CA1143800A

CA1143800A - Method of electroslag welding by plate-type electrodes and flux used in the welding process

Info

Publication number: CA1143800A
Application number: CA000331736A
Authority: CA
Inventors: Anatoly N. Safonnikov; Anatoly V. Antonov
Original assignee: Institut Elektrosvarki Imeni E O Patona Akademii Nauk Ukrainskoi Ssr
Current assignee: Institut Elektrosvarki Imeni E O Patona Akademii Nauk Ukrainskoi Ssr
Priority date: 1978-07-12
Filing date: 1979-07-12
Publication date: 1983-03-29
Also published as: FR2430815B1; SU935236A1; FR2430815A1; SU1055616A1; IT1122166B; IT7924333A0

Abstract

ABSTRACT OF THE DISCLOSURE

The invention relates to welding, and more particular-ly to electroslag welding by plate-type electrodes under the harmful influence of external magnetic fields of high magnetic induction. Parts to be welded are brought together to provide a gap between their edges. The relationship between the sur-face area "B" of the gap, in the area "A" of the horizontal cross section of the welding electrode, and the area "C" of the projection of welding pools surface, is expressed by the ratio:
A:B:C = 1 : (1.2 to 1.5) : (2.5 to 4.5).
For the given ratios of the areas, the open part of the welding pool surface has such dimensions that the magnetic field of the plate-type electrode neutralizes the action of the strong ex-ternal magnetic fields and prevents molten metal from splashing.

Description

~ 1 ~3 8~

METHOD OF E~EC~RO~LAG ~ELDI~G BY ~A'l'E-TYPE ~LECT~O~ES
~D ~LU~ U~ED I~ 'mE'i~ELDING PROCESS

~IELD ~ T~rE INVENTIO~
~ he inventio~ relates to welding and moIe particularly ~o electroslag welding b~ plate-type electrode~ u~der the harm~ul i~f`luence of external mag~etic field~ o~ high mag~e-tic inductio~, The expre~sion "el~ctroslag welding b~ plate-type electrodes'~ is used to de~ote electroslag weldi~g method characterized by the use of electrodes Iormed with plates of largs cross sectional area~, commensuIable with the gap between parts being welded.
~ arm~ul i~flue~ces of ex~ernal ma~etic ~ields upon the welding proces~ maniXest themselves, Xor exampla, durin~ the in~tallation o~ heavy aluminium bus bars ~or reduction cells employed at ~on~errous metallurg~ and chemical indust~y plants where exterllal mag~etic ~ields are active.

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38'~)0 BACKGROUND (:),F THE IN~ENTIoN

To date, the profilem of ~elding in external m~gnetic fields has not been solved to an~ satisfactory degree. Hand arc welding by nonconsumable electrodes in an inert atmos-phere and under a b~anket of flu~ fails to ensure the neces-sary weld qual~ty, particularly in installation of items, such as reduction cell bus ~ars, featuring considerable thickness ~100 to 200mml. Under usual conditions, thiS type lQ of item can readily be welded together by electroslag we].d-~ng w~th plate-type electrodes. However, in stron~ external magnetic fields, the process becomes unstable due to the fact that ~n electroslag welding a metal is melted by the heat of-molten slag itsel~ heated by a electric current pass-ing therethrough (see Slovar-spravochnik po svarke~Welding Dictionary-Handbook/, "Naukova dumka" Publishers, Kiev, 1974, p.l87~. The external magnetic field acts upon the melt of slag and metal as a current conductor, imparting it a motion pulse leading to a loss of stability by the process manifest~ng ~tself in a sharp misalignment of welding pool open surface.

It has been experimentally found that satisfactory welds are obta;nable if welding pool surface deviates from the horizontal by not more than 15. A greater misalignment results in a single-sided lack of penetration of edges being welded and splashing of molten bath.

2 -' .' - .

