WO2017059467A1

WO2017059467A1 - Component of a metal processing machine

Info

Publication number: WO2017059467A1
Application number: PCT/AT2016/000081
Authority: WO
Inventors: Bernhard MAYR-SCHMÖLZER; Martin Kathrein; Michael ANDROSCH; Thomas Huber
Original assignee: Plansee Se
Priority date: 2015-10-05
Filing date: 2016-09-02
Publication date: 2017-04-13
Also published as: AT14986U1

Abstract

The invention relates to a component of a metal processing machine, produced from a refractory metal (RM), selected from the group consisting of tungsten (W), W alloy, molybdenum (Mo), and Mo alloy, wherein at least parts of at least one surface of the component have a layer composed, at least in parts, of at least one compound of at least one element selected from the group consisting of carbon (C), boron (B) and nitrogen (N) with at least one element selected from the group consisting of W and Mo.

Description

COMPONENT OF A METAL PROCESSING MACHINE

The invention relates to a component of a metal processing machine made of a refractory metal (RM) selected from the group consisting of tungsten (W), W alloy, molybdenum (Mo) and Mo alloy. Furthermore, the invention relates to a method for producing such a component.

Metalworking machines, such as extrusion presses and forming units, contain components such as dies, dies, foundry molds, mandrels, etc.

These components are during operation of the

Metal processing machine high thermal and abrasive loads due to the processed metal melts or on

Forming temperature exposed to heated metals. Component damage occurs as a result of thermal stress as well as chemical and mechanical erosion. In addition, alloying or the formation of intermetallic phases between the components and the processed metal may occur. This leads to material removal on the surface of the components and it can lead to contamination of the metals to be processed or damage to the components of the machine.

The challenges in the operation of metal processing machines consist in the reduction of the wear of the components. Developments are therefore aimed at increasing the resistance of the components to the

increase prevailing conditions to achieve longer operating times. An increase in operating times also reduces, among other things, the operating costs of a metal processing machine.

Some ways to increase the life of such components have already been described in the relevant literature.

For the processing of metals such as aluminum or copper are often used as base material for corresponding components steels, as well

Refractory metals or their alloys used. The processing of metals such as aluminum or copper takes place at temperatures of about 500- 700 ° C or 750-1000 ° C and therefore exerts not only a purely thermal load, but also a high chemical load on the materials used .. The life of components of

Metal processing machines, for example, for aluminum or copper is therefore often greatly reduced.

Other problems that occur in the processing of metals and often lead to failure of components of metal processing machines are, for example, the formation of intermetallic, often brittle phases, the formation of low-melting eutectics or alloying.

For example, JP2007038251 A discloses a method of increasing the life of a forging mandrel of iron by diffusion coating with carbon.

Further known from the prior art by means of gas phase reactions, such as chemical vapor deposition (CVD) or gas phase nitriding, on corresponding base materials of corresponding components

deposited hard material layers to increase the wear resistance of the respective components.

However, the solutions known from the prior art often have poor adhesion to the base material, resulting in material removal and contamination of the metals to be processed or damage to the

Components of the machine can lead.

Furthermore, it is often desirable not to provide the entire surface of the base material with a wear protection layer, which is very poorly possible, for example, in deposited by a CVD method layers. The object of the invention is therefore to provide a solution, whereby the disadvantages described above can be avoided. In particular, it is an object of the invention to provide a solution in which the components of a metal processing machine have a higher resistance to the mentioned loads and thereby the service life of the

Components and thus the metal processing machine is increased.

In particular, the present invention is the material removal of

Reduce components, which reduces contamination or damage to the metals to be processed. This object is solved by the independent claims. Preferred embodiments are given in the subclaims.

A component of a metal processing machine according to the invention is made of a refractory metal (RM) selected from the group consisting of tungsten (W), W alloy, molybdenum (Mo) and Mo alloy and is characterized in that at least one surface of the component at least partially Layer, which is at least partially formed of at least one compound of at least one element selected from the group consisting of carbon (C), boron (B) and nitrogen (N) with at least one element selected from the group consisting of W and Mo. ,

The component according to the invention is preferably a die, a die a mandrel or a foundry mold.

