Ua hōʻoia ʻoe ua hana ʻia nā ʻāpana e like me ke kikoʻī. I kēia manawa, e hōʻoia ua hana ʻoe i nā hana e pale aku i kēia mau ʻāpana i nā kūlana e manaʻo ai kāu mea kūʻai aku. #kumu
ʻO ka passivation kahi hana koʻikoʻi i ka hoʻonui ʻana i ke kūpaʻa kumu o ka corrosion o nā ʻāpana mīkini kila a me nā ʻākoakoa. Hiki iā ia ke hana i ka ʻokoʻa ma waena o ka hana kūpono a me ka hāʻule mua ʻana. Inā hoʻokō pono ʻole ʻia, hiki i ka passivation ke hana i ka corrosion.
ʻO ka passivation kahi ʻano hana ma hope o ka hana ʻana e hoʻonui ai i ke kūpaʻa kūlohelohe o nā mea kila kila e hana ana i ka workpiece. ʻAʻole ia he hana descaling, ʻaʻole hoʻi he uhi pena.
ʻAʻohe manaʻo like ma ke ʻano kikoʻī o ka hana ʻana o ka passivation. Akā, he mea maopopo aia kahi kiʻiʻoniʻoni oxide pale ma luna o ka ʻili o ke kila kila passivated. Ua manaʻo ʻia he lahilahi loa kēia kiʻiʻoniʻoni ʻike ʻole ʻia, ʻaʻole i emi iho ma mua o 0.0000001 ʻīniha ka mānoanoa, ma kahi o 1/100,000 ka mānoanoa o ka lauoho kanaka!
ʻO kahi ʻāpana kila kila maʻemaʻe, i hana hou ʻia, i hoʻopili ʻia a i ʻoki ʻia paha e loaʻa koke i kēia ʻili oxide ma muli o kona ʻike ʻia ʻana i ka oxygen lewa. Ma lalo o nā kūlana kūpono, uhi piha kēia papa oxide pale i nā ʻili āpau o ka ʻāpana.
Eia nō naʻe, i ka hana maoli, hiki i nā mea haumia e like me ka lepo o ka hale kūʻai a i ʻole nā ​​​​ʻāpana hao mai nā mea ʻokiʻoki ke hoʻoili i ka ʻili o nā ʻāpana kila kila i ka wā o ka mīkini ʻana. Inā ʻaʻole e wehe ʻia, hiki i kēia mau kino haole ke hōʻemi i ka pono o ka ʻili pale mua.
I ka wā o ka hana ʻana i ka mīkini, hiki i kahi liʻiliʻi o ka hao manuahi ke komo i ka mea hana a hoʻoili i ka ʻili o ka mea hana kila kila. I kekahi mau hihia, hiki ke ʻike ʻia kahi papa lahilahi o ka popo ma ka ʻāpana. ʻO kēia ka pala o ke kila e ka mea hana, ʻaʻole o ka metala kumu. I kekahi manawa, hiki i nā māwae o nā ʻāpana kila i hoʻokomo ʻia mai nā mea hana ʻoki a i ʻole kā lākou huahana pala ke hana i ka ʻino o ka ʻāpana ponoʻī.
Pēlā nō, hiki i nā ʻāpana liʻiliʻi o ka lepo hale kūʻai ferrous ke pipili i ka ʻili o ka ʻāpana. ʻOiai ke ʻano ʻālohilohi o ka metala i ke ʻano mīkini, ma hope o ka ʻike ʻia ʻana i ka ea, hiki i nā ʻāpana ʻike ʻole ʻia o ka hao manuahi ke hana i ka popo o ka ʻili.
Hiki i nā sulfides i hōʻike ʻia ke lilo i pilikia. Loaʻa lākou mai ka hoʻohui ʻana i ka sulfur i ke kila kila e hoʻomaikaʻi i ka mīkini. Hoʻonui nā sulfides i ka hiki o ka alloy ke hana i nā ʻāpana i ka wā o ka mīkini ʻana, hiki ke hoʻopau loa ʻia mai ka mea ʻoki. Inā ʻaʻole i hoʻopau pono ʻia nā ʻāpana, hiki i nā sulfides ke lilo i wahi hoʻomaka no ka palaho ʻili ma nā huahana i hana ʻia.
