RU2442681C1 - Agglomerated flux of the 48ll-59 mark of origin applied for the automatic welding of pipe steel of the -90- -100 categories - Google Patents

Abstract

FIELD: welding techniques.

SUBSTANCE: invention can be applied to the automatic welding of the low-alloy cold resistant overstable steels with low-alloy leads at high speed; the flux has the following composition (%, mass): quartzy sand 2.0-10.0; electrocorundum 20.0-33.0; calcium fluoride 11.0- 46.0; sphen concentrate 25.0-35.0; metallic component 7.0-11.0; natrium-kalium silicate 7.7-20.0; the metallic component has the following composition (%, mass): Fe 18.0-21.0; B 0.3-0.5; Mn 55.0-65.0; Al 4.0-6.0; Mg 4.0-6.0; Ti 6.0-10.0; Si 2.0-4.0.

EFFECT: the agglomerated flux provides high mechanical features of the metal of the weld of the low-alloy cold resistant steels upon the preservation of the required welding and technological properties of the flux and cold resistance of the welded joint at the temperature up to minus 60°C.

1 dwg, 4 tbl

Description

The invention relates to welding materials, namely to agglomerated fluxes, and can be used for automatic welding of low alloy cold-resistant steels of high strength at high speeds with low alloy wires in various industries, for example, in the production of pipes, shipbuilding and petrochemical industries.

The production of steel structures is associated with large volumes of welding, including automatic submerged arc welding, usually performed at speeds of not more than 30-40 m / h.

The limitation of the welding speed is due to the features (formation of the weld (form of penetration). When the welding speed increases above 50 m / h, the formation of the weld is violated due to its insufficient width and excessive penetration depth. When the welding speed increases, the arc deviates in the direction opposite to the welding direction and the greater, the higher the marching speed of the welding machine (tractor), which leads to a decrease in the width of the seam and, consequently, to a decrease in the gain shape factor, which is equal to the ratio of the width reinforcements to its height, the seam becomes narrow, high, with undercuts. When the arc is deflected, the stability of burning decreases, and the “overpresses” of the seam form, and due to the high crystallization rates of the weld pool metal, it becomes difficult to degass, which leads to the formation of pores in seam metal.

For high-quality (formation of the weld, intensive removal of gas and slag inclusions from the liquid weld pool, the solidification temperature of the slag should be lower than the crystallization temperature of the metal, which is especially important when welding at high speeds, when the residence time of the metal in the liquid state is reduced. Heat shortage at high speed welding requires a lower melting temperature of the flux and its high viscosity in the molten state.

Favorable weld formation at high welding speeds is achieved by using multi-electrode welding (more than 1 electrode) and using a specially developed flux for high-speed welding, that is, welding at speeds up to 200 cm / min with current at the upper limit and with a consistent arc voltage, at condition for the qualitative formation of the weld.

However, at present, the level of requirements for the technological strength of the weld metal, appearance due to the quality of formation, as well as environmental friendliness and sanitary and hygienic characteristics of welding fluxes in industry has increased significantly. Fused fluxes, due to their characteristics and production method, no longer meet these requirements, and therefore they are replaced by agglomerated fluxes.

The closest in composition and purpose to the claimed is an agglomerated flux grade 48AF-55, adopted as a prototype containing the following ratio of components, wt.%:

electrocorundum 28.0-33.0 calcined magnesite 10.0-16.0 rutile concentrate 4.0-8.0 iron ore concentrate 0.4-0.5 alloy modifier 45.0-50.0 manganese metal 2.0-3.0 aluminum metal 0.7-1.0 ferrotitanium 1.5-2.0 ferroboron 0.2-0.7 sodium potassium silicate (dry residue of water glass) 7.7-8.9

Moreover, the ratio of ferrotitanium to ferroboron should be in the range of 4-10, the total content of manganese and metal aluminum should be at least 2.8 wt.%, And the modifier alloy included in it should contain the following components: CaO, Al ₂ O ₃ , CaF ₂ , MnO, and SiO ₂ in a ratio of 1.0: 1.5: 1.5: 1.0: 2.0, respectively (1).

This ceramic (agglomerated) flux prototype for welding low alloy steels provides the required welding and technological properties by reducing the viscosity of the slag and expanded technological capabilities of the flux when welding at high speeds due to the favorable shape of the weld, including the smoothness of the joint with base metal while maintaining high cold resistance of the welded joint at temperatures up to -60 ° C.

