CN104955612A

CN104955612A - Method of laser re-melt repair of superalloys using flux

Info

Publication number: CN104955612A
Application number: CN201480006745.7A
Authority: CN
Inventors: G.J.布鲁克; A.卡梅尔
Original assignee: Siemens Energy Inc
Current assignee: Siemens Energy Inc
Priority date: 2013-01-31
Filing date: 2014-01-29
Publication date: 2015-09-30
Also published as: KR20150110799A; EP2950973A1; RU2015136564A; JP2016516580A; WO2014120736A1

Abstract

A method of repairing service-induced surface cracks (92) in a superalloy component (90). A layer of powdered flux material (100) is applied over the cracks and is melted with a laser beam (98) to form a re-melted zone (104) of the superalloy material under a layer of slag (106). The slag cleanses the melt pool of contaminants that may have been trapped in the cracks, thereby eliminating the need for pre-melting fluoride ion cleaning. Optionally, alloy feed material may be applied with the powdered flux material to augment the volume of the melt or to modify the composition of the re-melted zone.

Description

Use the laser remolten restorative procedure of the superalloy of solder flux

The application is the part continuation application (publication number US 2012/0181255 A1) of the U.S. Patent Application No. in a review 13/005,656 that on January 13rd, 2011 submits to, is hereby incorporated by.

Technical field

The present invention relates generally to metal bond field, more specifically relates to the reparation of superalloy materials.

Background technology

Be on active service in gas-turbine unit after (service), hot gas road assembly (as blade and blade etc.) usually can produce the shallow-layer spider shape crack being known as be full of cracks (craze cracking).Owing to forming the limited solderability of the superalloy materials of these assemblies, the reparation in these cracks is difficult.Superalloy materials easily produces the cracking of weld seam and welding heat affected zone at welding solidificating period, and easily produces reheat cracking when the post weld heat treatment needed for reconstruction biomaterials performance subsequently.

United States Patent (USP) 7,69,242 describe, by the method using laser beam or other energy source material list surface layer that remelting 500 μm is dark in inert gas or vacuum to repair the medium and small surperficial casting flaw of superalloy materials.Consider the defect that reparation is darker and reduce the risk of thermal fragmentation defect, preheating object is mentioned.

Crack after military service is usually by various combustion process product pollution, and described combustion process product makes REPAIR WELDING more difficult.Fluorine ion cleaning (FIC) can be used to remove pollutant before welding, but it is to unusual narrow crack limited use; And due to its potentiality leaching important element from the base material of surrounding, if excessively used, then may be harmful.

There were significant differences according to the type of welding material for welding procedure.Some materials are easier to weld under numerous conditions, and other material require special process does not make the base material deterioration of surrounding to realize joint rational in infrastructure.

Conventional arc welding uses consutrode as feed material usually.In order to provide the protection for atmosphere to melted material in weldpool, such as, inert blanketing gases or flux material (flux material) can be used when welding many alloys (comprising, steel, stainless steel and nickel-base alloy).The inertia of inertia and combination and active gases technique comprise Gas-Tungsten-Arc welding (GTAW) (also referred to as Wolfram Inert Gas (TIG)) and gas metal arc welding (GMAW) (also referred to as Metallic Inert Gas (MIG) and metal active gas (MAG)).The technique of solder flux protection comprises submerged arc welding (SAW) (wherein usually adding solder flux), flux cored wire arc welding (FCAW) (wherein solder flux is included in the core of electrode) and shield metal-arc welding (SMAW) (SMAW) (wherein solder flux is applied to the outside of filler electrode).

Energy beam is used also to be known as thermal source for welding.Such as, laser energy has been used to make prepositioned powder of stainless steel be melted on carbon steel substrates, wherein uses powder flux material to provide the protection of melt pool.This solder powder can mix with powder of stainless steel or apply as independent cover layer.With regard to the knowledge of present inventor, also do not use flux material when welding superalloy materials.