The component is made of a refractory metal, wherein the

Refractory metal is selected from the group consisting of tungsten (W), W alloy, molybdenum (Mo) and Mo alloy. W, W alloys, Mo and Mo alloys are also abbreviated to RM in the following text. Therefore, an RM component is a component made of W, a W alloy, Mo, or a Mo alloy.

A surface of the RM component has, at least in regions, a layer which, at least in regions, comprises at least one compound of at least one element selected from the group consisting of

Carbon (C), boron (B) and nitrogen (N), with at least one element selected from the group consisting of W and Mo, is formed.

In the solution according to the invention, both the base body /

Base material, as well as the layer on a RM. In the context of the invention, the basic bodies are the areas of the component which have no layer or no layer yet.

It has now been found that by the embodiment according to the invention

Film adhesion problems, as observed in the prior art, do not occur. The components according to the invention are also significantly more resistant to a broad field of use conditions, compared to uncoated components of W, W alloys, Mo or Mo alloys.

Particularly advantageous compounds are the carbides, borides and nitrides. However, it is also excellent compounds that contain at least two elements of the group consisting of C, B and N in addition to W and / or Mo. For example, with compounds containing both C and B, excellent lifetime results could be achieved.

Preferably, the layer as RM on that element which also forms the majority of the main body. So it is advantageous if, for example, the base body is made of molybdenum or a molybdenum alloy, that the layer is formed by a compound of molybdenum. For example, excellent results could be achieved if the

Base body of the component is made of Mo and the layer comprises Mo ₂ B, MoB, MoC, M02C, Mo ₂ N or MoN. It is particularly advantageous if in the production of the layer

Compound formation takes place by reaction of C, B and / or N with the W and / or Mo of the main body, since an excellent layer adhesion can be achieved thereby.

The layer can completely cover the base body or can also be applied only in places of highest stress. In addition, the layer can be single or multi-layered and / or of mixed phases with varying

Composition be executed. If a Mo-W alloy is used as the base body for the component, which represents an advantageous embodiment, then the compound may have Mo and W as metallic constituents. Therefore, in the list of advantageous borides, carbides and nitrides listed below, without adversely affecting the properties, W may be partially replaced by Mo or Mo in part by W.

Particularly advantageous binary compounds are W ₂ B, WB, W2B5,

Wi- _X B ₃ , WB ₄ , WC, W ₂ C, WN, W ₂ N, W ₃ N ₂ , Mo ₂ B, MoB, Mo ₃ B ₂ , M0B ₄ , MoC,

Mo ₂ C, MoN, Mo ₂ N and Mo ₃ N ₂ to name. In particularly advantageous ternary and quaternary compounds, the non-metallic constituent of the aforementioned binary compounds is partially replaced by a (for ternary Compounds) or two (for quaternary compounds) further element (s) from the group C, B and N replaced. For example, for WC, the ternary compounds W (C, N) and W (C, B) and as the quaternary compound W (C, B, N).

In addition to the respective stoichiometric compositions of the compound, these may additionally contain further elements, for example C, B, N, W and / or Mo, in dissolved form.

A further advantageous embodiment is a composite layer. A composite layer is to be understood as a layer which is composed of at least two phase regions. A particularly advantageous embodiment of the invention should be emphasized if the layer contains the phases WC and / or W ₂ C. Another particularly advantageous embodiment is given when the layer contains WB and / or W ₂ B. The combination of WC and / or W ₂ C and WB and / or W ₂ B represents a particularly advantageous

Embodiment of the invention. For example, the outermost region of the layer of WC and / or WB be formed, followed by a region having W ₂ B and / or W ₂ C phase. W ₂ B and / or W ₂ C are adjacent to the main body of W or a W alloy. In an analogous manner, for example, the outermost region of the layer may be formed from MoC and / or MoB, followed by a region adjoining Mo ₂ B and / or Mo ₂ C

Phase has. Mo ₂ B and / or Mo ₂ C are adjacent to the main body of Mo or a Mo alloy.

