Teknụzụ ịgbado ọkụ laser, n'ihi oke ike ya, obere ntinye okpomọkụ na njirimara na-anaghị emetụ aka, aghọọla otu n'ime usoro dị mkpa na mmepụta nkenke nke oge a. Agbanyeghị, nsogbu dịka oxidation, porosity na ọkụ ihe sitere na kọntaktị nke ọdọ mmiri gbazere agbaze na ikuku n'oge ịgbado ọkụ na-egbochi ihe onwunwe igwe na ndụ ọrụ nke njikọta weld. Dịka isi ihe eji achịkwa gburugburu ebe a na-agbado ọkụ, nhọrọ nke ụdị, ọnụego mmiri na ụdị ikuku nke gas nchebe kwesịrị ijikọ ya na njirimara ihe (dịka ọrụ kemịkalụ, njikwa okpomọkụ) na ọkpụrụkpụ nke efere ahụ.
Ụdị gas nchekwa
Isi ọrụ nke gas nchekwa dị n'ịkewapụ oxygen, ịchịkwa omume nke ọdọ mmiri gbazere agbaze, na imeziwanye arụmọrụ nke njikọ ike. Dabere na njirimara kemịkalụ ha, enwere ike kewaa gas nchekwa n'ime gas na-adịghị arụ ọrụ (argon, helium) na gas na-arụ ọrụ (nitrogen, carbon dioxide). Gas ndị na-adịghị arụ ọrụ nwere nnukwu nkwụsi ike kemịkalụ ma nwee ike igbochi oxidation nke ọdọ mmiri gbazere agbaze nke ọma, mana ọdịiche dị ukwuu ha na ihe onwunwe okpomọkụ na-emetụta mmetụta njikọta nke ukwuu. Dịka ọmụmaatụ, argon (Ar) nwere nnukwu njupụta (1.784 kg/m³) ma nwee ike ịmepụta mkpuchi kwụsiri ike, mana obere njupụta okpomọkụ ya (0.0177 W/m·K) na-eduga na oyi nwayọ nke ọdọ mmiri gbazere agbaze na ntinye weld dị omimi. N'ụzọ dị iche, helium (He) nwere okpukpu asatọ karịa njupụta okpomọkụ (0.1513 W/m·K) karịa argon ma nwee ike ime ka oyi nke ọdọ mmiri gbazere agbaze dịkwuo ngwa ngwa ma mee ka ntinye weld dịkwuo elu, mana obere njupụta ya (0.1785 kg/m³) na-eme ka ọ dị mfe ịgbapụ, na-achọ ọnụego mmiri dị elu iji nọgide na-enwe mmetụta nchebe. Gas ndị na-arụ ọrụ dịka nitrogen (N₂) nwere ike ime ka ike ịgbado ọkụ dịkwuo mma site na ime ka ngwọta siri ike sie ike n'ọnọdụ ụfọdụ, mana ojiji gabigara ókè nwere ike ibute porosity ma ọ bụ mmiri ozuzo nke usoro gbawara agbawa. Dịka ọmụmaatụ, mgbe a na-agbado ígwè igwe anaghị agba nchara duplex, mgbasa nitrogen n'ime ọdọ mmiri gbazere agbaze nwere ike imebi nguzozi nke usoro ferrite/austenite, na-ebute mbelata na iguzogide nchara.
Foto nke 1. Ịgbado ọkụ laser nke ígwè anaghị agba nchara 304L (n'elu): Ihe mkpuchi gas Ar; (ala): Ihe mkpuchi gas N2
Site n'echiche nke usoro ọrụ, ike ionization dị elu nke helium (24.6 eV) nwere ike igbochi mmetụta nchebe plasma ma mee ka nnabata ike laser dịkwuo mma, si otú a na-eme ka omimi ịbanye n'ime ahụ dịkwuo elu. Ka ọ dị ugbu a, ike ionization dị ala nke argon (15.8 eV) na-enwekarị ike imepụta igwe ojii plasma, nke chọrọ iwepụ uche ma ọ bụ mgbanwe pulse iji belata nnyonye anya. Na mgbakwunye, mmeghachi omume kemịkalụ dị n'etiti gas na-arụ ọrụ na ọdọ mmiri gbazere agbaze (dịka nitrogen na-emeghachi omume na Cr na ígwè) nwere ike ịgbanwe nhazi weld, nhọrọ nlezianya dabere na ihe onwunwe dị mkpa.
Ihe atụ nke ngwa ihe:
• Ígwè: N'ime efere dị gịrịgịrị (<3 mm), argon nwere ike ime ka elu ya dị mma, yana ọkpụrụkpụ oyi akwa oxide nke naanị 0.5 μm maka ihe mkpuchi ígwè 1.5 mm nke na-enweghị carbon; maka efere dị arọ (>10 mm), a ga-etinye obere helium (He) iji mee ka omimi ịbanye n'ime ya dịkwuo elu.
