The consumable electrode welding method in inert gas medium is known/Svarka v mashinostroyenii. Directory, v.

1, M. Mashinostroeniye, 1978, pp. 228-244/. Metals from 4mm to 12mm thick may be welded by the method for two passes from both sides and metals 15-20 mm thick-for two-three passes with V-butt preparation of welded edges with 60'angle and blunting 2-4 mm.

Large-drop transfer of electrode metal and its sputtering, as well as low productivity of a welding process and defects presence such as pores, oxide inclusions especially at active metals and alloys welding are the shortcomings.

The non-consumable electrode welding method of high-strength steels in argon medium is known/Makara A. M., Kushnirenko B. N., Zamkov V. N. Argon-arc welding of high-strength steels of martensite grade with flux application.-Avtomaticheskaya svarka N°7,1968, pp. 73-74/ characterised by active flux application from a products' face.

The method known abroad as A-TIG welding allows to improve penetration ability of arc by 50-100 % and ensures obtaining of qualitative welded joints for one pass without welded edges preparation of products to 10 mm in thickness. But a shortcoming of the method is the necessity of a second cosmetic weld formation, heightened requirements to butt edges fitting and welding carrying out,

mainly by automatic method in lower position for welding arc stable length provision.

The steels welding method in carbon dioxide medium by a consumable electrode is also known/Paton B. E., Voropai N. M.- Welding by active consumable electrode in protective gas- Automaticheskaya svarka, N° 1,1979, pp. 1-7,13/ characterised by doping of active admixtures inside metal base of electrode wire, allowing to obtain jet or small-drop metal transfer favourable from engineering point of view. A shortcoming of the method is technically complex process of activators doping in electrode wire.

The closest method to the claimed one is steels welding method in protective gas medium by a consumable electrode/Varyukha E. N., Lenivkin V. A. Transfer of electrode metal at welding on a layer of activators.-Svarochnoye proizvodstvo, N° 5,1986, pp. 32-34/ characterised by active admixtures doping in the form of powder in holes, drilled in welded sheets in one raw with pitch 7-8mm, depth and diameter 6 mm. But, such method of activators application is ineffective because of non-uniform activators distribution on a welded joint violating welding process, leading to increase of electrode metal sputtering and weld formation impairment.

In this connection the objective of the invention is obtaining of jet or small drop transfer of electrode metal, improvement of welding process stability, increase of metal penetration, improvement of welded joints formation, decrease of sputtering of molten electrode metal and defects in welds at welding by a consumable electrode in inert gas medium of structural metals and alloys.

The objective is achieved by use at consumable electrode welding of structural metals and active fluxes alloys used in the form of paste,

applied before welding on welded edges at flux specific consumption 0,025-0,070 g/cm2in inert gas medium.

Welding of products on the offered method is carried out in inert gas medium with active flux-paste use applied from the face of welded sheets at flux specific consumption: -0,025-0,065 g/cm2 for welding of products of carbon and low- alloy steels; -0,030-0,060 g/cm2 for welding of products of alloy and stainless steels; -0,040-0,070 g/cm2 for welding of products of titanium and its alloys; -0,035-0,055 g/cm2 for welding of products of aluminium alloys.

Besides, at welding of products of aluminium alloys flux-pastes applied on welded edges from a reverse side are used additionally at flux specific consumption 0,03-0,1 g/cm2.

The method application provides obtaining of jet or small-drop transfer of electrode metal, deep penetration of welded metal, defects removal in a weld, improvement of welding process stability, decrease of welded metal sputtering, good weld formation and reliable protection of molten pool metal and thermal influence zone against environmental effect.

It should be noted that so far the method of welding by a consumable electrode in inert gas medium with flux-pastes use applied on the sheet surface has not been used and is new. One of the main advantages of the offered method of welding is an opportunity of metals welding to 10 mm thick for one pass without welded edges preparation.

The invention is illustrated by sketches where in fig. 1 a welding scheme at active flux-paste application from the face and in fig. 2 the same at paste application from the reverse side are depicted.

The method is performed as follows: sheet welding 1 of structural metals is carried out in medium 2 of protective gas by a consumable electrode 3 fed through a burner 4 by an active flux-paste 5, applied on edges of welded sheets from face and reverse sides (fig. 2).

At the use of active flux it's mixed in alcohol or acetone in ratio 1: 1,5.

The obtained flux-paste is applied by a brush on welded edges from the face, by a thin layer, the width and specific consumption of which depend on a welded metal. For example: -for welding in active gas medium of carbon and low-alloy steels a flux is used, containing 5-151/o of silicon dioxide, 20-35% of manganese dioxide and 50-60% of calcium fluoride at flux specific consumption 0,025-0,065 g/cm2; -for welding by a consumable electrode in inert gas medium of alloy and stainless steels a flux is used containing 30-40% of calcium fluoride, 10-25% of sodium fluoride, 20-30% of silicon dioxide 2-10% of manganese oxide, 5-15% of nickel oxide and 2-10 % of lanthanum oxide at flux specific consumption 0,030-0,060 g/cm2; -for welding by a consumable electrode in inert gas medium of titanium and its alloys a flux is used containing 40-60% of calcium fluoride, 60-40% of barium fluoride at flux specific consumption 0,040-0,070 g/cm2; -for welding by a consumable electrode in inert gas medium of aluminium alloys a flux is used containing 20-30% of calcium fluoride, 20-30% of potassium fluoride, 20-30% of sodium fluoride and 20-30

% of strontium fluoride at flux specific consumption 0,035-0,055 glcm2.