In a further advantageous embodiment, the layer is interlocked with the adjoining region of the base body. This gearing effect is achieved in a simple manner by the reaction of C, B and / or N with Mo and / or W of the main body. For this purpose, C and / or B and / or compounds of C, B and / or N are applied to the surface of the base body. By heating, C, B and / or N then diffuse into the

Basic body, where it comes to connecting formation. The toothing is advantageously formed by grains of the layer (for example and advantageously by W ₂ B, W ₂ C, Mo ₂ B and / or Mo ₂ C grains). When applying C and B to tungsten or molybdenum, for example, a carbide forms as the top layer layer, which is particularly resistant to wear. The introduction from N to the layer is preferably carried out by annealing in an N-containing atmosphere (reaction annealing). Preferably, NH ₃ or a mixture of at least two gases of the group consisting of NH ₃ , H ₂ and N ₂ and annealing temperatures, for example in the range 700 to 1 .300 ° C are used.

The advantageous average layer thickness can be selected within a wide range, with the preferred range being 1 to 300 μm, preferably 3 to 200 μm.

As advantageous materials for the main body are pure W, W - 0, 1 to 3 Ma% rare earth oxide, W heavy metal, pure Mo, Mo - titanium (Ti) - zirconium (Zr) - C (common name: TZM), Mo - hafnium (Hf) - C (common name: MHC) or Mo-W alloys. As a particularly suitable

Rare earth oxide is to strike out La ₂ 0 ₃ . W - La ₂ 0 ₃ has a significantly improved cutting behavior compared to pure W, whereby the manufacturing cost of the component can be significantly reduced. Pure-W or Rein-Mo are to be understood as meaning the metals of the usual technical purity.

Advantageously, the component has at least one of the following properties: The compound is selected from the group a or b, with:

Group a: carbides, borides and nitrides;

Group b: compound containing W and / or Mo and at least two

Elements of the group consisting of C, B and N.

The compound is selected from the group consisting of W ₂ B, WB, W ₂ B ₅ , Wi _-X B ₃ , WB ₄ , WC, W ₂ C, WN, W ₂ N, W ₃ N ₂ ; Mo ₂ B, MoB, Mo ₃ B ₂ , MoB ₄ ,

MoC, Mo ₂ C, MoN, Mo ₂ N and Mo ₃ N ₂ selected.

_ The layer is designed as a composite layer.

The composite layer has at least one region of a boride and at least one region of a carbide.

The outermost layer layer is at least partially formed by WC or WB.

_ The layer is interlocked with the adjoining base body. - The toothing is formed by grains of the layer. _ The RM component has the layer in places of high stress.

- At least one compound contains at least one element selected from the group consisting of B, C, N, W and Mo in dissolved form. The RM component is made of Rein-W, W-0.1 to 3% by mass rare earth oxide, W heavy metal, pure Mo Mo-Ti-Zr-C (TZM), Mo-Hf-C (MHC) or one Made of Mo-W alloy.

The object of the invention is also achieved by a method for producing an RM component.

The method has at least the following steps:

- Production of the geometry of the RM component by conventional

Method;

Applying at least one element and / or at least one

Compound of an element selected from the group consisting of C, B and N, preferably in powder or slurry form;

- Heat treatment to form a compound with at least one RM in vacuum, inert gas or reactive gas.

As usual methods for the production of the RM component are

Pressing / sintering process with subsequent mechanical processing,

Near-net-shape pressing / sintering, hot pressing, hot isostatic pressing, spark plasma sintering or metal powder injection molding to call.

