Ubuchwepheshe bokushisela nge-laser, ngenxa yobuningi bayo bamandla aphezulu, ukufakwa kokushisa okuphansi kanye nezici zokungathinti, sekungenye yezinqubo eziyinhloko ekukhiqizweni kokunemba kwesimanje. Kodwa-ke, izinkinga ezifana ne-oxidation, i-porosity kanye nokushiswa kwezinto okubangelwa ukuthintana kwechibi elincibilikisiwe nomoya ngesikhathi sokushisela zivimbela kakhulu izakhiwo zemishini kanye nokuphila kwenkonzo yomthungo wokushisela. Njengendlela eyinhloko yokulawula indawo yokushisela, ukukhethwa kohlobo, izinga lokugeleza kanye nemodi yokuvunguza yegesi evikelayo kudinga ukuhlanganiswa nezici zezinto (njengomsebenzi wamakhemikhali, ukuqhuba kokushisa) kanye nobukhulu bepuleti.
Izinhlobo zamagesi okuvikela
Umsebenzi oyinhloko wamagesi okuvikela ulele ekuhlukaniseni umoya-mpilo, ukulawula ukuziphatha kwechibi elincibilikisiwe, kanye nokuthuthukisa ukusebenza kahle kokuhlanganiswa kwamandla. Ngokusekelwe ezicini zawo zamakhemikhali, amagesi okuvikela angahlukaniswa ngamagesi angasebenzi (i-argon, i-helium) kanye namagesi asebenzayo (i-nitrogen, i-carbon dioxide). Amagesi angasebenzi anokuqina okuphezulu kwamakhemikhali futhi angavimbela ngempumelelo ukungcoliswa kwechibi elincibilikisiwe, kodwa umehluko wawo obalulekile ezicini zomzimba ezishisayo uthinta kakhulu umphumela wokushisela. Isibonelo, i-argon (Ar) inobuningi obukhulu (1.784 kg/m³) futhi ingakha ungqimba oluzinzile, kodwa ukuguquguquka kwayo okuphansi kokushisa (0.0177 W/m·K) kuholela ekupholiseni kancane kwechibi elincibilikisiwe kanye nokungena kwe-weld okungajulile. Ngokuphambene nalokho, i-helium (He) inokuguquguquka kokushisa okuphindwe kasishiyagalombili (0.1513 W/m·K) kune-argon futhi ingasheshisa ukupholisa kwechibi elincibilikisiwe futhi yandise ukungena kwe-weld, kodwa ubuningi bayo obuphansi (0.1785 kg/m³) kwenza kube lula ukuphuma, kudinga izinga lokugeleza eliphakeme ukuze kulondolozwe umphumela wokuvikela. Amagesi asebenzayo njenge-nitrogen (N₂) angathuthukisa amandla okushisela ngokuqinisa isixazululo esiqinile ezimweni ezithile, kodwa ukusetshenziswa ngokweqile kungabangela ukubhoboka noma ukuna kwezigaba ezibuthakathaka. Isibonelo, lapho kushiselwa insimbi engagqwali ephindwe kabili, ukusabalala kwe-nitrogen echibini elincibilikisiwe kungaphazamisa ibhalansi yesigaba se-ferrite/austenite, okuholela ekunciphiseni ukumelana nokugqwala.
Umfanekiso 1. Ukushisela nge-laser kwensimbi engagqwali engu-304L (phezulu): Ukuvikela igesi nge-Ar; (phansi): Ukuvikela igesi nge-N2
Ngokombono wenqubo yenqubo, amandla aphezulu e-ionization e-helium (24.6 eV) angacindezela umphumela wokuvikela i-plasma futhi athuthukise ukumuncwa kwamandla e-laser, ngaleyo ndlela andise ukujula kokungena. Okwamanje, amandla aphansi e-ionization e-argon (15.8 eV) athambekele ekukhiqizeni amafu e-plasma, okudinga ukususwa kokugxila noma ukuguqulwa kwe-pulse ukuze kuncishiswe ukuphazamiseka. Ngaphezu kwalokho, ukusabela kwamakhemikhali phakathi kwamagesi asebenzayo kanye nedamu elincibilikisiwe (njengokusabela kwe-nitrogen ne-Cr ensimbini) kungashintsha ukwakheka kwe-weld, futhi ukukhetha ngokucophelela okusekelwe ezimpahleni zezinto kuyadingeka.
Izibonelo zokusetshenziswa kwezinto ezibonakalayo:
• Insimbi: Ku-welding yepuleti elincane (<3 mm), i-argon ingaqinisekisa ukuqeda kobuso, ngobubanzi bengqimba ye-oxide obungu-0.5 μm kuphela kumthungo we-weld weld wensimbi ophansi wekhabhoni ongu-1.5 mm; kumapuleti aqinile (>10 mm), kudingeka kufakwe inani elincane le-helium (He) ukuze kwandiswe ukujula kokungena.
