Method of butt contact resistance welding of dissimilar metals
(57) Abstract:The method can be used when welding metals with different physical-mechanical properties, for example, high-speed steel construction. At the end of one part perform the ledge, and on the other end part of the recess. The ledge perform at the end of items with high resistivity, and a recess on the end face of the workpiece with a lower specific resistance. The ratio of the areas of the cross section of the parts in the junction is chosen from the condition of their direct proportionality resistivity of the material of the welded components. The protrusion and the recess can be performed with a tapered part, and with a cross section in the form of a polygon. The method can significantly improve the welding quality. 2 C.p. f-crystals, 4 Il. The invention relates to contact the resistance welding of metals with different physical-mechanical properties, such as high-speed steel construction, for manufacturing of end cutting tool or other products requiring high reliability in vibration, fatigue fracture and shock loads.The known method of flash butt welding of parts made of dissimilar metals, in which Shrivenham end IU the UE is softened and under the force of compression. plastically deformed, fills the volume of the undercut .The disadvantages of this method include: a large initial contact area on the cone and, as a consequence, a longer heating time required for the molten metal both welded parts. This reduces the efficiency of the process increases the energy consumption.The known method of flash butt welding of parts made of dissimilar metals with the preliminary preparation of the ends in the form of a wedge protrusion of the one part and the through-hole parallel to the end face of another part .The disadvantages of this method include the need for skilled works that are applicable only to the enterprises of the instrumental profile in serial production.The objective of the invention is to improve the quality of the welding on the outer belt, due to the simultaneous melting of the metals of the two components in the welding area; limiting the mechanical stresses in the weld due to the redistribution of mechanical loads between the weld seam and butt connection cones; increasing productivity and reducing energy intensity of the process.This task is achieved by the fact that in the world and perform a ledge and at the end of another part of the groove according to the claimed invention, the protrusion perform at the end of items with high resistivity, and a recess on the end face of the workpiece with a lower specific resistance, while choosing the ratio of the areas of the cross section of the parts in the junction of the conditions of their direct proportionality resistivity of the material of the welded components. In addition, the protrusion and the recess can perform the tapered part. In addition, the protrusion and the recess can perform with a cross section in the form of a polygon.As a result, the connection has two element mounting: weld on the outer belt and a shrink fit on the cone (Fig.4).In Fig.1 shows the shape of the ends of parts prepared for welding. Item 1 made of metal with a resistivity R1 [MSM], and item 2 with a resistivity R2 [ASM], with R1>R2. As the protrusion and the recess are cylindrical part L11-2 mm part 1, for orientation when positioned for welding, and cone L13-5 mm for connection to a hot landing. Dimensions L2, L2 part 2 more sizes L1, L1 parts 1 on a given amount of precipitation. In Fig.2 shows a variant of the preparation of the ends of parts.In Fig. 3 shows the relative path svarochnoye times what specific resistance R2 is less than the resistivity R1 of the metal part 1. The ratio of the densities of currents aligns the electrical power going to heat both parts near the joint, which heats the metal until tender and beginning of precipitation. In the process of precipitation increases the contact area detail 1 detail 2 on the cone. The current density parts 1 decreases, and the heating rate on the approach to the melting temperature, which provides a more uniform heating of the metal. This condition persists until the melting temperature.The training ends welded components also allows the equipment to weld parts with a diameter of 2-2 .5 times higher than indicated in the technical passport of welding equipment.Sources of information
1. USSR author's certificate 197793, CL 23 To 11/02, 19672. USSR author's certificate 785002, CL 23 To 11/02, 1980 1. Method of butt welding resistance of parts made of dissimilar metals, in which the end of one part perform the ledge, and on the other end part of the recess, wherein the projection performs at the end of items with a large specific Losada section details the junction of the conditions of their direct proportionality resistivity of the material of the welded components.2. The method according to p. 1, characterized in that the protrusion and recess comply with the tapered part.3. The method according to p. 1, characterized in that the protrusion and recess comply with section in the form of a polygon.
