SU1276470A1 - Charge for producing molden welding flux - Google Patents

Abstract

This invention relates to welding materials. The aim of the invention is to improve the quality of the produced flux when used for smelting the charge with low-grade manganese ores. Increasing the amount of waste slag from the production of silica-manganese to 35-60% in the charge with a reduced content of quartz sand of 5-15% reduces the melting point of the charge, which contributes to more intensive reduction and bonding. 1 hp f-ly, 3 tab. W

Description

The invention relates to welding and relates to mixtures for producing fused manganese fluxes used for automatic welding of general purpose carbon steels.

The aim of the invention is to improve the quality of manganese flux welding by reducing the phosphorus content when used in the composition of the mixture of low-grade manganese ores.

Of great importance in the production of high-manganic fluxes is the quality of the used manganese ore. In the production of fluxes, manganese ores of two types are used: high-quality manganese ores and ores having a lower manganese content and an increased concentration of phosphorus (Table 1).

The content of manganese and phosphorus in manganese ores of various deposits is given in table. one.

A low phosphorus content in manganese-rich ores is possible to produce high-manganese fluxes with a limited content of zinc, phosphorus. In this case, the introduction of silicomanganese production into the charge of waste slag was used as a technological method for reducing the melting temperature of the charge and increasing the melting rate of the flux.

The use of lower grade manganese ores necessitates an increase in its content in the mixture in order to retain the mouth flux. An increased amount of manganese monoxide, which, taking into account the higher phosphorus content in the ore, leads to an increase in the phosphorus concentration in the charge and in the resulting fluxes. When welding, phosphorus passes into the weld metal, causing a decrease in technological strength and the formation of cracks in the welded joints.

The selected ratio of the components of the mixture provides standard high-manganese flux type AN-64.

Increasing the content in the charge of waste slag from the production of silicomanganese makes it possible to obtain the required content of manganese monoxide in the welding fluxes with a significant decrease in the amount of manganese ore introduced. Since the maximum phosphorus content in waste slag is several times lower than the permissible phosphorus content in manganese ore, the proposed ratio of components provides a significant increase in the purity of the batch being prepared and, consequently, an increase in the metallurgical properties of the resulting fluxes by ensuring low (less than 0.10%) content

phosphorus. Improving the cleanliness of welding fluxes improves the plastic properties of the weld metal and contributes to an increase in the resistance of 5 welded joints against brittle fracture and the formation of trash; in. The investigated compositions of the mixture are given in table. 2. The compositions of the calculated mixture and the resulting fluxes are given in table. 20 . With the introduction of waste slag above 60%, along with an increase in the amount of manganese monoxide, an increase in the content of calcium oxide and a mixture of potassium and sodium oxides occurs, 5 which causes an increase in the basicity of the flux and leads to the formation of pores, especially if there is rust on the edges to be welded.

With the introduction of waste slag less than 35% in the produced fluxes, the established content of manganese monoxide is not ensured, which causes a violation of the optimum chemical composition of the weld metal at 5 welding of carbon steel

appointment n leads to a decrease. mechanical properties and technological strength of welded joints. A similar occurrence occurs when Q manganese ore is below 25%. Exceeding the established values of manganese ore content causes an increase in the concentrations of harmful impurities in the charge and a corresponding increase in phosphorus. - from melted fluxes above permissible limits. This adversely affects the metallurgical properties of welding fluxes, causing an intense transition of phosphorus jQ into the weld pool and the formation of cracks in the weld metal.

