SU437593A1 - The way plasma arc cutting machine - Google Patents

Description

The invention relates to the field of thermal cutting of materials, in particular to plasma arc cutting of metals and alloys, preferably of large thickness. The known method of plasma-arc cutting of materials of great thickness with low thermal conductivity. This method is characterized by the supply of flux into the cut cavity and the additional heating of the part of the cut cavity furthest from the cutter. Fine flux particles that mechanically act on the melt and facilitate its removal from the cut cavity serve as the flux Yu. Additional heating of the part of the cut cavity furthest from the cutter is exhausted with the help of 15 chemical combustion flames, for example, oxyacetylene. The known method is characterized by a small range of thicknesses of the materials being cut, the inexpediency of using the method for materials with high thermal conductivity and the lack of concentrated heating of the part of the cutting cavity furthest from the cutter, which causes a relatively low productivity of the process, especially when cutting materials with high thermal conductivity, such as aluminum. The aim of the invention is to expand the range of thicknesses of materials being cut, in particular with high thermal conductivity, by 30 5 20 example aluminum, and to increase the productivity of the process. This is achieved by the fact that according to the proposed method, additional heating of the part of the cutting cavity removed from cutting is carried out by feeding an exothermic mixture into it, and the flux, which has the ability to form gaseous products, is fed to the beginning of the frontal cavity of the cut. If necessary, an exothermic mixture and a gas-forming flux are additionally supplied to the middle part of the cut cavity in different ratios. The ratio (by weight) between them can vary from 1: 0.15 to 1: 0.6. It is advisable that in the case of cutting aluminum and its alloys, the flux supplied to the beginning of the frontal cavity of the cut contains a combination of halogens with metals, and an exothermic mixture of iron oxides. This method allows to increase the productivity of the cutting process, expand the range of thickness to be processed, and also perform metal cutting with different thermophysical properties at lower values of the power of the cutting arc. The proposed method is illustrated in the drawing. The plasma cutter 1 leads to the material being cut 2, excites the plasma arc 3 and moves the cutter in the direction.

shown by the arrow (see drawing). A gas-forming flux 5 and an exothermic mixture 6 are fed into the resulting cut cavity 4, which are fed through nozzles 7 and 8, respectively. The gas-forming flux 5 is fed to the beginning of the frontal cut cavity, and the exothermic mixture 6 to the part of the cut cavity remote from the cutter.

When cutting aluminum alloys, it is advisable to use compounds of halogens with metals as a gas-forming flux. At the same time, at the beginning of the frontal cavity of the cut, a chemical reaction takes place.

A1F, + 2A1 3A1F.

Thus, the interaction of the powdered flux containing A1Pz with the molten metal 9 provides for the formation of gaseous products in the form of A1F, which increase the kinetic energy of the plasma-forming gas stream acting on the molten metal bath.

As a result, the rate of flow of the molten metal 9 along the frontal edge 10 of the cut increases. This contributes to a more efficient transfer of heat from the plasma arc 3 to the edge 10 of the cut.

The temperature of the plasma arc in the part of the cut cavity that is remote from the cutter is significantly reduced compared to the temperature in the near part of the cut cavity, therefore the remote part of the cut cavity cannot be heated sufficiently effectively by the heat of the arc. Submission to this part of the cavity exothermic mixture containing in the case of cutting aluminum oxides of iron, ensures the flow of the next reaction

ЗРе, О «+ 8А1 4AUO, + 9Ре + 773.7 -.

mole

- The exothermic reaction creates a concentrated, intense heating of the part of the cut cavity that is remote from the cutter, which ensures an intense melting of the metal in this part of the cavity, as a result of which the range of thickness to be cut increases. Sonnet intensive heating of the remote part of the cutting cavity with an increase in the kinetic energy of the flow of plasma-forming gases contributes to an increase in the productivity of the process. In addition, a more uniform heat input along the height of the cut cavity provides a better shape of the cut, due to a decrease in barrel shape, and due to an increase in cutting speed, the width of the plasma arc cut is reduced.

Subject invention

Claims (2)

1. A method of plasma-arc separation cutting materials of large thickness, in which flux is supplied to the frontal cavity of the cut and a part of the cavity of the cut removed from the cutter is further heated, characterized in that, in order to increase the productivity of the process and increase the range of thicknesses of materials being cut, the flux is fed into the beginning of the frontal cavity of the cut, with a substance having the ability to form gaseous products being used as a flux, and additional heating of the cut cavity remote from the cutter is carried out Uteem feed therein substances react exothermically with the material being cut. 2. A method according to claim 1, characterized in that the said substances and flux are additionally supplied to the middle part of the cutting cavity in a ratio (by weight) of from 1: 0.15 to 1: 0.6. M