Ma nā hihia ʻelua, pono ka passivation e hoʻonui i ke kūpaʻa kūlohelohe o ke kila kila. Hoʻopau ia i nā mea haumia o ka ʻili, e like me nā ʻāpana lepo hale kūʻai ferrous a me nā ʻāpana hao i nā mea ʻokiʻoki, hiki ke hana i ka popo a lilo paha i wahi hoʻomaka no ka corrosion. Hoʻopau pū ka passivation i nā sulfides i hōʻike ʻia ma ka ʻili o nā mea hao kila kila ʻokiʻoki manuahi.
ʻO ke kaʻina hana ʻelua-ʻanuʻu e hāʻawi i ke kūpaʻa maikaʻi loa i ka pala: 1. Hoʻomaʻemaʻe, kahi kaʻina hana maʻalahi akā i kekahi manawa i nānā ʻole ʻia; 2. ʻAuʻau ʻakika a i ʻole ka lāʻau passivation.
Pono ka hoʻomaʻemaʻe ʻana i mea nui mau. Pono e hoʻomaʻemaʻe pono ʻia nā ʻili mai ka momona, ka mea hoʻoluʻu a i ʻole nā ​​ʻōpala hale kūʻai ʻē aʻe no ke kūpaʻa maikaʻi loa i ka pala. Hiki ke holoi pono ʻia nā ʻōpala mīkini a i ʻole ka lepo hale kūʻai ʻē aʻe mai ka ʻāpana. Hiki ke hoʻohana ʻia nā mea hoʻomaʻemaʻe a i ʻole nā ​​mea hoʻomaʻemaʻe kalepa e wehe i nā aila hana a i ʻole nā ​​​​mea hoʻoluʻu. Pono paha e wehe ʻia nā mea ʻē e like me nā oxides thermal ma o nā ʻano hana e like me ka wili ʻana a i ʻole ka pickling.
I kekahi manawa, e hōʻalo paha ka mea hoʻohana mīkini i ka hoʻomaʻemaʻe maʻamau, me ka manaʻo kuhihewa e hana like ʻia ka hoʻomaʻemaʻe a me ka passivation ma ka hoʻoluʻu wale ʻana i kahi ʻāpana i piha i ka momona i loko o kahi ʻauʻau waikawa. ʻAʻole kēia e hana ʻia. I ka ʻaoʻao ʻē aʻe, hana ka momona i haumia me ka waikawa e hana i nā pehu ea. Hōʻiliʻili kēia mau pehu ma ka ʻili o ka workpiece a hoʻopilikia i ka passivation.
I mea e ʻoi aku ai ka ʻino, ʻo ka haumia o nā hopena passivation, kahi i loaʻa i kekahi manawa nā chlorides kiʻekiʻe, hiki ke hana i ka "ʻālohilohi." ʻAʻole like me ka loaʻa ʻana o ka ʻili oxide i makemake ʻia me kahi ʻili ʻālohilohi, maʻemaʻe, a kū i ka corrosion, hiki i ka flash etching ke hopena i kahi ʻili i ʻoki nui ʻia a ʻeleʻele paha—ʻo ka ʻili i hoʻolālā ʻia e hoʻomaikaʻi i ka passivation.
Hoʻopaʻakikī ʻia nā ʻāpana i hana ʻia mai ke kila kila martensitic [magnetic, kūpaʻa iki i ka corrosion, ikaika hua a hiki i kahi 280 ksi (1930 MPa)] ma nā mahana kiʻekiʻe a laila hoʻomaʻamaʻa ʻia e hōʻoia i ka paʻakikī i makemake ʻia a me nā waiwai mechanical. ʻO nā alloys precipitation hardenable, nona ka ikaika a me ke kūpaʻa i ka corrosion ma mua o nā alloys martensitic, hiki ke mālama ʻia i ka hopena, mīkini hapa, ʻelemakule i nā mahana haʻahaʻa, a laila hoʻopau ʻia.