Should understand superalloy materials is one of the material being difficult to most weld, and this is because they to solidify the sensitiveness of crack and strain-aging crack (strain age cracking) to welding.Using term " superalloy " at this, is because it often uses in this area; That is, the highly corrosion-resistant and oxidation resistant alloy of one, it has excellent mechanical strength and high-temperature creep resistance.Superalloy generally includes high nickel or cobalt content.The example of superalloy comprises the alloy sold with following trade name and trade mark: Hastelloy, Inconel alloy (such as IN 738, IN 792, IN 939), Rene alloy (such as Rene N5, Rene 80, Rene 142), Haynes alloy, Mar M, CM 247, CM 247LC, C263,718, X-750, ECY 768,282, X45, PWA 1483 and CMSX (such as CMSX-4) single crystal alloy.

The REPAIR WELDING of some superalloy materials successfully realizes, and it significantly increases the ductility of material in repair process by preheating the extremely very high temperature of this material (such as extremely higher than 1600 °F or 870 DEG C).This technology is called the REPAIR WELDING of the welding of hot case or high temperature superalloys welding (SWET), and it uses manual GTAW method to realize usually.But hot case welding is limited to and is difficult to maintain homogeneous component artistic face temperature and be difficult to maintain inert gas protection completely, and to the health difficulty that the operating personnel near component operation apply at so extreme temperature.

Coldplate can be used to carry out some superalloy materials welding application with the heating limiting base material; Thus restriction substrate heat affecting and cause the existence of stress of problem of Cracking.But the geometry for many wherein parts is unfavorable for the reparation application using coldplate, and this technology does not have practicality.

Fig. 6 is the relative solderability of illustrating multiple alloy as the conventional diagram of the function of its aluminium and Ti content.Alloy as iN718 has these lower elements of relative concentration, and therefore have relatively low γ phase content (gamma prime content), these alloys are thought relatively welding, although this welding is limited to the low stress zones of assembly usually.Alloy as iN939 has these higher elements of relative concentration, and it is considered to nonweldable usually, or above-mentioned specific process only can be used to weld, and these methods increase the temperature/ductility of material and minimize the heat input of the method.At this, for purposes of discussion, dotted line 80 represent above solderability region below online 80 and line 80 without the border between solderability region.This line 80 intersects at ordinate and 3 % by weight aluminium and intersects at abscissa and 6 % by weight titaniums.Without in solderability region, the alloy with most high aluminium content is usually found to be and is difficult to most to weld.

Also known use selective laser melting (SLM) or selective laser sintering (SLS) are to be melted in the thin layer of superalloy powder particle in superalloy substrate.This melt pool shields this atmosphere by applying inert gas in LASER HEATING process as argon gas.These methods are easy to be mingled with (trap) and are attached to oxide (oxide of such as aluminium and chromium) on the surface of the particle in the material layer of deposition, cause the porous relevant to trapped oxide, filler and other defect.High temperature insostatic pressing (HIP) (HIP) after usual use process disintegrates these spaces, filler and crack, to improve the character of deposited coating.

For the superalloy materials in some non-solderability regions, there is no the acceptable welding of known business or renovation technique.And, along with the new superalloy higher with alloy content is by Persisting exploitation, split the joint of hair in the commericially feasible of superalloy materials and the challenge sustainable growth of renovation technique.

Accompanying drawing explanation

The present invention makes an explanation in below with reference to accompanying drawing, and accompanying drawing shows:

Fig. 1 illustrates the method for coating using multiple layer powder.

Fig. 2 illustrates the method for coating using mixed layer powder.

Fig. 3 illustrates the method for coating using flux cored filler welding wire (a cored filler wire) and cold metal arc welding blowtorch (cold metal arc welding torch).

Fig. 4 illustrates the method for coating using flux cored filler welding wire and energy beam.

Fig. 5 illustrates the folded replica formula of energy beam.

Fig. 6 is the figure of prior art, shows the relative solderability of multiple superalloy.

Fig. 7 illustrates the laser remolten renovation technique using solder powder.

