Bearing component having a metallic base body and an alloy-steel coating

Abstract

A bearing component such as a bearing ring includes a metallic base body and at least one alloy steel coating on the base body, the coating being applied to the base body by deposition welding. The base body is preferably non-alloy steel or cast iron, and the alloy includes at least one carbide-forming transition metal such as niobium, tantalum, zirconium, titanium, hafnium, tungsten, molybdenum, vanadium, or manganese. The coating can form a raceway of the bearing component or a structural element such as a flange. Also a method of forming such a bearing component is provided.

Claims

1. A bearing component, including: a metallic base body constituting a core of the bearing component and being composed of a non-alloy steel; and at least one alloy steel coating forming a cladding that is fused to a raceway surface of the core; wherein: the non-alloy steel has a composition (in wt %) of C: ≤0.4, Mn: ≤1.60, Ni: ≤0.4, P: ≤0.05, S: ≤0.05, Si: ≤0.4, Cr: ≤0.4, Mo: ≤0.1, N: ≤0.009, the remainder being iron and unavoidable impurities; and the cladding has a composition (in wt %) of C: 0.93-1.05, Si: 0.15-0.75, Mn: 0.25-1.20, P: ≤0.025, S: ≤0.015, Cr: 1.35-2.05, Mo: ≤0.060, Al: ≤0.050, Cu: ≤0.30, and a total of 0.5-3 wt % of the at least one carbide-forming transition metal, which is selected from the group consisting of Nb, Ta, and Zr, the remainder being iron and unavoidable impurities.

2. The bearing component according to claim 1, wherein: the cladding has a thickness that is between 1-10% of a total thickness of the core and the cladding; the core and the cladding each contain at least 70 volume % martensitic and/or bainitic microstructure; the cladding contains between 1-10 volume % of carbide-transition metal particles; the carbide-transition metal particles in the cladding have a number-weighted average particle size of 1 micron or less; the at least one carbide-forming transition metal includes at least Nb; and the bearing component is a bearing ring.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 is a schematic cross-sectional view of a rolling-element bearing according to the present disclosure.

DETAILED DESCRIPTION

(2) In the following, identical or functionally equivalent elements are designated by the same reference numbers.

(3) In FIG. 1 a rolling-element bearing 1 is illustrated that includes a bearing inner ring 2 having a raceway 9 and a bearing outer ring 3 having a raceway 10. Rolling elements 4 are disposed therebetween that roll on the raceways 9, 10.

(4) The bearing inner ring 2 includes a base body (core) 5 that forms the bearing inner ring 2 and a metallic coating (cladding) 6 applied onto the base body 5, which metallic coating 6 forms the raceway for the rolling elements 4. Here the coating 6 is applied onto the base body 5 by deposition welding (cladding, e.g., laser cladding).

(5) The base body 5 optionally may be manufactured from a non-alloy steel, for example, S235, S355, C22, or C35. In such embodiments of the present teachings, the base body 5 can be manufactured relatively cost-effectively due to the selection of a less expensive material for the core. The coating 6 itself includes an alloy steel, which enables the required hardness and rolling contact fatigue resistance to be achieved for the raceway 9.

(6) According to one preferred exemplary embodiment the alloy of the coating 6 comprises the through-hardened rolling-element-bearing steel 100Cr6 as the base steel, and the transition metal zirconium in a concentration of 2.0 wt. % as a further component. This comparatively high proportion of the transition metal zirconium can be made possible in the alloy since the coating 6 is applied onto the base body 5 by the deposition welding process, wherein the alloy is formed “in situ” in the welding process. It is noted, for purposes of comparison, that such a high proportion of the transition metal can be achieved using known steel manufacturing techniques only with considerable technical effort.

(7) The bearing outer ring 3 also may be formed in an analogous manner; in particular, the bearing outer ring 3 may include a base body 7 and a coating 8 that is applied in a similar manner onto the raceway of the bearing outer ring 3.

(8) In summary a bearing component is provided that includes a base body and a coating, wherein the coating is distinguished by exhibiting a particularly high hardness and rolling wear resistance. Here the coating is formed on the base body “in situ” during a deposition welding process. In comparison to conventional melt-metallurgical steel manufacturing, with subsequent precipitation of carbides, carbonitrides, or nitrides, e.g., in the context of a heat treatment, using the inventive method, slag losses in particular can be more easily avoided during steel manufacturing.

(9) Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved bearing components having metallic base bodies and an alloy-steel coating.

(10) Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

(11) All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

REFERENCE NUMBER LIST

(12) 1 Rolling-element bearing 2 Bearing inner ring 3 Bearing outer ring 4 Rolling element 5 Base body of the bearing inner ring 6 Coating of the bearing inner ring 7 Base body of the bearing outer ring 8 Coating of the bearing outer ring 9 Raceway of the bearing inner ring 10 Raceway of the bearing outer ring