Itekhnoloji yokuwelda nge-laser, ngenxa yobuninzi bayo bamandla aphezulu, ukungenisa ubushushu obuphantsi kunye neempawu zokungadibani, iye yaba yenye yeenkqubo eziphambili kwimveliso yanamhlanje yokuchaneka. Nangona kunjalo, iingxaki ezifana ne-oxidation, i-porosity kunye nokutsha kwezinto ezibangelwa kukudibana kwechibi elinyibilikisiweyo nomoya ngexesha lokudityaniswa zithintela kakhulu iipropati zoomatshini kunye nobomi benkonzo yomthungo wokudityaniswa. Njengesixhobo esiphambili sokulawula imeko-bume yokudityaniswa, ukukhethwa kohlobo, isantya sokuhamba kunye nendlela yokuvuthela igesi ekhuselayo kufuneka idityaniswe neempawu zezinto (ezifana nomsebenzi weekhemikhali, ukuqhuba kobushushu) kunye nobukhulu bepleyiti.
Iintlobo zeegesi zokukhusela
Umsebenzi ophambili weegesi zokukhusela uxhomekeke ekuhlukaniseni ioksijini, ukulawula indlela echibini elinyibilikisiweyo, kunye nokuphucula ukusebenza kakuhle kokudibanisa amandla. Ngokusekelwe kwiipropati zazo zeekhemikhali, iigesi zokukhusela zinokwahlulwa zibe ziigesi ezingasebenziyo (i-argon, i-helium) kunye neegesi ezisebenzayo (i-nitrogen, i-carbon dioxide). Iigesi ezingasebenziyo zinozinzo oluphezulu lweekhemikhali kwaye zinokuthintela ngempumelelo i-oxidation yechibi elinyibilikisiweyo, kodwa umahluko wazo obalulekileyo kwiipropati zomzimba zobushushu uchaphazela kakhulu isiphumo sokudibanisa. Umzekelo, i-argon (Ar) inoxinano oluphezulu (1.784 kg/m³) kwaye inokwenza ugqubuthelo oluzinzileyo, kodwa uxinano lwayo oluphantsi lobushushu (0.0177 W/m·K) lukhokelela ekupholiseni kancinci kwechibi elinyibilikisiweyo kunye nokungena kwe-weld enganzulu. Ngokwahlukileyo koko, i-helium (He) inoxinano oluphindwe kasibhozo lobushushu (0.1513 W/m·K) kune-argon kwaye inokukhawulezisa ukupholisa kwechibi elinyibilikisiweyo kwaye yonyuse ukungena kwe-weld, kodwa uxinano lwayo oluphantsi (0.1785 kg/m³) lwenza ukuba ikwazi ukuphuma, ifuna izinga eliphezulu lokuhamba ukuze igcine isiphumo sokukhusela. Iigesi ezisebenzayo ezifana ne-nitrogen (N₂) zinokonyusa amandla okuwelda ngokuqinisa isisombululo esiqinileyo kwiimeko ezithile, kodwa ukusetyenziswa ngokugqithisileyo kunokubangela ukubola okanye ukuna kwezigaba ezibuthathaka. Umzekelo, xa kudityaniswa intsimbi engagqwaliyo ezimbini, ukusasazeka kwe-nitrogen kwidama elinyibilikisiweyo kunokuphazamisa ibhalansi yesigaba se-ferrite/austenite, okubangela ukwehla kokumelana nokugqwala.
Umfanekiso 1. Ukuwelda nge-laser yentsimbi engagqwaliyo engama-304L (phezulu): Ukukhusela igesi; (ezantsi): Ukukhusela igesi ye-N2
Ngokwembono yenkqubo, amandla aphezulu e-ionization e-helium (24.6 eV) anokuthintela isiphumo sokukhusela i-plasma kwaye aphucule ukufunxwa kwamandla e-laser, ngaloo ndlela andise ubunzulu bokungena. Okwangoku, amandla aphantsi e-ionization e-argon (15.8 eV) anomdla wokuvelisa amafu e-plasma, nto leyo efuna ukususwa kwe-focus okanye i-pulse modulation ukunciphisa ukuphazamiseka. Ukongeza, impendulo yekhemikhali phakathi kweegesi ezisebenzayo kunye nedama elinyibilikisiweyo (njenge-nitrogen esabela nge-Cr kwintsimbi) inokutshintsha ukwakheka kwe-weld, kwaye ukukhetha ngononophelo ngokusekelwe kwiimpawu zezinto kuyimfuneko.
Imizekelo yokusetyenziswa kwezinto:
• Intsimbi: Kwi-welding yepleyiti encinci (<3 mm), i-argon inokuqinisekisa ukugqitywa komphezulu, kunye nobukhulu be-oxide layer ye-0.5 μm kuphela kwi-1.5 mm low-carbon steel weld seam; kwiipleyiti ezityebileyo (>10 mm), kufuneka kongezwe inani elincinci le-helium (He) ukuze kwandiswe ubunzulu bokungena.
