RU2566235C1 - Flux for welding and surfacing - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: flux contains components in the following ratio in wt %: dusty ladle slag of rail steel production - 30.0-50.0, dusty wastes of aluminium production - 5.0-30.0, liquid glass 0 40.0-65.0. Said dusty ladle slag of rail steel production comprises the following components, wt %: FeO 0.3-1.5, MnO 0.1-2.0, CaO 50.8-53.8, SiO₂ 24.5-26.2, CaF₂ 0.01-1.0, Al₂O₃ 3.4-5.0, MgO 7.8-8.7, C_tot 0.1-0.6, S 0.1-0.4, P 0.3-0.6. Said dusty wastes of aluminium production feature the following chemical composition, wt %: Al₂O₃ 21-43.27, F 18-27, Na₂O 8-13, K₂O 0.4-6, CaO 0.7-2.1, SiO₂ 0.5-2.48, Fe₂O₃ 2.1-2.3, C_tot 12.5-28.2, MnO 0.03-0.9, MgO 0.04-0.9, S 0.09-0.46, P 0.1-0.18.

EFFECT: lower costs, flux higher strength, stable arc, reduced loss of doping elements.

1 tbl

Description

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

Known fused flux for electric arc welding of cold-resistant steels [1], containing silicon dioxide, calcium oxide, magnesium oxide, calcium fluoride, aluminum oxide, manganese oxide, iron oxide, which has a basicity of 1.5-2.0 and additionally contains potassium oxide and sodium in the following ratio of components, weight. %: silicon dioxide SiO ₂ - 21-27, calcium oxide CaO - 11-17, magnesium oxide MgO - 21-25, calcium fluoride CaF ₂ - 14-20, aluminum oxide Al ₂ O ₃ - 10-14, manganese oxide MnO - 4-7, (potassium + sodium) oxides Na ₂ O + K ₂ O - 2-5, iron oxide Fe ₂ O ₃ - 1-3.

Significant disadvantages of this flux for welding are:

- the absence of carbon-containing components that allow the removal of oxygen in the form of gaseous compounds of CO and CO ₂ that do not pollute the weld with oxide non-metallic inclusions and, as a result, increase the mechanical properties of the welded structure;

- high oxidation of flux (content of iron and manganese oxides), leading to a significant oxidation of alloying elements in welded steels;

- increased contamination of the weld and weld metal with non-metallic inclusions in connection with reduced refining properties of the resulting slag due to the high concentration of MgO and increased melting points and flux viscosity;

- high cost in connection with the use of expensive natural materials and costs associated with crushing and grinding;

- unstable burning of the arc due to the insufficient number of elements that facilitate the excitation and stabilize the burning of the arc (in particular, sodium and potassium).

Known selected as a prototype, a flux for welding [2], containing silicon dioxide, manganese oxide, calcium oxide, magnesium oxide, aluminum oxide, potassium oxide, sodium oxide, iron oxide, calcium fluoride, characterized in that as materials based on silica and manganese oxide used pulverized waste production of ferrosilicon; 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, C _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;

- increased oxidation of flux due to uncontrolled content of iron and manganese oxides, leading to uncontrolled oxidation of alloying elements in welded and deposited products;

- 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 the increase in this regard, the melting temperature and viscosity of the flux.

The technical results of the invention are:

- cost reduction in the production of flux;

- increasing the strength of the flux and the stability of the arc burning due to the optimization of the concentration of liquid glass;

- reduction in the fumes of alloying elements during welding and surfacing due to a decrease in oxidation;

- a decrease in the level of pollution became exogenous non-metallic inclusions.

To do this, we propose a flux for welding and surfacing containing silicon dioxide, manganese oxide, calcium oxide, magnesium oxide, alumina, potassium oxide, sodium oxide, iron oxide, calcium fluoride and potassium-sodium liquid glass, in which, as mentioned oxides and fluorides used pulverized ladle slag production of rail steel and dusty waste from aluminum production, in the following ratio of components, wt. %:

dusty ladle slag rail steel production 30.0-50.0 dusty waste aluminum production 5.0-30.0 liquid glass 40.0-65.0

while pulverized ladle slag production of rail steel contains, by weight. %: FeO 0.3-1.5, MnO 0.1-2.0, CaO 50.8-53.8, SiO ₂ 24.5-26.2, CaF ₂ 0.01-1.0, Al ₂ O ₃ 3.4-5.0, MgO 7.8-8.7, C _total 0.1-0.6, S 0.1-0.4, P 0.3-0.6, and dusty aluminum production wastes have the following chemical composition, wt. %: Al ₂ O ₃ 21-43.27, F 18-27, Na ₂ O 8-13, K ₂ O 0.4-6, CaO 0.7-2.1, SiO ₂ 0.5-2, 48, Fe ₂ O ₃ 2.1-2.3, C _total 12.5-28.2, MnO 0.03-0.9, MgO 0.04-0.9, S 0.09-0.46 P 0.1-0.18.