Summary of the invention

Conveniently reader, the Fig. 1-5 that should note herein shows many aspects and the application of the technology of the present invention as herein described, and the purposes of the technology of the present invention that the description of following Fig. 7 is repaired in particular to the laser remolten for superalloy that application claims is protected.

Present inventor has developed material joint method, and it can be used successfully to the superalloy materials engaging and/or repair and be difficult to most weld.Although previously do not use flux material during welding superalloy materials, the embodiment of the inventive method advantageously used powder flux material in fusing with again in process of setting in superalloy substrate.Some embodiments also utilize the input control of the energy accurately ability of energy beam heating process (such as laser beam heats).Described powder flux material effectively provides beam energy trapping, impurity cleaning, atmosphere shielding, appearance of weld and chilling temperature to control; combine with the free from flaw realizing superalloy materials, and weld or use coldplate without the need to high-temperature heat box or use inert protective gas.Although multiple element of the present invention is known in welding industry reach decades, present inventor innovatively develops a kind of step combination of superalloy joint method, which solves the problem of Cracking of these materials long-standing.

Fig. 1 illustrates a kind of method, is wherein at room temperature deposited on superalloy substrate material 12 by the covering 10 of superalloy materials, and does not carry out any preheating or inapplicable coldplate to base material 12.This base material 12 such as can form a part for blade of gas turbine, and in some embodiments, this method for coating can be a part for repair procedure.Granular powder bed 14 is on the base 12 prepositioned, and the covering 10 that laser beam 16 is covered by molten slag layer 18 with melting powder and formation through powder bed 14.This covering 10 and slag 18 are formed by powder bed 14, and this powder bed 14 comprises the powder superalloy materials layer 20 covered by powder flux material layer 22.

Flux material 22 and gained molten slag layer 18 provide several functions, and it is conducive to the cracking preventing covering 10 and base material below 12.First, they are for protecting the atmosphere of (but still heat) clad material 10 LASER RETROFIRE 16 downstream area of melted material region and solidification.This slag is floated to surface to be separated from this atmosphere by the metal of melting or heat, and can prepare this solder flux in some embodiments to produce protective gas, avoids or minimize the use of expensive inert gas thus.The second, slag 18 makes the material of solidification slow and Homogeneous cooling as cover layer (blanket), thus reduces residual stress, and after promoting welding, heating or strain-aging ftracture (strain age cracking) again for they.3rd, slag 18 contributes to pool of molten metal is shaped to keep it close to 1/3 required height/width ratio.4th, flux material 22 provides cleaning action to remove trace impurity as sulphur and phosphorus, and it can promote that cracking is solidified in welding.This clean comprising makes metal dust deoxidation.Due to this this metal dust of solder powder close contact, thus it is to complete this function aspects effective especially.Finally, flux material 22 can provide energy absorption and entrapping function, with more effective, laser beam 16 is converted into heat energy, thus is convenient to accurately control heat input, such as, in 1-2%, and makes closely to control material temperature in this process.In addition, this solder flux can be prepared to compensate the volatile element that loses in process or to be initiatively added in deposit by the element do not provided by metal dust itself.In a word, can only by hot case method or by using the coldplate material that could engage, these method steps create the free from flaw deposit of the superalloy be coated in superalloy substrate in room temperature for thinking up to now.

Fig. 2 illustrates another embodiment of the present invention, and wherein the clad 30 of superalloy materials is deposited on superalloy substrate material 32, and it is shown to have the material of the directional solidification of multiple columnar grain 34 in this embodiment.In this embodiment, powder bed 36 surface that is preset in or adds to base material 32 is as the conforming layer of mixture comprising powder alloy material 38 and powder flux material 40.In some embodiments, powder bed 36 can be 1 normally used a few tenths of a mm to a few millimeters thick but not in selective laser melting and sintering method.Such as, the flux material of typical powder prior art has the particle size of 0.5-2mm.But the particle size range (size of mesh scope) that powder alloy material 38 can have is 0.02-0.04mm or 0.02-0.08mm or their any subrange.The difference of this size of mesh scope can in the implementation of figure 1 well suited (wherein material forms independent layer); But, in the embodiment of fig. 2, in order to promote the mixing of powder and charging and provide the solder flux of improvement to cover in fusion process, advantageously, powder alloy material 38 and powder flux material 40 have overlapping size of mesh scope, or have identical size of mesh scope.

