim 12, wherein the aluminum alloy spray layer is sintered together with the brake disk main element during the laser powder build-up welding process and the aluminum alloy spray layer is an Al—Mg spray layer.

14. A process for producing a brake disk with a brake disk main element composed of aluminum or an aluminum alloy, wherein a protective coating is produced at least on the brake side of the brake disk main element using the process according to claim 1.

15. A process for producing a brake disk with a brake disk main element made of gray cast iron material, wherein an aluminum alloy spray layer is applied to the brake side of the brake disk main element made of gray cast iron, the spray layer is sintered together with the brake disk main element and a protective coating is produced at least on the brake side using the process according to claim 1.

16. The process according to claim 15, wherein the aluminum alloy spray layer is an Al—Mg spray layer.

17. The process according to claim 15, wherein the brake side of the brake disk main element is roughened before application of the spray layer.

18. The process according to claim 15, wherein the brake side of the brake disk main element is subjected to a turning process before roughening.

19. A process for producing a protective coating at least on a brake side of a brake disk main element, the process comprising: producing at least one of an NbC—FeCr powder and a Cr.sub.3C.sub.2—FeCr powder by agglomeration and sintering of at least one of NbC particles and Cr.sub.3C.sub.2 particles, respectively, with particles of a metallic matrix composed of a stainless steel; and producing a protective coating using a laser powder build-up welding process, wherein during the laser powder build-up welding process the at least one of the NbC—FeCr powder and the Cr.sub.3C.sub.2—FeCr powder is supplied simultaneously with an aluminum alloy powder to a molten surface region of the brake disk main element melted by a laser.

20. The process according to claim 19, wherein at least one of copper, iron, chromium and nickel is supplied simultaneously to the molten surface region of the brake disk main element during the laser powder build-up welding process.

Description

DRAWINGS

(1) In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

(2) FIG. 1 shows a flow diagram for a working example of a process according to one form of the present disclosure for producing a brake disk; and

(3) FIG. 2 shows a flow diagram for a further working example of a process according to another form of the present disclosure for producing a brake disk.

(4) The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

(5) The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

(6) FIG. 1 shows a flow diagram for a working example of a process according to one form of the present disclosure for producing a brake disk.

(7) In process step 101, an NbC metal matrix powder or a Cr.sub.3C.sub.2 metal matrix powder is produced by agglomeration and sintering of NbC particles or Cr.sub.3C.sub.2 particles and particles of a metallic matrix composed of a stainless steel. In one form of the present disclosure, the metallic matrix is composed of an FeCr. It is in this way possible to produce, for example, an NbC—FeCr powder or Cr.sub.3C.sub.2—FeCr powder, where the NbC metal matrix powder or the Cr.sub.3C.sub.2 metal matrix powder will hereinafter be referred to as NbC—FeCr powder or as Cr.sub.3C.sub.2—FeCr powder, respectively, however the present disclosure is not restricted thereto. Here, the NbC—FeCr powder or Cr.sub.3C.sub.2—FeCr powder is produced so that a size of particles of the NbC—FeCr powder or Cr.sub.3C.sub.2—FeCr powder is in the range from 10 μm to 125 μm, or from 15 μm to 45 μm. The proportion of NbC in the NbC—FeCr powder or the proportion of Cr.sub.3C.sub.2 in the Cr.sub.3C.sub.2 FeCr powder is in the range from 50% by weight to 90% by weight, or from 75% by weight to 85% by weight in the case of NbC and from 70% by weight to 80% by weight in the case of Cr.sub.3C.sub.2.

(8) In process step 102, a brake disk main element is produced from aluminum or an aluminum alloy. Various production methods may be employed. Apart from casting of aluminum alloys, in one form Al—Si-based alloys having a silicon content of from 7% by weight to 22%, by weight the brake disk main element can also be produced by forming or forging or powder metallurgically or by joining of components, for example by friction welding of rings composed of an aluminum alloy onto brake disk pots composed of the same or different materials.

