RU2643026C1 - Welding flux - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: flux contains, wt %: silicomanganese production slag 60.0-85.0, dust-like wastes of aluminium production, 4.0-7.0; potassium-sodium liquid glass 15.0-40.0. The silicomanganese production slag includes, wt %: SiO₂ 25-49, Al₂O₃ 4-28, CaO 15-32, CaF₂ 0.1-1.5, MgO 1.7-9.8, MnO 3-17, FeO 0.1-3.5, S≤0.20 and P≤0.05. Dust-containing waste of aluminium production contains, wt %: Al₂O₃ 21-38.27; F 18-27; Na₂O, 8-13; TO₂O 0.4-6.6; CaO 0.7-2.1; SiO₂ 0.5-2.48; Fe₂O₃ 2.1-2.3; C_total 12.5-27.2; MnO 0.03-0.9; MgO 0.04-0.9; S 0.09-0.46 and P 0.1-0.18. The flux is in the form of granules of 0.45-2.5 mm size, and the fraction of silicomanganese production slag is less than 0.45 mm.

EFFECT: increased level of mechanical properties level of the weld and stability of arc burning while the flux cost is reduced due to effective reclaiming of obtained fine fraction.

1 cl

Description

The invention relates to welding, specifically to submerged arc welding, in particular to fluxes intended for welding low and medium alloy steels.

Known flux for welding [1], containing silicon dioxide, manganese oxide, calcium oxide, magnesium oxide, aluminum oxide, potassium oxide, sodium oxide, iron oxide, calcium fluoride, in which dust materials are used as materials based on silicon dioxide and manganese oxide ferrosilicon waste; as materials based on calcium oxide, magnesium oxide used pulverized waste production of lime; as materials based on aluminum oxide, potassium oxide, sodium oxide, iron oxide and calcium fluoride, dusty waste from aluminum production was used, and as a binder material containing potassium oxide, sodium oxide, potassium-sodium liquid glass was used, while dusty waste from lime production gas cleaning dust with a CaO content of at least 85 wt. %, dust of gas purification of ferroalloy production with a content of SiO _{2 of} not less than 98 wt.% was used as pulverized waste from the production of ferrosilicon. %, and dust of electrostatic precipitators having the following chemical composition, wt. %: Al ₂ O ₃ = 21-46.23; F ⁺ = 18-27; Na ₂ O = 8-15; K ₂ O = 0.4-6%, CaO = 0.7-2.3; SiO ₂ = 0.5-2.48; Fe ₂ O ₃ = 2.1-3.27; With _total = 12.5-30.2, MnO = 0.07-0.9, MgO = 0.06-0.9, S = 0.09-0.59, P = 0.1-0.18 ; in the following ratio of components, wt. %:

Dusty waste lime production 33.9-44.5 Dusty waste ferrosilicon production 20.5-31.1 Dusty waste aluminum production 22-27 Liquid glass 8-13

Significant disadvantages of this flux for welding are:

- increased cost in the production of flux in connection with the use of a multicomponent system;

- insufficient strength of the flux during the operations of transportation, pouring and delivery, as well as in some cases unstable arc burning due to the low concentration of liquid glass in the flux;

- in some cases, increased contamination of the weld and deposited metal by non-metallic inclusions of exogenous nature due to the reduced refining properties of the resulting slag due to the high concentration of MgO and low MnO content.

Known selected as a prototype [2] flux for welding, containing silicon oxide, aluminum oxide, calcium oxide, magnesium oxide, manganese oxide, calcium fluoride, the sum of the oxides of potassium and sodium, sodium fluoride, iron oxide, in which as a material based silicon oxide, aluminum oxide, calcium oxide, magnesium oxide, manganese oxide, slag of silicomanganese production was used; and as a material based on calcium fluoride, potassium and sodium oxides, sodium fluoride, dusty waste from aluminum production and liquid glass were used in the following ratio of components, wt. %:

Silicomanganese Slag 88.0-98.0 Dusty waste aluminum production 1.0-6.0 Liquid glass 1.0-6.0

Significant disadvantages of this flux for welding are:

- increased cost of flux in connection with the use of equipment for crushing and grinding slag for the production of silicomanganese, as well as the formation of a significant amount of finely dispersed fraction during crushing, which cannot be used for submerged arc welding, and therefore its disposal is required;

- when using the manufactured flux without screening the fine fraction, there is an increased rejection of welds according to surface defects and a decrease in the level of mechanical properties.