The energy beam 42 of the embodiment of Fig. 2 is for having the diode laser bundle of the transverse shape of usual rectangle, although the energy beam of other known types can be used, as electron beam, plasma beam, one or more circular laser beam, scanning laser beam (one dimension, two dimension or 3-D scanning), integrate laser beam etc.This rectangle can be particularly conducive to the embodiment with larger area to be covered, as repairing blade of gas turbine top.The wide area bundle that diode laser produces contributes to reducing thermal weld stress, heat affected area, from the dilution of substrate and residual stress, it all reduces the tendency of usually relevant to superalloy reparation cracking role.The optical condition exposed for generation of wide area laser and optical hardware can include but not limited to: defocusing of laser beam; The use of the diode laser in rectangular energy source is produced at focus place; Integrated optical device is if the use of segmented mirror is to produce rectangular energy source at focus place; At one or more dimensional searches (scanning (rastering)) laser beam; With use the focusing optics of variable beam diameter (being such as changed to the 2.0mm for the not too focus place of fine work for the 0.5mm at the focus place of fine work).As in selective laser melting or sintering method, the motion of optics and/or substrate can be programmed the deposit setting up custom-shaped layer (custom shape layer).Compare known laser fusion or sintering method, the advantage of the method comprises: high deposition rate and thick deposit in treated layers; The shielding of the improvement that the metal of heat deposition extends and do not need inert gas; Solder flux will strengthen the clean of component deposition thing, otherwise it will cause solidification cracking; Solder flux is by enhancing laser beam absorption and minimize the reflection returning treatment facility; Slag is formed and will be shaped and support deposit, preserves heat and slows down cooldown rate, thus reduces residual stress, otherwise it can cause strain-aging (the heating again) cracking in welding after-baking; Solder flux can compensating elements loss or add alloying element, and effectively selectively can carry out powder and solder flux pre-placing or interpolation because sedimental thickness greatly reduce total parts set up involved by time.

The embodiment of Fig. 2 also illustrates and uses base alloy feed material 44 (or being called as filler material).Feed material 44 can be the form of line or belt, and it is added or vibrates to substrate 32 and melted by energy beam 42, thus contributes to melt pool.If necessary, this feed material can preheat (such as electrical heating) to reduce the gross energy needed for laser beam.Although be difficult to the form that maybe some superalloy materials can not be formed as line or belt, material such as pure nickel or nickel-chromium or nickel-chromium-cobalt can be easy to obtain with these forms.In the embodiment of fig. 2, base alloy feed material 44, powder alloy material 38 and powder flux material 40 is advantageously selected to make cladding material 30 have the composition of required superalloy materials.This filler material can be only the extrudable subgroup of the element of the element combinations of the superalloy materials needed for restriction, and this powder metal materials comprises the element of element in additional fillers material to obtain the element combinations of the superalloy materials needed for limiting.This filler material and powder metal materials mix the reparation surface forming required superalloy materials layer 30 in melt pool.As Fig. 1, the method produces molten slag layer 46, and it makes clad material 30 obtain protection, be shaped and heat insulation.