I kēia hihia, pono e hoʻomaʻemaʻe pono ʻia ka ʻāpana me kahi degreaser a mea hoʻomaʻemaʻe paha e wehe i nā koena o ka wai ʻoki ma mua o ka mālama wela ʻana. A i ʻole, hiki i ka wai ʻoki i koe ma ka ʻāpana ke hana i ka oxidation nui. Hiki i kēia kūlana ke hana i nā ʻāpana liʻiliʻi e liki ma hope o ka wehe ʻia ʻana o ka unahi e nā ʻano waikawa a i ʻole abrasive. Inā ʻae ʻia ka wai ʻoki e noho ma nā ʻāpana paʻakikī ʻālohilohi, e like me ka umu vacuum a i ʻole ka lewa pale, hiki ke hana i ka carburization o ka ʻili, e hopena ana i ka nalowale o ke kūpaʻa ʻana i ka pala.
Ma hope o ka hoʻomaʻemaʻe pono ʻana, hiki ke hoʻokomo ʻia nā ʻāpana kila kila i loko o kahi ʻauʻau waikawa passivating. Hiki ke hoʻohana ʻia kekahi o nā ʻano ʻekolu - passivation waikawa nitric, waikawa nitric me ka passivation sodium dichromate, a me ka passivation waikawa citric. ʻO ke ʻano hana e hoʻohana ai ma muli o ke ʻano o ke kila kila a me nā pae hoʻomaopopo i kuhikuhi ʻia.
Hiki ke hoʻopau ʻia nā papa chrome-nickel kū i ka pala i loko o kahi ʻauʻau waikawa nitric 20% (v/v) (Kiʻi 1). E like me ka mea i hōʻike ʻia ma ka papa, hiki ke hoʻopau ʻia ke kila kila kūpaʻa ʻole ma ka hoʻohui ʻana i ka sodium dichromate i kahi ʻauʻau waikawa nitric, e hoʻolilo ana i ka hopena i ʻoi aku ka oxidizing a hiki ke hana i kahi kiʻiʻoniʻoni passive ma luna o ka ʻili metala. ʻO kekahi koho e pani ai i ka waikawa nitric me ka sodium chromate, ʻo ia ka hoʻonui ʻana i ka nui o ka waikawa nitric i 50% ma ka nui. ʻO ka hoʻohui ʻana o ka sodium dichromate a me ke kiʻekiʻe o ka nui o ka waikawa nitric e hōʻemi i ka manawa kūpono o ka flash i makemake ʻole ʻia.
ʻO ke kaʻina hana no ka passivating free-machining stainless steels (i hōʻike ʻia hoʻi ma ke Kiʻi 1) he ʻokoʻa iki ia mai nā mea no nā papa kila kila ʻole free-machining. ʻO kēia no ka mea i ka wā o ka passivation i loko o kahi ʻauʻau nitric acid maʻamau, ua wehe ʻia kekahi a i ʻole nā ​​​​sulfides machinable grade i loaʻa ka sulfur, e hana ana i nā discontinuities microscopic ma ka ʻili o ka ʻāpana i mīkini ʻia.
ʻOiai ka holoi wai maikaʻi loa e waiho i ke koena waikawa i loko o kēia mau discontinuities ma hope o ka passivation. A laila e hoʻouka kēia waikawa i ka ʻili o ka ʻāpana ke ʻole ia e neutralized a wehe ʻia paha.
I mea e hoʻopau pono ai i ke kila kila maʻalahi, ua hoʻomohala ʻo Carpenter i ke kaʻina hana AAA (Alkali-Acid-Alkali), kahi e hoʻopau ai i ke koena waikawa. Hiki ke hoʻopau ʻia kēia ʻano passivation ma lalo o 2 mau hola. Eia ke kaʻina hana ʻanuʻu:
Ma hope o ka hoʻohemo ʻana i ka ʻaila, e hoʻomohu i nā ʻāpana i loko o kahi hopena sodium hydroxide 5% ma 160°F a i 180°F (71°C a i 82°C) no 30 mau minuke. A laila holoi pono i nā ʻāpana i loko o ka wai. A laila, e hoʻoluʻu i ka ʻāpana no 30 mau minuke i loko o kahi hopena waikawa nitric 20% (v/v) e loaʻa ana he 3 oz/gal (22 g/l) sodium dichromate ma 120°F a i 140°F (49°C) a i 60°C). Ma hope o ka wehe ʻana i ka ʻāpana mai ka ʻauʻau, e holoi me ka wai a laila e hoʻoluʻu i loko o ka hopena sodium hydroxide no 30 mau minuke. E holoi hou i ka ʻāpana me ka wai a hoʻomaloʻo, e hoʻopau i ke ʻano AAA.