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 pulverized ladle slag into the flux composition of rail steel production provides the required flux basicity and viscosity obtained during welding of the slag system. The basicity (CaO / SiO ₂ ) is selected based on the conditions for ensuring good covering properties and the optimal refining ability of the resulting slag with respect to non-metallic inclusions. The selected limits for CaF ₂ , Al ₂ O ₃ , MgO provide good slag formation and high refining and covering properties of the formed slag. The content of FeO and MnO was selected based on the provision, on the one hand, of low oxidation of alloying elements, and, on the other hand, of good fluidity of the slag system.

Introduction to the composition of the flux of pulverized waste from aluminum production allows:

- conduct active deoxidation due to the formation of CO and CO₂, formed by the interaction of carbon fluoride CF_x (1≥x> 0) with oxygen dissolved in the steel, while due to the fact that carbon is in a bound state, carbonization of steel practically does not occur;

- carry out the removal of hydrogen 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 ), decomposing at temperatures of welding processes with the release of fluorine, which in in turn, interacts with hydrogen dissolved in steel to form a gaseous HF compound;

- increase the stability of arc burning due to elements that facilitate ionization in the arc column (potassium and sodium).

The introduction of liquid glass is due, on the one hand, to use it as a binder of the inventive flux for welding and surfacing, 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 as a pulverized ladle slag for the production of rail steel used slag with a content, wt. %: FeO = 0.3-1.5, MnO = 0.1-2.0, CaO = 50.8-53.8, SiO ₂ = 24.5-26.2, CaF ₂ = 0.01- 1.0, Al ₂ O ₃ = 3.4-5.0, MgO = 7.8-8.7, C _total = 0.1-0.6, S = 0.1-0.4, P = 0.3-0.6.

As dusty waste from aluminum production - dust from electrostatic precipitators of aluminum production with the following chemical composition, wt. %: Al ₂ O ₃ = 21-43.27, F = 18-27, Na ₂ O = 8-13, K ₂ O = 0.4-6, CaO = 0.7-2.1, SiO ₂ = 0.5-2.48, Fe ₂ O ₃ = 2.1-2.3, C _total = 12.5-28.2, MnO = 0.03-0.9, MgO = 0.04-0, 9, S = 0.09-0.46, P = 0.1-0.18.

As 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 was carried out by mixing the components. The resulting mixture was mixed in a mixer for 25-35 minutes until a homogeneous mass. Next, the mixture was kept at a temperature of 15-30 ° C for 24-28 hours, dried at a temperature of 150-300 ° C for 20-30 minutes, after which crushing and sieving through a sieve (mesh 3 × 3 mm) were performed. Larger granules were sent for grinding. The inventive flux for welding and surfacing was used on samples of steel grades 09G2D, 09G2S, 09G2, 40G, 65G, 30KhGSA, 35KhGSA, welding was performed using Sv-08GA wire.

The effect of changes in the chemical composition of components with boundary, foreign and claimed limits of the flux for surfacing welding on various welding parameters is given in the table.

Using the inventive mixture in comparison with the base (prototype) allows you to:

1. Reduce the cost of flux production by 27-56 rubles / t;

2. Increase flux strength (screenings when pouring fractions less than 0.1 mm are reduced by an average of 4.6%);

3. To reduce the fumes of manganese and silicon in the weld and deposited metal by an average of 0.8 and 1.34%, respectively;

4. To improve the formation of the weld during welding and surfacing due to stabilization of arc burning;

5. To reduce the level of contamination of steel with exogenous non-metallic inclusions (contamination of steel with oxide exogenous non-metallic inclusions is reduced to 0.2-0.7 mm).

List of sources

1. Pat. RF 2313434, B23K 35/362.

2. Pat. RF 2492983, B23K 35/36.

Claims (1)

Welding and surfacing flux containing silicon dioxide, manganese oxide, calcium oxide, magnesium oxide, aluminum oxide, potassium oxide, sodium oxide, iron oxide, calcium fluoride and potassium-sodium liquid glass, characterized in that as the mentioned oxides and fluorides used pulverized ladle slag for rail steel production and pulverized waste from aluminum production, with the following ratio of components, wt.%:
dusty ladle slag rail steel production 30.0-50.0 dusty waste aluminum production 5.0-30.0 liquid glass 40.0-65.0
wherein the pulverized ladle slag for rail steel production contains, wt.%: FeO 0.3-1.5, MnO 0.1-2.0, CaO 50.8-53.8, SiO ₂ 24.5-26.2 , CaF ₂ 0.01-1.0, Al ₂ O ₃ 3.4-5.0, MgO 7.8-8.7, C _total 0.1-0.6, S 0.1-0.4 , P 0.3-0.6, and pulverized waste from aluminum production has the following chemical composition, wt.%: Al ₂ O ₃ 21-43,27, F 18-27, Na ₂ O 8-13, K ₂ O 0 , 4-6, CaO 0.7-2.1, SiO ₂ 0.5-2.48, Fe ₂ O ₃ 2.1-2.3, C _total 12.5-28.2, MnO 0.03 -0.9, MgO 0.04-0.9, S 0.09-0.46, P 0.1-0.18.