~1~38~)~

~ here is known, f`or example, a me-thod for electroslag welding by a pla-te-type elec-trode (cf.USSR Inventor's Cer--tificate No. 149,166) consis-ting in tha-t par-ts being welded are set a specified dis-tance apart and provided wi-th moul-ding arrangements composed o* a pocke-t-t~pe pan~ sid~ moulds and -top discharge planks intended to hold a sla~ ba-th at ~the final stage of the welding process. A portion o~ weldlng flux is placed in-to the pocket of the pan, then a plate-type elec-trode is introduced in-to -the gap be-tween edges of par-ts being welded and connec-ted to one of the poles of a source o~
welding curren-t, the other pole being connec-ted to par-ts being welded and the pan. 'rhe welding process is intitiated by making -the eQd face o~ the electrode con-tact the pocket bottom, this producing an elec-tric arc which melts th~ p~or-tion of flux to ~orm a slag bath. Molten s~ag being an elec--tric conductor, shunts the arc and so initiates the electro-slag welding process consisting in -that a welding curre~t passes through and overheats molten slag.
In turn, -the overheated slag heats in-tensively the edges of parts being welded and -the electrode, so that the metal they are made from melts. ~'he molten metal wi-th a bla~ke-t of molten slag over it forms a welding pool, side areas o-f which are formed beneath areas of non-fused metal o~ the ed-ges shaped as steps whose wid-th corresponds to the depth of`
mel-ting (penetra-tion) of the edges. As me-tal mel-ts, -the level o~ the m~lt in the gap rises -to heat and mel-t new areas .
, '. ~

3~

4 --of edges and of the electrode, -the above steps and the weld-ing pool as if contlnually moving upwards.
A-t the same time, -the ~e-tal solidi~ies in -the bot-tom part o~ -~he weldi~g pool producing a welding seam as the welding pool moves from bo~ttom up. 'rhe weld thus obtained features a high ~uality owing to homogeneity of weld me-tal and good welding -thereo~ -to the metal o~ the parts involved.
However, if the a-bove electroslag welding process is carried out in an external rnagne-tic ~ield, -the result is, due tO the reasons mentioned, a sh~rp misalignmen~t o~ ~the welding pool sur~ace (up -to 90 ~rom the horizon-tal), accompanied by projec-tions o~ the welding pool melt ~rom -the gap. r~hese phenomena are encouraged by a relatively large open part o~
the welding pool sur~ace, because of which the magnetic ~ield induced by the welding current is incapable o~ ~eutralizing -the ac-tion o~ the ex-ternal magnetic ~ield throughout the open part o~ the melt sur~ace ~nd of preventi~g a vertical motion o~ the melt on any peripheral area of the sur~ace, -this resulting in the misalignment o~ the open par-t of the welding pool surf`ace.
As mean-t here7 the open part o~ the welding pool sur~ace is the part of the melt sur~ace limi-ted by the projection of the gap area upon the above sur~ace, '~he term "gap area" is used here and below to denote the area limited by the edges of the parts ~eing welded, nu-merically equal t;o the product o~ the gap width by the edge wid-th.

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~ ' ' ' 1~38~l~

r~he misalignmen-t of the open part o~ the welding pool surface incIeases the area wetted by the melt of one o~ the edges being welded, so redistribu-ting the welding current between the edges. ~his, in turn, results in a lack o~ pene-tration on one o~ the edges and a ~ore intensive meltinK o~ the other edge, so that the step o~ non-melted metal on this edge acquires a gentl~ sloping shape of'~er:in~ no obstracle ~o the external magne-tic ~'ield to displace the mel-t previously con--tained by the step, with the e~fec-t that the whole o~ the welding pool sur~ace is misaligned, and the melt, projected from the gap.
A ~airl~ wide gap, and, in consequ~nce, a large open weld-ing pool sur~ace area are then necessar~ to preven-t the harm~ul turbulent processes in the welding pool, as narrowing of the gap hinders the removal o~ gases evolving actively as a result o~ the heating o~ the slag-forming ~luæ and causes a satura-tion of the welding pool metal with gases.
The term "slag-~orming fluxl' is used here and below to denote a welding ~lux which is melted to create a slag bath.
Intensive evolution o~ gas `~uring welding process is due to that the currently employed ~luxes boil readily under the e~fect o~ welding temperature and give o~ volatile compounds.
This type o~ fluxes includes, for example, a ~lux ~'or welding aluminium according to the U.~.~.R. Inventorls Certi~icate No. 279,3119 containing in per cent by weight:
lithium fluoride 20 to 22 3E~

sodium fluoride 28 -to 30 po-tassium f`luoride 15 to 20 sodium chloride 30 to 35 SU~AL~Y ~F THE INVEN~ION

