SU1682099A1 - Method of producing fused oxidative fluxes - Google Patents

Abstract

The invention relates to the production of welding fused fluxes, in particular oxidizing fluxes. The purpose of the invention is to improve the forming properties of the fluxes by reducing their bulk density. The method of manufacturing fused oxidizing fluxes includes the operations of preparing the charge, loading the charge into the furnace, melting the charge, oxidizing the melt, draining the melt, granulating, drying, screening, and quality control. The operation of introducing the oxidant into the melt is combined with the operation of draining the melt from the furnace. The oxidizer is introduced into the stream from the entrance of the kiln, including the hopper, to the level of the water in the granbasin. Reducing the time of possible reduction of ferric oxides reduces the consumption of oxidizer and, therefore, reduces the melt to a lesser extent, which ensures the formation of pumice, i.e. flux with a lower bulk density. 1 tab.

Description

The invention relates to the production of welding fused fluxes and is intended to improve the quality of the fluxes, namely their forming properties.

The best formation of weld metal, especially at high linear welding speeds (80 m / h and above), is provided by pumice fluxes, i.e. fluxes with a bulk density of less than 1.3 kg / dm3. However, when welding under these fluxes, the lowest impact toughness of the weld metal is observed.

Under the same welding conditions, under the glassy oxidative fluxes, the highest impact strength and the worst formation of the weld metal are observed.

The reason for the low toughness of the metal of the seams is the absence of free oxygen in the pumiceane flux, i.e. oxygen weakly bound to chemical compounds in the flux. Such chemical compounds are known to be oxides of iron, manganese and titanium.

The most effective increase in the toughness of the weld metal is provided by iron oxides, as evidenced by the use of vitreous oxidative fluxes AN-17, AN-17 M and AN-43. This is explained by the fact that these oxides are the most readily reducing and give the maximum amount of oxygen with a minimum content.

The purpose of the invention is to improve the shaping properties of oxidative fused fluxes by reducing the bulk density of the latter below 1.3 kg / dm.

In the manufacture of fused oxidizing fluxes, the operation of introducing the oxidant into the melt is combined with the operation of draining it from the furnace, and the input of the oxidant is carried out into the melt stream from the furnace tap hole, including the hopper, to the water level in the granite basin,

Our proposed method contains the following operations.

Preparation of the charge.

Loading charge into the furnace.

Melting of the charge.

Enter the oxidant in the melt + melt drain.

Granulation in the granulation basin.

Drying.

Quality control.

The operation of introducing the oxidant is carried out outside the furnace, namely, in the section of the melt flow from the furnace head, including the accumulator, to the water level in the granbassin.

After the entire charge (except the oxidizer) is melted, the furnace is tilted and the drain starts. At the same time, an oxidizing agent, iron oxide, is fed from an additional bunker to the melt flowing out of the tap hole,

Once in the melt, the overwhelming amount of ferric iron oxides ReaOz (of which almost all iron scale) consists of is converted into ferrous iron oxides FeO. The latter, however, can no longer be restored to pure iron, since the residence time of the melt in the furnace is several seconds (for a known method, this time is 15-20 minutes, i.e., two orders of magnitude higher).

This circumstance is crucial for achieving the goal: with this method of making flux, the oxidizer is used more efficiently, therefore, with the same content of oxidant in fluxes made by different methods, the new method requires less consumption of oxidant, therefore, when the oxidant is introduced into the melt, there is less cooling melt, which ensures the formation of pumice (flux with a bulk density of less than 1.3 kg / dm, i.e. achievement of the goal. Proof that the goal is achieved in this way invention, follows from the results of the studies presented in the table.

Meltings 1, 2, 3, 4, AN-17M-2 were made by a known method in an industrial furnace with a volume of 3 tons with carbon lining. Melting 5, 6, 7, AN-17M -1 produced by the proposed method. An increase in the consumption of the oxidizing agent increases the bulk density of the fluxes in all methods of their manufacture, however, with the proposed method, the content of iron oxides in the flux increases faster than its bulk density increases. So, for example, at an oxidizer consumption of 40 kg / t, the total content of Fe oxides in the pumiceous flux produced by a known method will be almost 1%, and in the same flux made according to the invention three times more. If we compare the data on fluxes 2 and 6, it is clear that in these fluxes the bulk density is less than 1.3 kg / dm, the same total iron content is provided by different oxidant consumption (for a known method this consumption is 4.1 times higher than for the proposed ). Among the iron oxides in the flux 6 are ferric oxides, i.e. stronger oxidizer than FeO, from which

iron oxides in flux 2 are composed. This means that with an equal total content of iron oxides, the flux produced by the proposed method is more oxidized,

Easily repairable oxides of ferric iron in pumiceous fluxes are contained only in those made by the proposed method (for example, fluxes 5-7).

Evidence of the advantages of the proposed method in comparison with the known contains a table, which presents numerical indicators for fluxes 3 and 7, as well as data for flux grade AN-17M-1, smelted in a 100-kilogram furnace according to the proposed method and known (AN-17M-2 ). From these data it follows that the flux 3, manufactured by a known method, contains only oxides of divalent

iron and is vitreous, i.e. It has

bulk density more than 1.3 kg / dm3;

Flux 7, manufactured according to the proposed

contains trivalent oxides

iron and is pumiceous (its bulk density is 1.3 kg / dm3); - consumption of scale in the manufacture of flux AN-17M-1 is 2.5 times less than for flux AN-17M-2; flux AH-17M-1 is pumiceous (bulk density less than 1.3 kg / dm3); iron oxides in the flux AH-17M-1 contain ferric oxides, i.e. this flux is more oxidized than flux AN-17M-2; AN-17M-1 flux, under the same welding conditions, forms a weld metal without coarse flakes, with

smooth smooth surface, i.e. better than flux AN-17M-2.

The economic efficiency of the method can be estimated from the fact that the pumiceum flux produced by the proposed method provides an increase in welding productivity by 20% compared to the best vitreous flux AN-47 currently used for the same purpose.

Claims (1)

The invention of the method of manufacturing fused oxidizing fluxes, including operations preparing the charge, loading the charge into the furnace, melting the charge, introducing the oxidant into the melt, draining the melt through the hopper, granulating in the granite basin, drying, screening, quality control, which in order to improve the formative properties of the oxidizing flux by reducing them the bulk density, the operation of introducing the oxidant into the melt is combined with the operation of draining the melt from the furnace, and the input of the oxidant is carried out into the melt stream in the area from the furnace tap, including the hopper, to the level of water in the granite basin. The rest of the amount of MDO, MpO and other oxides.