Kev siv tshuab laser vuam, vim nws lub zog ceev ceev, cua sov tsawg thiab cov yam ntxwv tsis sib cuag, tau dhau los ua ib qho ntawm cov txheej txheem tseem ceeb hauv kev tsim khoom niaj hnub no. Txawm li cas los xij, cov teeb meem xws li oxidation, porosity thiab cov khoom hlawv tawm los ntawm kev sib cuag ntawm lub pas dej molten nrog huab cua thaum lub sijhawm vuam txwv tsis pub cov khoom siv kho tshuab thiab lub neej ua haujlwm ntawm cov vuam seam. Raws li lub hauv paus nruab nrab rau kev tswj hwm qhov chaw vuam, kev xaiv hom, tus nqi ntws thiab hom tshuab ntawm cov roj tiv thaiv yuav tsum tau ua ke nrog cov yam ntxwv ntawm cov khoom siv (xws li kev ua haujlwm tshuaj lom neeg, thermal conductivity) thiab qhov tuab ntawm lub phaj.
Hom roj tiv thaiv
Lub luag haujlwm tseem ceeb ntawm cov pa roj tiv thaiv yog cais cov pa oxygen, tswj tus cwj pwm ntawm lub pas dej ua kua, thiab txhim kho kev ua haujlwm ntawm kev sib txuas hluav taws xob. Raws li lawv cov khoom siv tshuaj lom neeg, cov pa roj tiv thaiv tuaj yeem faib ua cov pa roj inert (argon, helium) thiab cov pa roj nquag (nitrogen, carbon dioxide). Cov pa roj inert muaj kev ruaj khov tshuaj lom neeg siab thiab tuaj yeem tiv thaiv kev oxidation ntawm lub pas dej ua kua, tab sis lawv qhov sib txawv tseem ceeb hauv cov khoom siv thermal lub cev cuam tshuam rau qhov cuam tshuam ntawm kev vuam. Piv txwv li, argon (Ar) muaj qhov ceev siab (1.784 kg / m³) thiab tuaj yeem tsim cov txheej txheem ruaj khov, tab sis nws cov thermal conductivity qis (0.0177 W / m · K) ua rau qeeb qeeb ntawm lub pas dej ua kua thiab qhov nkag mus rau hauv qhov vuam ntiav. Qhov sib piv, helium (He) muaj yim npaug siab dua thermal conductivity (0.1513 W / m · K) dua li argon thiab tuaj yeem ua kom nrawm dua ntawm lub pas dej ua kua thiab ua rau qhov nkag mus rau hauv qhov vuam, tab sis nws qhov ceev qis (0.1785 kg / m³) ua rau nws yooj yim khiav tawm, xav tau tus nqi ntws siab dua kom tswj tau qhov cuam tshuam tiv thaiv. Cov pa roj nquag xws li nitrogen (N₂) tuaj yeem ua kom lub zog vuam zoo dua los ntawm kev ua kom cov kua khov kho hauv qee qhov xwm txheej, tab sis kev siv ntau dhau tuaj yeem ua rau porosity lossis cov dej nag ntawm cov theem brittle. Piv txwv li, thaum vuam duplex stainless hlau, nitrogen diffusion mus rau hauv lub pas dej molten yuav cuam tshuam qhov sib npaug ntawm ferrite / austenite theem, ua rau txo qis kev tiv thaiv corrosion.
Daim Duab 1. Kev vuam laser ntawm 304L stainless hlau (sab saum toj): Ar roj shielding; (hauv qab): N2 roj shielding
Los ntawm qhov pom ntawm cov txheej txheem txheej txheem, lub zog ionization siab ntawm helium (24.6 eV) tuaj yeem tiv thaiv cov nyhuv tiv thaiv plasma thiab txhim kho kev nqus zog laser, yog li ua rau qhov tob nkag mus. Lub caij no, lub zog ionization qis ntawm argon (15.8 eV) yog qhov yooj yim tsim cov huab plasma, uas xav tau defocusing lossis pulse modulation kom txo qhov cuam tshuam. Tsis tas li ntawd, cov tshuaj tiv thaiv ntawm cov pa roj nquag thiab lub pas dej molten (xws li nitrogen reacting nrog Cr hauv hlau) tuaj yeem hloov pauv cov khoom sib txuas, thiab kev xaiv ua tib zoo raws li cov khoom siv yog qhov tsim nyog.
Piv txwv ntawm kev siv cov khoom siv:
• Hlau: Hauv kev vuam phaj nyias (<3 hli), argon tuaj yeem ua kom tiav qhov chaw, nrog rau qhov tuab ntawm txheej oxide tsuas yog 0.5 μm rau 1.5 hli cov hlau qis-carbon vuam seam; rau cov phaj tuab (>10 hli), me me ntawm helium (He) yuav tsum tau ntxiv rau kom nce qhov tob nkag mus.