I-t is thereo~re an objec-t of the inven~ion to provide a method for electroslag welding by a pla~te--type electrode and a welding flux ensuring -the stability of the welding pro-cess in external magnetic ~ields -through op-timization of the dimensions o~ the open par-t of -the welding pool surface.
Another object o~ the presen-t invention is -to raise the boiling point of the flux.
The above and other objects o~ ~the invention are attained in a method for electroslag welding by a plate-type electrode, comprising providing a gap be-tween edges of parts being wel-ded, in-troducing a plate-type elec-trode into the g~p and mel-ting the electrode and the edges by -the heat of an electri-cally heated slag to create an upward-moving welding pool, side areas of the surface thereof being formed, as -the edges melt~ underneath moving steps of non-m~lted me-tal, according to -the ~nvention~ parts to be welded are brought toge-ther to form a gap, the sur-~ace area "B" thereof being in a ratio to the area "A" of the horizontal cross sec-tion of -the elec-trode and to the area ~a~ 0~ the projection o~ the surface of -the welding pool upon a horizontal surface of A : B : C =

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1 ~ ~ 38~ ~

= 1 (1.2 to 1.5 : (2.5 -to 4.5) in order -to keep the misa-lign~nt o~ the ~el~ing pool surface within 15 with the aid of the moving steps~ which limit -the vertical motion o~ the side areas of the welding pool sur~ace~ equal in area -to between 40 and 75 per cent of the area thereo~, and o~ the mag-netic ~ield o~ the elec-trode.
'rhe above method for elec-troslag welding by a plate~-type elec-trode ~ea-tures s-tability o~ -the process in ex-ternal mag-netiG ~ields through -tha-t, for a given ratio o~` the sur~ace areas A, B, C, the open part o~ the welding pool sur~ace has such dimensions that -the magnetic field of` the plate--type ele-c-trode neutralizes -the action OL stron~ external ma~netic ~ield~
and prevents splashing o~ the melt. ~dditionally~ the moving steps ha~e su~icient dimensions and a ~avourable shape for containing the side areas of the welding pool sur~ace no-twith standing the action of the external magnetic fields.
It is good practice to impart the moving steps a speci--~ied shape by applying upon the edges of parts being welded an electric insulating ma-terial having a brea~down tempera-ture ~ rll aDove the melting point "~m" of the metal of the parts being welded by a f`ac~or o~ 1.1 to 1.5.
Placi~g the moving steps in a speci~ied position; ~or exam-ple, close to a hori~ontal one7 enhances their capability of preventing -the misalignment o~ the side areas of the welding pool sur~ace under the ac-tion of external magnetic ~ields~
The moving s-teps acquire a speci~ied shape because -the ~1~38~(1 insulatlng material restric-ts the we-tting of the unmelted metal by the melt, and, therQ~ore~ the intensity of -the thermal action, -to predeterm:ined areas. If ~br~l~ m, -the electric insulating material will break down below the surface of -the slag ba-th, and so no speci~ied shape of steps will be obtained. If ~br> 1.5 ~m' ~he insulating material will not have enough time to break down completely be~ore it comes into contact with the me-tallic ba-th, -this resulting in slag inclusions in -the weld.
~ he electric insula-ting material should pre~erably con-tain a non-organic compound - sal-~ - and/or mixture of salts of ~a, Na, K, Mg, Ca~ Zn, B, Al and /or their oxides and/or their carbides, as these compounds poss~ss the necessary ther-mal chara~teristic~.
It is also suggested -that the electric insulating ma-terial contain an organic compound, such as cellulose, ve-neer, organic resin, as this type of materials possess the necessary thermal charadteristics and, additionally~ can rea-dily be secured to the surface of edges of parts to be wel-ded.
~ he above and other objects are attained also by providing a flux for electrosla~ welding, comprising lithium fluoride and sodium fluoride, and according to the inven-tion9 additi~
onally containing potassium fluoride a~d calcium fluoride in the f`ollowing proportions, per cent by weight:

~38~

lithium :Eluoride 60.0 to 90.0 sodium ~luoride 5.0 to 20.0 calcium ~luoride 1.0 -to 5~0 potassium ~luo.ride 4.~ -to 15~0 'l'he above flux has a boiling point higher than the wo.r-king electroslag welding temperature, ~his sharply reduci.ng gas e~olution during weldi.ng, requiring no large ~ap between the edges of par-ts belng welded ~or removal of the gases and making i-t possible -to decrease the sur~ace area of the open part of -the sur~ace of welding pool~ so as to, as men-tioned, stabilize -the welding process where carried out in an ext~rnal magnetic field.
It is also advantageous to provide a calcium fluoride to sodium fluoride ratio of l-to-5~ -the proportions of all the components being as follows7 per cent by weight:
li-thium fluoride 6000 ~o ~0.0 sodium fluoride 5.0 to 20.0 calcium fluoride 1.0 to 4.0 potassium ~luoride 4~0 to 15.0 ~he above calcium fluoride to sodium fluoride ra-tio achi-eves a maximum activity of -the -flux with respec-t to a metal being welded.
BRIEF D~S~RIPTION 0~ ~EE DRAWINGS
~ hese and other objec-ts and fea-tures o~ -the inven-tion become readily apparent from one embodiment thereof which :