Fig. 3 illustrates a kind of embodiment, wherein uses cold metal arc welding blowtorch 54 that superalloy materials layer 50 is deposited into superalloy substrate 52.This blowtorch 54 has the filler material 56 (it comprises the hollow metal sheath 57 being filled with powder core core material (powdered core material) 59) of medicine heart yearn (cored material) or strip material form for charging and fusing.This powder core core material 59 can comprise powder metal alloy and/or flux material.Advantageously, this protective metal shell 57 is formed by the material that can be easy to be formed as hollow shape, as nickel or nickel-chromium or nickel-chromium-cobalt, and selects dusty material 59 to make to form required superalloy compositions when filler material 56 melts.This sheath comprises enough nickel (or cobalt) to obtain required superalloy compositions, and therefore the solid of sheath relative powder core core material such as can remain on the ratio of 3:2 to the ratio of solid.The heat melts filler material 56 of electric arc and form the superalloy materials layer 50 needed for being covered by molten slag layer 58.Powder flux material to may be provided in filler material 56 (Assessment of Nuclear Volume of such as 25%) or it can be prepositioned or be deposited on the surface of substrate 52 and (do not show that – is see Fig. 2), or flux material can be used electrode coated, or any combination of these alternative way.In multiple embodiments, this solder flux can be (electroslag) of electrical conductance or (submerged arc (the submerged arc)) of not electrical conductance, and it can be chemically neutral or adds.As mentioned above, this filler material can be preheated to reduce required Process Energy-be derived from cold metal electric arc blowtorch in this case.Use solder flux to provide shielding, reduce or eliminate the demand to required inertia usual in cold metal arc method or part inert gas thus.

Fig. 4 illustrates a kind of embodiment, wherein uses energy beam such as laser beam 64 to be deposited in superalloy substrate 62 superalloy materials layer 60 to melt filler material 66.As above about described in Fig. 3, this filler material 66 comprises protective metal shell 68, it is by being easy to the material construction being configured as hollow shape, as nickel or nickel-chromium or nickel-chromium-cobalt, and selects dusty material 70 to make to form required superalloy compositions when filler material 66 is melted by laser beam 64.This dusty material 70 can comprise powder solder flux and alloying element.The heat melts filler material 66 of laser beam 64 and form the superalloy materials layer 60 needed for being covered by molten slag layer 72.As mentioned above, this filler material (such as can be used electric current) and preheat to reduce required Process Energy-be derived from laser beam in this case.

Arrange filler material 56, an embodiment of 66 is with following deposit alloy 247 material:

-sheath solid volume is about 60% of total metal solid volume and is pure Ni;

-core core metal powder volume is about 40% of total metal solid volume, and this total metal solid volume comprises enough Cr, Co, Mo, W, Al, Ti, Ta, C, B, Zr and Hf; It when melting and mixing together with the pure nickel coming from sheath, produces alloy 247 composition of following nominal weight percentage: 8.3Cr, 10Co, 0.7Mo, 10W, 5.5Al, 1Ti, 3Ta, 0.14C, 0.015B, 0.05Zr and 1.5Hf; And

-core core solder powder volume represents other, is mainly nonmetallic line volume, and its size may approximate metal dust volume and the ratio of the aluminium oxide comprised, fluoride and silicate is 35/30/35.The size of mesh scope of solder flux makes to be uniformly distributed in core core metal powder.

For the embodiment wherein being provided melting heat by electric arc, in solder flux or protective gas, usually provide oxygen or carbon dioxide to keep arc stability.But, oxygen or carbon dioxide can react with titanium and some titaniums can lose as steam or oxide in fusion process.The inventive method allows the amount of the titanium comprised in filler material to exceed the amount of titanium required in deposited superalloy compositions to compensate this loss.For the example of above-mentioned alloy 247, the amount of the titanium comprised in core core metal powder can be increased to 3% from 1%.

Will be appreciated that, similar method can be used to deposit other alloy, such as stainless steel etc., its center core raw material is filled with the powder core core material containing powder solder flux and powdered-metal.Powdered-metal can be used to the component of increase sheath material to obtain the clad material of required chemical process.For the embodiment wherein causing material unaccounted-for (MUF) in the process of fusing step because of vaporization, powdered-metal can comprise excessive loss material to recover damage.Such as, when under the protective gas oxygenous or carbon dioxide during deposit alloy 321 stainless steel sheath material, some titaniums in sheath material are because losing with oxygen or carbon dioxide reaction.In such embodiments, powder core core material can comprise powder solder flux and Powdered Titanium to recover damage, thus provides the required coated component of alloy 321.