FIELD: mechanical engineering.
SUBSTANCE: proposed method is intended for manufacturing fuel elements using resistance-butt welding primarily for their joining to zirconium alloy cans. Welding is effected at equipment electrical resistance not over 30-fold resistance of can section forming welded joint having or not point discontinuities in the form of separate spots or chain of such spots forming no continuous line and measuring maximum ten thicknesses of weld in cross-sectional area of welded joint under check disposed at distance equal to two or three thicknesses of can wall from butt-end of plug located inside fuel element, welded joint being checked by uniformity of external fin. Length of poor fin formation section does not exceed 10% of joint perimeter.
EFFECT: enhanced quality of welds and reliability of fuel element sealing.
FIELD: mechanical engineering; manufacture of devices for contact butt welding of pipes with plugs for sealing rod-type fuel elements of nuclear reactors.
SUBSTANCE: proposed method consists in stacking the current lead, stop-cooler made from set of metal plates at increased electric resistance and holder made from dielectric material. Stack thus made is subjected to machining and to aging by welding the specimens. Stop-cooler is electrically shunted by means of plate-type shunts located in holes made over perimeter of device. Plate-type shunts are rolled in cylinder and are fixed in holes by releasing deformable electric plugs fitted in these holes.
EFFECT: reduced labor consumption; enhanced operational stability; extended functional capabilities.
2 cl, 1 dwg
FIELD: machine engineering, namely methods for contact-butt welding of tube with plug for making fuel elements of nuclear power stations.
SUBSTANCE: method comprises steps of fixing tube at embedding tube end in opening of welding fitting having predetermined value of electric resistance; placing plug having portion welded in tube wall and outer portion in electrode for supplying welding current to outer portion of plug; compressing parts by applying welding effort; heating parts by means of welding electric current and welding them. Outer portion of plug has several parts; its part adjacent to portion welded into tube wall has diameter exceeding diameter of said part but less than diameter of opening of welding fitting. At welding process part of outer portion of plug adjacent to portion welded into tube wall is at least partially introduced into opening of welding fitting for forming annular gap between said part of outer portion and tube end. Said annular gap is filled with outer burrs. Part of outer portion of plug that is not adjacent to portion welded into tube wall has diameter exceeding diameter of opening of welding fitting.
EFFECT: improved characteristics of articles, enhanced versatility of method.
4 cl, 3 dwg, 1 ex
FIELD: nuclear engineering; fuel elements of nuclear reactors.
SUBSTANCE: proposed fuel element plug has section welded deep into can, its diameter being smaller than outer diameter of can but greater than its inner diameter; it also has end cap. The latter has surface for supplying welding current and applying force. End cap diameter is not smaller than that of fuel element can. Annular drilling is disposed between part to be welded in and surface for supplying welding current. End surface of annular drilling crosses surface of section being welded in. Diameter of annular drilling ranges between diametric dimensions of adjacent sections of plug.
EFFECT: reduced hydraulic resistance to coolant flow in reactor, facilitated manufacture, universal mechanical design.
1 cl, 3 dwg
FIELD: mechanical engineering; welding nuclear engineering.
SUBSTANCE: invention relates to resistance butt-welding of tubular jackets with plugs at sealing of rod-type elements of nuclear reactors. Device for forming of joints contains current supply and shaping parts in which hole is made form end of tubular jacket. Current supply and shaping parts are made integral in form of metal non-split plate or metal split plate divided into sectors along planes passing through hole for end of tubular jacket. Diameter of hole for end of tubular jacket in current supply part is either equal to or greater than diameter of hole in shaping part.
EFFECT: simplified design of device, improved reliability in operation and quality of welding.
3 cl, 4 dwg
FIELD: mechanical engineering; welding nuclear engineering.
