01
Ua ntej
Vim nws lub zog siab ceev, tsis tshua muaj hluav taws xob tawm tswv yim, thiab tsis yog -kev sib cuag, laser vuam tshuab tau tshwm sim 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 elemental burn-tawm- tshwm sim los ntawm kev sib cuag ntawm lub pas dej ua ke thiab cov huab cua thaum lub sij hawm vuam txheej txheem -hnyav hnyav rau cov khoom siv thiab kev pab cuam lub neej ntawm weld seams. Raws li qhov nruab nrab tseem ceeb rau kev tswj cov vuam ib puag ncig, kev xaiv cov khoom siv hluav taws xob tiv thaiv, tus nqi ntws, thiab txoj kev xa khoom yuav tsum ua tib zoo ua ke nrog cov khoom siv tshwj xeeb (xws li tshuaj tiv thaiv thiab thermal conductivity) thiab thickness ntawm lub workpiece.
Laser & Electron Beam ua
02
Hom Shielding Gases
Lub luag haujlwm tseem ceeb ntawm kev tiv thaiv roj yog cais tawm cov pa oxygen, tswj cov kev coj tus cwj pwm hauv pas dej, thiab txhim kho lub zog sib txuas. Raws li lawv cov khoom siv tshuaj, cov khoom siv tiv thaiv tuaj yeem faib dav rau hauv cov pa roj tsis zoo (xws li argon thiab helium) thiab cov pa roj (xws li nitrogen thiab carbon dioxide). Inert gases muaj tshuaj lom neeg ruaj khov, zoo tiv thaiv oxidation ntawm lub pas dej ua ke; Txawm li cas los xij, qhov sib txawv tseem ceeb hauv lawv cov khoom siv thermophysical tuaj yeem cuam tshuam qhov txiaj ntsig ntawm vuam. Piv txwv li, argon (Ar) nta qhov ntom ntom (1.784 kg / m³), ua kom nws tsim ib daim pam tiv thaiv ruaj khov hla lub pas dej ua ke; conversely, nws cov thermal conductivity tsawg (0.0177 W / m·K) ua rau qeeb weld pas dej txias thiab qhov tob tob tob. Hauv qhov sib piv, helium (Nws) nthuav tawm cov thermal conductivity kwv yees li yim npaug ntawm argon (0.1513 W / m·K), yog li ua kom lub pas dej ua kom txias thiab nce qhov tob tob; Txawm li cas los xij, nws qhov ntom ntom qis (0.1785 kg / m³) ua rau nws yooj yim rau kev tawg sai sai, xav tau cov nqi ntws ntau dua kom muaj kev tiv thaiv zoo. Cov pa roj carbon monoxide-xws li nitrogen (N₂)- tuaj yeem, hauv qee yam kev siv, txhim kho weld seam zog los ntawm cov khoom siv- kev daws teeb meem; Txawm li cas los xij, lawv siv ntau dhau tuaj yeem ua rau porosity lossis nag lossis daus ntawm nkig theem. Piv txwv li, thaum welding duplex stainless hlau, kev sib cais ntawm nitrogen rau hauv lub pas dej ua ke tuaj yeem cuam tshuam cov ferrite- austenite theem sib npaug, uas ua rau txo qis hauv corrosion kuj.
Los ntawm qhov kev xav ntawm cov txheej txheem txheej txheem, helium lub siab ionization zog (24.6 eV) suppresses cov nyhuv plasma shielding thiab txhim kho laser zog nqus, yog li nce qhov tob tob. Hloov pauv, argon lub zog qis ionization (15.8 eV) nyiam tsim cov ntshav plasma, xav tau kev siv cov txuj ci xws li defocusing lossis mem tes hloov kho kom txo qis kev cuam tshuam. Tsis tas li ntawd, tshuaj lom neeg cov tshuaj tiv thaiv ntawm cov khoom siv tiv thaiv hluav taws xob thiab lub pas dej molten-xws li kev tsim cov nitrides los ntawm cov tshuaj tiv thaiv ntawm nitrogen nrog chromium hauv hlau- tuaj yeem hloov cov khoom sib txuas; Yog li ntawd, qhov kev xaiv ntawm shielding roj yuav tsum tau ua nrog ceev faj, coj mus rau hauv tus account cov khoom siv tshwj xeeb.
** Cov ntaub ntawv thov piv txwv:**
• **Steel:** Nyob rau hauv vuam ntawm nyias daim hlau (<3 mm), argon ensures a high-quality surface finish; for instance, the oxide layer thickness on a weld in 1.5 mm low-carbon steel is merely 0.5 μm. For thick plates (>10 hli), txawm li cas los xij, ib qho me me ntxiv ntawm helium (Nws) yuav tsum tau nce qhov tob tob.
• **Stainless Steel:** Argon shielding tiv thaiv depletion ntawm chromium (Cr) cov ntsiab lus; Nyob rau hauv ib tug weld ntawm 3 hli tuab 304 stainless hlau, cov ntsiab lus Cr ncav cuag 18.2% (ze ze ze rau lub hauv paus hlau 18.5%). Duplex stainless hlau, ntawm qhov tod tes, yuav tsum muaj Ar-N₂ sib tov (nrog N₂ Tsawg dua lossis sib npaug li 5%) kom muaj qhov sib npaug ntawm theem. Cov kev tshawb fawb qhia tias thaum vuam 8 hli tuab 2205 duplex stainless hlau siv Ar-2%N₂ sib tov, cov ferrite - rau- austenite theem piv stabilizes ntawm 48:52, yielding ib tensile zog ntawm 780 MPagon2 shielding (superior).
• **Aluminium Alloys:** * Cov phaj nyias (<3 mm):* The high reflectivity of aluminum alloys results in low energy absorption; helium, with its high ionization energy (24.6 eV), helps stabilize the plasma. Research shows that when welding 2 mm thick 6061 aluminum alloy under helium shielding, the penetration depth reaches 1.8 mm-a 25% increase compared to argon shielding-while porosity remains below 1%. *Thick Plates (>5 mm): * Vuam tuab aluminium daim hlau yuav tsum muaj lub zog siab; a helium-argon sib tov (Nws: Ar=3:1) muaj qhov sib npaug ntawm kev ua tiav qhov tob tob tob thiab tswj cov nqi. Piv txwv li, thaum vuam 8 hli tuab 5083 daim hlau, tiv thaiv nrog qhov sib tov no ua rau qhov tob tob ntawm 6.2 hli- txhim kho 35% ntawm cov ntshiab argon-thaum ib txhij txo cov nqi vuam los ntawm 20%.