3~3QO

~ lo --will now be d~scribed b~ wa~ of example with re:~erence to the accompanying drawing~ 7 ln which:
Fig l is a schema-tic longi-tudinal ver-tical sec-tion of a general welding setup with moulding arrangements f`or assemb-ling parts to be welded and carrying ou-t the electroslag welding method, according to the invention;
~ ig.2 is a schematic longi-tudinal ver-tical section o~` a se-tup with moulding arrangements ~or par-ts -to be welded whose edges are half covered with an insulating material;
Fig.3 is a schema-tic horizontal section of a setup, in-cluding moulding arrangements, Yor assembling parts to be welded with selectively coated sur~aces o~ edges;
Fig.4 is a schematic horizontal section o~ a setup with moulding arrangemen-ts ~or a heavy single-piece part and an assembled packe-t o~ parts;
Fig.5 is a scheamtic longitudinal vertical section o~ a setup, inclu~ing moulding arrangements, ~or parts to be wel-ded with alternative coating o~ edges ~or welding elements of various heat removal capacities.
DESCRIPrIION OF r~HE ~REFER~ED EMBODI~E~'~
The me-thod ~or electroslag welding is carried out in an active magne~ic Yield having a magne-tic induction o~ up to 40 or 45-10-3 '~0 '~he edges of parts 1 and 2 (see ~ig.l) to be welded, ~or example, ~us bars~ are coated with an electric inaulating 313~(~

ma-terial 3 having a breakdown tempera-ture ~br by a ~'actor of 1.1 to 1.5 higher -~han the meltin~ point ~m of -the parts, no-t less than 5G% of the sur~ace area of the edges being coated and -the parts being posi-t:ionecl so as to provide a gap between -the edges~
~ he moulding arrangemen-ts consistlng of a pan 4 having a pocket ~, side moulds 6 and top discharge pl.anks 7 are mounted nex~ on the parts 1 and 2~ A portion of a slag-~orming ~lux is charge~ into the pocket 5, the composition of the Ilux being as ~ollows, per cent by weight:
lithium fluoride 60.0 -to 90.0 sodium fluoride 5.0 -to 20.0 calcium fluoride 1.0 -to 5.0 po-tassium fluoride ~ to 15.0 A pla-te-type electrode 8 con~ected -to one of the poles of a welding current source (omi-tted on -the drawings) is i~troduced into -the gap t the other pole of -the welding cur-rent source being connected to the parts to be welded 1 and 2 and the pan 4.
~ he parts 1 and 2 are brought -together so as to form -the gap Y~hose surface area 77B7~ iS in a ratio to -the sur~ace area "A" of the horizontal cross section of the electrode of A : B - 1 , (1.2 to 1.5).
~ he welding process is s-tarted by bringing the end ~ace of the electrode 8 in-to contact wi-th the bo-t-tom of the pocket

5, this initiating an elec-tric arc which mel-ts the abo~e por-~1~3~300 tion o~ ~lux to produce a bath 9 of molten slag. '~he mol-ten slag shwnt~ -the arc, and so startc;-the elec-tIoSlag welding pro-cess. A welding current passes through and overhea-ts -the molten slag, -the heat ~hereof causing, in the areas where the slag comes in-to direct con-tac-t with the me-tal of the electrode and o~ the edges o~ the parts to be welded~ an int~nsive mel-ting of the me-tal which flows in-to -the pocket 5. The mol-ten me-tal -together with the bath 9 of mol-ten slag covering i-t .Eorms a welding pool 10 ~vhose side areas are formed beneath areas of non-melted metal of the edges having the shape of moving steps 11 and ~3 whose width corresponds -to -the depth o~ pe-netration of the edges. ~he depth of -the penetra-tion is such that .;~he area "A" and -the horizontal cross sectional area of the electrode are in a ratio to the area "Cl' of the pro-jec-tion of -the surface of the welding pool upon a horizontal plane of 1 : (2.5 to ~.5) 'l'his is achieved by adjusting the parameters of the welding process Iw and Unl~ which are respectively the in-tensity of -the welding current and the no-load voltage of the weldi~g current source.
As the edges o~ the par-ts 1 and ~ are coa-ted with an electric insula-ting material 3, the moving steps 11 and 12 are in a posi-tion close to -the horizo.ntal, as the area o~ the intensive ther~al action of the slag bath ~ upon the metal o~ the parts 1 a:nd 2 is limited to -tha-t of direct contac-G.
'1'he ex~ernal magne-tic ~ield acts upon the welding pool 10 as upon a current conductor, impar~ing a mo-tion pulse there~o.