(9) In some variations of the present disclosure, the order of the process steps 101 and 102 may be reversed. Both the brake disk main element as substrate and the NbC—FeCr powder or the Cr.sub.3C.sub.2—FeCr powder and optionally further desired powders for setting a metallic matrix have to be provided at the same time for the laser powder build-up welding process.

(10) In process step 103, a protective coating is produced on a brake side or on two brake sides of the brake disk main element, i.e. on the friction ring of the brake disk main element, using a laser powder build-up welding process. During the laser powder build-up welding process, the NbC—FeCr powder or the Cr.sub.3C.sub.2—FeCr powder and optionally further powders for setting a desired metallic matrix based on aluminum are supplied simultaneously to a surface region of the brake disk main element which has been melted by a laser. The further powder supplied is based on aluminum and in its total composition may have a proportion of silicon of from 12% by weight to 50% by weight and can be referred to as aluminum-silicon powder. In addition, proportions of copper, iron, chromium and/or nickel can be present, but the proportion of these is limited so that a total amount of not more than 15% by weight of these elements is present in the metallic matrix of the protective coating in order to inhibit embrittlement of the metallic matrix.

(11) FIG. 2 shows a flow diagram for a further working example of a process according to another form of the present disclosure for producing a brake disk.

(12) In process step 201, an NbC metal matrix powder or a Cr.sub.3C.sub.2 metal matrix powder is produced by agglomeration and sintering of NbC particles or Cr.sub.3C.sub.2 particles and particles of a metallic matrix composed of a stainless steel, i.e., for example, FeCr, so as to produce, for example, NbC—FeCr powder or Cr.sub.3C.sub.2—FeCr powder. Here, the NbC metal matrix powder or Cr.sub.3C.sub.2 metal matrix powder is produced in such a way that a size of particles of the NbC metal matrix powder or Cr.sub.3C.sub.2 metal matrix powder is in the range from 10 μm to 125 μm, or in the range from 15 μm to 45 μm. A proportion of NbC in the NbC metal matrix powder or a proportion of Cr.sub.3C.sub.2 in the Cr.sub.3C.sub.2 metal matrix powder is in the range from 50% by weight to 90% by weight, or from 75% by weight to 85% by weight in the case of NbC and from 70% by weight to 80% by weight in the case of Cr.sub.3C.sub.2.

(13) In process step 202, a brake disk main element is produced from a gray cast iron material. The production operation in process step 202 can comprise casting and cooling of the brake disk main element. In addition, the production operation in process step 202 can encompass machining in the form of turning the brake disk main element. Furthermore, the production operation in process step 202 encompasses roughening the brake side of the brake disk main element by water blasting.

(14) In some variations, the order of process steps 201 and 202 may be reversed.

(15) In process step 203, an aluminum alloy spray layer is applied, for example, by electric arc spraying to the roughened brake side of the brake disk main element. The aluminum alloy spray layer may be an Al—Mg spray layer.

(16) In process step 204, the spray layer is sintered together with the brake disk main element at about 570° C. for about 30 minutes.

(17) In process step 205, a protective coating is produced on a brake side or two brake sides using a laser powder build-up welding process. During the laser powder build-up welding process, the NbC metal matrix powder or Cr.sub.3C.sub.2 metal matrix powder and powder for the targeted setting of an aluminum alloy matrix are simultaneously supplied to a surface region of the protective layer which has been melted by a laser used for this purpose. The proportion of silicon in the aluminum alloy powder may be in the range from 12% by weight to 50% by weight. During the laser powder build-up welding process, the elements copper, iron, chromium and/or nickel can be supplied to the molten surface region of the protective layer in order to achieve an increase in strength of the metallic matrix by formation of fine precipitates of intermetallic phases with aluminum. In order to provide fine distribution of the precipitates and thus inhibit embrittlement of the metallic matrix, the total content of the elements copper, iron, chromium and/or nickel should be limited to not more than 15% by weight in the protective coating.

(18) Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.

(19) As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

(20) The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.