The method of welding with non-consumable electrode submerged arc
The method can be used in the welding industry. During welding with non-consumable electrode submerged arc exercise coercive pressure on the weld pool by the magnetic field of the solenoid. The magnitude of the magnetic induction is 0,12 - 0,20 TL. Solenoid set behind the electrode on the front side of the seam. The method can improve the formation of a welded joint by eliminating unilateral cutting without re-penetration weld. 2 Il. The invention relates to mechanical engineering and can be used in the welding industry.There is a method of submerged arc welding in which to eliminate cutting to improve the quality of the formation of a seam, perform the second pass of the surface arc with reduced current and increased arc voltage [welding in engineering/Handbook so 1/Ed. by N. A. Olshansky - M.: Mashinostroenie, 1978, S. 221].The disadvantages are the counterpart of the decline in productivity with increasing labor and energy costs, the inadmissibility of repeated heating of a range of materials with low heat input (for example, the possibility of podelki welding area).The known method arc svarc the e pressure on the liquid metal in the rear part of the tub [ed. St. USSR 1240530, MKI 23 To 8/13, 1986].The disadvantages are the counterpart significant consumption of scarce protective gas, the leakage of liquid metal on the surface of the welded edges, unacceptably large for many materials the cooling rate of the weld metal.The known method arc metal [ed. St. USSR 585000, MKI 23 To 9/08, 1973] , in which a pulsed magnetic field effect on the tail of the welding bath.The disadvantage of analogue is that the electromagnet to provide a reversal of the volume forces acting in the interval of crystallization, and therefore the method cannot provide the offset of the molten metal in the desired direction, i.e. to eliminate the one-sided undercut.The closest in technical essence and the achieved result is a method of arc welding in different security environments [SU 218349, MKI 23 To 9/16, 29.08.68], in which behind the arc creates a forced pressure on the weld pool.The disadvantage of analogue is that when any proposed method of pressure, provided in the analog offset of the molten metal occurs in both directions from the axis of the weld and in the presence of unilateral cutting (Fig.1) is the leakage of liquid metal on the surface is their flow of inert gas or slider creates unacceptably large for many materials the cooling rate of the weld metal.When the submerged arc welding in one pass of the material of a thickness exceeding 5 mm due to the large currents in the molten metal have significant volumetric electromagnetic force towards the axis of the weld. As a result, the edges of the seam having undercuts. Reduction of scores is possible to achieve a significant reduction in welding speed, but in this case you lose the main advantage of the method. Bilateral symmetrical undercut occurs when placing electrical power supply close enough to the axis of the weld. In real structures the current lead, as a rule, placed on one side of the seam (for example, when welding the annular and circular seams, the seams are not straight), so that the current density from the electrical power supply and more. This leads to the violation of the symmetry of the cross-section of the seam and there is a one-sided undercut on the side opposite to the electrical power supply (Fig.1).The task to be solved by the invention is to improve the formation of a welded joint by eliminating unilateral cutting with simultaneous reduction of the weld reinforcement.This object is achieved in that in the method of welding submerged arc forced pressure on the weld pool create permanent mvuu part of the welding bath. The interaction of the current flowing in the rear part of the weld pool, with the external magnetic field creates an electromagnetic force, displacing the molten metal in the direction of the expected cut, thereby eliminating the latter.The solenoid is rigidly connected with the electrode angle of the burner and has with him a common nozzle, protecting the weld pool and the cooling part of the weld metal. The cross-section of the nozzle has the shape of an ellipse.The value of magnetic induction In the solenoid, it is recommended to create a 0.12 to 2.0 Tesla. The smaller the value of induction does not provide the correct cutting with a larger value of induction, the formation of the cut from the opposite side of the seam. The magnitude of the magnetic induction is expected to increase with increasing depth of the required penetration (i.e., with increase of welding current).The scheme of the action of the electromagnetic forces on the tail of the welding bath is shown in Fig.2, where 1 is the arcing zone, 2 - electrode, 3 - conductors, 4 - direction magnetic fields 5 - the direction of the current in the molten metal i, 6 - direction electromagnetic force fi7 - side of the seam, where it is expected the formation of a unilateral cut.A specific example of implementation of the method.Welding is carried out on the samples of the Z axis of the joint.The welding process start the process plate with the gradual penetration of the electrode to a value of 3 mm, providing a penetration of up to 6 mmWelding mode: welding current I=900 A, arc voltage Ud=12 V, welding speed VSt=10 m/hUsing a solenoid placed behind the electrode, create a magnetic field. The magnitude of the magnetic induction B=0.12 T.While cooked sample Podrez is missing.When welding databases filler wire in the sample occurs unilaterally cutting depth of 1.5...2 mmThus, the proposed method allows to eliminate one-sided undercut without re-penetration weld.