The disadvantage of this flux prototype is the low performance of the impact when welding high-strength low-alloy steels of categories X90-X100.

The technical result of the invention is the creation of an agglomerated flux providing high mechanical characteristics of welds when welding steels of the X90-X100 category at high speeds and forced modes while maintaining high cold resistance of the welded joint at temperatures up to -60 ° C and good welding and technological properties.

The technical result is achieved by the fact that the agglomerated flux for automatic multi-arc welding of low alloy cold-resistant steels of high strength at high speeds, containing electrocorundum, a metal component and sodium-potassium silicate as a binder, additionally contains quartz sand, fluorspar, sphene concentrate in the following ratio of components , wt.%:

quartz sand 2.0-10.0 electrocorundum 20.0-33.0 fluorspar 11.0-46.0 sphene concentrate 25.0-35.0 metal component 7.0-11.0 sodium potassium silicate 7.7-20.0

Moreover, the metal component has the following composition, wt.%:

Fe 18.0-21.0 B 0.3-0.5 Mn 55.0-65.0 Al 4.0-6.0 Mg 4.0-6.0 Ti 6.0-10.0 Si 2.0-4.0

The indicated limits of the content of sodium-potassium silicate in the flux provide the best granulation of the flux in its manufacture, i.e. the diameter of the granules is 0.3-2.0 mm.

The content of electrocorundum below or above the specified limits leads to a deterioration in the welding and technological characteristics of the flux during welding and the inability to obtain the desired shape of the weld and its interface with the base metal, as well as a decrease in the impact work in the weld metal.

The presence in the flux composition of sphenic concentrate and fluorspar in the indicated amounts ensures easy separation of the slag from the surface of the weld and full coating of the molten metal with liquid slag, which ensures its complete protection from ambient air.

A decrease in the content of these components below the specified lower limits will lead to a deterioration in welding and technological properties, and an increase in their content above the specified limits will lead to a deterioration in the formation of weld metal and the separability of the slag crust.

An increase in the content of the metal component above the specified upper limit leads to a significant increase in the strength of the weld and a decrease in its visco-plastic properties, and a decrease in the deterioration of the mechanical properties of the weld metal.

The introduction of quartz sand in the indicated amounts provides the necessary slag viscosity.

The proposed agglomerated flux for automatic welding is made according to the following technology.

Prepared components of the charge (dried and crushed to a particle size of 0.2-0.3 mm) are weighed in doses for one batch, placed in a cube and transported to the mixer. The components are mixed in two stages: “dry” and “wet” (with a liquid solution of sodium potassium silicate). After mixing, the wet flux is fed to the coiler to compact the granules and give them the desired size and shape, then the flux is fed into the drying oven, and then into the calcining furnace. After cooling, the flux is sieved, weighed and packaged.

Three variants of compositions were made that were close to the composition of the proposed agglomerated flux, conventionally designated I, II, III and are shown in table 1. The composition of the agglomerated flux prototype used for comparison, conventionally designated IV, is also shown there.

For welding with these fluxes, samples of steel of category X90 with a size of 1000 × 2000 × 20 mm were used.

Welding of samples of butt joints was carried out automatically by multi-arc welding with wire Sv-08GN2MDTA and Sv-03KhN3MD with a diameter of 4 mm. The first arc is alternating current, the rest is direct at reverse polarity.

Welding mode:

1 arc - Current (A) ... 900; Voltage (V) ... 32; Welding speed (cm / min) ... 177;

2 arcs - Current (A) ... 800; Voltage (V) ... 34; Welding speed (cm / min) ... 177;

3 arc - Current (A ... 750; Voltage (V) ... 38; Welding speed (cm / min) ... 177;

1 arc - Current (A) ... 700; Voltage (V) ... 40; Welding speed (cm / min) ... 177.

Table 2 shows the chemical compositions of the weld metal made using the flux composition options listed in Table 1, and the mechanical properties of the weld metal and evaluation of the welding and technological characteristics of these agglomerated flux variants are shown in Table 3.

