The method of repair of structural elements
(57) Abstract:Usage: repair and restoration of metal, made of metal and casting thickness of not more than 40 mm, including the construction of bridges, elements and nodes handling and road-building machines. The inventive method is that at the end of the crack drill hole, after which produce cutting cracks and welding, with a hole drilled at a distance from the end of the crack is equal to 0.4 - 0.5 in diameter, in the direction of the tangent to the radius of curvature of the plot arc near the end of the crack and cutting crack is produced at an angle 50o75o. After welding the crack opening rassverlivajut to diameter, depending on the thickness of the structural element. After welding cracks also produce multiple, but not less than three, the loading design with excess voltage in the element by 25% from nominal and single loading design to the nominal level of stresses in the element. Cutting cracks are produced with variable angle cutting along its length. 2 C.p. f-crystals, 3 ill. The invention relates to the field of repair of constructions made of metal and pouring and road-building machines.There is a method of repair of structural elements with a thickness of 5 to 25 mm in the case of cracks, namely, that limit the spread of cracks by drilling holes near the end of the crack, after which the edges of the crack is cut for welding and crack brewed along the entire length, and made a hole is not brewed. The end and the beginning of the welding seam smooth out any mechanical method 
The disadvantage of this method is that it does not specify rules for the selection of the diameter of the running of the hole depending on the thickness of the element and does not take into account the level and distribution of residual welding stresses, the value of which under certain conditions can reach in certain areas of the weld yield stress, which can lead to a significant reduction of the fatigue strength of a structural element.There are also known methods of repair of structural elements, namely, that limit the propagation of cracks by drilling their end with the installation of a completed bolt hole  or a group of bolts near the end of the cracks  are then tightened to create the field (s), compressive stresses. The disadvantages of these methods mo is free access to the defective portions of the elements on both sides, and for a full recovery of the carrying capacity of the elements of steel structures, installation of reinforcing plates (plates) on the defective place is impossible.The aim of the present invention is to improve the quality of the repair and restoration of the bearing capacity of structural members and increase their service life.To achieve this goal hole drilled at a distance from the end of the crack is equal to 0.4 to 0.5 of its diameter, in the direction of the tangent to the radius of curvature of the plot arc near the end of the crack and cutting crack is produced at an angle 50o75oand after welding the crack opening rassverlivajut to diameter, depending on the thickness of the structural element. After welding cracks produce multiple, but not less than three, the loading design with excess voltage in the element by 25% from nominal and single loading design to the nominal level of stresses in the element. Cutting cracks are produced with variable angle cutting along its length.In Fig. 1 shows a section of the element structures with crack;
in Fig. 2 cutting the cracks in the section AA of Fig. 1;
in Fig. 3, in the section B-B.Method of repair of items con is the construction with crack 2 in the direction of its propagation along the tangent 3 to the radius of curvature R of the plot arc near the end of the crack 2 drill 4 hole diameter d110 12 mm centre distance (0,4 0,5)d1from the identified visual way of end cracks 2 (Fig. 1). Edge sewerlines cracks cut for welding any mechanically (Fig. 2, 3) up to a previously completed holes d1and to ensure a more favourable distribution of welding residual stresses after welding cracks 2 the angle a of the cutting edges may be variable for each structural element 1 of a thickness not exceeding 16 mm: from a 50o5othe free edges 5 of the element 1 (Fig. 1) to a 75o5o(Fig. 3) near the end of the crack 2 (Fig. 1) with smooth measurement along its length or a 50o5othe length (0,3 0,4)lTr.from the free edge 5 of the element 1 and a 75o5othe length (0,7-0,6)lTr.or constant for items 1 thickness 16 of 40 mm and equal to a 50o5owhere lTr.the maximum length of the identified visual or otherwise cracks.Welding cracks produced by any method available to provide the necessary strength and plastic characteristics of the compounds. To reduce the residual stresses after welding and removal of possible defects in the area of the end of the welding seam should:
1. to produce agreeeee 25%
2. after three loading of the metal element in the fourth process of loading up to the level of nominal voltage, nezavisne 4 hole diameter 10 to 12 mm drilled to the proper diameter d2determined by the thickness of the element 1 with crack 2 (Fig. 1):