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~l143~0~13 However, since the proce~s is car:ried out a^t the specified ratio of -the surface areas A, B, C, the open part of` the surYace of the welding pool 10 has such a size -that the magne-tic field of the plate--1-ype electrode 8 neutralizes -the action o~ -the external magnet:ic field, whereas the moving steps 11 and 12 have suf~icient dimension~ and e a shape adquate for restricting the displacement o~ -the side areas of -the welding pool surface. ~hi.s enables the misalign-ment of the welding pool -to be kep-t withln the range of 0 to 15 from the horizontal and the effec-t of the ex-ternal magnetic ~ield -to be neutralized. ~he welding process acquires stabili-ty with the ef-~ect that -the weldi..ng pool rises withou-t misalignment up -the gap-as the metal of the edges and of -the electrode melts and the steps 11 and 12 move upwards. At the same -time, -the metal solidi~ies in -the bottom part o~ the welding pool to form a weld..
The invention will now be described by the following illustrative E~amples.
Example 1.
~ luminium bus bars 1 and 2,140 mm thick, are electro-slag-welded in a magnetic field o~ a magnetic induction of 40-10 3 ~. Edges to be welded of bus bars ha~e bee~ coa-ted in advance with an electric insulating material 3 based on ~aCl whose breakdown temperature is ~br=800 to 900C, i.e~
b~ a factor of 1~2 to 1.3 higher -than -the melting poi.n-t ~m ~ 660C of aluminium~ A welding pla-te-type electrode 8 .

3~0 Irom aluminium was 20 mm -thick. ~le process was stabllized by providing a ra-tio of A : B : a = 1 : 1 . 2 : 2.5, the wid-th of the gap be-tween the welding edges and the depth of pene_ tra-tion of -the welding edges having been accordingly calcula-ted equal ~o respec-tively ~4 and :L3 mm.
In accordance with -the calculations, ~he bus bars 1 and 2 were brough-k together -to provide a gap between the edges o-~24 mm.
Moulding arrangements consisting a pan 4 with a pocke-t 5, side moulds 6 and -top discharge planks 7 were assem'bled on ~he bus bars 1 and 2D
As the boiling poin-t ~bsl ~ -the slag-~or~ning~ I'lux had to be greater than the welding tempera-ture of the aluminium bus bars TW=1200 to 1400C, the ~lux had -the composition 'below, % by weight:
lithium ~luoride 60.0 sodium -~luoride 20 ~ 0 calcium fluoride 5.0 potassium ~'luoride 15.0 the boiling point being ~-b=1500C.
~ portion o~ slag~~orming f'lux was charged into ~he po-cke-t 5. ~ plate--type electrode 8 was then in-kroduced into the gap, and an elec-troslag welcling process was initia-ted.
A required depth of penetra-tion was achieved by conducting the process under ~he conditions below:
w = 7~ kA
~nl = 44 V

~1~313()0 ~ he resul-ting moving s-teps 11 and 12 had R posltion close to the horizontal, and the misalignment of -the sur~`ace o~
-the welding pool was not more tha~ 15C
~he effec-t of this procedure was a quali-ty bus bar weld 50 mm wide.

