1. Hoʻāʻo Manaʻo a me ka Nānā ʻana
O nā 3nā kiwikā o ka huilanā laʻana i hāʻawi ʻia e ka hui, 2 he mau kiwikā, a ʻo 1 he kiwikā i hoʻohana ʻole ʻia. No A a me B, ua hōʻailona ʻia ka kiwikā i hoʻohana ʻole ʻia he hina hina. Kiʻi Piha 1. He pāpaʻu ka ʻili waho o ka kiwikā A, ʻo ka ʻili waho o ka kiwikā B ka ʻili, ʻo ka ʻili waho o ka kiwikā C ka ʻili, a ʻo ka ʻili waho o ka kiwikā C ka ʻili. Ua uhi ʻia nā kiwikā A a me B me nā huahana pala. Ua māwae ʻia ka kiwikā A a me B ma nā kūlou, aia ka ʻaoʻao waho o ke kūlou ma ka kiwikā, ua māwae ka waha o ke apo kiwikā B i ka hopena, a ua hōʻailona ʻia ka pua keʻokeʻo ma waena o nā ʻili māwae ma ka ʻili o ka kiwikā A. Mai luna mai, aia nā māwae ma nā wahi a pau, ʻo nā māwae ka mea nui loa, a aia nā māwae ma nā wahi a pau.
ʻO kahi ʻāpana o kakiwikā huilaUa ʻoki ʻia nā laʻana A, B, a me C mai ke kūlou ʻana, a ua nānā ʻia ke ʻano o ka ʻili me kahi microscope electron scanning ZEISS-SUPRA55, a ua kālailai ʻia ka haku mele ʻana o ka micro-area me EDS. Hōʻike ka Kiʻi 2 (a) i ka microstructure o ka ʻili valve B. Hiki ke ʻike ʻia he nui nā ʻāpana keʻokeʻo a ʻālohilohi ma ka ʻili (i hōʻike ʻia e nā pua keʻokeʻo ma ke kiʻi), a ʻo ka loiloi EDS o nā ʻāpana keʻokeʻo he nui ka nui o S. Hōʻike ʻia nā hopena loiloi spectrum ikehu o nā ʻāpana keʻokeʻo ma ke Kiʻi 2(b).
ʻO nā Kiʻi 2 (c) a me (e) nā microstructures o ka ʻili o ka valve B. Hiki ke ʻike ʻia mai ke Kiʻi 2 (c) ua aneane uhi ʻia ka ʻili e nā huahana corrosion, a ʻo nā mea corrosive o nā huahana corrosion e ka loiloi spectrum ikehu e komo pū me S, Cl a me O, ʻoi aku ka nui o ka ʻike o S ma nā kūlana pākahi, a ua hōʻike ʻia nā hopena loiloi spectrum ikehu ma ke Kiʻi 2 (d). Hiki ke ʻike ʻia mai ke Kiʻi 2 (e) aia nā micro-cracks ma ke apo valve ma ka ʻili o ka valve A. ʻO nā Kiʻi 2 (f) a me (g) nā micro-morphologies o ka ʻili o ka valve C, ua uhi piha ʻia ka ʻili e nā huahana corrosion, a ʻo nā mea corrosive e komo pū me S, Cl a me O, e like me ke Kiʻi 2 (e). ʻO ke kumu o ka haki ʻana, ʻo ia ka stress corrosion cracking (SCC) mai ka loiloi huahana corrosion ma ka ʻili valve. ʻO ke Kiʻi 2(h) kekahi ka microstructure o ka ʻili o ka valve C. Hiki ke ʻike ʻia ua maʻemaʻe iki ka ʻili, a ua like ke ʻano kemika o ka ʻili i kālailai ʻia e EDS me ko ka metala keleawe, e hōʻike ana ʻaʻole i pala ka valve. Ma ka hoʻohālikelike ʻana i ke ʻano microscopic a me ka hoʻonohonoho kemika o nā ʻili valve ʻekolu, ua hōʻike ʻia aia nā mea ʻino e like me S, O a me Cl i ke kaiapuni a puni.
