Hangarau whakarewa taiaho, nā te nui o te kaha, te iti o te wera e uru mai ana, me ngā āhuatanga kore-pa, kua noho ko tētahi o ngā tukanga matua o te hanga tino tika o ēnei rā. Heoi, ko ngā raruraru pēnei i te waikura, te porosity me te wera o ngā huānga i puta mai i te pa o te puna rewa ki te hau i te wā e whakarewa ana ka tino whakawhāiti i ngā āhuatanga miihini me te roa o te mahi o te hononga whakarewa. Hei reo matua mō te whakahaere i te taiao whakarewa, me hono te kōwhiringa o te momo, te tere rere me te aratau pupuhi o te hau tiaki ki ngā āhuatanga rauemi (pēnei i te mahi matū, te kawe wera) me te matotoru o te pereti.
Ngā momo hau tiaki
Ko te mahi matua o ngā hau tiaki kei te wehe i te hāora, te whakahaere i te whanonga o te puna rewa, me te whakapai ake i te whai huatanga o te hononga pūngao. I runga i ō rātou āhuatanga matū, ka taea te whakarōpū i ngā hau tiaki ki ngā hau kore mahi (argon, herium) me ngā hau hohe (hauota, hauhā waro). He tino pumau te matū o ngā hau kore mahi, ā, ka taea te ārai i te waikura o te puna rewa, engari ko ō rātou rerekētanga nui i roto i ngā āhuatanga ā-tinana wera ka pā nui ki te pānga whakarewa. Hei tauira, he nui te kiato o te argon (Ar) (1.784 kg/m³) ā, ka taea te hanga i tētahi paninga pumau, engari ko tōna kawe wera iti (0.0177 W/m·K) ka arahi ki te whakamatao puhoi o te puna rewa me te urunga papaku o te whakarewa. He rerekē, e waru ngā wā teitei ake te kawe wera o te herium (He) (0.1513 W/m·K) i te argon, ā, ka taea te whakatere i te whakamatao o te puna rewa me te whakanui ake i te urunga whakarewa, engari ko tōna kiato iti (0.1785 kg/m³) ka ngawari ki te mawhiti, me te hiahia kia nui ake te tere rere hei pupuri i te pānga tiaki. Ka taea e ngā hau hohe pēnei i te hauota (N₂) te whakarei ake i te kaha o te whakarewa mā te whakapakari i te otinga totoka i roto i ētahi āhuatanga, engari ko te whakamahinga nui rawa ka puta he porosity, he maturuturunga iho rānei o ngā āhua pakarukaru. Hei tauira, i te whakarewatanga o te maitai kore waikura takirua, ka taea e te horapa o te hauota ki roto i te puna rewa te whakararuraru i te taurite āhua ferrite/austenite, ka hua ake he hekenga o te ātete ki te waikura.
Ahua 1. Te whakarewatanga taiaho o te maitai kore waikura 304L (runga): Te parenga hau Ar; (raro): Te parenga hau N2
Mai i te tirohanga o te tikanga tukanga, ka taea e te kaha whakakoi teitei o te helium (24.6 eV) te pehi i te pānga tiaki plasma me te whakarei ake i te mimiti kaha laser, ā, ka whakanui ake i te hohonutanga o te urunga. I taua wā, ko te kaha whakakoi iti o te argon (15.8 eV) he ngāwari ki te whakaputa kapua plasma, e hiahia ana kia whakakorehia te arotahi, kia whakarerekētia rānei te pāorooro hei whakaiti i te pokanoa. Hei tāpiri, ko te tauhohenga matū i waenga i ngā hau hohe me te puna rewa (pēnei i te tauhohenga hauota me te Cr i roto i te maitai) ka whakarerekē pea i te hanganga whakarewa, ā, me whiriwhiri tupato i runga i ngā āhuatanga rauemi.
Ngā tauira tono rauemi:
• Rino: I roto i te whakarewanga pereti angiangi (<3 mm), ka taea e te argon te whakarite i te mutunga o te mata, me te matotoru o te paparanga waikura o te 0.5 μm anake mō te hononga whakarewa maitai waro-iti 1.5 mm; mō ngā pereti matotoru (>10 mm), me tāpiri he iti o te herium (He) hei whakanui ake i te hohonutanga o te urunga.