After the geometry has been produced, at least one element or at least one of the regions which are to have the layer in use is produced

Compound of an element selected from the group consisting of C, B and N, applied. The application can be done for example by dumping, by brushing, by dipping or by spraying. Particularly suitable is the application of a slurry to mention, since it is also possible to coat parts with complex geometries in a simple and advantageous manner. After application of C and / or B and / or a C, B and / or N-containing compound, the component is placed in vacuum,

Inert gas or reactive gas heat treated. Suitable reactive gases are in particular gases or gas mixtures which are N (for example NH ₃ or a mixture of at least two gases of the group consisting of NH ₃ , H ₂ and N ₂ ), C (for example CH ₄ ) and / or B (for example BH ₃ ). The

In this case, the temperature is advantageously 700 to 2000 ° C. (annealing in vacuum) or 700 to 1300 ° C. (annealing in reactive gas), whereby the range which is most suitable for the respective compound can be determined by simple experiments. During the heat treatment, C, B and / or N then diffuse into the base material and together with it form the invention

Connection.

In conventional CVD methods, a layer is deposited on the outside of the base material. As a result, it may be that tolerances of the components can no longer be met and the components must be reworked. In the coating according to the invention, this is not necessary since the dimensional stability is ensured in this method.

In contrast, for example, to a gas phase nitration, in which the

Surface of the entire component, i. all areas which are achieved by the gas flow, nitrided and it is not possible to selectively expose certain areas, can be masked by the inventive method areas, whereby it is possible to apply the coating, for example, only in tribologically contaminated zones. By means of this targeted masking of the components, it is possible to realize hard or resistant as well as soft or tough regions on the same component.

Another advantage compared to gas-phase nitriding is that layer thicknesses in a wide range from 1 to 300 μm can be achieved with the method according to the invention. In gas phase nitriding only thicknesses of 1 to 15 pm can be achieved. Due to the higher layer thicknesses of the

Range of application, or the duration of use of the coated

Components are significantly extended.

The size of the components that can be coated is another distinguishing feature for gas-phase nitriding

Gas phase nitriding is not only the size of the plant, but also the

Gas guidance in this crucial. In the case of uneven gas conduction, as is increasingly the case with large components, it can happen that the components are coated only partially or inadequately. The coating according to the invention can be carried out largely geometry-independent, with only the size of the system for the required heat treatment is limiting.

In the method according to the invention, automation is great

Scale feasible with manageable effort. This is at a

Gas phase nitration is difficult to carry out, since in addition to the high manual effort for the charging and the size of the system has a very limiting effect. By appropriate automation, it is possible to reduce the manufacturing cost per piece and at the same time to achieve an improvement in properties such as hardness and wear properties.

In addition to the methods described above, the layer may also be applied by other conventional methods such as PVD, CVD, thermal spraying or annealing in reactive gas (for example in the aforementioned gases / gas mixtures).

In the following, the invention will be described in more detail by way of example and compared with the prior art.

FIG. 1 shows a two-layered molybdenum boride / diboride layer on Mo.

Figure 2 shows a multilayer composite layer, the areas of

Molybdenum carbide and areas of molybdenum boride comprises.

FIG. 3 shows a GDOES profile of the layer in FIG. 2

FIG. 4 shows a sketch of a matrix with partial coating (thick lines).

Figure 5 shows a coated part of a die.

FIG. 6 shows an EBSD image of a two-layered tungsten boride /

Tungsten carbide layer on W.

example 1

Basic bodies of W, W - 1 Ma% La ₂ O ₃ (WL) and Mo were used

Provide diffusion processes with different layers. For this purpose, a slurry containing carbon and / or boron was applied by dipping on the surface of the base body. The respective C and B components can be taken from Tables 1 and 2. Thereafter, the samples were subjected to annealing at 1500 ° C / 10h in vacuum. The involved components C, B and N formed the corresponding compounds during the heat treatment. As an example, this is reproduced for the sample 19 according to Table 2 in FIG.

The EBSD measurement was performed as follows.

_ 120 pm electron beam aperture

- High current mode, 20kV acceleration voltage

- Scan area 57 x 24 pm ²

- Magnification 1500x _ increment 0.05 pm

- binning 4x4

- Camera Gain 17,06

_ Camera exposure 4.50

Substrate Correction: Static subtraction combined with

normalized intensity histogram

- System: FEG-REM Zeiss Ultra plus 55 with EDAX Trident XM4 analytics package, Hikari EBSD camera

Tables 1 and 2 show an overview of the samples.