Table 1 Ingredients and their ratio The content of ingredients in the flux, wt.% I II III IV prototype Quartz sand 2.0 5.5 10.0 - Electrocorundum 20,0 29.8 33.0 31.5 Fluorspar 46.0 27.3 11.0 - Manganese metal - - - 2.0 Sphene Concentrate 25.0 29.3 35.0 - Ferrotitanium - - - 1.7 Ferroboron - - - 0.2 Metal mix 7.0 8.1 11.0 - Calcined Magnesite - - - 10.0 Rutile concentrate - - - 6.5 Iron ore concentrate - - - 0.5 Alloy Modifier - - - 46.8 Aluminum metal - - - 0.8 Sodium Potassium Silicate 13.0 8.5 11.5 8.5

table 2 Flux Options The content of elements in the weld metal,% C Si Mn Ni ABOUT S P I 0.05 0.14 0.55 0.90 0,022 0.009 0.011 II 0,03 0.23 0.62 0.96 0,023 0.010 0,020 III 0,03 0.28 1.25 0.93 0,021 0.008 0.010 IV 0.08 0.21 1.42 0.90 0,025 0.009 0.010

Table 3 Flux Options σ _in , MPa σ _in , MPa σ ₅ ,% ψ,% Work shock, KV, J at temperature -20 ° C -40 ° C -60 ° C one 2 3 four 5 6 7 8 I

II

III

IV

The end of table 3 Flux Options Amplification form The presence of a burn Stitching Slag crust separation one 9 10 eleven 12 I Smooth mating with base metal Along the edge of the seam Absent Spontaneous II Smooth mating with base metal Absent Absent Spontaneous III Smooth mating with base metal Absent Present in places Spontaneous IV Smooth mating with base metal Absent Absent Spontaneous

The optimal content limits of the components of the agglomerated flux of the claimed composition, as well as their ratio, were determined by the results of tests of the impact work of fracture of the weld metal of samples at -40 ° C and -60 ° C and by determining the chemical composition of the deposited metal.

As follows from table 3, the welds obtained using agglomerated flux made according to the invention provide a shock of weld metal of at least 70 J at a test temperature of -60 ° C and at least 100 J at a temperature of -40 ° C, thereby showing advantages over the prototype, and also have good welding and technological properties - easy (spontaneous) separability of the slag crust and good weld formation.

From table 3 it is also clear that the welds obtained using the proposed flux have the following parameters of the shape of the weld: the weld has a favorable shape with a smooth transition from the weld to the main, undercuts and pores are absent.

Based on the test results to determine the work of the fracture of the weld metal at -40 and -60 ° C, as well as to determine the welding and technological characteristics of the flux, the optimal composition of the proposed flux was selected, which is composition II, the content of the components of the mineral and alloying parts of which is indicated in table 1.

As a result of subsequent studies, it was found that the developed flux provides a higher cold resistance of the weld metal at temperatures up to -60 ° C, better formation of the weld (more favorable ratios of width and depth, width and height of the weld) (Table 4) compared to flux prototype.

Table 4 Flux Weld geometry Outer seam Inseam Width mm Depth mm Height mm Width mm Depth mm Height mm Flux prototype 21.0 6.5 3.0 18.0 6.0 2.0 The proposed flux 25.0 7.2 2.0 22.0 6.3 1,6

Thus, the proposed agglomerated flux for automatic welding of low alloy cold-resistant steels of high strength allows, while maintaining high cold resistance of the welded joint at temperatures up to -60 ° C, to provide high mechanical characteristics of the weld metal, as well as to ensure the favorable formation of weld metal in multi-arc welding at high speeds by low alloy wires .

Information sources

RF patent No. 2295431, B23K 35/362 - prototype.

Claims (2)

1. Agglomerated flux for automatic multi-arc welding of low alloy cold-resistant steels of high strength at elevated speeds, containing electrocorundum, a metal component and sodium-potassium silicate as a binder, characterized in that it additionally contains silica sand, fluorspar, sphene concentrate in the following ratio components, wt.%:
quartz sand 2.0-10.0 electrocorundum 20.0-33.0 fluorspar 11.0-46.0 sphene concentrate 25.0-35.0 metal component 7.0-11.0 sodium potassium silicate 7.7-20.0 2. The agglomerated flux according to claim 1, characterized in that the metal component has the following composition, wt.%:
Fe 18.0-21.0 B 0.3-0.5 Mn 55.0-65.0 Al 4.0-6.0 Mg 4.0-6.0 Ti 6.0-10.0 Si 2.0-4.0