Claims (2)

With the introduction of less than 5% sand into the charge, the established support of silicon oxide is not ensured, which negatively affects the welding and technological properties of the flux. The introduction of sand above 15% also leads to a violation of the established limits for the holding of silicon oxide, which causes an intensive process of the silicon process and the clogging of the deposited metal with oxide silicate inclusions. A decrease in the fluorspar content below the set values causes an increased tendency of the flux to be porous during welding, and the introduction of it above 14% negatively affects the flux forming properties in the resultant increased fluidity of the slag formed during welding. In addition to a purely quantitative decrease in the phosphorus concentration in the charge, by replacing part of manganese ore containing up to 0.245% of phosphorus with waste slag of manganese silicon production, the phosphorus content of which does not exceed 0.01%, the proposed mixture has a favorable refining effect changes in the conditions of smelting welding fluxes. The mixture is prepared by mixing pre-weighed components in ratios providing flux type AN-64. Smelting of flux is carried out in gas-plasma continuous melting furnaces followed by wet granulation. A higher content in the proposed mixture of low-melting slag produced by silicomanganese with a reduced silica content and the absence of refractory magnesite leads to a decrease in the melting temperature of the mixture by 200-250 C. This allows the total melt temperature of the slag to be aged at the same thermal power which causes a more intense endothermic reaction for the reduction and binding of phosphorus to metal cores according to the scheme. (MpO),. + 11Ге5 :::: 3: MpO + 2Ре, Р + J f. } O + 5FeO-47700 cal. Increasing the fluidity of the flux due to the higher content in the mixture of fluorspar promotes better mixing of the melt, which creates additional favorable conditions for the coagulation of the resulting iron-phosphide particles and deposition on the bottom of the furnace. 704 Table. 2 (2-4) examples of the composition of the proposed mixture and the chemical composition of the flux obtained are presented, and compositions 1 and 5 of the mixture go beyond the proposed limits. Taking into account that the phosphorus content in manganese ore used to obtain the examples was 0.215%, the calculated phosphorus content in the indicated fluxes (not taking into account the formation of metal sludge) was determined. Comparison of the calculated and actual values of the phosphorus content in the fluxes made it possible to eliminate the relative removal of phosphorus (refining) during smelting. A summary of the determination of the refining capacity of fluxes and the characteristics of the welds obtained are presented in Table. 3. Compositions 2-4 table. 2 correspond to the average and limiting values of the proposed mixture, providing the established content of manganese monoxide and phosphorus in the fluxes. Compositions 1 and 5, in which the content of manganese ore and slag of silicomanganese does not meet the established limits, do not provide the required amount of manganese monoxide. The phosphorus content in the flux, when used in the charge, of an increased amount of manganese ore (composition 1) exceeds the permissible concentration of 0.12%. The production of a lower phosphorus content in the prototype charge, as compared with a similar charge of composition 1, is due to the use of high-grade manganese ore with a phosphorus content of 0.14%. An analysis of the calculations of the relative removal of phosphorus during smelting in the case of using different mixtures of the charge shows that the proposed charge in the entire range of the specified limits provides a more complete refining compared to the prototype charge. This allows, in the case of using manganese ore with a low manganese content and a high phosphorus concentration as the initial charge component, to limit the phosphorus content in the resulting fluxes, which results in low-phosphorus welds with a high resistance of cracked welds. Claim 1. Batch for producing fused welding flux containing manganese ore, quartz sand, waste slag of silicomanganese production and fluorspar, which in order to improve the quality of manganese welding flux by reducing the phosphorus content when used in the blend manganese ores, components are taken in the following ratio, wt.%: Manganese ore 25-36 Quartz sand 5-15 Dump slag production 35-60 silicomanganese 6-14 Fluor spar 2. The mixture according to claim 1, 1 and 2 tons of h and h aa so that the components that are dumped to the production of silicomanganese are used in the following terms, wt%: Manganese monoxide 26-32 Silica 45-50 Alumina 8-12 Calcium oxide 6 -10 Magnesium oxide 2-5 Mixture of potassium oxides and sodium 2-6 Iron monoxide 0.1-3 T a b l and c a 1 Manganese (not less) (in terms of 39 36 30 25 20 32 35 1 2 3 4 5 54 60 65 43 34 table 2 eight 14 6 ten ten Composition one 2 3 4 5 1276470 8 Continuation of table 2 Table 3