• Intsimbi engagqwaliyo: Ukhuselo lwe-Argon lunokuthintela ukulahleka kwezinto ze-Cr, kunye nomxholo we-Cr we-18.2% kumthungo we-weld we-stainless steel weld ongu-3 mm ubukhulu obuyi-3 mm osondela kwi-18.5% yesinyithi esisisiseko; kwintsimbi engagqwaliyo ephindwe kabini, kufuneka umxube we-Ar-N₂ (N₂ ≤ 5%) ukulinganisela umlinganiselo. Izifundo zibonise ukuba xa usebenzisa umxube we-Ar-2% N₂ kwintsimbi engagqwaliyo ephindwe kabini engu-2205 ubukhulu obuyi-8 mm, umlinganiselo we-ferrite/austenite uzinzile kwi-48:52, kunye namandla okutsalwa angama-780 MPa, angcono kunokhuselo lwe-argon olucocekileyo (720 MPa).
• I-aluminium alloy: Ipleyiti ebhityileyo (<3 mm): Ukukhanya okuphezulu kwee-aluminium alloys kukhokelela kwisantya esiphantsi sokufunxwa kwamandla, kwaye i-helium, enegunya layo eliphezulu le-ionization (24.6 eV), ingazinzisa i-plasma. Uphando lubonisa ukuba xa i-aluminium alloy eyi-2 mm ubukhulu ikhuselwe yi-helium, ubunzulu bokungena bufikelela kwi-1.8 mm, bunyuka nge-25% xa kuthelekiswa ne-argon, kwaye izinga le-porosity liphantsi kune-1%. Kwiipleyiti ezixineneyo (>5 mm): Iipleyiti ezixineneyo ze-aluminium alloy zifuna amandla aphezulu okufaka, kwaye umxube we-helium-argon (He:Ar = 3:1) unokulinganisela ubunzulu bokungena kunye neendleko. Umzekelo, xa udibanisa iipleyiti eziyi-8 mm ubukhulu be-5083, ubunzulu bokungena bufikelela kwi-6.2 mm phantsi kokhuseleko lwegesi exutyiweyo, bunyuka nge-35% xa kuthelekiswa negesi ye-argon ecocekileyo, kwaye ixabiso lokudibanisa lincitshiswa nge-20%.
Qaphela: Umbhalo wokuqala uneziphene kunye nokungangqinelani. Uguqulelo olunikiweyo lusekelwe kuhlobo olulungisiweyo noluhambelanayo lombhalo.
Impembelelo yesantya sokuhamba kwegesi ye-argon
Izinga lokuhamba kwegesi ye-argon lichaphazela ngokuthe ngqo amandla okugubungela igesi kunye nokuguquguquka kolwelo lwedama elinyibilikisiweyo. Xa izinga lokuhamba linganelanga, umaleko wegesi awunakuwuhlukanisa ngokupheleleyo umoya, kwaye umda wedama elinyibilikisiweyo uthambekele ekutshisweni kwe-oxidation kunye nokwakheka kwee-pores zegesi; xa izinga lokuhamba liphezulu kakhulu, linokubangela i-turbulence, enokuhlamba umphezulu wedama elinyibilikisiweyo kwaye ikhokelele ekuxinanisweni kwe-weld okanye ukuchitheka. Ngokwenani likaReynolds le-fluid mechanics (Re = ρvD/μ), ukwanda kwezinga lokuhamba kuya kwandisa isantya sokuhamba kwegesi. Xa i-Re > 2300, ukuhamba kwe-laminar kujika kube yi-turbulent flow, eya kutshabalalisa ukuzinza kwedama elinyibilikisiweyo. Ke ngoko, ukumisela izinga lokuhamba elibalulekileyo kufuneka kuhlalutywe ngokusebenzisa iimvavanyo okanye ii-numerative simulations (ezifana ne-CFD).
Umfanekiso 2. Iziphumo zeMilinganiselo eyahlukeneyo yokuhamba kwegesi kwi-Weld Seam
Ukulungiswa kokuhamba komoya kufuneka kulungiswe ngokudibeneyo nokuqhuba kobushushu bezinto kunye nobukhulu beplate:
• Kwintsimbi kunye nentsimbi engatyiwayo: Kwiipleyiti zentsimbi ezibhityileyo (1-2 mm), izinga lokuhamba lingcono libe yi-10-15 L/min. Kwiipleyiti ezityebileyo (>6 mm), kufuneka zinyuswe ziye kwi-18-22 L/min ukuze kuncitshiswe ukubola komsila. Umzekelo, xa izinga lokuhamba kwentsimbi engatyiwayo eyi-6 mm ubukhulu be-316L liyi-20 L/min, ukufana kobunzima be-HAZ kuphucuka nge-30%.
• Kwi-alloy ye-aluminium: Ukuqhuba okuphezulu kobushushu kufuna isantya esiphezulu sokuhamba kwamanzi ukuze kwandiswe ixesha lokukhusela. Kwi-alloy ye-aluminium eyi-7075 enobukhulu obuyi-3 mm, isantya se-porosity sesona siphantsi (0.3%) xa isantya sokuhamba kwamanzi singama-25-30 L/min. Nangona kunjalo, kwiiplate ezinobukhulu obuphezulu (>10 mm), kuyimfuneko ukudibanisa nokuvuthuza okuhlanganisiweyo ukuze kuthintelwe ukuxinana.