Table 1

N °. Substrate atmosphere C and B content in the slurry

annealing material (reference: C (a%) + B (Ma%) = 100%)

1 W R

2 WL R

3 W E V C: 100%

4 W E V C: 80% / B: 20%

5 W E V C: 50% / B: 50%

6 W E V C: 20% / B: 80%

7 WL E V C: 100%

8 WL E V C: 80% / B: 20%

g WL E V C: 50% / B: 50%

10 WL E V C: 20% / B: 80%

Legend:

R ... reference sample E ... sample according to the invention V ... vacuum Table 2

Example 2

Coated matrix from MHC

A template of MHC was cleaned alkaline in the ultrasonic bath.

Subsequently, parts of the template were covered with adhesive tape. The thus prepared template was immersed in an aqueous suspension with graphite and boron (in the ratio 20:80 by weight) and dried in air. Still in the green state, the tape was removed. This masking ensured that the coating takes place only at the desired locations of the matrix. A sketch with the coated areas of such a coated matrix (thick lines) is shown in Figure 4.

The heat treatment was carried out under vacuum at 1500 ° C for 4h, forming a multilayered layer of molybdenum carbides and molybdenum borides. A scanning electron micrograph of a portion of the thus treated matrix is shown in FIG.

Claims

claims

1. component of a metal processing machine made of a

Refractory metal (RM) selected from the group consisting of

Tungsten (W), W alloy, molybdenum (Mo) and Mo alloy,

characterized,

at least one surface of the component has, at least in some areas, a layer which is at least partially composed of at least one compound of at least one element selected from the group consisting of carbon (C), boron (B) and nitrogen (N) with at least one element selected from among Group consisting of W and Mo, is formed.

2. Component according to claim 1, characterized in that the

Compound selected from group a or b, with:

- group a: carbides, borides and nitrides;

Group b: compounds containing W and / or Mo and at least two elements of the group consisting of C, B and N.

3. Component according to claim 1 or 2, characterized in that the compound from the group consisting of W ₂ B, WB, W ₂ B ₅ , W _1-X B ₃ , WB ₄ , WC, W ₂ C, WN, W ₂ N, W ₃ N _2, Mo ₂ B, MoB, Mo ₃ B _2, M0B _4, MoC, Mo ₂ C, MoN, Mo ₂ N and Mo ₃ is selected N _2.

4. Component according to one of the preceding claims, characterized

in that the layer is a composite layer which has at least one region of a boride and at least one region of a carbide.

5. Component according to claim 4, characterized in that WC or WB at least partially forms the outermost layer layer.

6. Component according to one of the preceding claims, characterized

characterized in that the layer with the adjoining area from RM is toothed.

7. Component according to claim 6, characterized in that the

Gearing is formed by grains of the layer.

8. Component according to one of the preceding claims, characterized

characterized in that the RM component in places higher

Stress has the layer.

9. Component according to one of the preceding claims, characterized

in that at least one compound contains at least one element selected from the group consisting of B, C, N, W and Mo in dissolved form.

10. Component according to one of the preceding claims, characterized

characterized in that the RM component consists of pure W, W - 0.1 to 3% by mass rare earth oxide, W heavy metal, pure Mo, a Mo - titanium (Ti) zirconium (Zr) - C alloy (TZM), a Mo - hafnium (Hf) - C alloy (MHC) or a Mo-W alloy is made.

11. Component according to one of the preceding claims, characterized

characterized in that it is a die, a die, a mandrel or a foundry mold.

12. A method for producing a component according to one of

preceding claims, characterized in that it comprises the following steps:

Production of the geometry of the RM component by conventional

Method;

Applying at least one element and / or at least one

Compound of an element selected from the group consisting of C, B and N, preferably in powder or slurry form; Heat treatment for forming a compound with at least one RM.