Besides, at aluminium alloys welding additionally a flux-paste is used, consisting of 15-25% of barium fluoride, 10-20% of lithium fluoride, 20-30% of potassium fluoride, 15-20% of strontium fluoride and 0,5-10% of titanium powder applied on welded edges from the reverse side at flux specific consumption 0,03-0,1 g/cm2.

For experimental check of welded joints'properties obtained by the proposed method of welding samples welding of carbon stainless steels, titanium and aluminium alloy with fluxes use, applied on welded edges from the face with different fluxes specific consumption in claimed ranges was carried out. Results of experiments are given in fig. 1-4.

Table 1 N Welded Method Type and Specific-Welding Metal Presence ° metal of polarity of flux con-stability losses for of defects welding current sumption, sputtering, in a weld _ g/cm2 1 0,025 good 3 no 2 continuous 0,040 good 2 no 3 CT20 on flux current of 0,065 aood 4 no 4 normal 0,024 fair 7 yes 5 polarity 0,066 fair 9 yes 6 withou-fair 12 yes t flux Table 2 N Welde Method Type and Specific flux Welding Metal Presence of ° d of polarity of consumption, stability losses for defects in a metal welding current g/cm2 sputtering weld 0, 030 good 3 no 2 continuou 0,045 good 3 no s 3 X18H on flux current of 0,060 good 4 no IOT 4 reversed 0029 fair 7 no 5 polarity 0'061 fair 8 yes 6 without-fair 10 yes flux

Each of the said values is arithmetical mean of no more than three measurements after welding of sheets of carbon steel Ct20, stainless steel X18HIOT and titanium OT4 of 6,0mm in thickness, 150 mm in length and 50mm in width, as well as aluminium alloy AMr3 of 6,0mm in thickness, 300mm in length and 150 mm in width.

All experiments, connected with welding at fluxes use with specific flux consumption being in the claimed ranges (examples 1,2,3, tables 1-4) determined an opportunity of deep penetration of welded metal, defects removal in a weld, improvement of welding process stability, decrease of molten metal sputtering and reliable protection of molten pool metal and zone of thermal effect against negative influence of environment.

Table 3 N Weld Method of Type and Specific Welding Metal losses Presence of ° ed welding polarity of flux con-stability for defects in a metal current sumption, sputtering, weld g/cm2 0, 040 good 2 no 2 continuous 0,055 good 2 no 3 OT4 on flux current of, 0,070 good 2 no 4 reversed 0,039 fair 5 no 5 polarity 0,071 fair 6 yes 6 without-fair 9 yes flux Table 4 N Weld Method of Type and Specific flux Welding Metal losses Presence of o ed welding polarity of con sumption, stability for defects in a metal current g/cm2 sputtering, weld 1 0, 035 good 5 no 2 continuou 0,045 good 4 no s 3 AMr on flux current 0,055 good 6 no 3 of, 4 reversed 0,034 fair 10 yes 5 polarity 0,056 fair 12 yes 6 without-fair 20 yes flux

Vice versa, experiments (examples 4 and 5 of tables 1-4), connected with fluxes application with specific consumption exceeding the claimed ranges and without flux use (example 6 of tables 1-4) are characterised by large sputtering of molten metal and presence of defects in welds.

Besides, for experimental check of welds penetration formation of aluminium alloys, obtained by the offered method samples welding of aluminium alloy AMr3 of 3,0 in thickness with flux use applied on welded edges from the reverse side was carried on. Results of the experiment are given in Table 5.

Each of the said values is arithmetical mean of no less than three measurements after welding of sheets of aluminium alloy AMr3 of 3,0 mm in thickness, 300 mm in length and 150 mm in width.

All experiments, connected with welding at flux use, applied on a reverse side of sheets with specific flux consumption, being in claimed ranges (examples 1,2,3, tables 5), promote removal of weld penetration sagging and formation of a welded joint of good quality.

Table 5 Welde Method Thicntss Flux Weld'Sagging of Ratio Washing o d of of wel-specific s weld h/b-off flux metal welding ded me-consumpti width penetration residues tal, mm on, g/cm2 b, mm h, mm 1 0, 03 5, 5 0, 9 0,145 good 2 0, 05 6 0, 6 0,10 good 3 AMr3 on flux 3,0 0, 1 6, 5 0, 5 0, 076 fair 0, 02 5 1, 2 0,24 good 5 0, 11 6, 5 0, 5 0,10 poor 6 without-5 1,7 0,34 flux

On the contrary, experiments (examples 4 and 5, table 5) connected with flux application at specific consumption being outside the claimed ranges either don't promote effective sagging decrease of weld penetration (example 4) or possess poor welding and technological properties (example 5).