The restorative procedure of superalloy materials can comprise, superalloy materials surface to be repaired is prepared by grinding to remove defect on demand, this surface clean, then will comprise the layer of powder material pre-placing of flux material or be added into this surface, then make energy beam pass this surface to be melted in the melt pool with floating molten slag layer by powder and surperficial upper strata, then make melt pool and slag solidification.This fusing function repairs any blemish on substrate surface, usual remove slag by known machinery and/or chemical method after obtain the surface that upgrades.This dusty material can be only flux material, or for the embodiment of the material layer wherein needing superalloy coated, this dusty material can comprise metal dust, it is be placed in the independent layer under powder flux material layer, or mix with powder flux material, or be mixed together in composite particles with flux material, make this be melted in surface and form coating layer material.Optionally, feed material can be introduced melt pool with the form of band or line.This powdered-metal and feed material (if any), and any metal (it can be neutrality or additional) provided by flux material, in melt pool, merge the clad producing the composition with required superalloy materials.In some embodiments, nickel, nickel-chromium, nickel-chromium-cobalt or other feed material being easy to the metal extruded mix to produce superalloy compositions required in clad with suitable alloyed metal powder, thus avoid the problem required superalloy materials being configured as line or belt form.

Although preheated substrate must do not needed to obtain acceptable result, but may need heat to be applied to superalloy substrate and/or feed material and/or powder in some embodiments before fusing step, such as, increase the ductility of base material and/or reduce the beam energy for melting filler required in addition.Higher than alloy melting temperature about 80% temperature realize some superalloy substrate ductility improve.Similarly, cooling device (chill fixture) can optionally for embody rule, and the combination that the accurate thermal of itself and energy beam inputs can minimize the stress because fusion process produces in the material.And method as herein described does not need inert protective gas, although supplementary protective gas can be used in some applications if necessary.If use filler material 44, can preheat it so in some embodiments.

Spendable flux material comprises commercially available solder flux, as with those of following sold: Lincolnweld P2007, Bohler Soudokay NiCrW-412, ESAB OK 10.16 or 10.90, particulate metal NT100, Oerlikon OP76, Sandvik 50SW or SAS1.Size of mesh scope less needed for flux particle can being ground to form before the use.Flux material known in the art can comprise aluminium oxide, fluoride and silicate usually.Advantageously, the embodiment of method disclosed herein can comprise the metal component of required clad material, such as chromium oxide, nickel oxide or titanium oxide.The conventional any at present available superalloy based on iron, nickel or cobalt of high temperature application as gas-turbine unit that be used for will use method of the present invention to connect, repair or coating, comprise those above-mentioned alloys.

Other scheme can provide melting heat not provide energy beam through feed material or to combine with energy beam.Such as, the line or belt feed material 44 of Fig. 2 can be powered to produce electric arc under the layer of powder and solder flux, and wherein this line is for the material (namely not superalloy materials) that is easy to form of extruding and obtains and this powder comprises alloying element needed for other to form required superalloy compositions in the melt pool of mixing.Or this powder and solder flux can be selected as conducting electricity, such as to promote slag Welding method thus effectively to form the coated material layer of superalloy.In another embodiment, can use usual plasma electric arc coating equipment (plasma arc cladding equipment) (optionally having the equipment of cooling device) that the solder powder mixed with superalloy dusty material is fed to superalloy substrate.In multiple embodiments, this substrate, feed material and/or powder can preheat.Because the accuracy of this heat input (± 1-2%) when using energy beam, higher than electrode (± 10-15%), therefore expects the half using energy beam to input more than total heat.This beam energy this submerged arc bootable or electroslag method cause the preparation melt pool (preliminary melt pool) with the minimum dilution factor (dilution) being derived from substrate, then this submerged arc or electroslag feed (contribution) can be added into the volume of deposition, and not significantly further substrate impact, thus minimize dilution effect.

