SU745624A1 - Method of producing powdered electrode materials - Google Patents

Description

/. . -, The invention relates to the welding industry, in particular to the technology of manufacturing powder electr. rods for surfacing of alloys based on refractory compounds (carbides, borides, nitrides, etc.). A known method of making porous wires in which the mixture is preliminarily alloyed into spherical grains and fed into a metal sheath for compaction 1. The use of cast grains as a filler for cored wires limits the use of a number of refractory compounds, for example, borides, which can decompose. In addition, spherical grains do not allow packaging inside the shell. This leads to a decrease in the shell filling ratio and the concentration of refractory particles in the weld layer. There is also known a method of producing flux-cored wire by filling the metal shell with a mixture of refractory components that are pre-granulated and sintered. The disadvantage of this method is that the technology for manufacturing granulated sintered mixture is extremely difficult and time-consuming, since it involves fine grinding of refractory compounds, mixing the blend components with a plasticizer, drying, wiping and rolling pellets of fragmentation form on the grid, sintering at high temperatures (1200-1800s), repeated roseivanie granules, mixing them with the fluxing additives, loading the resulting blend into the hopper feeder drawing mill, drawing the tape while filling the charge formiruyuscheys wire, multiple wire drawing to compress the charge and achieve the desired diameter. In addition, compaction of the charge due to repeated wire drawing by a known method does not allow to obtain high filling factors for the powder electrodes (more than 60%), since drawing leads to wire breakages due to loss of ductility of the charge and thinning of the shell. In order to increase the filling ratio, the mixture is pressed into tabs and tapes before being fed into the metal shell.

Preliminary pressing of the charge according to the proposed method, unlike the known ones, allows separating the operations of compacting the charge and forming the casing, thereby eliminating most of the technological operations and simplifying the process of drawing.

The method of obtaining powder electrode materials includes the following operations: mixing the powder components of the charge; pressing that (5 years of a predetermined shape and size; feeding the preformed charge to the feeder of a watering mill, winding mill, and drawing the casing with a single preformed charge;;

Preliminary pressing of tablets of a given size makes it possible to refuse repeated drawing and to obtain a powder electrode of the desired cross section.

Pre-pressing powdered materials ensures a high density of the charge, reaching 75-95% of the density of the monolithic material. This ensures a high value of the fill factor of powder electrodes {K = 70-86%).

The specific pressing pressure depends on the plasticity of the charge, the required density and should be sufficient to obtain tablets that do not deteriorate during transportation.

The specific pressing pressure for each particular composition of the charge is determined empirically and is in the range of 5-20 tons / cm.

The powder electrode materials according to the method can be produced both in the form of cored wire and in the form of cored tape,

Figure 1 shows the cored wire with a tableted mixture (where 1 is a tableted mixture, cylindrical, 2 is the sheath of cored wire, d is the diameter of the tablet, h is the thickness of the tablet); in fig. 2 is a powder tape with a tableted charge (where 3 is a tablet form charge of a rectangular shape, 4 and 5 is the shell size, h is the thickness of the tablet, c is the length of the tablet).

Tablet sizes are specified by the required cross-section of the electrode, taking into account the flexibility of Continuous Powder Electrodes. The following ratios of tablet sizes are recommended: for pow- der. coaxial wires (fig. 1) h (0.52, 5) d, and for powder tapes (fig. 2) (0.1-0.5) L

Example. Production of powdered rovule with a tableted charge of a mechanical mixture of wolfam carbide (relit) and arganese alloying powders, and nickel. Relita granules with granulation up to 1.2 mm; Manganese and nickel powders of O, 1-0.2 mm granulation are mixed together with the technological additive in the form of fluoropolymer powders for two hours. The bulk density of the finished mixture is 5.8 g / cm. After mixing, the finished mixture enters the receiving hopper of the rotary tablet machine, where it is pressed at a specific pressure of 6 t / cm to form tablets with a diameter of 3 mm and a thickness of 4 mm. After pressing, the density of the charge is 12 r / CNT. Then, using a vibrating lifter, the pelletized mixture enters the mill feeder for pulling wire, where the tablets fill the trough of Melklorovaya MN-19 tape, wide 1Q mm in thickness and 3 mm thick, from the profiling device. The wire passes once. through the die plate, where it is formed to a predetermined diameter size. At the same time, the tableted charge is additionally compacted and fixed. The wire fill factor is 77 wt.%.

After surfacing made with malfunctioning wire on a steel sample, a layer of a composite alloy based on ralite with a manganese melblbr matrix MNMts - 20-20 is obtained. The volume concentration of raelite is 55-60%, the hardness of the deposited layer is 80-85Н A.

The use of this method of manufacturing powder electrode materials provides, in comparison with the known ones, the following advantages: the manufacture of powder electrode materials with a mixture based on refractory compounds is greatly simplified; the filling ratio is increased to 75-80%, th, which makes it possible to increase the wear resistance of the weld metal due to an increase in the concentration of refractory wear-resistant particles in the reinforced layer; the welding-technological characteristics of the surfacing material are significantly improved by eliminating the uneven distribution of the hardening phase in the deposited layer, spattering and porosity are reduced due to the dense filling of the powder electrode charge; deposition rate increases 1.3-1.5 times; in the manufacture of tablet blend, allow the use of standard equipment of the pharmaceutical and pharmaceutical industry in combination with equipment for the production of powder electrode materials. This method also does not exclude the possibility of manufacturing electrodes when the preformed mixture is fed into a seamless casing.

Claims (2)

1. Authors certificate of the USSR 257277, cl. 23 K 35/40, 1967. 2. USSR author's certificate number 377223, cl. In 23 K 35/40, 1971 (prototype).