SUBSTANCE: invention relates to methods of resistance butt welding for sealing of jackets of fuel elements of nuclear reactors and in process of manufacture of clusters of fuel elements. Method comes to compressing pipe and plug by welding force directed along axis of pipe and plug, heating them by electric current with subsequent welding-in with deepening of plug into pipe. Diameter of plug on section of formation of weld seam is greater than inner diameter of pipe, but is smaller than outer diameter of pipe. Welding current and force is applied to plug in different cross sections. Surface to apply welding current is arranged parallel to axis of plug and at angle of 90° to surface for application of welding force between said surface and part of plug welding into pipe.
EFFECT: provision of multipurposeness of method, improved quality of welding and service and technological characteristics of article.
FIELD: mechanical engineering; welding; nuclear engineering.
SUBSTANCE: invention relates to resistance butt-welding of tubular jackets of fuel elements with plugs. According to proposed method, end of pipe and end of plug are fixed in electrodes. Ends of pipe and plug whose outer diameter is greater than inner but smaller than outer diameter of pipe are compressed. Relative heating of pieces by welding current is carried out with subsequent driving plug into pipe. Welding is done mainly by heating of plug. Seating place is formed in process of displacement of plug between surface of its welded-in part and inner surface of pipe in direction of plug travel out of zone of thermal influence in pipe jacket. Larger part of fin formed at welding, and zone with maximum structural changes caused by thermal influence are brought outside. Zone with maximum structural changes is arranged out of zone of weld joint, and fin brought out is used to form smooth mating between outer surface of pipe and plug.
EFFECT: improved operating qualities of welded joints and their manufacturability.
1 ex, 2 dwg
FIELD: mechanical engineering; welding; nuclear engineering.
SUBSTANCE: invention relates to manufacture of fuel elements of nuclear power stations which are sealed by resistance butt-welding. Proposed method of welding of fuel element jacket with plug comes to placing end of jacket with depression into welding equipment with preset electric resistance value and welding-in of plug into jacket wall to depth not less than twice thickness of jacket wall, with control of parameters of welding rate. Welding is carried out at rates providing distribution between areas of inner, found under jacket and outer, metal-fin forced out of butt joint of section at ratio not exceeding 3. Ratio of areas of sections of inner metal-fin arranged at two sides in any diametral section of weld joint made along its axis does not exceed two.
EFFECT: improved operation reliability of fuel elements owing to quality forming of weld joints.
1 ex, 2 dwg
FIELD: processes and equipment for joining tubular parts in hazard zones, for example for welding tubes used in oil production and (or) well tubes in oil- or gas -producing platforms.
SUBSTANCE: method comprises steps of placing joined end portions of tube parts at mutual gap (possibly, several mm) inside chamber filled with shield gas; pumping to said chamber explosion-proof mixture of fluids containing nitrogen and hydrogen; heating ends of tube parts in said space at least by means of three electrodes forced to wall of each tube part and spaced one from other along circle near end of respective tube. Electrodes provide passing of HF- current practically in circumference direction through segment of tubular part between said electrodes. Uniformly heated ends of tubular parts are moved one towards other for forming forge welded joint between heated ends of tubular parts.
EFFECT: possibility of high-quality welding tube ends, possibly ends of irregular-shape tubes at minimum inclusions of oxidized metal.
20 cl, 10 dwg
FIELD: machine engineering, namely apparatuses for forming joint of tube and plug by resistance contact butt welding at sealing rod fuel elements of nuclear reactors.
SUBSTANCE: apparatus includes assembled to pack annular electric current supply lead and casing of dielectric material. In said casing annular cooler-stop having increased resistance to welding current is arranged. Said cooler-stop is in the form of set of metallic plates electrically connected one to other by means of shunts placed in openings of apparatus. Said shunts are cylindrical ones and they are fixed in openings by means of plugs in which threaded screwed-in members are mounted. Openings are cylindrical ones and plugs are made of elastic dielectric material. Development length of shut surface exceeds circle length of opening where shut is placed.
EFFECT: simplified design, enhanced operational reliability and enlarged manufacturing possibilities of apparatus.
2 cl, 1 dwg