SU1107994A1 - Ceramic flux for welding steels - Google Patents

Abstract

CERAMIC FLUES FOR WELDING STEELS, predominantly gsakakirovannyh aluminum, containing ferrosilicon, ferromanganese, manganese ore, fluorspar, marble, wollastonite, iron oxide, characterized in that, in order to increase the ductility and viscosity of the metal of the seam due to the oxidation of aluminum, followed, followed by subsequent oxidation of aluminum, followed by subsequent oxidation of the metal of the weld seam due to the oxidation of aluminum, followed by subsequent oxidation alumina in slag, as well as improving the welding and technological properties of the flux, it additionally contains chromium oxide, nickel, sodium silicofluoride and rutile, and iron oxide is introduced in the form of iron oxides and the following ratio of components, May.%: Ferrosilicon 0.4-2.0 Ferromanganese 0.6-3.0 Manganese ore 2-8 Fluor spar20-30 Marble4-8 Rutile5-10 Iron scale 12-16 Wollastonite 11-30 Oxide chromium 4-8 nickel5-9 sodium silicofluoride4-8

Description

The invention relates to compositions of ceramic fluxes for mechanized welding of steel structures with aluminum coating.

Known ceramic flux for welding steel structures with aluminum coating 11, containing the following components, wt.%:

1.2-2.9 0.5-0.6

1.5-9.0 11.5-17.7

calcium 0.3-0.6

nor 0.6-0.75

horse 1.2-2.25

titanium 0.36-0.75

0.09-0.15 The Rest

Also known ceramic flux2 containing the following components, wt.%:

Ferrosilicon 0.2-2.0 Ferromanganese 0.2-2.0 Ferrotitanium 0.2-2.5 Manganese

ore 2,0-5,0

Hematite10.0-12.0

Magnesite22.0-40.0

Fluorspar 20,0-30,0 Alumina14,0-20,0

Marble3.0-8.0

Aluminum powder2, 0-5.0 Rutile 3.0-9.0 Feldspar 3.0-8.0 The known fluxes do not possess non-flowing welding or technological properties when welding aluminum-coated steels due to significant transition of aluminum from the welded coating the seam, resulting in a reduction in the plastic-viscous properties of the seam and slag separability. I

Known ceramic flux 3, holding the components in the following respect, May.%:

Wollastonite 10-40 Ferrosilicium 0.2-5.0 Manganese ore 2,0-8,0 Hematite (oxide

gland)

1.0-3.0 30-50 Magnesite 7-20 Fluor spar 6-20 Alumina

5-12 Marble

Aluminum powder 0.5-3.0

Ferrotitanium 0,2-5,0

Ferromanganese 0.2-5.0

This flux provides a higher ductility of the weld metal, but also does not contribute to the removal of aluminum from the weld metal.

The aim of the invention is to increase the ductility and viscosity of the weld metal due to oxidation of the aluminum by the subsequent removal of aluminum oxide in the slag, as well as the improvement of the welding-technological properties of the flux when welding steel structures coated with an aluminum layer with a thickness of 200-300 microns.

This goal is achieved by the fact that ceramic (Blues for welding steel structures containing iron oxide, ferrosilicon, ferromanganese, manganese ore, plvarspar, marble, wollastonite, additionally contains chromium oxide, nickel, silicofluoride sodium and rutile, and iron oxide is introduced as iron dross in the following ratio of components, ma.G

0.4-2.0

Ferrosilicon 0.6-3.0

Ferromanganese

2-8

Manganese ore 20-30

Fluorspar 4-8

Marble 5-10

Rutile

Zhelezna

12-16

dross 11-30

Wollastonite

4-8

Chrome oxide

5-9

Nickel

Fluorosilicate

4-8

sodium

The percentage of scale introduced into the flux (12.0-16.0) is determined by calculating its mass with a molten aluminum coating ratio of 3: 1-4: 1 (the ratio of the mass of the converted flux to the mass of the weld metal is approximately equal to unit This ratio allows you to fully implement the exometric reaction ЗРеОг2А1 А120з + ЗРе

Fe-O.) And, that (similarly with Fe20j and

In this way, aluminum can be removed from the weld by oxidizing it and removing the resulting oxide in the shell. This makes it possible to avoid deterioration of the plastic-viscous properties of the weld and the separation of the slag crust due to significant transition of aluminum from the coating to the weld.

made of aluminum coated metal structures.

The choice of scale compared with other oxidants, such as hematite, was made on the basis of a significantly lower content of sulfur (no more than 0.0414) and phosphorus (no more than 0.052%) in its composition, which are harmful impurities in the weld metal (concentration of sulfur and phosphorus in hematite to 0.15% each). In addition, iron oxide is a waste product from the production of steel billets; it is cheap and not scarce.

The introduction of wollastonite and sodium silicofluoride makes it possible to obtain the necessary ratios between CaO and 5i02 J N 2O and SiF, improve the melting of the flux by lowering its melting temperature, increase the fluidity, reduce the danger of pore formation, and obtain a dense metal. When the content of wollastonite is less than 11.0% and sodium silicofluoride is less than 4.0%, the effect of their introduction is negligible. The upper limit of the content of wollastonite 30.0% and sodium silicofluoride 8.0% was chosen for reasons of limiting the number of gas-slag components of the flux.

Introduction of more than 5% nickel into the flux increases the impact strength of the weld metal at low temperatures.