The technical results of the invention are:

- reducing the cost of production of flux and welding process due to the efficient utilization obtained by crushing a fine fraction of flux;

- increase the level of mechanical properties of the weld;

- increasing the stability of arc burning and improving the quality of the weld.

For this purpose, a flux for welding low-alloyed and medium-alloyed steels is proposed, containing slag from silicomanganese production, pulverized waste from aluminum production and liquid glass, while slag from silicomanganese production includes, by weight. %: SiO ₂ 25-49, Al ₂ O ₃ 4-28, CaO 15-32, CaF ₂ 0.1-1.5, MgO 1.7-9.8, MnO 3-17, FeO 0.1- 3,5, S≤0,20 and P≤0,05, and pulverized aluminum production waste contains, wt. %: Al ₂ O ₃ 21-38.27; F 18-27; Na ₂ O 8-13; K ₂ O 0.4-6.6, CaO 0.7-2.1; SiO ₂ 0.5-2.48; Fe ₂ O ₃ 2.1-2.3; C _total 12.5-27.2, MnO 0.03-0.9, MgO 0.04-0.9, S 0.09-0.46 and P 0.1-0.18, while the flux is made in the form of granules with a size of 0.45-2.5 mm, and the slag of silicomanganese production has a fraction of less than 0.45 mm in the following ratio of components, wt. %: slag production of silicomanganese 60.0-85.0; pulverized waste from aluminum production 4.0-7.0; potassium-sodium liquid glass 15.0-40.0.

The declared limits are selected empirically based on the quality of the welds obtained during welding, the stability of the welding process and surfacing, as well as the required mechanical properties.

The introduction of silicomanganese production into the slag flux composition ensures good slag formation and high refining and covering properties of the formed slag.

Introduction to the flux composition of pulverized waste from aluminum production allows: to carry out active deoxidation due to the formation of CO and CO ₂ generated by the interaction of carbon fluoride CF _x (1≥х> 0) with oxygen dissolved in steel, while due to the fact that carbon It is in a bound state, carburization of steel practically does not occur; carry out hydrogen removal due to a complex of fluorine-containing compounds (such as Na ₂ SiF ₆ , NaF, KF, CF _x (1≥x> 0), AlF ₃ , Na ₃ AlF ₆ ), which decompose at welding process temperatures with the release of F, which in its the turn interacts with hydrogen dissolved in steel to form a gaseous HF compound.

The introduction of potassium-sodium liquid glass is due, on the one hand, to use it as a binder of the inventive flux for welding, and on the other hand, as a material that increases, due to the contained potassium and sodium, the stability of arc burning.

For the manufacture of flux for welding, slag from silicomanganese was used as slag from the production of silicomanganese. It was melted in ore-thermal furnaces by a carbon thermal method using a continuous process with a content of, wt. % .: SiO ₂ = 25-49, Al ₂ O ₃ = 4-28, CaO = 15-32, CaF ₂ = 0.1-1.5, MgO = 1.7-9.8, MnO = 3- 17, FeO = 0.1-3.5, S 0 0.20, P ,0 0.05.

As dusty waste from aluminum production, dust from electrostatic precipitators of aluminum production with the following chemical composition, wt. %: Al ₂ O ₃ = 21-38.27; F = 18-27; Na ₂ O = 8-13; K ₂ O = 0.4-6.6, CaO = 0.7-2.1; SiO ₂ = 0.5-2.48; Fe ₂ O ₃ = 2.1-2.3; With _total = 12.5-27.2, MnO = 0.03-0.9, MgO = 0.04-0.9, S = 0.09-0.46, P = 0.1-0.18 .

