Patent Application
20170307338
This application claims priority from European Patent Application EP 16000912.2 filed on Apr. 22, 2016.
The invention relates to a method and a device for producing an armor plating for protected vehicles. The invention particularly relates to a method and a device for producing an armor plating of materials for protected vehicles.
The armor plating of civil or military vehicles is in most cases produced of hardened steel plates consisting of special alloys of any type and shape, synthetic fibers such as aramid fibers, as well as ceramics and other materials. In this case, the resistance to different impacts is ensured by the material, its thickness, as well as its number of layers or structure. In this respect, a greater resistance is also associated with a significant weight increase.
The present invention therefore is based on the objective of making available an improved method for producing an armor plating for protected vehicles.
Accordingly, a method for producing an armor plating for protected vehicle is proposed. The method comprises the following steps: supplying a substrate made of a metal and/or a nonmetal and coating the substrate with the aid of a thermal spraying process.
For example, the substrate may consist of a steel plate of any type and shape. The method is particularly suitable for making available an armor plating of materials for protected vehicles. In the present context, the term nonmetals refers to synthetic materials such as Kevlar, ceramics, composite materials and composite fiber materials. The term thermal spraying process refers to a surface coating process. In this case, additional materials in the form of so-called spray additives are fused or molten inside and outside a burner, accelerated in the form of a particle spray in a flow of gas and thrown on the surface of the substrate to be coated. In this case, the surface of the substrate is not molten and only subjected to low thermal stress. A layer formation takes place because the spray particles more or less flatten depending on the process and the material when they impact on the surface of the substrate such that they remain adherent, primarily by interlocking mechanically, and thereby build up the spray coating layer-by-layer. Quality characteristics of such spray coatings are a low porosity, a sound connection to the substrate, the absence of cracks and a homogenous microstructure. The attained layer properties are decisively influenced by the temperature and the speed of the spray particles at the time of their impact on the surface to be coated. For example, an electric arc, a plasma jet, an oxy-fuel flame or high-velocity oxy-fuel flame, fast preheated gases or a laser beam may be used as energy carriers for fusing or melting the spray additive. Examples of thermal spraying processes are melt spraying, arc spraying, plasma spraying, flame spraying, high-velocity flame spraying, detonation spraying, cold gas spraying or laser spraying.
The thickness and therefore also the weight of the substrate can be reduced by coating the substrate. Conventional coatings, which are not applied by means of a thermal spraying process, chip off over large areas due to their brittleness. The required armor plating therefore is no longer ensured with conventional methods. The coating applied on the substrate has an extremely high hardness, as well as a certain ductility and adhesion. In case particles nevertheless chip off during the bombardment, no larger areas are exposed such that the protection standard can be met. A significant improvement of the armor plating can already be achieved with small layer thicknesses between 50 and 400 μm.
According to an embodiment, the substrate is coated with the aid of an arc spraying process.
The arc spraying process, which is also referred to as arc wire spraying or wire arc spraying, is a highly effective wire spraying process for producing coatings, in which electrically conductive materials are sprayed. In this case, an arc is ignited between two wire-shaped spray materials of identical or different types. The wire tips are molten at a temperature of around 4000 to 5000° C. and blown on the prepared surface of the substrate by means of an atomizing gas or process gas. Oxidation of the materials is reduced if an atomizing gas in the form of nitrogen or argon is used instead of air. Practically any electrically conductive wire-shaped material can be used as material for the spray wires. Hard material layers can also be produced by using hollow wires with carbidic or ceramic fillings. The arc spraying process is characterized by very high application rates.
According to another embodiment, the arc spraying process is carried out with a process gas in the form of nitrogen, a nitrogen-active gas mixture or air.
Oxidation of the coating material and/or the substrate material can be prevented by using nitrogen. The use of an active gas makes it possible to achieve a chemical reaction.
According to another embodiment, a coating with a layer thickness of 50 to 400 μm is applied on the substrate.