Chromium oxide, as well as iron oxides, introduced in the form of scale, and manganese oxides, introduced in the form of manganese ore, are reduced with an aluminum coating during the welding process to alloy the weld metal and increase the deposition rate of 1 ton. Restored chromium contributes to an increase in the strength characteristics of the welded joint. When the content of chromium oxide is less than 4.0%, the effect of its introduction is negligible. Increasing the nickel content in the flux with a constant or lower content of chromium oxide can lead to the appearance of hot cracks in the weld.

The limits of the content of ferromanganese are 0.6–3.0% and ferrosilicon 0.4–2.0% are chosen so that the ratio of manganese and silicon in the flux is close to 3: 1, which is optimal for obtaining the required plasticity Swannst welded

compounds. The upper limit of the content of ferrosilicon in the flux (2.0%) is limited due to the increase in the number of non-metallic inclusions in the weld with increasing silicon content. The lower limit of the content of ferromanganese (0.6%) and ferrosilicon (0.4%) is limited by the specified values of the characteristics of the strength of the weld metal, which decrease with the decrease in the content of manganese and silicon.

The presence in the composition of the flux of manganese oxides creates an oxidizing atmosphere in the zone of the arc, which reduces the partial pressure of hydrogen in the gas phase and thereby helps to prevent porosity in the weld metal. At the same time hydrogen is bound by fluorine due to the presence of calcium fluoride in the composition of the flux. All this makes it possible to get a weld without pores. The limits of the content of manganese ore are 2.0–8.0% chosen so that the total content of manganese introduced into the weld through manganese ore and ferromanganese is in the range of 0.7–1.1%.

When the fluorspar content in the flux is less than 20%, the required viscosity of the slag is not ensured, and if its content is more than 30%, the slag becomes highly fluid, badly covering the roller. In addition, a further increase in the content of Plavixv spar is limited by the conditions of steady arc burning and the emission of harmful gases during welding.

The limits of the content of marble in the flux of 4.0-8.0% are selected on the basis of ensuring effective gas protection of the weld metal.

The limits of rutile content 5,010, 0% are chosen from the conditions of good formation of the welded joint.

Specific compositions of fluxes are given in table 1.

For the manufacture of flux used liquid glass with a density of 1.30 in the amount of 20% by weight of the dry mixture. The decrease in the density of liquid glass below the specified reduces the mechanical strength of the flux grains. Increasing the density makes it difficult to perform the subsequent granulation operation, and also leads to an increase in the amount of sodium silicate in the flux, which is undesirable. $ 110 The amount of liquid glass should be adjusted depending on a number of factors, such as the degree of grinding of components, the temperature of materials and the environment, the modulus of liquid glass, etc. A sign of a sufficient amount of liquid glass in a flux mass can be the appearance when the mass of lumps is mixed with the speaker out with liquid glass. The insufficient amount of liquid glass introduced into the dry mixture leads to the formation during granulation of a large amount of fines in the flux and insufficient strength of its grains. Too much liquid glass makes granulation difficult. Operation 1 of the adjustment should ensure the maximum yield of the fraction with a grain size of 1-3 mm. The temperature of flux calcination is 650-680 C. The flux when welding steel with an aluminum coating with a thickness of 200-300 μm ensures a steady flow of the arc process, good formation of the weld and separation of the slag crust. The welding was performed by an ABS device with a direct current of reverse polarity from the VS-600 rectifier. Plates 200x100x12 mm of StZsp steel of composition were welded,%: С 0.15%; Mp 0.55; Si 0.2 P 0.02; 5 0.03 j coated with the method of electric arc spraying with an aluminum layer of 200-300 microns, butt joint. Three compositions of ceramic fluxes (Table 1, compositions 2–4) in accordance with the invention, as well as two, were tested. composition of fluxes consisting of the same components, but in percentage terms, beyond the limits established by the invention (compounds 1 and 5). A The studies were carried out in the following range of modes: welding current 380-420 A, arc voltage 25-35 V, welding speed 13.5-24.5 m / h. Chemical analysis determined the content of aluminum, sulfur, phosphorus in the weld metal. Impact viscosity at temperature was determined on samples of type U1 (GOST 9454-78X Slag separability was determined by applying a shock load from the root of the weld of the welded plate and assigning the area of the separated slag to the impact work. The weld temperature in determining separability was about 450 ° C. The averaged test results are summarized in Table 2. Thus, the flux has a sufficient oxidizing ability with respect to the aluminum of the coating, as evidenced by a 4 to 8 times decrease in the aluminum content in the weld , which provides an increase of more than 3 times in toughness at a temperature of 40 ° C. In addition, the amount of harmful impurities (sulfur and phosphorus) in the weld metal decreased. The separation of slag crust improved. obtained for compounds 1 and 5, allow us to conclude that the correctly selected content limits for the components of bb.The proposed flux can be used for welding steel structures with aluminum coating, providing good properties of welded joints eni. Table 1

1107994

8 Continuation of table 1

Claims (1)

CERAMIC FLUX FOR WELDING STEELS, mainly clad with aluminum, containing ferrosilicon, ferromanganese, manganese ore, fluorspar, marble, wollastonite, iron oxide, characterized in that, in order to increase the ductility and toughness of the weld metal due to oxidation of the aluminum coating with subsequent removal of oxide aluminum to slag, as well as improving the welding and technological properties of the flux, it additionally contains chromium oxide, nickel, sodium silicofluoride and rutile, and iron oxide is introduced in the form of iron oxide the ratio of the components, May.%: Ferrosilicon 0.4-2.0 Ferromarg an e ts 0.6-3.0 Manganese ore 2-8 Fluffy spar 20-30 Marble 4-8 Rutile 5-10 Iron scale 12-16 Wollastonite 11-30 Chromium oxide 4-8 Nickel 5-9 Silicofluoride sodium 4-8