Chain element, chain pin, and method for producing same

Abstract

Chain element (2), particularly a chain pin (4) for joining at least two chain links (3), which element is formed from a base material (5) containing carbon, particularly steel, characterized in that it has a surface layer (7) containing boron and vanadium, wherein the surface layer (7) is produced by a method according to which, in a first method step, an intermediate layer (6) containing carbon and vanadium is formed by at least one measure for the diffusion of vanadium into surface regions close to the surface of the base material (5) and, in a subsequent second method step, the surface layer (7) is formed by the transformation of the intermediate layer (6) by at least one measure for the diffusion of boron into the intermediate layer (6).

Claims

1. A method for the production of a chain element formed from a substrate material containing carbon with a surface layer containing boron and vanadium, comprising the steps of: performing a first diffusion process of vanadium into areas of a substrate material containing carbon and forming a chain element, the areas are close to a surface thereof for constructing an intermediate layer containing carbon and vanadium and subsequently, performing a second diffusion process of boron into the intermediate layer, so that the intermediate layer is completely converted into a surface layer via formation of the surface layer containing the boron and the vanadium, such that the intermediate layer is no longer present, wherein the intermediate layer is formed with a thickness of 1-5 microns and the surface layer is formed with a thickness of 5-20 microns.

2. The method according to claim 1, further comprising performing a vanadizing process of the substrate material for the diffusion of the vanadium into areas of the substrate material close to the surface for the construction of the intermediate layer containing the carbon and the vanadium and performing a borizing process as the diffusion of the boron into the intermediate layer for the construction of the surface layer containing the boron and the vanadium.

3. The method according to claim 1, further comprising performing the diffusion of the vanadium into areas of the substrate material close to the surface for the construction of the intermediate layer containing carbon and the vanadium at a temperature range of 900-1300 C., and performing the diffusion of the boron into the intermediate layer for the construction of the surface layer containing the boron and the vanadium at a temperature range of 800-1100 C.

4. The method according to claim 1, further comprising performing the diffusion of the vanadium into areas of the substrate material close to the surface for the construction of the intermediate layer containing the carbon and the vanadium and the diffusion of the boron into the intermediate layer for the construction of the surface layer containing the boron and the vanadium for a duration of 1-24 hours.

5. A chain element, produced in accordance with the method according to claim 1.

6. A chain pin for connecting two chain links, produced in accordance with the method according to claim 1.

7. The method according to claim 1, wherein the first diffusion process includes chemically reacting a gaseous vanadium-chloride compound with the substrate material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) One embodiment of the invention is shown in the drawing and will be described in more detail below. Shown are:

(2) FIG. 1 a characteristic section of a chain comprising multiple chain elements,

(3) FIG. 2 a chain element in the form of a chain pin for connecting at least two chain links of a chain, and

(4) FIGS. 3-6 the essential processing steps during the production of a chain element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) FIG. 1 shows a characteristic cutout of a chain 1 comprising multiple chain elements 2. The chain 1 can be constructed as a toothed chain and used, for example, for transmitting force in the drive train or as part of the drive train of a motor vehicle.

(6) Clearly the chain 1 comprises multiple chain elements 2 in the form of chain links 3, in particular, clip-shaped links, which are arranged one after the other and are connected to each other by chain pins 4. FIG. 2 shows a separate representation of a chain element 2 in the form of a chain pin 4 for connecting at least two chain links 3 of a chain 1.

(7) The chain elements 2 forming the chain 1, that is, the chain links 3 and the chain pins 4, are formed from a metallic substrate material 5, in particular, a steel, e.g., CK75, based on carbon and iron. The chain elements 2 have been subjected to two different thermochemical surface treatments.

(8) After the preparation (see FIG. 3) of a chain element 2 formed from a substrate material 5, i.e., a steel, e.g., CK75, containing carbon and iron, as a first step a measure for the diffusion of vanadium into the substrate material 5 of the chain element 2 is performed, wherein an intermediate layer 6 directly adjacent to the substrate material 5 is formed that contains essentially carbon and vanadium or carbon-vanadium compounds, in particular, vanadium carbide (VC) (see FIG. 4).

(9) Then a measure for the diffusion of boron into the intermediate layer 6 is performed, wherein the intermediate layer 6 is converted completely into a surface layer 7 (see FIG. 5), i.e., a surface layer 7 is formed that contains essentially boron and vanadium or boron-vanadium compounds, in particular, vanadium boride (VB.sub.2) (see FIG. 6).

(10) Consequently, the intermediate layer 6 exists only temporarily and is no longer present after the surface layer 7 is formed by the complete conversion of the intermediate layer 6.

(11) The surface layer 7 can be considered as the outer surface of the chain element 2.

(12) Specifically, as a measure for the construction of the intermediate layer 6, a thermochemical vanadizing process of the chain element 2 is performed, in which vanadium atoms or vanadium compounds diffuse into the substrate material 5 of the chain element 2 from a powder containing vanadium or vanadium compounds applied onto the chain element 2 or a paste containing vanadium or vanadium compounds at elevated temperatures in the range of 950-1250 C., wherein this process forms the intermediate layer 6.

(13) As the subsequently performed measure for converting the intermediate layer 6 or for forming the surface layer 7, a thermochemical borizing process of the intermediate layer 6 is performed, in which boron atoms or boron compounds diffuse into the intermediate layer 6 containing essentially vanadium-carbon compounds, such as vanadium carbide, from a powder containing boron or boron compounds applied on the intermediate layer 6 or a paste containing boron or boron compounds at elevated temperatures in the range of 950-1000 C., wherein this process converts the intermediate layer 6 into the surface layer 7 and forms the surface layer 7.

(14) The processing duration for performing the vanadizing process or the subsequent borizing process can equal, e.g., overall, 6 hours.

(15) The formed surface layer 7 has, e.g., a thickness of approx. 20 m.

(16) The hardness of the surface layer 7 is approx. 2500 HV (Vickers hardness).

(17) The surface layer 7 imparts an improved characteristics profile to the chain element 2, wherein, in particular, the wear resistance and also the corrosion resistance are improved due to the high hardness in the range of approx. 2500 HV of the surface layer 7.

(18) The production of a chain element 2, in particular, of a chain pin 4 for connecting at least two chain links 3, with a surface layer 7 containing boron and vanadium is performed by a method with the steps of preparing a chain element 2 (see FIG. 3) formed from a substrate material 5, in particular, steel, containing carbon, performing at least one measure for the diffusion of vanadium into areas of the substrate material 5 close to the surface for forming an intermediate layer 6 (see FIG. 4) containing carbon and vanadium, and subsequently performing at least one measure for the diffusion of boron into the intermediate layer 6, so that the intermediate layer 6 is converted into the surface layer 7 (see FIGS. 5, 6) under the formation of the surface layer 7 containing boron and vanadium.

(19) As mentioned, as a measure for the diffusion of vanadium into areas of the substrate material 5 of the chain element 2 close to the surface for forming the intermediate layer 6 containing carbon and vanadium, preferably a thermochemical vanadizing process of the substrate material 5 is performed and as a measure for the diffusion of boron into the intermediate layer 6 for forming the surface layer 7 containing boron and vanadium, preferably a thermochemical borizing process of the intermediate layer 6 is performed.

LIST OF REFERENCE NUMBERS

(20) 1 Chain 2 Chain element 3 Chain link 4 Chain pin 5 Substrate material 6 Intermediate layer 7 Surface layer