ClaimsThe method of welding with non-consumable electrode submerged arc forced pressure on the weld pool, characterized in that the forced pressure exercised by the magnetic field of a solenoid with a magnetic induction of 0.12 - 0.20 T installed behind the electrode on the front side of the seam.
FIELD: restoration of parts cast of aluminum alloys with use of fusion welding.
SUBSTANCE: method comprises steps of cutting out flaw containing portion spaced equidistantly by distance (3 - 8)n from boundary of flaw; making insert of deformed aluminum alloy welded with casting alloy of restored part at relation of coefficients of percentage elongation Gd/Gc = 9 - 25, where Gd and Gc coefficients of percentage elongation respectively of deformed and casting aluminum alloys, n - thickness of cast part in restoration zone.
EFFECT: lowered labor consumption at restoring parts of aluminum alloys.
3 dwg, 1 tbl
FIELD: processes for making large-size thick-sheet orthotropic plates of carbon low-alloy steels in different branches of industry, particularly for bridge building.
SUBSTANCE: method comprises steps of relative orienting members of orthotropic plates; tack welding oriented members by means of non-consumable tungsten electrode in mixture of shield gases Ar (95 - 97)% + (3 - 5%) CO2 ; performing automatic continuous-seam welding and then trimming surface of welded seam. It allows simplify method for making welded large-size thick-sheet orthotropic plates of carbon low-alloy steels.
EFFECT: lowered labor consumption, shortened time cycle for making enhanced-quality plates, improved reliability of welded structures.
6 dwg, 1 ex
FIELD: electric arc welding of materials by means of non-melting electrode, namely methods for automatic argon-arc pulse welding of steel tubes.
SUBSTANCE: method comprises steps of preliminarily dressing tube butts and forming annular chamfers on inner surfaces of butts; abutting tubes; moving welded edges relative to electrode by step axial rotation of abutted tubes at revolution number 1 -1.5 rev/min; igniting arc 2 - 5 s before starting rotation of tube in order to heat welded seam zone; performing welding by means of torch inclined to tube axis by angle 60 - 85° relative to vertical line; sustaining electric current intensity in range 110 - 155 A for pulse duration 0.7 - 0.9 s; keeping electric current at pause period in range 10 - 30 A for pulse duration 0.5 - 0.7 s. Overlapping value of welded seam is in range 10 - 25 mm. It allows eliminate cracking of welded seam of tubes at bending samples by angle exceeding 160°.
EFFECT: enhanced quality of welded seam of tubes.
3 dwg, 1 tbl
FIELD: automatic welding increased-thickness joints of titanium alloys in inert gas by means of submerged tungsten electrode.
SUBSTANCE: method comprises steps of forming in welded edges cutout which is in the form of П-shaped dressing of edges at welding parts with slit gap; keeping relation of depth of dressing to its width less than 1; rounding acute angles of dressing; before welding introducing granulated additive material into slit gap and performing first pass at minimally admissible value of shape factor of fusion. In order to provide guaranteed fusion of walls, second and third passes are realized in the same mode. Electrode is placed in such a way that it is shifted relative to butt axis. At double-side welding passes are realized according to next order: first and second passes, then third, fourth and fifth passes.
EFFECT: enlarged manufacturing possibilities of method due to increased limit thickness of welded parts.
3 cl, 5 dwg
FIELD: machine engineering, possibly gas-shield electric arc welding by means of non-consumable electrode.