Ua wehe ʻia ka māwae o ka valve B ma o ka hoʻāʻo kūlou, a ua ʻike ʻia ʻaʻole i komo ka māwae i loko o ka ʻāpana holoʻokoʻa o ka valve, ua māwae ma ka ʻaoʻao o ke kua, a ʻaʻole i māwae ma ka ʻaoʻao e kū pono ana i ke kua o ka valve. Hōʻike ka nānā ʻana o ka haki he ʻeleʻele ke kala o ka haki, e hōʻike ana ua pala ka haki, a he ʻeleʻele kekahi mau ʻāpana o ka haki, e hōʻike ana he ʻoi aku ka koʻikoʻi o ka pala ma kēia mau ʻāpana. Ua ʻike ʻia ka haki o ka valve B ma lalo o kahi microscope electron scanning, e like me ka mea i hōʻike ʻia ma ke Kiʻi 3. Hōʻike ke Kiʻi 3 (a) i ke ʻano macroscopic o ka haki valve B. Hiki ke ʻike ʻia ua uhi ʻia ka haki waho kokoke i ka valve e nā huahana pala, e hōʻike hou ana i ke alo o nā mea pala i ke kaiapuni a puni. Wahi a ka loiloi spectrum ikehu, ʻo nā ʻāpana kemika o ka huahana pala ʻo S, Cl a me O, a ʻo ka nui o nā mea o S a me O he kiʻekiʻe loa, e like me ka mea i hōʻike ʻia ma ke Kiʻi 3 (b). Ke nānā nei i ka ʻili haki, ua ʻike ʻia ʻo ke ʻano ulu o ka haki ma ke ʻano kristal. Hiki ke ʻike ʻia ka nui o nā māwae lua ma ka nānā ʻana i ka haki ma nā hoʻonui kiʻekiʻe, e like me ka mea i hōʻike ʻia ma ke Kiʻi 3(c). Ua hōʻailona ʻia nā māwae lua me nā pua keʻokeʻo ma ke kiʻi. Hōʻike hou nā huahana pala a me nā ʻano ulu māwae ma ka ʻili haki i nā ʻano o ka haki palaho koʻikoʻi.
ʻAʻole i wehe ʻia ka haki o ka valve A, e wehe i kahi ʻāpana o ka valve (me ke kūlana haki), wili a hoʻowali i ka ʻāpana axial o ka valve, a hoʻohana i ka hopena Fe Cl3 (5 g) +HCl (50 mL) + C2H5OH (100 mL) i kālai ʻia, a ua ʻike ʻia ke ʻano metallographic a me ke ʻano ulu ʻana o ka haki me ka microscope optical Zeiss Axio Observer A1m. Hōʻike ka Kiʻi 4 (a) i ke ʻano metallographic o ka valve, ʻo ia hoʻi ka α+β dual-phase structure, a he ʻano maikaʻi a granular ʻo β a ua hoʻolaha ʻia ma ka matrix α-phase. Hōʻike ʻia nā ʻano hoʻolaha haki ma nā māwae circumferential ma ke Kiʻi 4(a), (b). No ka mea ua piha nā ʻili o ka haki me nā huahana corrosion, ua ākea ka hakahaka ma waena o nā ʻili māwae ʻelua, a he paʻakikī ke hoʻokaʻawale i nā ʻano hoʻolaha haki. ʻIke ʻia hoʻi nā māwae lua he nui (i hōʻailona ʻia me nā pua keʻokeʻo ma ke kiʻi) ma kēia māwae mua, e ʻike i ke Kiʻi 4(c), a ua hoʻolaha ʻia kēia mau māwae lua ma ke ʻano palaoa. Ua nānā ʻia ka hāpana valve i kālai ʻia e SEM, a ua ʻike ʻia he nui nā micro-cracks ma nā kūlana ʻē aʻe e like me ka māwae nui. Ua puka mai kēia mau micro-cracks mai ka ʻili a hoʻonui ʻia a hiki i loko o ka valve. Ua bifurcation nā māwae a ua hoʻolōʻihi ʻia ma ke ʻano o ka palaoa, e ʻike i ke Kiʻi 4 (c), (d). ʻO ke kaiapuni a me ke kūlana koʻikoʻi o kēia mau microcracks ua aneane like me ko ka māwae nui, no laila hiki ke hoʻomaopopo ʻia he intergranular hoʻi ke ʻano hoʻolaha o ka māwae nui, kahi i hōʻoia ʻia e ka nānā ʻana i ka haki o ka valve B. Hōʻike hou ka hanana bifurcation o ka māwae i nā ʻano o ka haki ʻana o ka corrosion stress o ka valve.
2. Ka Nānā ʻana a me ke Kūkākūkā ʻana
I ka hōʻuluʻulu ʻana, hiki ke hoʻomaopopo ʻia ua hana ʻia ka pōʻino o ka valve e ka haki ʻana o ka corrosion stress i hoʻokumu ʻia e SO2. Pono ka haki ʻana o ka corrosion stress e hoʻokō i ʻekolu mau kūlana: (1) nā mea i maʻalahi i ka corrosion stress; (2) ka mea corrosive medium i maʻalahi i nā mea hao keleawe; (3) kekahi mau kūlana stress.