Example 2 Ingots of an alloy based on aluminium and containing 5-8~o magnesium, 140 mm thick, were electroslag-l.velded in a magne-tic field o~ a magnetic induc-tion o~ 40-10 3 ~
~he mel-ting poin-t o~ the alloy was '~m-654C. Edges were insulated electrical]~ with a coat of Na3AlF6 having a break-do~ point of '~br=1000C
~he plate-type electrode was 20 mm -thick.
~he ratio of the areas was A : B : C = 1 : 2.3 : 3.5.
Gap width was 26 mm.
~dge penetra-tion dep-th was 22 mm.
Welding conditions :
~ Iw = 9~5 kA
Unl = ~2 V
~he welding temperature: ~W=1200 to 1400C.
~he ~lux had the chemical compo3ition below, % by wei~h-t:
lithium fluoride 90.0 sodium fluoride 5.0 calcium fluoride 170 potassium fluoride 4~0 .
: . . , ~ -' The boiling poin-t o~ -the flu~ was r~b=1510C.
The moulcling arrangements were assembled, anrl the elec-troslag welding process, ini-tia-ted~ as in -the EXA~E 1. '~he mi~alignment of -the surface of the welding pool was no-t greater than 15 ~rom -the horizontal. 'l'he resul-t of the above proce-dure was a quality weld, 70 mm wide.
Example 3 B ~e ~ orgings ~sx elec-troslag-welded in a magne-tic field o~ a magne-tic induc-tion of 40010 3~.
~ he material o~ the ~orgings and of the electrode was an iron alloy containing, ~0 : C, 0.10; Si, 0~54; ~n5 1.10;
Cr, 17.75; ~i, 9.3; ~i, 0.51; ~e, the balance to 100.
Tm = 1385C-Ingot thickness was ~00 mm.
The coat material was a mixture o~ MgSo4 and A1~03 taken in a ratio of l-to-l.
~ br=1530 C.
'~he coat was applied over 50 % o~ the area o~ edges, in their -top part (see ~igo2)~ 'L'his led to a more intensive initial stage of ~he weldi~g process with -the position o~
the stops being kept close to the horizontal.
~ he plate-t~pe electrode was 12 mm thick.
'L'he ratio of the areas was A : ~ : C = 1 . 1.5 : 4.5 .
Gap width was 18 mm.
Edge penetratio~ depth was 18 mm~
Welding condi-tions:

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386~(~

Iw = 6 kA
Unl = 38 V
'rhe welding temperature was TW=1540C~
r~he flux employed had -the ~ollowing compc3ition~ ~0 by weight:
lithium ~luoride 70.0 sodium ~luoride 20.0 calcium ~luoride 4.0 potassium ~luoride 6.0 ~b = 1520C.
~ he moulding arrangements were assembled, and the elec-troslag welding process, in-titiated, as in the EXAMP~E 1.
Welding pool surface misalignment was not greater than 15 from.the horizontal.
~ he procedure resulted in a quali-ty ~orging weld, 54 mm thick.
~xample 4 Forgings were electroslag-welded in a magnetic ~ield o~ a magnetic induction of 40-10 3 ~
The material o~ tke ~orgings a~d o~ the electrode was an iron-nickel based alloy con~taining~ %: C, 0.04; Si, 0.51;
Ni, 0.27; Cr, 19,60; Ni, 27.~0; B, 4.78; Mn~ 2.90; Nb~ 1.05 ~e, the balance to 100.
~ m = 1~20C.
Ingot t~ick~ess was 100 mrn.

~43800 ~ 18 -'~he material o~ the coat was a mix-ture of Na203, K207 Li20, CaO -taken in a ra-tio of 1 : 1.1 lo '~br = lL~0C.
IrO economize ~he ma-terial, the coa-t was applied onto the boundaries o~ the edges -to be welded (see Fig,3~ so as to cover 50% of the sur~ace area -thereo~ `he moving steps remained prac-tically horizon-tal during welding.
~he plate-type elec-trode was 10 mm thick.
~he ratio of the areas was A : B : C = 1 : 1.3 : 3~5.
rlhe gap wi~-th was 13 mm.
'~he edge penetration depth was 11 mm;
The welding conditions were as follows:
Iw = 2.0 kA
Unl = 36 V
~rhe welding temperature was TW_1500C.
'~he composi-tion of the flux, % by weight:
lithium ~luoride 85.0 sodium fluoride 4.0 calcium fluoride L~ . o potassium fluo~ide 7.0 Tb = lslsa.
r~he moulding arrangements were assembled~ and -the electroslag-welded, initiated, the same as in -the ~XAMPIE 1.
rl`he misalignment of the welding pool ~ur~ace was not greater than 15 from the horizon~al. '~he procedure yielded a ~uality weld o~ -the ~orgings, 35 mm wide.

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~3~30 Example 5 Bus bars were electroslRg-welded in a magnetic -~ield o~ a magnetic induc-tion o~ 40 10 3 '~.
Ma-terial of -the bus bars and -Ghe electrode was copper.
~m = 1080C.
bus bar thick~ess was lO~ mm~
A l1~he ma-terlal o~ the coat was based on -' q! = lL~20C.
The plate-type electrode was 20 mm -thick ~he ratio o~ the areas was A : B : a ~ . 5 : 4.5.
~he gap wid-th was 3G mm.
11he edge penetration depth was 30 mm.
Welding conditions:
Iw = lO kA
Unl = 44 kA
~w = 1450~
~lux composition, ~0 by weight:
lithium ~luoride 90 0 sodium ~luoride 5.0 calcium fluoride l.0 potassium ~luoride 4~0 Tb=1505C.
The moulding arra~gemen-ts were assembled, and the electroslag welding process, initiated, the same as in -the :E5X ~PIæ 1 .