Impembelelo yendlela yokuqhuma kwegesi
Indlela yegesi evuthelayo ichaphazela ngokuthe ngqo indlela yokuhamba kwamanzi echibini elinyibilikisiweyo kunye nesiphumo sokucinezela isiphene ngokulawula indlela kunye nokusasazwa kokuhamba kwegesi. Indlela yegesi evuthelayo ilawula ukuhamba kwamanzi echibini elinyibilikisiweyo ngokutshintsha i-gradient yoxinzelelo lomphezulu kunye nokuhamba kweMarangoni (ukuhamba kweMarangoni). Ukuvuthela emacaleni kunokubangela ukuba ichibi elinyibilikisiweyo lihambe kwicala elithile, kunciphisa iimbobo kunye nokufakwa kwe-slag; ukuvuthela okuhlanganisiweyo kunokuphucula ukufana kokwakheka kwe-weld ngokulinganisela ukusasazwa kwamandla ngokusebenzisa ukuhamba kwegesi okuhamba ngamacandelo amaninzi.
Iindlela eziphambili zokuvuthela ziquka:
• Ukuvuthela nge-coaxial: Ukuhamba kwegesi kukhutshwa nge-coaxial kunye nomqadi we-laser, ogubungela idama elinyibilikisiweyo ngokulinganayo, elifanelekileyo lokuwelda ngesantya esiphezulu. Inzuzo yalo kukuzinza kwenkqubo ephezulu, kodwa ukuhamba kwegesi kunokuphazamisana nokujolisa nge-laser. Umzekelo, xa usebenzisa ukuvuthela nge-coaxial kwishidi lesinyithi eligalelweyo leemoto (1.2 mm), isantya sokuwelda sinokunyuswa siye kwi-40 mm/s, kwaye izinga lokusasazeka lingaphantsi kwe-0.1.
• Ukuvuthela ecaleni: Ukuhamba kwegesi kungeniswa ecaleni kwechibi elinyibilikisiweyo, elinokusetyenziselwa ukususa ukungcola kweplasma okanye ezantsi, okufanelekileyo kwi-deep penetration welding. Umzekelo, xa uvuthela kwintsimbi ye-Q345 enobukhulu obuyi-12 mm kwi-engile ye-30°, ukungena kwe-weld kuyanda nge-18%, kwaye izinga le-porosity esezantsi liyancipha ukusuka kwi-4% ukuya kwi-0.8%.
• Ukuvuthela okudityanisiweyo: Ukudibanisa ukuvuthela okudityanisiweyo nokudityanisiweyo ecaleni, kungathintela ngaxeshanye ukuphazamiseka kwe-oxidation kunye ne-plasma. Umzekelo, kwi-aluminium alloy eyi-6061 enobukhulu obuyi-3 mm enoyilo lwe-nozzle ephindwe kabini, izinga le-porosity liyancipha ukusuka kwi-2.5% ukuya kwi-0.4%, kwaye amandla okutsalwa afikelela kwi-95% yezinto ezisisiseko.
Impembelelo yegesi yokukhusela kumgangatho wokuwelda ngokusisiseko ivela kulawulo lwayo lokudluliselwa kwamandla, i-thermodynamics yedama elinyibilikisiweyo, kunye neempendulo zeekhemikhali:
1. Ukudluliselwa kwamandla: Ukuhanjiswa kwamandla aphezulu kwe-helium kukhawulezisa ukupholisa kwechibi elinyibilikisiweyo, kunciphisa ububanzi bendawo echaphazelekileyo kubushushu (HAZ); ukuhanjiswa kwamandla aphantsi kwe-argon kukwandisa ixesha lokubakho kwechibi elinyibilikisiweyo, nto leyo eluncedo ekwakhiweni komphezulu weepleyiti ezincinci.
2. Uzinzo lwedama elinyibilikisiweyo: Ukuhamba kwegesi kuchaphazela ukuhamba kwedama elinyibilikisiweyo ngamandla okucheba, kwaye izinga lokuhamba elifanelekileyo linokuthintela ukuchitheka; izinga lokuhamba eligqithisileyo liya kubangela i-vortex, nto leyo ekhokelela kwiziphene zokuwelda.
3. Ukhuseleko lweekhemikhali: Iigesi ezingasebenziyo ziyazahlula ioksijini kwaye zithintele ukuxinana kwezinto ze-alloy (ezifana ne-Cr, i-Al); iigesi ezisebenzayo (ezifana ne-N₂) zitshintsha iipropati ze-weld ngokuqinisa isisombululo esiqinileyo okanye ukwakheka kwe-compound, kodwa uxinzelelo kufuneka lulawulwe ngokuchanekileyo.
Ixesha lokuthumela: Epreli-09-2025