However, the layer thickness may also be greater than 400 μm,
According to another embodiment, the coating is produced of a hard material alloy.
The coating is preferably produced of a metallic material. However, the coating may also be produced of a ceramic material.
According to another embodiment, the substrate is a steel plate.
However, the substrate may also be made of a different metallic or non-metallic material.
A device for producing an armor plating for protected vehicles is furthermore proposed. The device comprises a supply apparatus for supplying a substrate consisting of a metal and/or a nonmetal and a coating apparatus for coating the substrate with the aid of a thermal spraying process.
The device particularly is an arc spraying device,
According to an embodiment, the device comprises a first wire feed for a first spray wire and a second wire feed for a second spray wire.
Each wire feed preferably features two rollers, between which the respective spray wire is arranged. The respective spray wire can be advanced by rotating the rollers. The device may also feature more than two wire feeds and therefore process more than two spray wires,
According to another embodiment, the device furthermore comprises a first wire guide for the first spray wire and a second wire guide for the second spray wire.
The first wire feed particularly delivers the first spray wire to the first wire guide and the second wire feed delivers the second spray wire to the second wire guide. The wire guides are realized in the form of contact tips and therefore electrically conductive. The wire guides may be made, for example, of a copper alloy. The wire guides preferably form part of an electric circuit of the device. In addition to the wire guides, the electric circuit also comprises a power source, particularly a dc power source. For example, the first wire guide is wired as the positive pole and the second wire guide is wired as the negative pole of the electric circuit.
According to another embodiment, the device furthermore comprises an atomizer nozzle that is arranged between the first wire guide and the second wire guide.
The device particularly comprises an atomizer nozzle that is cylindrically arranged around both wire guides. The spray wires guided through the wire guides preferably meet in front of the atomizer nozzle such that an arc forms in front of the atomizer nozzle. Process gas conveyed through the atomizer nozzle atomizes the material of the spray wires molten in the arc and throws it on the substrate to be coated.
Other potential implementations of the method and/or device also include combinations of characteristics and embodiments described above and below, which are not explicitly mentioned. In this respect, a person skilled in the art may also add individual aspects to the respective basic principle of the method and/or device as enhancements or supplements.
Other advantageous embodiments and aspects of the method and/or device form the objects of the dependent claims, as well as the exemplary embodiments of the method and/or the device described below. Preferred embodiments of the method and/or device accordingly are described in greater detail below with reference to the attached figures.
If not indicated otherwise, identical or functionally identical elements are identified by the same reference symbols in the figures.
The vehicle 1 illustrated in
In a thermal spraying process according to DIN EN 657, additional materials in the form of so-called spray additives are fused or molten inside and outside a burner, accelerated in the form of a particle spray in a flow of gas and thrown on the surface of the substrate 5 to be coated. In this case, the surface of the substrate 5 is not molten and only subjected to low thermal stress. A layer formation takes place because the spray particles more or less flatten depending on the process and the material when they impact on the surface of the substrate 5 such that they remain adherent, primarily by interlocking mechanically, and thereby build up the coating 6 layer-by-layer,
The device 3 is particularly suitable for applying the coating 6 on the substrate 5 in an arc spraying process. The device 3 therefore is an arc spraying device and, in particular, a wire flame spraying device. The device 3 comprises a first wire feed 7 for advancing a first spray wire 8 and a second wire feed 9 for advancing a second spray wire 10. The first spray wire 8 is guided through a first wire guided 11 and the second spray wire 10 is guided through a second wire guide 12. The wire guides 11, 12 are made of a metallic material. For example, the wire guides 11, 12 may be made of a copper alloy.
The wire guides 11, 12 form part of an electric circuit 13 with a power source 14. The power source 14 may be a dc power source. For example, the first wire guide 11 may be wired as the positive pole and the second wire guides 12 may be wired as the negative pole or vice versa. An atomizer nozzle 15 is provided between the wire guides 11, 12. A pressurized atomizing gas or process gas 16 is conveyed through the atomizer nozzle 15. The process gas may consist, for example, of nitrogen, a nitrogen-active gas mixture or air.
