PL238237B1 - Method for producing top composite layers on the steel armour surfaces - Google Patents

Description

The subject of the invention is a method of producing composite outer layers on the surface of steel armor.

The known and used so far technologies for the production of composite outer layers on the surface of steel armors consist in applying layers to the steel substrate by means of thermal spraying. In one application, a mixture of metal powder, matrix and ceramic powder, the strengthening phase, is heated and fused in an electric arc or gas flame, and then at high speed it is hit on the rough surface of the armor, which leads to the formation of composite outer layers connected to the steel. adhesive armor. The use of thermal spraying processes is advantageous due to the significantly limited thermal effect on the steel armor in these processes, compared to the deposition technology of composite layers. The need to limit the thermal impact on steel armor when producing composite layers on its surface results from the fact that armor steels belong to the group of heat treated steels. Heating these steels to temperatures as high as approx. 250 ° C leads to their tempering and, consequently, lowering their ballistic resistance.

The disadvantage of thermally sprayed composite top layers is the lack of a metallurgical connection between the top layer and the steel armor, which in the event of a bullet hitting the armor leads to decohesion, i.e. detachment of the layer over a large area, significantly reducing the ballistic resistance of the armored vehicle.

In the case of surface layers connected with the substrate metallurgically, in the case of surfaced layers, the damage to the layer takes place in the immediate vicinity of the projectile impact, which reduces the level of ballistic resistance of the vehicle to a much lesser extent. However, the disadvantage of the methods of surfacing composite layers on steel armor is the large thickness of the tempered layer in the armor steel substrate. In the case of laser surfacing technology, characterized by the lowest thermal impact on the base material, compared to other surfacing technologies, the minimum thickness of the tempered layer in the steel armor is approx. 3 mm.

Therefore, it is necessary to use methods of producing composite outer layers with a metallurgical connection with the substrate, which will simultaneously ensure a minimal thermal effect on the steel armor.

The object of the invention is a method of producing composite outer layers on steel armor, ensuring a metallurgical connection of the layer with the substrate and minimal thermal impact on the steel armor.

The method of producing composite surface layers on the surface of steel armor is based on the fact that the surfaces of the steel armor are melted to a depth of up to 500 μm, creating a pool of liquid metal using a laser with an even energy distribution on the surface of the laser beam focus, and then a stream of ceramic particles is fed to the pool. WC type, WC / W2C eutectic or C3C2 with granulation in the range of 100-300 μm.

The method according to the invention ensures the production of composite surface layers with a metallurgical connection with steel armor, minimal thermal impact on the steel armor limiting the thickness of the tempered layer in the armor steel substrate to approx. 1 mm and uniform distribution of the ceramic phase, the volume share of which can reach 80%, thickness the tempered layer in the steel armor can be limited to approx. 1 mm.

Example

In order to obtain composite surface layers with a metallurgical connection with a steel armor and to obtain a minimum thermal effect on the steel armor, the armor surface of the armor is melted using a high-power HPDDL, DL020 diode laser by Rofin Sinar with a rectangular beam focus with dimensions of 6.8 χ 1 , 8 mm and even distribution of energy on the surface of the focus. The liquid metal generated in this way is used as a metallic matrix of the composite layer, in which the strengthening phase is made of ceramic particles such as WC, WC / W2C or C3C2 eutectic, with a granulation in the range of 100-300 μm, characterized by high wettability in liquid metal, which it enables the use of high rates of layer formation and, at the same time, minimal heat input to the steel armor. A beam of laser radiation with a power of 1 kW is focused on the upper surface of armor made of 15 mm ARMOX 500T armor steel and moves along the armor surface at a speed of 0.15 m / min, which creates a pool of liquid metal with a depth of approx. 500 μm, to which the powder stream is fed

PL 238 237 B1

WC, with an intensity of 10 g / min and granulation of 100-300 μm, through a flat nozzle inclined at an angle of 45 ° to the surface of the steel armor. The process is carried out with straight stitches with an overlap of 30%. The molten steel armor material is the matrix metal of the composite layer, the ceramic particles being completely wetted by the molten pool metal.

The created armor has the following parameters:

- composite layer thickness: 1.0 mm - including 0.5 mm deep into the armor surface and 0.5 mm above the armor surface,

- average hardness of the produced composite layer: 1600 HV,

- WC particles volume fraction in the layer: 80%,

- thickness of the tempered layer in steel armor: 1.0 mm,

- average hardness of the tempered layer (zone): 400 HV,

- substrate hardness (armor steel ARMOX 500T): 500 HV.

Claims (1)

1. The method of producing composite surface layers on the surface of steel armor, characterized in that the surfaces of the steel armor are melted to a depth of up to 500 μm, creating a pool of liquid metal using a laser with an even energy distribution on the surface of the laser beam focus, and then a stream is fed to the pool ceramic particles such as WC, WC / W2C or Cr3C2 eutectics with granulation in the range of 100-300 μm.