d216 mm when d < 8 mm;
d20,0332+ 14 mm at 16d8;
d2=24, 40d>16 mm with subsequent review of the conditions of strength;
3. reamed hole 4 is not brewed, but its edge is treated mechanically to remove burrs and the like defects with the aim of improving the fatigue strength of the metal elements.After performing strength calculation, if necessary, to produce amplification of the structural element, for example by installing plates, overlapping the crack. If there is a crack has a maximum length lTr.not exceeding (5 10)d, where d is the thickness of the structural element, after brewing cracks subsequent drilling of 4 holes with a diameter of d1up to a diameter d2can be carried out without prior loading of the structural element 1.The above method of repair of structural elements effective in R is vechnosti not less than 30% in comparison with the known, currently used, methods of repair of structures with cracks. 1. The method of repair of structural elements made of metal, namely, that at the end of the crack drill hole, after which produce cutting cracks and welding, characterized in that the drill hole at a distance from the end of the crack is equal to 0.4 0.05 to its diameter in the direction of the tangent to the radius of curvature of the plot arc near the end of the crack and cutting crack is produced at an angle 5075and after welding cracks holes rassverlivajut to diameter, depending on the thickness of the structural element.2. The method according to p. 1, wherein after welding cracks produce multiple, but not less than three, loading design with excess voltage in the element by 25% from nominal and single loading to the nominal level of stresses in the element.3. The method according to p. 1, characterized in that the cutting cracks are produced with variable angle cutting along its length.
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: metal working, namely correction of flaws of metals such as aluminum and its alloys, possibly in nuclear industry branch at making fuel elements, in machine engineering.
SUBSTANCE: method comprises steps of fusing flaw by means of electron beam along path in the form of eight-end star; providing variable according to cyclogram electric current values of beam, time periods of acting upon surface, frequency and amplitude of scanning. Decision unit provides control of said parameters according to demands for welding zone parameters such as depth of welding through, width of welded seam, depth of shrinkage recess in center of seam, trend of seam to occurring of shrinkage cracking. It is realized with use of model equations for each parameters of welding zone.
EFFECT: enhanced stability of quality characteristics, increased strength of welded seam, lowered number of rejections caused by welding process, flexible control in case of changing demands to welded seam.
2 cl, 5 dwg, 1 tbl, 1 ex
FIELD: mechanical engineering; instrumentation engineering; repair of surface and under-surface defects in metals and alloys in form of pores and micro-cracks of structural and technological nature.
SUBSTANCE: proposed method consists in revealing defects and forming flaw-free zone by repeated action on section under test by laser beam at simultaneous monitoring of quality; flaw-free zone is formed by melting the surface layer at simultaneous active location of near-surface layer of section treated by surface acoustic waves arising on section being treated at generation of laser plasma; generation of laser plasma is monitored till reaching preset minimum of amplitude difference of two adjacent pulses of acoustic waves, after which surface is again shifted relative to laser beam. Laser beam is simulated in space in plane of focusing on surface of metal.
EFFECT: hardening of metals at hidden flaws; increased productivity.
2 cl, 2 dwg, 1 tbl
FIELD: welding and surfacing, namely forming melt surfaced part on main material, possibly monocrystalline or crystalline material produced by directional crystallization, restoration processes of defective zone of main material, joining methods of main material with additional one, restoration of turbine blades, air-jet engines and other machines of similar designation.
SUBSTANCE: welding is realized for forming on main material large number of surfaced portions while keeping preliminarily set gaps between adjacent surfaced portions. Then surfaced portions are formed in each gap. Main material is monocrystal received by directional crystallization. Surfaced portion is formed in direction normal to crystal growth direction of main material. At joining additional material with main, crystalline or monocrystalline material, all said operations are realized. At restoring, defective portion of cast metal is removed and respective concave portion is formed on surface of cast metal and it is filled with surfacing metal.
EFFECT: improved strength of surfaced parts due to elimination of cracking.
23 cl, 23 dwg
FIELD: process for restoring metallic surfaces by surfacing, possibly at removing flaws of machine part surface at repairing.