• Kowiri tira: Ka taea e te tiakitanga o te haukini te ārai i te ngaronga o te huānga Cr, me te ihirangi Cr o te 18.2% i roto i te hononga whakarewa kowiri tira 304 matotoru 3 mm e tata ana ki te 18.5% o te konganuku turanga; mō te kowiri tira takirua, me whai ranunga Ar-N₂ (N₂ ≤ 5%) hei taurite i te ōwehenga. Kua whakaatuhia e ngā rangahau ina whakamahia he ranunga Ar-2% N₂ mō te kowiri tira takirua 2205 matotoru 8 mm, he pumau te ōwehenga ferrite/austenite i te 48:52, me te kaha kume o te 780 MPa, he pai ake i te tiakitanga o te haukini parakore (720 MPa).
• Konumohe konumohe: Pereti angiangi (<3 mm): Ko te whakaata nui o ngā konumohe konumohe ka hua ake he iti te tere mimiti pūngao, ā, ka taea e te heriuma, me tōna pūngao ionization teitei (24.6 eV), te whakau i te plasma. E whakaatu ana ngā rangahau ina tiakina te konumohe konumohe 6061 he 2 mm te matotoru e te heriuma, ka eke te hohonutanga o te urunga ki te 1.8 mm, ka piki ake mā te 25% ki te whakataurite ki te argon, ā, he iti iho te tere porosity i te 1%. Mō ngā pereti matotoru (>5 mm): Me nui te kaha o te urunga o ngā pereti matotoru konumohe, ā, ka taea e te ranunga heriuma-argon (He:Ar = 3:1) te whakataurite i te hohonutanga o te urunga me te utu. Hei tauira, i te wā e whakarewahia ana ngā pereti 5083 he 8 mm te matotoru, ka eke te hohonutanga o te urunga ki te 6.2 mm i raro i te tiakitanga hau whakauru, ka piki ake mā te 35% ki te whakataurite ki te hau argon parakore, ā, ka whakaitihia te utu whakarewa mā te 20%.
Kia mōhio: Kei roto i te tuhinga taketake ētahi hapa me ētahi taupatupatu. Ko te whakamāoritanga i tukuna mai i ahu mai i te putanga kua whakatikatikaina, kua mārama hoki o te tuhinga.
Te awe o te tere rere o te hau argon
Ka pā tika te tere rere o te hau argon ki te kaha o te kapi hau me te hihiri wai o te puna rewa. Ina kore e ranea te tere rere, kāore e taea e te paparanga hau te wehe katoa i te hau, ā, ka ngāwari te taha o te puna rewa ki te waikura me te hanganga o ngā pūwero hau; ina nui rawa te tere rere, ka puta he pōrearea, ka taea te horoi i te mata o te puna rewa, ka arahi ki te hekenga whakarewa, ki te ruirui rānei. E ai ki te tau Reynolds o te tikanga wai (Re = ρvD/μ), ka piki ake te tere rere o te hau mēnā ka piki ake te tere rere. Ina neke ake te Re i te 2300, ka huri te rere laminar hei rere pōrearea, ka whakangaro i te pumau o te puna rewa. Nō reira, me tātari te whakatau i te tere rere matua mā roto i ngā whakamātautau, i ngā whakatauira tau rānei (pēnei i te CFD).
Pikitia 2. Ngā Pānga o ngā Rere Rere Hau Rerekē ki te Hononga Whakarewa
Me whakarerekē te arotautanga o te rere me te kawe wera o ngā rauemi me te matotoru o te pereti:
• Mō te maitai me te kowiri tira: Mō ngā pereti maitai angiangi (1-2 mm), ko te tere rere he pai ake kia 10-15 L/min. Mō ngā pereti matotoru (>6 mm), me whakanui ake ki te 18-22 L/min hei pehi i te waikura hiku. Hei tauira, ina 20 L/min te tere rere o te kowiri tira 316L matotoru 6 mm, ka pai ake te ōritetanga o te pakeke HAZ mā te 30%.