SUBSTANCE: method comprises steps of alternatively feeding several gases or their mixtures by pulses; at each next pulse feed using gases (gas mixtures) having ionization potentials different in comparison with those of gases or gas mixtures of previous pulse feed; periodically changing electric arc gap simultaneously with gas feed pulses; setting basic voltage of electric arc equal to optimal voltage in medium of gas or gas mixture with minimum ionization potential; setting difference between maximum and minimum voltage values of arc at periods of previous and next pulse feed of gases or gas mixtures in range 1 - 7 V.
EFFECT: enhanced quality of welded joints, possibility for adjusting fusion depth.
1 tbl, 1 ex
FIELD: gas-shield welding process with use of non-consumable electrode, namely torches for such welding.
SUBSTANCE: torch includes body of collet chuck holder. Said body has cylindrical surface near its working end and it is welded to electrically conducting gas conduit. Collet chuck is mounted in body for securing non-consumable electrode. Nozzle has cylindrical surface passing to cone surface and then again passing to cylindrical surface near its working end. Asbestos-cement insulator is arranged on surface of body of collet chuck holder; brass sleeve is put onto said insulator. Insulator is fixed to body by means of pressure ring-splitter having cylindrical surface passing to cone surface with radial openings.
EFFECT: possibility for making small-size torch for welding butts of metallic structures in hard-to-reach places of installation zone.
FIELD: plastic working of metals, namely processes for forming butt welded seams on tubes at making tube studs of U-shaped tube bundles using effect of localized hot plastic deforming of welded seam and near-seam zones.
SUBSTANCE: method comprises steps of preliminarily working tube ends by expanding them from cylinder to cylinder; assembling tubes with use of mandrel and placing intermediate member of additive material between joined end surfaces of end portions of tubes sized by expansion and end surfaces of step ring. Welded seams are formed by argon-arc welding due to melting material of intermediate member at its both sides adjacent to tube ends. The intermediate member is heated up and it is subjected to hot radial squeezing while concentrating its initial deformation in surface layers according to position of ring steps, welded seams and near-seam zones on mandrel for providing size of their outer diameter equal to initial outer diameter of tubes.
EFFECT: improved quality of welded seams.
FIELD: mechanical engineering; argon-arc welding.
SUBSTANCE: invention relates to methods of automatic argon-arc welding of austenitic steel pipes in manufacture of important constructions, such as high-pressure pipes used at nuclear power stations. Proposed method includes mechanical preparation of welding surface zone, veeing edges to miter of 3.0-3.5 mm and subsequent multiple-pass welding with nonconsumable negative electrode using filler wire. Welding edges are veed to miter of 2.7-3.0 mm. Welding at first pass is carried out with heat input of 0.35-0.55 MJ/m by impulse current. Welding at second pass is done with heat input of 0.6-0.86 MJ/m by impulse current at cross oscillations of electrode. Welding at third and subsequent passes is carried out with heat input of 0.62-1.16 MJ/m by steady current with cross oscillations of electrode.
EFFECT: increased capacity art welding and quality of weld joint owing to reduction of intercrystalline cracking of weld joint.
FIELD: mechanical engineering; welding.
SUBSTANCE: invention relates to design of torches for gas-shielded arc-welding by nonconsumable electrode. Proposed head of torch contains chuck with hole for electrode secured in body and gas fed channels, nozzle and partition arranged inside nozzle and formed by pack of gauzes. Gauze partition is made convex relative to welding arc flame. Head is furnished additionally with partition made of pack of gauzes arranged between chuck and gauze convex partition and made concave relative to flame of welding arc. Packs of gauzes are made of stainless steel of 3 to 5 layers. Gauze mesh is 0.3-0.5 mm.
EFFECT: provision of high quality of welding at relatively simple design.
5 cl, 2 dwg
FIELD: technological processes.
SUBSTANCE: invention concerns electric arc welding, particularly method of automatic argon arc welding of overlapping joints of steel pipes by non-melting electrode. The method involves preliminary pipe edge preparation and welding by tilted electrode with pipes rotating against electrode to form weld seam. Axial rotation speed of welded pipes is 0.1-0.8 rpm. Electrode is tilted in two planes: by 50-70 degrees against the article axis and by 60-85 degrees against weld seam plane.
EFFECT: improved quality of weld seams in overlapping joints of steel pipes, reduced hopping during rotation of long-length welded article, reduced cost of welded product.
3 cl, 3 dwg, 1 tbl