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~ 20 --~ he misalignmen-t of the welding pool sur~ace was not greater -than 15 from the horizontal.
r~he pro~edure yieldecl a qualit~ ingot weld 90 mm -thick.
E~ample 6 Aluminium bus bars were electroslag welded in a magne~ic field. 'rhe bus bar 1 was formed with an ingo-t, and the bus ~ar 2, wi-th a package of sheets (see ~ig.4), ~he magne-tic in-duction of the field was L~O- 10 3 ~, ~ he bus bars were 140 mm -thick.
'~m = 660C.
~ he material of the coat a veneer shee-t 2 mm thick.
~ br = 730-750C.
The edge of the bus bar 2 was covered completely, and the edge of the bus bar 17 from the top -to half -their width (see ~ .5), this to allow for the differen-t hea~ removal proper-ties of the bus bars 1 and 2.
~ he pla-te-type electrode was 20 mm thick.
~ he ratio of the areas was A:B:C - 1 : 1.2 : 2.5.
~ he gap width was 24 mm.
~ he ed~e penetra-tio~ depth was 13 mm.
Welding conditions:
Iw = 7- kA
U~
~w = 1200C.
The composition of the flux was as follows 3 % by weight:

,' ll1~380(~

lithium ~luoride 75.0 sodium ~luoride 15.0 calcium ~luoride 3.0 -potas~ium ~luoride 7.0 tb = 1500C.
~he mouldi~g arran~emen~s were assembled, and the electro-slag welding process 3 intitiated, -the same as i~ -the ~XA~PIæ
1.

'l`he procedure yielded a quality weld 50 mm thick.
Example ~
I-tems were welded in a magnetic ~ield o~ a magnetic induction of 40-10 3 '~'.
: 'I'he material o~ the ~orgings and o~ -the elec-trode was an iron-based allo~ containing, % : C, 0.10; Si~ 0.54; Mn, 1.10;
Cr, 17,75; Mi, 9~3; ~i~ 0~51; ~e, ~he bal~nce.

'~m = 1385C.
: ~hickness o~ the ~`orgings was 140 mm.
~he material o~ the coat was rosin with a CaO ~iller.
=1530 C.
~he b,--ickness of the plate-type electrode was 12 mm.
~: ~he r~tio of ~he areas was A: B: C - 1: 1.5: 405, .: The width o:~ the gap was 18 mm.
:~ ~he depbh o~ pene-tratio~ of the ed~es was 18 mm.

;~ Welding conditions :

w = 6 kA
U~l = 3 . .: ~ . . - . . . - :
.: - : - :

:"

: ; ~ ~ . . .

- 22 _ ~w = 15~0~.
~he composition o~ -the ~lux was as ~ollows~ % ~y wei~ht.
li~hium ~luoride 6~.0 sodium ~luoride 20.0 calcium ~luoride 5.0 potassium fluoride 10.0 ~b= 1550C.
The moulding arrangements were assembledg and the electro-slag welding process, ini-tiated, as in the EXAMP1E 1. ~he mi-salignment o~ -the welding pool was no-t greater than 15 ~rom the horizontal.
'~he above procedure yielded a quali-t~ weld o~ -the forgings, 54 mm wide.
Example 8 ~he ~orgings were electroslag-welded in a magnetic field of a magnetic induc-tion of 40-10 3'~.
'~he material o~ the forglngs and o~ the electrode was an aluminium-based allo~ containing 5.8 % magnesium.
'~m = ~54C.
'~he thickness o~ the ingots was 140 mm~
'~he material of the coat was based on cellulose.
~br = 730C.
'~he thickness of the plate-type electrode was 20 mm.
~he ratio o~ the areas was A : B : C = 1 : 1.3 : 3.5.
~he width of the gap was 26 mm.

:

~1~380 23 _ ~he depth of -the penetration of the edges was 22 mm.
Welding conditions were as follows:
Iw = 9 5 kA
Unl = 42 V
The co~o~l~io~ ~ the ~lux was as foIlows, % by weight:
lithium ~luoride 75.0 sodium fluoride 15.0 calcium fluoride 3.0 potassium ~`luoride 7.0 rrb = 1490~-'~h~ moulding arrangeme~ts were assembled, and the electro-~lag welding process, initiated, as in the ~XAMP~E 1. r~he misalignment of the surface o~ -the welding pool was not greater than 15 ~rom ~he horiæon-tal.
~he procedure yielded a quality weld o~ the forgi~gs 70 mm wide.
E~ample 9 Ingots were electroslag-welded in a magnetic Yiedl of a magnetic induction o~ 40-10 3 '~.
he material of thé ~orgings and of the electrode was ~ an iron-and-nickel-~ased alloy containing, ~0 : C~ 0~04;
; Si, 0.51; Mn, 0.27; Cr, 19.6 ; ~i, 27.8; B, 4~78; Mo, 2.9;
Nb~ 1.05; Fe, the balance.
r~m = 1320C.
he~thickness of the ingots wa~ 100 mm.
~` 'rhe ma-terial of the coat was laminated ins~latio~.