• Ígwè anaghị agba nchara: Nchedo argon nwere ike igbochi mfu ihe Cr, yana ọdịnaya Cr nke 18.2% na akwa 3 mm nke ígwè anaghị agba nchara 304 dị arọ na-eru nso 18.5% nke ígwè ntọala; maka ígwè anaghị agba nchara duplex, a chọrọ ngwakọta Ar-N₂ (N₂ ≤ 5%) iji hazie nha nha ahụ. Ọmụmụ ihe egosila na mgbe ị na-eji ngwakọta Ar-2% N₂ maka ígwè anaghị agba nchara 2205 dị arọ 8 mm, oke ferrite/austenite kwụsiri ike na 48:52, yana ike nrụgide nke 780 MPa, nke ka mma karịa nchedo argon dị ọcha (720 MPa).
• Aluminom alloy: Efere dị gịrịgịrị (<3 mm): Oke mmụgharị nke alloy aluminom na-eduga na obere ọsọ nnabata ike, helium, yana ike ionization ya dị elu (24.6 eV), nwere ike ime ka plasma kwụsie ike. Nnyocha na-egosi na mgbe helium na-echebe alloy aluminom 6061 dị arọ 2 mm, omimi ntinye ahụ ruru 1.8 mm, na-abawanye site na 25% ma e jiri ya tụnyere argon, ọnụego porosity ahụ dịkwa ala karịa 1%. Maka efere dị arọ (>5 mm): Efere dị arọ nke alloy aluminom chọrọ ntinye ike dị elu, ngwakọta helium-argon (He:Ar = 3:1) nwere ike ịhazi ma omimi ntinye na ọnụ ahịa. Dịka ọmụmaatụ, mgbe ị na-agbakọta efere 5083 dị arọ 8 mm, omimi ntinye ahụ ruru 6.2 mm n'okpuru nchekwa gas agwakọtara, na-abawanye site na 35% ma e jiri ya tụnyere gas argon dị ọcha, ọnụ ahịa ịgbado ọkụ ahụ na-ebelata site na 20%.
Rịba ama: Ederede mbụ ahụ nwere ụfọdụ mmejọ na ihe ndị na-adịghị mma. Nsụgharị enyere dabere na ụdị ederede edoziri ma dị n'otu.
Mmetụta nke ọsọ ọsọ nke argon gas
Oke mmiri gas argon na-emetụta ikike mkpuchi gas na ike mmiri nke ọdọ mmiri ahụ gbazere agbaze. Mgbe oke mmiri ahụ ezughi oke, oyi akwa gas enweghị ike ikewapụ ikuku kpamkpam, akụkụ ọdọ mmiri ahụ gbazere agbaze na-enwekarị oxidation na ịmepụta oghere gas; mgbe oke mmiri ahụ dị oke elu, ọ nwere ike ibute ọgba aghara, nke nwere ike ịsacha elu ọdọ mmiri ahụ gbazere agbaze ma duga na mbelata ịgbado ọkụ ma ọ bụ gbasasịa. Dịka ọnụọgụ Reynolds nke usoro mmiri mmiri (Re = ρvD/μ) si dị, mmụba na oke mmiri ga-eme ka ọsọ mmiri gas dịkwuo elu. Mgbe Re > 2300, oke mmiri laminar na-aghọ mmiri ọgba aghara, nke ga-emebi nkwụsi ike nke ọdọ mmiri gbazere agbaze. Ya mere, a ga-enyocha mkpebi nke oke mmiri dị mkpa site na nnwale ma ọ bụ ihe atụ ọnụọgụgụ (dịka CFD).
Foto nke 2. Mmetụta nke Ọkwa Mmiri Gas Dị Iche Iche na Seam Weld
Ekwesịrị ịgbanwe nhazi usoro mmiri yana njikọta nke ihe na-eme ka okpomọkụ dị n'ime ihe na ọkpụrụkpụ efere:
• Maka ígwè na ígwè anaghị agba nchara: Maka efere ígwè dị gịrịgịrị (1-2 mm), ọnụego mmiri kwesịrị ịdịkarịa 10-15 L/min. Maka efere ndị dị arọ (>6 mm), a ga-amụba ya ruo 18-22 L/min iji gbochie oxidation ọdụ. Dịka ọmụmaatụ, mgbe ọnụego mmiri nke ígwè anaghị agba nchara 316L dị mm 6 dị arọ bụ 20 L/min, nha anya nke ike HAZ na-aka mma site na 30%.