According to other embodiment, the submerged-arc welding solder of mixing and alloy 247 powder are placed on 2.5 to the 5.5mm degree of depth in advance and realize free from flaw laser cladding deposit after the heat treatment of confirmation after final welding.The yttrium fibre laser power level of 0.6 to 2 kilowatt is used together with galvanometer scanning optics (galvanometer scanning optics), makes deposit width be 3 to 10mm and the speed of service is about 125mm/min.Detected by the dye penetrant test of deposit cross section and metallographic and confirm to there is not crack.Should understand in the area maximum without the difficulty in solderability region that alloy 247 falls into as shown in Figure 6, prove the operability of the present invention for the superalloy compositions of all scopes thus, comprise aluminium content be greater than 3 % by weight those.

Should understanding and no matter whether deposit additional clad material, the advantage using powder flux material can be realized when repairing superalloy substrate.Surface crack in superalloy substrate is by following reparation: with powder flux material covering surfaces, and then the area of heating surface and flux material are to form the melt pool with floating molten slag layer.Solidify this melt pool under the protection of molten slag layer after, formation do not had crannied surface totally.

Laser energy can be applied across surf zone by using the diode laser with usual rectangular energy density.Or, when it moves forward along substrate can traversing of probe circular laser beam with feasible region Energy distribution.Fig. 5 illustrates the scan mode of an embodiment, and the light beam wherein with the substantial circular of diameter D moves to second place 74' from primary importance 74, then moves to the 3rd position 74 ", etc.The amount of the overlapping O of the beam diameter pattern (beam diameter pattern) of the position changed in its direction preferably at the 25-90% of D, to provide the best heating and melting of material.Or two energy beams can be scanned to obtain through the Energy distribution needed for surf zone simultaneously, and the scope overlapping the 25-90% of each beam diameter between beam mode.

Should understand the deposition of the material using the classification of dusty material promotion functions, the composition of the material wherein deposited changes along with Time and place.Such as, alloy composite can change from product inwall to outer wall, or product inside changes to close to its surface.This alloy composite can change in response to needing the operating condition of the expection of different machinery or corrosion resistance, and by the cost consideration of material interior.

Fig. 7 shows the method for repairing near surface flaw (be full of cracks on such as assembly rear surface, superalloy steam turbine hot gas road (after-surface)).The base material 90 with one or more nearly surface crack 92 moves relative to the direction of prosthetic device 96 along arrow 94.By prosthetic device 96 by energy beam as laser beam 98 guides the layer of the powder 100 comprising powder solder into, described powder solder is fed to surface or optionally prepositioned in substrate 90 by nozzle 102.The thin surf zone of laser beam 98 melting powder 100 and substrate 90, and remelting region 104 is formed in the substrate 90 covered by molten slag layer 106.When remelting region 104 moves apart laser beam 98, it solidifies for 106 times again at slag, thus forms repaired fissureless surperficial 108.When without the need to using inert blanketing gases, after the solder flux of powder 100 prevents melt and heat, material (hot trailing material) reacts with air.For guaranteeing that fusing is fully goed deep into substrate 90 thus eliminates surface crack 92, solder flux also effectively can combine and catch laser and heat.

The method of Fig. 7 advantageously provides the mechanism of cleaning and deoxygenated melt pool, thus remove the pollutant that is present in crack 92, and without the need to by with pollutant reaction and make pollutant float to surface forming part slag 106 weld before fluorine ion cleaning.For removing the pollutant of ceramic heat-barrier coating or the surface attachment covered before reflow process, wire brush or grit-blasting treatment process such as can be used to carry out removing surface to substrate 90, but in the embodiment of some, the cleaning of subsurface crack, as fluorine ion cleaning, be optional and be evitable.The method be conducive to repairing in superalloy materials cause because being on active service the crack of (service-induced) (described superalloy materials comprise there is Fig. 6 line 80 above those materials without the composition in solderability region), and there is no a thermal crack(ing again (post weld reheat cracking) of postwelding without the need to preheating.Although without requiring reheating substrate to obtain acceptable result, but may need in some embodiments to apply heat in fusing step forward direction superalloy substrate and/or powder, increase the ductility of base material with this and/or reduce the beam energy required in addition.