SUBSTANCE: method comprises steps of taking out flaw before surfacing and deforming edges of turned out zone for forming on worked surface shoulder with height 0.3 - 0.5 mm and with width 2 - 3 mm. Then surfacing is performed till half of shoulder width. Then surfaced metal is taken out till level of worked surface.
EFFECT: improved quality of worked surface.
5 dwg, 1 ex
FIELD: welding production process, possibly flaw correction of castings of nickel-base high-alloy refractory alloys.
SUBSTANCE: method comprises steps of hot gas-static compaction of castings; separating flaw containing casing portion having surface micro-porosity just before compaction; subjecting said portion of sand-blast treatment; then spraying onto it coating whose chemical content is almost the same as of casting material; performing heat treatment of casting in vacuum at temperature lower than temperature of alloy homogenizing; rayed coating has thickness no less than 200 - 300 micrometers.
EFFECT: reliable effective correction of flaws of casting of gas turbine engine blades.
2 cl, 1 ex
FIELD: restoration of surface of metals by surfacing process, possibly removing flaws of machine part surfaces at restoring them.
SUBSTANCE: method comprises steps of taking up flaw before surfacing; deforming edges of taken up zone for forming on worked surface bead with height 0.3 - 0.5 mm and width 2 - 3 mm; performing surfacing operation whose boundary achieves half of bead width; removing surfaced metal till level of worked surface.
EFFECT: improved quality of worked surface.
1 ex, 5 dwg
FIELD: production of ingot-blanks by electroslag refining of low-ductile steel containing boron and rolling tubes of such blanks in tube rolling plants with pilger mills for further conversion of rolled tubes to hexahedral tube-blanks used for compacted storage of waste nuclear fuel.
SUBSTANCE: method comprises steps of casting ingots with size 470-490 x 1700-1750 mm by electroslag refining; mechanically working them by turning to ingot-blanks with size 460 - 480 x 1700 - 1750 mm; drilling central opening with diameter 100±5.0 mm; heating them till yielding temperature 1060 - 1090°C; piercing ingots in skew rolling mill on mandrel with diameter 275 mm to sleeve with size 470 - 480 x 290 in. x 2500 - 2600 mm at elongation degree 1.47 - 1.51; rolling sleeves in pilger mill with backing carbonaceous rings to conversion tube-lengths with size 290 x 12 x 22000-23000 on mandrel with diameter 264 -265 mm at elongation degree 10.25 - 11.0; cutting off pilger heads and seed ends by hot cutting saw; cutting tube-lengths by two tubes of the same length or to tubes with length multiple to length of conversion blank; further straightening tubes in six-roll straightening machine at using temperature of heating for rolling. Electroslag refining ingots are cast in the form of hollow ingots with size 480 x 270 in. x 2450 ± 50 mm. Bottom and shrinkage portions of hollow electroslag refining ingots forming pilger head and seed end at rolling conversion tubes are cast of ductile carbon kinds of steel. Height values of bottom and shrinkage portions of ductile carbon steel are determined from expressions Lb = (0.12 - 0.15)Lt, Ls = (0.05 - 0.06)Lt where Lb - height of bottom portion of hollow ingot of ductile carbon steel, mm; Ls - height of shrinkage portion of hollow ingot of ductile carbon steel, mm; Lt -total height of hollow ingot (2450±50)mm. Hollow ingots are bored and turned at shrinkage side to hollow blanks with size 470 x 280 in. mm till boundary of fusion of two metals in bottom portion of ingots or till shifting to side of ductile carbon steel by 50 - 80 mm at surface roughness degree Rz = 40 mcm or less. At turning, smooth transition from main metal to ductile carbon steel in bottom portion of ingot is provided in the form of truncated cone along distance 50 - 80 mm. Bimetallic hollow ingot-blanks are heated till yielding temperature 1040 -1060°C according to mode for heating steel containing 1.3 - 1.8% of boron. After removing technological crops such as pilger heads and seed ends of ductile carbon steel, - at side of pilger heads and seed ends portions of tubes of ductile carbon steel with length 500 -700 mm are left. Then after cutting tube-lengths by two tubes of the same length or by tubes with length multiple to length conversion blank, tubes are guided for further warm straightening in six-roll straightening machine by their ends of ductile carbon steel. Openings for pulling chain at warm shaping are drilled in tube-blanks with carbon ductile end portions in zones of tube-blanks of ductile carbon steel. Ends of tube-blanks of ductile carbon steel are removed before heat treatment while performing all further operations of manufacturing process.