• Insimbi Engagqwali: Ukuvikelwa kwe-Argon kungavimbela ukulahleka kwe-Cr element, ngokuqukethwe kwe-Cr okungu-18.2% kumthungo we-weld we-stainless steel ongu-3 mm ubukhulu obungu-3 mm osondela ku-18.5% wensimbi eyisisekelo; ngensimbi engagqwali ye-duplex, ingxube ye-Ar-N₂ (N₂ ≤ 5%) iyadingeka ukulinganisela isilinganiso. Izifundo zibonise ukuthi uma usebenzisa ingxube ye-Ar-2% N₂ yensimbi engagqwali ye-duplex engu-2205 ubukhulu obungu-8 mm, isilinganiso se-ferrite/austenite sizinzile ku-48:52, ngamandla okuthamba angu-780 MPa, okuphakeme kunokuvikelwa kwe-argon emsulwa (720 MPa).
• Ingxubevange ye-aluminium: Ipuleti elincane (<3 mm): Ukukhanya okuphezulu kwe-aluminium alloys kuholela esilinganisweni sokumuncwa kwamandla aphansi, kanti i-helium, enamandla ayo aphezulu e-ionization (24.6 eV), ingazinzisa i-plasma. Ucwaningo lubonisa ukuthi lapho ingxubevange ye-aluminium engu-2 mm ubukhulu ivikelwe yi-helium, ukujula kokungena kufinyelela ku-1.8 mm, kukhuphuke ngo-25% uma kuqhathaniswa ne-argon, futhi izinga le-porosity liphansi kune-1%. Kumapuleti amakhulu (>5 mm): Amapuleti amakhulu engxubevange ye-aluminium adinga ukufakwa kwamandla aphezulu, kanti ingxubevange ye-helium-argon (He:Ar = 3:1) ingalinganisa kokubili ukujula kokungena kanye nezindleko. Isibonelo, lapho kushintshwa amapuleti angu-8 mm ubukhulu be-5083, ukujula kokungena kufinyelela ku-6.2 mm ngaphansi kokuvikelwa kwegesi exubile, kukhuphuke ngo-35% uma kuqhathaniswa negesi ehlanzekile ye-argon, futhi izindleko zokushintshwa zincishiswa ngo-20%.
Qaphela: Umbhalo wokuqala uqukethe amaphutha kanye nokungahambisani. Ukuhumusha okunikeziwe kusekelwe enguqulweni elungisiwe neqondakalayo yombhalo.
Ithonya lesilinganiso sokugeleza kwegesi ye-argon
Izinga lokugeleza kwegesi ye-argon lithinta ngqo ikhono lokumboza igesi kanye nokuguquguquka koketshezi kwechibi elincibilikisiwe. Uma izinga lokugeleza linganele, ungqimba lwegesi alukwazi ukuhlukanisa umoya ngokuphelele, futhi unqenqema lwechibi elincibilikisiwe luthambekele ekungcolisweni nasekubunjweni kwama-pores egesi; lapho izinga lokugeleza liphezulu kakhulu, lingabangela ukuphazamiseka, okungageza ubuso bechibi elincibilikisiwe futhi kuholele ekucindezelweni kwe-weld noma ekuchithekeni. Ngokusho kwenombolo kaReynolds ye-fluid mechanics (Re = ρvD/μ), ukwanda kwezinga lokugeleza kuzokwandisa ijubane lokugeleza kwegesi. Lapho i-Re > 2300, ukugeleza kwe-laminar kuphenduka ukugeleza okuguquguqukayo, okuzobhubhisa ukuzinza kwechibi elincibilikisiwe. Ngakho-ke, ukunqunywa kwezinga lokugeleza okubalulekile kudinga ukuhlaziywa ngokusebenzisa izivivinyo noma ukulingisa ngezinombolo (njenge-CFD).
Umfanekiso 2. Imiphumela Yezinga Elihlukene Lokugeleza Kwegesi Kumthungo Wokushisela
Ukulungiswa kokugeleza kufanele kulungiswe kuhlanganiswe nokushisa kwezinto ezibonakalayo kanye nobukhulu bepuleti:
• Ngensimbi nensimbi engagqwali: Kumapuleti ensimbi amancane (1-2 mm), izinga lokugeleza kungcono libe ngu-10-15 L/min. Kumapuleti amakhulu (>6 mm), kufanele akhuliswe abe ngu-18-22 L/min ukuze kuncishiswe ukushiswa komsila. Isibonelo, lapho izinga lokugeleza lensimbi engagqwali engu-6 mm ubukhulu engu-316L lingu-20 L/min, ukufana kobulukhuni be-HAZ kuthuthukiswa ngo-30%.