During the operation of the device, the two electrically conductive spray wires 8, 10 with identical or different composition are moved in front of the atomizer nozzle 15 with a controlled wire feed. The power transmission is realized by means of the wire guides 11, 12 in this case. After the wire feeds 7, 9 have been activated, the two spray wires 8, 10 are advanced through the wire guides 11, 12 until they contact one another. Significant heating occurs as a result of the short circuit current such that the metal of the spray wires 8, 10 evaporates and an arc 17 is ignited, which then optimally remains short circuit-free.
The attainable temperatures in the arc 17 lie at about 4000 to 5000° C. The material of the spray wires 8, 10 is molten and the process gas 16 discharged from the atomizer nozzle 15 atomizes the molten material, accelerates the particles up to 150 m/s and throws them on the substrate 5 to be coated. The particle atomization and particle acceleration can be influenced by choosing the atomizer nozzle 15 accordingly. The arc spraying process can likewise be carried out with more than two spray wires 8, 10, e.g. with three or four spray wires, in the form of a multi-wire arc spraying process. For example, the application rate of the device 3 lies between 8 and 20 kg/h. The atomized material of the spray wires 8, 10 is deposited on the substrate 5 with the aid of a spray cone 18 formed by the process gas 16 and the atomized material of the spray wires 8, 10.
In an arc spraying process, the arc 17 is subject to many interferences and, in contrast to welding technology, represents a discontinuously burning dc arc. The interferences leading to irregular burning and therefore constant restabilizing are caused by the process gas 16 and irregular processes between the two spray wires 8, 10, as well as by melting the wire ends of the spray wires 8, 10 and the spray particles created thereby. If they separate, the cross-sectional areas and the respective diameters of the spray wires 8, 10, as well as the length of the arc 17 on the wire ends of the spray wires 8, 10, is reduced.
With respect to a stable spraying process, it is advantageous to realize the shortest arc 17 possible because such an arc heats the wire ends of the spray wires 8, 10 more evenly, is subjected to less interference by separating spray particles and the gas flow and therefore encounters more consistent conditions. This results in very high melting rates. Depending on the material of the spray wires 8, 10 used, the voltages lie in the range between 18 and 40 V. In this respect, the spray wires 8, 10 should always be processed with the lowest voltage possible. The optimal arc voltage corresponds to the lowest voltage, at which the spray wires 8, 10 still burn off short circuit-free and therefore without sputters. The feed rate of the spray wires 8, 10 makes it possible to adjust the current between 50 and 350 A in dependence on the required application rate, the material, the wire diameter and the available arc system.
All electrically conductive spray additives that can be produced in the form of a spray wire 8, 10 are suitable for the arc spraying process. In most cases, spray wires with a diameter of 1.6 mm are used. If they are made of low-melting materials such as zinc, the spray wires 8, 10 used may have a diameter of 2.0 mm. The highest application rates of all spraying processes can be achieved with the arc spraying process. When aluminum is processed, an application rate of up to 15 kg/h can be achieved, wherein an application rate of up to 45 kg/h can be achieved when processing zinc and an application rate of up to 30 kg/h can be achieved when processing steel. If a particularly strong adhesion should be achieved, e.g. on undercoatings, the spraying distance can be reduced to 80 mm. Coatings 6 of materials or material combinations, which cannot be produced in the form of a wire, can be applied by means of filled hollow wires.
The device 3 particularly comprises a supply apparatus 25 for supplying the substrate 5. The supply apparatus 25 may consist, for example, of a conveyor belt or a transfer gripper. The device 3 furthermore comprises a coating apparatus 26. The coating apparatus 26 may comprise the electric circuit 13, the wire feeds 7, 9, the wire guides 11, 12 and the atomizer nozzle 15.
Although the present invention was described entirely with reference to exemplary embodiments, it can be modified in various ways.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16000912.2 | Apr 2016 | EP | regional |