EFFECT: lowered quantity of rejected tubes, improved efficiency of pilger mills, reduced cost of commercial hexahedral tube-blanks.
10 cl, 1 tbl
FIELD: production of cover hexahedral tube-blanks of low-ductile boron steel for compacted storage of waste nuclear fuel, possibly manufacture of hexahedral tube-blanks of given size, restoration of rejected hexahedral blanks after boring, turning and repairing of their outer surfaces according to rolling-origin flaws.
SUBSTANCE: method comprises steps of rolling conversion tubes with size 290 x 12 x 2100-2200 mm; cutting tube lengths by means of hot cutting saw by tubes; marking out tubes for cutting by blanks; marking blanks; cutting tubes by blanks; measuring geometry parameters of blanks; straightening blanks with common curvature along length more than 3.0 mm; boring blanks for further quality control of their inner surface and inner diameter; marking blanks inside by means of paint; forming inner and outer chamfers; turning blanks in machine tools with servo system; technologically controlling wall thickness of blanks; inspecting and repairing defect zones of outer surface; measuring thickness of wall; repairing zones of outer surface having flaws and thickness of wall outside plus limit size; performing secondary turning if necessary; transferring number of blank by means of stamps onto outer surface of blanks; degreasing blanks; subjecting blanks to induction heat treatment, ultrasound flaw detection and to spectroscope control; drilling openings for drawing chain for profiling on marked ends of blanks; applying salt lubricant onto blanks; warm shaping of hexahedral blanks; controlling geometry sizes of hexahedral blanks; degreasing them; heat treating hexahedral blanks; controlling size 257 ± 2 x 6 + 1.75/-1.0 mm; correcting portions whose sizes are outside plus allowance field; controlling total curvature of faces along length of hexahedral blanks; marking out and cutting hexahedral blanks by measured length 4300+80/-20 mm; selecting templates in order to make samples for mechanical testing; transferring marking; removing fins, trimming and blowing through hexahedral blanks; straightening in press hexahedral blanks with curvature more than 3.0 mm along length of tube-blank; inspection after straightening curvature and controlling size; controlling hexahedral blanks for passing templates through them; straightening if necessary; controlling geometry size of hexahedral blanks; trimming portions of hexahedral blanks whose sizes are outside plus limit values along wall thickness and finish sizes; reception; brightening; testing metal templates of hexahedral blanks by mechanical properties; final reception; marking and packaging hexahedral tube-blanks. Blanks after boring, turning and repairing flaws of outer surface with wall thickness in repairing places less than 5.0 mm are fed for further operations of manufacturing process including degreasing of blanks and then flaw zones are repaired by electric arc surfacing under flux layer or in argon shield atmosphere by means of electrode of boron steel. Repaired zones are subjected to grinding till predetermined wall thickness and smooth joining with planes of hexahedron and then they are subjected to heat treatment at performing all next technological operations according to manufacturing process.
EFFECT: lowered metal consumption, reduced cost of commercial hexahedral tube-blanks.
3 cl, 1 tbl
FIELD: technological processes.
SUBSTANCE: after preliminary cleaning of defective part of surface of pipe by an abrasive wheel, the edges of the cracks are determined using penetrant flaw detection method and the defective part is then melted by an unsmeltable tungsten electrode. The process of melting starts and ends 10-15 mm from the beginning of the crack and after its end with formation of a depression with fused edges. The obtained depression filled along its whole length by an argonarc method with a filler wire. The surface is then cleaned, flush with the main metal and quality is controlled using ultrasonic flaw detection. Subsequent hardening is carried out using ultrasound pulse processing of the cleaned surface. The method reduces labour intensiveness of the repairing pipes which are in use and with defects in form of stress-corrosion cracks.
EFFECT: increased longevity of gas pipelines.
4 dwg, 1 ex