• Nge-aluminium alloy: Ukushisa okuphezulu kudinga izinga lokugeleza eliphezulu ukuze kwandiswe isikhathi sokuvikela. Nge-aluminium alloy engu-7075 enobukhulu obungu-3 mm, izinga lokugeleza liphansi kakhulu (0.3%) uma izinga lokugeleza lingu-25-30 L/min. Kodwa-ke, ngamapuleti anobukhulu obukhulu kakhulu (>10 mm), kuyadingeka ukuhlanganisa nokushaywa okuhlanganisiwe ukuze kugwenywe ukuxokozela.
Ithonya lemodi yegesi evuthelayo
Imodi yegesi evuthelayo ithinta ngqo iphethini yokugeleza kwechibi elincibilikisiwe kanye nomphumela wokucindezela amaphutha ngokulawula isiqondiso nokusatshalaliswa kokugeleza kwegesi. Imodi yegesi evuthelayo ilawula ukugeleza kwechibi elincibilikisiwe ngokushintsha i-gradient yokucindezeleka kobuso kanye nokugeleza kweMarangoni (ukugeleza kweMarangoni). Ukuvuthela eceleni kungabangela ichibi elincibilikisiwe ukuba ligeleze ohlangothini oluthile, kunciphisa ama-pores kanye nokufakwa kwe-slag; ukuvuthela okuhlanganisiwe kungathuthukisa ukufana kokwakheka kwe-weld ngokulinganisela ukusatshalaliswa kwamandla ngokugeleza kwegesi okunezindlela eziningi.
Izindlela eziyinhloko zokushaya zifaka:
• Ukufuthwa kwe-coaxial: Ukugeleza kwegesi kukhishwa ngokulingana nogongolo lwe-laser, okumboza ichibi elincibilikisiwe ngokulinganayo, okufanelekela ukufuthwa ngesivinini esikhulu. Inzuzo yako ukuzinza kwenqubo ephezulu, kodwa ukugeleza kwegesi kungaphazamisa ukugxila kwe-laser. Isibonelo, uma usebenzisa ukufuthwa kwe-coaxial ephepheni lensimbi eligayiwe lezimoto (1.2 mm), isivinini sokufuthwa singakhushulwa sibe ngu-40 mm/s, futhi izinga lokufafaza lingaphansi kuka-0.1.
• Ukufutha emaceleni: Ukugeleza kwegesi kungeniswa ohlangothini lwechibi elincibilikisiwe, elingasetshenziswa ukususa ukungcola kwe-plasma noma phansi, okufanelekela ukushisela okujulile. Isibonelo, uma ufutha insimbi ye-Q345 engu-12 mm ubukhulu nge-engeli engu-30°, ukungena kwe-weld kuyanda ngo-18%, kanti izinga le-porosity engezansi liyancipha lisuka ku-4% liye ku-0.8%.
• Ukufutha okuhlanganisiwe: Ukuhlanganisa ukufutha kwe-coaxial kanye nokwezinhlangothi, kungacindezela ngasikhathi sinye ukuphazamiseka kwe-oxidation kanye ne-plasma. Isibonelo, ku-aluminium alloy engu-6061 enobukhulu obungu-3 mm enomklamo we-nozzle ephindwe kabili, izinga le-porosity lincishisiwe kusuka ku-2.5% kuya ku-0.4%, futhi amandla okuthamba afinyelela ku-95% wezinto eziyisisekelo.
Ithonya legesi yokuvikela ekhwalithini yokushisela livela ngokuyinhloko ekulawulweni kwayo kokudluliselwa kwamandla, i-thermodynamics yedamu elincibilikisiwe, kanye nokusabela kwamakhemikhali:
1. Ukudluliselwa kwamandla: Ukushisa okuphezulu kwe-helium kusheshisa ukupholisa kwechibi elincibilikisiwe, kunciphisa ububanzi bendawo ethintekile ekushiseni (HAZ); ukushisa okuphansi kwe-argon kwandisa isikhathi sokuba khona kwechibi elincibilikisiwe, okuzuzisa ukwakheka kobuso bamapuleti amancane.
2. Ukuqina kwechibi elincibilikisiwe: Ukugeleza kwegesi kuthinta ukugeleza kwechibi elincibilikisiwe ngamandla okushefa, futhi izinga lokugeleza elifanele lingavimbela ukuchitheka; izinga lokugeleza ngokweqile lizobangela i-vortex, okuholela ezifweni zokushisela.
3. Ukuvikelwa kwamakhemikhali: Amagesi angasebenzi ahlukanisa umoya-mpilo futhi avimbele ukushiswa kwezinto ze-alloy (njenge-Cr, i-Al); amagesi asebenzayo (njenge-N₂) ashintsha izakhiwo ze-weld ngokuqinisa isixazululo esiqinile noma ukwakheka kwe-compound, kodwa ukuhlushwa kudinga ukulawulwa ngokunembile.
Isikhathi sokuthunyelwe: Ephreli-09-2025