Powder 100 in the method for Fig. 7 can optionally comprise some powder alloy materials, and as filler material, it can be pre-mixed with solder flux, or places adding remelting region to separately in advance.Alternately, as shown in Figure 2, filler material can be used as line or belt shape material and carrys out charging.Mechanical performance such as in order to provide some different to remelting region 104, such filler can substrate 90 form identical or different.As discussed above, solder flux and filler powder can have overlapping or identical size of mesh scope.Various types of laser (CO can be used ₂, NdYAG, fiber, diode etc.) with various types of optics (focusing, defocus, integrated bundle, scanning beam etc.).

Although shown herein and described multiple embodiments of the present invention, obviously these embodiments only provide as an example.Multiple change, change and replacement can be made without deviating from the invention.Therefore, expect that the present invention only limited by the essence of claims and scope.

Claims

1. a method comprises:

Powder flux material is applied to the surface of the superalloy substrate containing defect;

Make energy beam pass described surface with by form remelting region in the substrate that covers of the molten slag layer covered;

Remelting region is made to solidify to form the flawless surface through repairing under described molten slag layer.

2. the process of claim 1 wherein that described energy beam is laser beam.

3. the method for claim 1, is also included in the step that energy beam passes and filler material is applied to described surface, to add the filler material of fusing to remelting region.

4. the method for claim 3, also comprises and described filler material is applied to described surface as powder alloy material.

5. the method for claim 4, the size of mesh scope of wherein said powder alloy material and the size of mesh overlapping ranges of described powder flux material.

6. method described in claim 3, also comprises and applies described filler material as line or belt shape material.

7. the method for claim 1, wherein said superalloy substrate is included in the composition outside the solderability region of drawing and the figure of the superalloy of Ti content relative aluminium content limiting, and wherein the upper bound in solderability region is the line intersecting at 6 % by weight places with Ti content axle and intersect at 3 % by weight places with aluminium content axle.

8. the method for claim 1, is applied to described substrate by heat before being also included in the step that energy beam passes.

9. a method comprises:

Substrate is covered with powder flux material layer, described substrate is included in the composition outside the solderability region of drawing and the figure of the superalloy of Ti content relative aluminium content limiting, and wherein the upper bound in solderability region is the line intersecting at 6 % by weight places with Ti content axle and intersect at 3 % by weight places with aluminium content axle;

The surf zone of described powder flux material and described substrate is melted to form the remelting region of substrate under molten slag layer with energy beam;

Described remelting region is made to cool under described molten slag layer and solidify;

Removing slag; And

Described substrate is heat-treated and does not form thermal crack(ing again.

10. the method for claim 9, wherein said energy beam is laser beam.

The method of 11. claims 9, also comprises with energy beam fusing filler material to add the filler material of fusing to remelting region.

The method of 12. claims 11, also comprises and applies described filler material as powder alloy material.

The method of 13. claims 12, the size of mesh scope of wherein said powder alloy material and the size of mesh overlapping ranges of described powder flux material.

The method of 14. claims 11, also comprises and applies described filler material as line or belt shape material.

The method of 15. claims 9, is applied to described substrate by heat before being also included in fusing step.

16. 1 kinds of methods comprise:

Superalloy hot gas road assembly is removed from the service of gas-turbine unit;

Flux material is applied to the assembly surface containing defect;

Described assembly surface and described flux material is melted to form remelted layer under slag with energy beam;

Described remelted layer is cooled under described slag; And

Remove described slag to expose the flawless assembly surface through repairing.

The method of 17. claims 16, also comprises and carries out described fusing step and do not carry out any substrate crack cleanup step in advance.

The method of 18. claims 16, wherein said substrate is included in the composition outside the solderability region of drawing and the figure of the superalloy of Ti content relative aluminium content limiting, and wherein the upper bound in solderability region is the line intersecting at 6 % by weight places with Ti content axle and intersect at 3 % by weight places with aluminium content axle; And

After removal slag step, described assembly heat-treated and do not form thermal crack(ing again.

The method of 19. claims 16, is applied to described surface by heat before being also included in fusing step.