.
-.................... , ~

~, 11~38~0 '~br = 1460C.
~he -thickness o~ ~he plate-t~pe electrode was 10 mm~
~he ratio of the areas was A : B : G _ 1 : 1.3 : 3.5.
The width of the gap was 13 mm~
~l~he aepth o~ pene~ration of ~he e~g~s was 11 mm.
Welding conditions:

Iw = 2.0 kA
U = 36 ~, nl = 1500C.
~he composition o~ the flux was as follows, ~0 by weight:
lithium fluoride 75.0 sodium ~luoride 15.0 calcium fluoride 3.0 potassium fluoride 7.0 Tb= 1510C.
The moulding arrangements were assembled, and the electro~
slag welding process, lnitiated, the same as i~ the EXAMPI~ 1.
~he misaligment of -the welding pool surface was not greater than 15 from the horizontal.
~he procedure yielded a qualit~ weld o~ the ~orgings, ~ 35 mm wide.
:~ :
Example 10 Bus bars were elec-troslag-welded in a mag~etic -~ield.
The magne-tio induotion of the field was 40-10 3 ~.
; ~he material o~ -the ingots (bus bars) and of the electrode was copper.

; ~:

'':
:: : ~ . .

~m = 1080C.
'~hickness of -the i~gots was lO0 mm.
~he material of the coat was te~olit, '~br ~ 1420C.
~he thickness of the plate-t~pe elec-trode was 20 mm~
'~he ratio of the areas A : B : C = l : 1.5 : ~,5.
'~he wid-th of the gap was 30 mm.
'~he dep-th of the pene~ration o~ the edges was 30 mm.
Welding condltions:
Iw = lO kA
Unl = 44 ~.
r~ = 1450C.
. .
The co~po~ition o~ the ~lux was as follows, ~0 b~ weight:
lithium ~luoride 80.0 sodium ~`luoride lO~0 calcium fl~oride 2.0 potassium ~luoride 8~0 ~b = 1505 C.
~he moulding arrangements were assembled~ and -the elsctroslag welding process, initiated, the same as in the EXAMP1E 1. '~he misalignment of the weldi~g pool surface ~ was not grea-ter than 15 ~rom the horizontal~
`~; rL'he procedure yielded a qualit~ weld o~ the ingots, 90 mm wide.
::

:

: ;, .::

,: , . .

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: .

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of electroslag welding by a plate-type electrode, comprising: setting parts to be welded apart so as to provide a gap between edges thereof; introducing the plate-type electrode into said gap; creating an upward moving welding pool by melting said electrode and said edges by the heat of an electrically-heated slag; shaping the surface of said welding pool, side areas thereof being formed in the process of melting of said edges by moving steps of unmelted metal; bringing to-gether said parts to be welded to provide said gap, the relation-ship between the area "B" of the gap, the area "A" of horizon-tal cross section of said electrode, and the area "C" of the projection of said welding pool surface upon a horizontal plane, being expressed by the ratio:
A:B:C = 1 : (1.2 to 1.5) : (2.5 to 4.5) so as to keep the misalignment of said welding pool surface with-in 15° of the horizontal with the aid of said moving steps, which limit the vertical motion of the side areas of said weld-ing pool surface, amounting to 40 to 75% of the area thereof, and of the magnetic field of the electrode.

2. A method as claimed in claim 1, wherein the moving steps are given a specified shape by applying in advance upon the edges of the parts to be welded a coat of an electric insula-ting material having a breakdown temperature exceeding the melt-ing point of a metal of the parts to be welded by a factor of 1.1 to 1.5.

3. A method as claimed in claim 2, wherein the edges of the parts to be welded are coated with an electric insulating material, containing an inorganic compound such as a salt or a mixture of salts and/or their oxides, or their carbides.

4. A method as claimed in claim 2, wherein the edges of the parts to be welded are coated with an organic compound, such as cellulose, veneer, organic resin.