• Mō te koranu konumohe: Me tere te rere o te wai wera kia roa ake ai te wā tiaki. Mō te koranu konumohe 7075 he 3 mm te matotoru, ko te tere porosity te mea iti rawa (0.3%) ina he 25-30 L/min te tere rere. Heoi, mō ngā pereti matotoru rawa (>10 mm), me whakakotahi ki te pupuhi hiato hei karo i te aueue.
Te awe o te aratau pupuhi hau
Ka pā tika te aratau pupuhi hau ki te tauira rere o te puna rewa me te pānga pehi hapa mā te whakahaere i te ahunga me te tohatoha o te rere o te hau. Ka whakahaere te aratau pupuhi hau i te rere o te puna rewa mā te whakarerekē i te pikinga o te kukū mata me te rere o te Marangoni (rere o te Marangoni). Ka taea e te pupuhi taha te akiaki i te puna rewa kia rere i tētahi ahunga motuhake, ka whakaiti i ngā pore me te whakaurunga o te para; ka taea e te pupuhi hiato te whakapai ake i te ōritetanga o te hanganga whakarewa mā te whakataurite i te tohatoha pūngao mā te rere o te hau maha-aronga.
Ko ngā tikanga matua mō te pupuhi ko:
• Te pupuhi honohono: Ka tukuna te rere hau ki te hihi taiaho, ka hipokina te puna rewa kia ōrite, he pai mō te whakarewa tere. Ko tōna painga he pumau te tukanga, engari ka taea e te rere hau te whakararuraru i te arotahi taiaho. Hei tauira, ina whakamahia te pupuhi honohono ki runga i te pepa maitai whakapūmau motuka (1.2 mm), ka taea te whakanui ake i te tere whakarewa ki te 40 mm/s, ā, he iti iho i te 0.1 te tere o te ruirui.
• Te pupuhi taha: Ka tukuna te rere o te hau mai i te taha o te puna rewa, ka taea te whakamahi hei tango i ngā poke o te plasma, o raro rānei, he mea tika mō te whakarewa hohonu. Hei tauira, ina pupuhihia ki runga i te maitai Q345 matotoru 12 mm i te koki 30°, ka piki ake te whakarewa mā te 18%, ā, ka heke te tere o te pūngao o raro mai i te 4% ki te 0.8%.
• Te pupuhi whakakotahi: Mā te whakakotahi i te pupuhi coaxial me te pupuhi taha, ka taea te pehi i te waikura me te pokanoa plasma i te wā kotahi. Hei tauira, mō te konumohe konumohe 6061 matotoru 3 mm me te hoahoa pūwero takirua, ka whakaitihia te tere porosity mai i te 2.5% ki te 0.4%, ā, ka eke te kaha kume ki te 95% o te rauemi turanga.
Ko te awe o te hau ārai ki te kounga o te whakarewa e ahu mai ana i tana whakahaere i te whakawhiti pūngao, te pāmahana o te puna rewa, me ngā tauhohenga matū:
1. Whakawhiti pūngao: Mā te kawe wera nui o te hēriuma ka tere ake te whakamatao o te puna rewa, ka whakaitihia te whānui o te rohe e pāngia ana e te wera (HAZ); mā te kawe wera iti o te argon ka roa ake te noho o te puna rewa, he mea pai mō te hanganga mata o ngā pereti angiangi.
2. Te pumau o te puna rewa: Ka pā te rere o te hau ki te rere o te puna rewa mā te kaha kutikuti, ā, mā te tere rere tika ka taea te pehi i te tauhiuhi; mā te tere rere nui rawa ka puta he awhiowhio, ka hua ake he hapa whakarewa.
3. Tiakitanga matū: Ka wehea te hāora e ngā hau kore mahi, ā, ka ārai i te waikura o ngā huānga koranu (pērā i te Cr, Al); ka huri ngā hau hohe (pērā i te N₂) i ngā āhuatanga whakarewa mā te whakapakari i te wairewa totoka, te hanganga matū rānei, engari me tino whakahaere te kukū.
Wā tuku: Paenga-whāwhā-09-2025