• Hlau tsis xeb: Kev tiv thaiv argon tuaj yeem tiv thaiv kev poob ntawm Cr, nrog rau cov ntsiab lus Cr ntawm 18.2% hauv 3 hli tuab 304 stainless hlau weld seam ze rau 18.5% ntawm cov hlau hauv paus; rau duplex stainless hlau, ib qho sib tov Ar-N₂ (N₂ ≤ 5%) yog qhov xav tau los sib npaug qhov piv. Cov kev tshawb fawb tau qhia tias thaum siv Ar-2% N₂ sib tov rau 8 hli tuab 2205 duplex stainless hlau, qhov piv ferrite / austenite ruaj khov ntawm 48:52, nrog lub zog tensile ntawm 780 MPa, uas yog qhov zoo dua li kev tiv thaiv argon ntshiab (720 MPa).
• Cov hlau txhuas: Phaj nyias (<3 hli): Qhov kev cuam tshuam siab ntawm cov hlau txhuas ua rau muaj qhov nqus hluav taws xob tsawg, thiab helium, nrog nws lub zog ionization siab (24.6 eV), tuaj yeem ua kom cov plasma ruaj khov. Kev tshawb fawb qhia tau tias thaum 2 hli tuab 6061 hlau txhuas raug tiv thaiv los ntawm helium, qhov tob nkag mus txog 1.8 hli, nce 25% piv rau argon, thiab qhov porosity qis dua 1%. Rau cov phaj tuab (> 5 hli): Cov hlau txhuas tuab xav tau lub zog nkag siab siab, thiab cov khoom sib xyaw helium-argon (He:Ar = 3: 1) tuaj yeem sib npaug ob qho tib si qhov tob nkag thiab tus nqi. Piv txwv li, thaum vuam 8 hli tuab 5083 phaj, qhov tob nkag mus txog 6.2 hli nyob rau hauv kev tiv thaiv roj sib xyaw, nce 35% piv rau cov roj argon ntshiab, thiab tus nqi vuam raug txo los ntawm 20%.
Lus Cim: Cov ntawv thawj muaj qee qhov yuam kev thiab tsis sib xws. Cov lus txhais no yog raws li cov ntawv kho thiab sib xws.
Qhov cuam tshuam ntawm cov roj argon ntws npaum li cas
Tus nqi ntws ntawm cov roj argon cuam tshuam ncaj qha rau lub peev xwm npog roj thiab cov kua dej ntawm lub pas dej ua kua. Thaum tus nqi ntws tsis txaus, cov txheej roj tsis tuaj yeem cais cov huab cua tag nrho, thiab ntug pas dej ua kua yuav yooj yim rau oxidation thiab tsim cov qhov roj; thaum tus nqi ntws siab dhau, nws yuav ua rau muaj kev kub ntxhov, uas tuaj yeem ntxuav qhov chaw pas dej ua kua thiab ua rau muaj kev nyuaj siab lossis tawg. Raws li Reynolds tus lej ntawm cov txheej txheem kua (Re = ρvD / μ), kev nce ntxiv ntawm tus nqi ntws yuav ua rau kom muaj kev nrawm ntawm cov roj ntws. Thaum Re > 2300, qhov ntws laminar hloov mus ua qhov ntws turbulent, uas yuav rhuav tshem qhov ruaj khov ntawm lub pas dej ua kua. Yog li ntawd, kev txiav txim siab ntawm tus nqi ntws tseem ceeb yuav tsum tau soj ntsuam los ntawm kev sim lossis kev ua lej (xws li CFD).
Daim Duab 2. Cov Nyhuv ntawm Cov Nqi Roj Sib Txawv ntawm Cov Seam Weld
Kev ua kom zoo dua ntawm cov dej ntws yuav tsum tau kho ua ke nrog cov khoom siv thermal conductivity thiab phaj tuab:
• Rau cov hlau thiab cov hlau tsis xeb: Rau cov hlau nyias nyias (1-2 hli), qhov nrawm ntws zoo dua yog 10-15 L/min. Rau cov hlau tuab (>6 hli), nws yuav tsum tau nce mus txog 18-22 L/min kom tiv thaiv kev oxidation ntawm tus tw. Piv txwv li, thaum qhov nrawm ntws ntawm 6 hli tuab 316L hlau tsis xeb yog 20 L/min, qhov sib xws ntawm HAZ hardness tau txhim kho los ntawm 30%.