As the liquid glass, potassium-sodium liquid glass with a density at 15-25 ° C of 1.30-1.55 g / cm ³ and a silicate module [SiO ₂ : (K ₂ O + Na ₂ O) ⋅ 1.0323 was used ] = 2.6-3.0.

The manufacture of the inventive flux for welding took place in 3 stages.

At the first stage, slag from silicomanganese production was obtained. Ferroalloy - silicomanganese smelted in ore-thermal furnaces - was produced together with a by-product - slag into a ladle. After casting silicomanganese, the slag was drained from the ladle and cooled. After that, crushing, screening and sieving through a fine sieve (less than 0.45 mm) were carried out.

At the second stage, a small fraction of silicomanganese slag was mixed with dusty waste from aluminum production.

At the third stage, a mixture of a fine fraction of silicomanganese slag and dusty waste from aluminum production with liquid glass was mixed. The resulting mixture was dried according to the developed regime, after which grinding was performed. Next, sieving was carried out with the isolation of a fraction of 0.45-2.5 mm. Granules larger than 2.5 mm were sent for grinding, and a fraction of less than 0.45 mm was supplied for mixing with liquid glass.

, Н/мм², предела текучести -

, Н/мм², относительного удлинения δ, %, ударной вязкости при температуре минус 40°С - KCU^-40°C, Дж/см²), а так же макро- и микроисследований.The inventive flux for welding was tested on samples of steel grades 09G2S and 09G2. Welding was carried out with Sv-08GA wire on plates with a length of at least 500 mm using an ASAW-1250 welding tractor. From welded plates, samples were cut for mechanical tests (tensile strength -

, N / mm ² , yield strength -

, N / mm ² , relative elongation δ,%, impact strength at a temperature of minus 40 ° С - KCU ^{-40 ° C} , J / cm ² ), as well as macro and micro studies.

The technological parameters obtained as a result of laboratory research formed the basis for the technology of submerged-arc welding of oil storage tanks. The inventive flux was made and used in the conditions of JSC "Novokuznetsk factory of reservoir steel structures named after N. Ye. Kryukova ”for welding sheets of steel grades 09G2S and 09G2. In welding and surfacing, a fraction of 0.45-2.5 mm was used.

The use of the inventive flux for welding in comparison with the prototype allowed:

1. Reduce the cost of flux production by 26-32%.

2. To reduce the level of rejection for surface defects by an average of 0.19-0.30%.

и предел прочности

на 0,1-0,2 Н/мм², относительное удлинение на 0,04%, ударной вязкости при отрицательных температурах в среднем на 0,09 Дж/см².3. To increase the overall level of mechanical properties of the weld, yield strength

and tensile strength

by 0.1-0.2 N / mm ² , elongation by 0.04%, impact strength at negative temperatures by an average of 0.09 J / cm ² .

Information sources

1. Pat. RF 2492983 B23K 35/36.

2. Pat of the Russian Federation 2576717 B23K 35/362.

Claims (1)

A flux for welding low-alloyed and medium-alloyed steels containing slag from silicomanganese production, pulverized waste from aluminum production and liquid glass, while slag from silicomanganese production includes, by weight. %: SiO ₂ 25-49, Al ₂ O ₃ 4-28, CaO 15-32, CaF ₂ 0.1-1.5, MgO 1.7-9.8, MnO 3-17, FeO 0.1- 3,5, S≤0,20 and P≤0,05, and pulverized aluminum production waste contains, wt. %: Al ₂ O ₃ 21-38.27; F 18-27; Na ₂ O 8-13; K ₂ O 0.4-6.6; CaO 0.7-2.1; SiO ₂ 0.5-2.48; Fe ₂ O ₃ 2.1-2.3; C _total 12.5-27.2; MnO 0.03-0.9; MgO 0.04-0.9; S 0.09-0.46 and P 0.1-0.18, characterized in that the flux is made in the form of granules with a size of 0.45-2.5 mm, and the slag production of silicomanganese has a fraction of less than 0.45 mm, the following ratio of components, wt. %: slag production of silicomanganese 60.0-85.0; pulverized waste from aluminum production 4.0-7.0; potassium-sodium liquid glass 15.0-40.0.