Manaʻo nui ʻia ʻaʻole e ʻeha nā metala maʻemaʻe i ka palaho koʻikoʻi, a ʻo nā mea hoʻohui āpau he maʻalahi i ka palaho koʻikoʻi i nā kekelē like ʻole. No nā mea keleawe, manaʻo nui ʻia he ʻoi aku ka maʻalahi o ka hoʻolālā ʻelua-phase i ka palaho koʻikoʻi ma mua o ka hoʻolālā hoʻokahi-phase. Ua hōʻike ʻia ma nā palapala i ka wā e ʻoi aku ai ka nui o ka Zn i loko o ka mea keleawe ma mua o 20%, ʻoi aku ka maʻalahi o ka palaho koʻikoʻi, a ʻo ke kiʻekiʻe o ka nui o ka Zn, ʻoi aku ka kiʻekiʻe o ka maʻalahi o ka palaho koʻikoʻi. ʻO ke ʻano metallographic o ka nozzle gas i kēia hihia he α+β dual-phase alloy, a ʻo ka nui o ka Zn ma kahi o 35%, ʻoi aku ka nui ma mua o 20%, no laila he kiʻekiʻe kona ʻike i ka palaho koʻikoʻi a hoʻokō i nā kūlana mea e pono ai no ka haki ʻana o ka palaho koʻikoʻi.
No nā mea keleawe, inā ʻaʻole i hana ʻia ka hoʻomaha ʻana i ke kaumaha ma hope o ka deformation hana anu, e kū mai ka palaho kaumaha ma lalo o nā kūlana kaumaha kūpono a me nā wahi corrosive. ʻO ke kaumaha e hoʻoulu ai i ka haki ʻana o ka palaho kaumaha he kaumaha tensile kūloko ia, hiki ke hoʻopili ʻia i ke kaumaha a i ʻole ke kaumaha koena. Ma hope o ka hoʻopiha ʻia ʻana o ka huila kalaka, e hoʻopuka ʻia ke kaumaha tensile ma ke kuhikuhi axial o ka nozzle ea ma muli o ke kaomi kiʻekiʻe i loko o ka huila, kahi e hoʻoulu ai i nā māwae circumferential i loko o ka nozzle ea. Hiki ke helu maʻalahi ʻia ke kaumaha tensile i hoʻokumu ʻia e ke kaomi kūloko o ka huila e like me σ=p R/2t (kahi ʻo p ke kaomi kūloko o ka huila, ʻo R ke anawaena o loko o ka valve, a ʻo t ka mānoanoa o ka paia o ka valve). Eia naʻe, ma ke ʻano laulā, ʻaʻole nui loa ke kaumaha tensile i hoʻokumu ʻia e ke kaomi kūloko o ka huila, a pono e noʻonoʻo ʻia ka hopena o ke kaumaha koena. Aia nā kūlana haki o nā nozzles kinoea ma ke kua, a ua maopopo he nui ka deformation koena ma ke kua, a aia kekahi kaumaha tensile koena ma laila. ʻO kaʻoiaʻiʻo, i loko o nā ʻāpana keleawe hana he nui, ʻaʻole pinepine ka haki ʻana o ka corrosion stress e nā stress hoʻolālā, a ʻo ka hapa nui o lākou e hana ʻia e nā stress koena i ʻike ʻole ʻia a hoʻowahāwahā ʻia. I kēia hihia, ma ke kūlou hope o ka valve, ʻo ke kuhikuhi o ke stress tensile i hana ʻia e ke kaomi kūloko o ka huila e kūlike me ke kuhikuhi o ke stress koena, a ʻo ka superposition o kēia mau stress ʻelua e hāʻawi i ke kūlana stress no ka SCC.
3. Hopena a me nā Manaʻo
Hopena:
ʻO ka haki ʻana o kakiwikā huilaʻo ke kumu nui ia o ka nahā ʻana o ka palaho stress i hoʻokumu ʻia e SO2.
Manaʻo kōkua
(1) E huli i ke kumu o ka mea ʻino i loko o ke kaiapuni a punikiwikā huila, a e hoʻāʻo e pale i ka hoʻopili pololei ʻana me ka mea ʻino e hoʻopuni ana. No ka laʻana, hiki ke hoʻopili ʻia kahi papa o ka uhi anti-corrosion i ka ʻili o ka valve.
(2) Hiki ke hoʻopau ʻia ke koʻikoʻi tensile i koe o ka hana anu e nā kaʻina hana kūpono, e like me ka hoʻomaha ʻana i ke koʻikoʻi ma hope o ke kūlou ʻana.
Ka manawa hoʻouna: Sep-23-2022