• Rau cov hlau txhuas: Kev ua kom muaj cua sov siab xav tau qhov ntws siab kom ntev lub sijhawm tiv thaiv. Rau cov hlau txhuas 7075 tuab 3 hli, qhov porosity qis tshaj plaws (0.3%) thaum qhov ntws yog 25-30 L / feeb. Txawm li cas los xij, rau cov phaj tuab heev (> 10 hli), nws yog qhov tsim nyog los ua ke nrog kev sib xyaw ua ke kom tsis txhob muaj kev ntxhov siab.
Qhov cuam tshuam ntawm hom pa tshuab
Hom roj tshuab ncaj qha cuam tshuam rau tus qauv ntws ntawm lub pas dej ua kua thiab qhov cuam tshuam ntawm kev tswj hwm qhov kev taw qhia thiab kev faib tawm ntawm cov roj ntws. Hom roj tshuab tswj hwm qhov ntws ntawm lub pas dej ua kua los ntawm kev hloov pauv qhov nro ntawm qhov chaw thiab Marangoni ntws (Marangoni ntws). Kev tshuab sab tuaj yeem ua rau lub pas dej ua kua ntws mus rau hauv ib qho kev taw qhia tshwj xeeb, txo cov qhov hws thiab cov slag suav nrog; kev sib xyaw ua ke tuaj yeem txhim kho qhov sib xws ntawm kev tsim weld los ntawm kev sib npaug ntawm kev faib tawm lub zog los ntawm ntau txoj kev ntws roj.
Cov txheej txheem tseem ceeb ntawm kev tshuab muaj xws li:
• Coaxial blowing: Cov pa roj ntws tawm coaxial nrog lub teeb laser, sib npaug npog lub pas dej molten, tsim nyog rau kev vuam ceev ceev. Nws qhov zoo yog kev ruaj khov ntawm cov txheej txheem, tab sis cov pa roj ntws tuaj yeem cuam tshuam rau kev tsom laser. Piv txwv li, thaum siv coaxial blowing ntawm cov hlau galvanized tsheb (1.2 hli), qhov ceev vuam tuaj yeem nce mus txog 40 hli / s, thiab tus nqi spatter tsawg dua 0.1.
• Tshuab rau sab: Cov pa roj ntws los ntawm sab ntawm lub pas dej uas yaj, uas siv tau los tshem tawm cov plasma lossis cov khoom tsis huv hauv qab, tsim nyog rau kev vuam tob. Piv txwv li, thaum tshuab rau ntawm 12 hli tuab Q345 hlau ntawm lub kaum sab xis ntawm 30 °, qhov kev nkag mus ntawm vuam nce ntxiv 18%, thiab qhov porosity hauv qab txo qis los ntawm 4% mus rau 0.8%.
• Kev tshuab sib xyaw ua ke: Kev sib xyaw ua ke ntawm coaxial thiab sideways blowing, nws tuaj yeem tiv thaiv kev oxidation thiab plasma interference tib lub sijhawm. Piv txwv li, rau 3 hli tuab 6061 txhuas alloy nrog ob lub nozzle tsim, qhov porosity tus nqi raug txo los ntawm 2.5% mus rau 0.4%, thiab lub zog tensile ncav cuag 95% ntawm cov khoom siv hauv paus.
Qhov cuam tshuam ntawm cov roj tiv thaiv rau qhov zoo ntawm vuam yog los ntawm nws txoj kev tswj hwm kev hloov pauv zog, cov thermodynamics ntawm lub pas dej molten, thiab cov tshuaj lom neeg:
1. Kev hloov pauv zog: Qhov ua kom sov siab ntawm helium ua rau lub pas dej ua kom txias sai dua, txo qhov dav ntawm thaj chaw cuam tshuam los ntawm cua sov (HAZ); qhov ua kom sov qis ntawm argon ua rau lub sijhawm nyob ntawm lub pas dej ua kom sov ntev dua, uas yog qhov zoo rau kev tsim cov phaj nyias.
2. Kev ruaj khov ntawm lub pas dej yaj: Cov pa roj ntws cuam tshuam rau qhov ntws ntawm lub pas dej yaj los ntawm lub zog txav, thiab qhov nrawm ntws tsim nyog tuaj yeem tiv thaiv kev tawg; qhov nrawm ntws ntau dhau yuav ua rau muaj cua ntsawj, ua rau muaj qhov tsis zoo ntawm kev vuam.
3. Kev tiv thaiv tshuaj lom neeg: Cov pa roj inert cais cov pa oxygen thiab tiv thaiv kev oxidation ntawm cov khoom sib xyaw (xws li Cr, Al); cov pa roj nquag (xws li N₂) hloov cov khoom sib txuas los ntawm kev ua kom cov kua khov kho lossis kev tsim cov khoom sib xyaw, tab sis qhov kev sib xyaw yuav tsum tau tswj hwm kom meej.
Lub sijhawm tshaj tawm: Plaub Hlis-09-2025