• Maka alloy aluminom: Oke ike okpomọkụ chọrọ oke mmiri iji gbatịa oge nchekwa. Maka alloy aluminom 7075 nke dị mm 3 n'obosara, ọnụego porosity bụ nke kacha ala (0.3%) mgbe ọnụego mmiri ahụ bụ 25-30 L/min. Agbanyeghị, maka efere ndị dị oke arọ (>10 mm), ọ dị mkpa ijikọta ya na ikuku ngwakọta iji zere ọgba aghara.
Mmetụta nke ụdị gas na-efe efe
Ụdị gas a na-efe efe na-emetụta usoro mmiri nke ọdọ mmiri a gbazere agbaze na mmetụta mgbochi ntụpọ site n'ịchịkwa ntụziaka na nkesa nke mmiri gas ahụ. Ụdị gas a na-efe efe na-achịkwa mmiri nke ọdọ mmiri a gbazere agbaze site na ịgbanwe usoro nrụgide elu na mmiri Marangoni (mmiri Marangoni). Ịfụ ihe n'akụkụ nwere ike ime ka ọdọ mmiri a gbazere agbaze na-efe n'otu ntụziaka kpọmkwem, na-ebelata oghere na ntinye slag; ịfụ ihe mejupụtara nwere ike ime ka nhazi nke weld dịkwuo mma site n'ịhazi nkesa ike site na mmiri gas dị iche iche.
Ụzọ ndị bụ isi e si afụ ụfụ gụnyere:
• Ịfụ ọkpọkọ: A na-ewepụta ikuku gas ahụ site na iji laser blank, na-ekpuchi ọdọ mmiri gbazere agbaze nke ọma, nke dabara adaba maka ịgbado ọkụ ọsọ ọsọ. Uru ya bụ nkwụsi ike usoro dị elu, mana ikuku gas nwere ike igbochi ntinye leza. Dịka ọmụmaatụ, mgbe ị na-eji ịfụ ọkpọkọ na mpempe ígwè galvanized ụgbọala (1.2 mm), ọsọ ịgbado ọkụ nwere ike ịbawanye ruo 40 mm/s, ọnụego ịgbado ọkụ ahụ erughị 0.1.
• Ịfụ ihe n'akụkụ: A na-esi n'akụkụ ọdọ mmiri ahụ gbazere agbaze ewebata gas ahụ, nke enwere ike iji wepụ ihe ruru unyi plasma ma ọ bụ ala n'ụzọ ntụziaka, nke dị mma maka ịgbado ihe miri emi. Dịka ọmụmaatụ, mgbe ị na-afụ ihe n'elu ígwè Q345 dị mm 12 n'akụkụ 30°, ntinye ihe n'ime ígwè ahụ na-abawanye site na 18%, ọnụego porosity ala na-ebelata site na 4% ruo 0.8%.
• Ịfụ ọkpọkọ: Ijikọta ịfụ ọkpọkọ na akụkụ, ọ nwere ike igbochi oxidation na nnyonye anya plasma n'otu oge. Dịka ọmụmaatụ, maka alloy aluminom 6061 nke dị milimita 3 n'obosara nwere nhazi nozzle abụọ, a na-ebelata ọnụego porosity site na 2.5% ruo 0.4%, ike nrụgide ahụ na-erukwa 95% nke ihe ndị bụ isi.
Mmetụta nke gas nchekwa na mma ịgbado ọkụ sitere na nhazi ya nke mbufe ike, thermodynamics nke ọdọ mmiri gbazere agbaze, na mmeghachi omume kemịkalụ:
1. Nnyefe ike: Oke ike nke helium na-eme ka ọdọ mmiri gbazere agbaze dị ngwa, na-ebelata obosara nke mpaghara okpomọkụ metụtara (HAZ); obere ike nke argon na-eme ka oge ịdị adị nke ọdọ mmiri gbazere agbaze dị ogologo, nke bara uru maka nhazi elu nke efere dị gịrịgịrị.
2. Nkwụsi ike nke ọdọ mmiri a kpụrụ akpụ: Mmiri gas na-emetụta mmiri nke ọdọ mmiri a gbazere agbaze site na ike shear, ọnụego mmiri kwesịrị ekwesị nwekwara ike igbochi mmiri a gbazere agbaze; oke mmiri a na-agbafe ga-akpata vortex, na-eduga na ntụpọ nke weld.
3. Nchedo kemịkalụ: Gas ndị na-adịghị arụ ọrụ na-ewepụ oxygen ma gbochie oxidation nke ihe ndị mejupụtara alloy (dịka Cr, Al); gas ndị na-arụ ọrụ (dịka N₂) na-agbanwe njirimara njikọta site na ime ka ngwọta siri ike sie ike ma ọ bụ nhazi ngwakọta, mana ọ dị mkpa ka a chịkwaa ntinye ahụ nke ọma.
Oge ozi: Eprel-09-2025