Ke kaulana nei ka passivation waikawa citric me nā mea hana e makemake ana e pale i ka hoʻohana ʻana i nā waikawa mineral a i ʻole nā ​​​​​​hoʻonā i loaʻa ka sodium dichromate, a me nā pilikia hoʻolei a me nā hopohopo palekana e pili ana i kā lākou hoʻohana. Ua manaʻo ʻia ka waikawa citric he launa maikaʻi i ke kaiapuni ma nā ʻano āpau.
ʻOiai ʻo ka passivation citric acid e hāʻawi ana i nā pono kaiapuni maikaʻi, ʻo nā hale kūʻai i kūleʻa me ka passivation inorganic acid a ʻaʻohe hopohopo palekana e makemake paha e noho ma ke ala. Inā loaʻa i kēia poʻe hoʻohana kahi hale kūʻai maʻemaʻe, nā lako hana i mālama pono ʻia a maʻemaʻe, ʻaʻohe mea hoʻoluʻu o ka hale kūʻai ferrous, a me kahi hana e hoʻopuka ai i nā hopena maikaʻi, ʻaʻohe pono maoli no nā hoʻololi.
Ua ʻike ʻia he mea pono ka passivation i loko o ka ʻauʻau waikawa citric no kahi ākea o nā kila kila kila, me kekahi mau papa kila kila kila pākahi, e like me ka mea i hōʻike ʻia ma ke Kiʻi 2. No ka maʻalahi, ua hoʻokomo ʻia ke ʻano passivation waikawa nitric kuʻuna ma ke Kiʻi 1. E hoʻomaopopo ʻia ua hōʻike ʻia nā ʻano hana waikawa nitric kahiko ma ka pakeneka leo, ʻoiai ua hōʻike ʻia nā ʻano waikawa citric hou ma ka pakeneka kaumaha. He mea nui e hoʻomaopopo i ka wā e hoʻokō ai i kēia mau kaʻina hana, he mea nui ke kaulike akahele o ka manawa hoʻomohu, ka mahana ʻauʻau a me ka noʻonoʻo ʻana e pale aku i ka "ʻālohilohi" i wehewehe ʻia ma mua.
ʻOkoʻa nā hana passivation e like me ka nui o ka chromium a me nā ʻano mīkini o kēlā me kēia papa. E hoʻomaopopo i nā kolamu e kuhikuhi ana i ke Kaʻina Hana 1 a i ʻole ke Kaʻina Hana 2. E like me ka mea i hōʻike ʻia ma ke Kiʻi 3, ʻoi aku ka liʻiliʻi o nā ʻanuʻu o ke Kaʻina Hana 1 ma mua o ke Kaʻina Hana 2.
Ua hōʻike ʻia nā hoʻokolohua hale hana e ʻoi aku ka maʻalahi o ke kaʻina hana passivation citric acid i ka "ʻālohilohi" ma mua o ke kaʻina hana nitric acid. ʻO nā mea e kōkua ana i kēia hoʻouka kaua ʻana, ʻo ia ka mahana ʻauʻau kiʻekiʻe loa, ka manawa hoʻomoʻa lōʻihi loa, a me ka haumia ʻauʻau. Loaʻa nā huahana citric acid i loaʻa nā mea hoʻopaʻa corrosion a me nā mea hoʻohui ʻē aʻe e like me nā mea hoʻomaʻū a ua hōʻike ʻia e hōʻemi i ka maʻalahi i ka "flash corrosion".
ʻO ke koho hope loa o ke ʻano passivation e hilinaʻi ʻia i nā pae ʻae i kau ʻia e ka mea kūʻai aku. E ʻike iā ASTM A967 no nā kikoʻī. Hiki ke kiʻi ʻia ma www.astm.org.
Hana pinepine ʻia nā hoʻāʻo e loiloi i ka ʻili o nā ʻāpana passivated. ʻO ka nīnau e pane ai, "Hoʻopau anei ka passivation i ka hao manuahi a hoʻonui i ke kūpaʻa ʻana i ka pala o nā māka ʻoki manuahi?"
He mea nui e kūlike ke ʻano hoʻāʻo me ka māka e loiloi ʻia ana. ʻO nā hoʻāʻo paʻakikī loa e hāʻule i nā mea maikaʻi loa, ʻoiai ʻo nā hoʻāʻo palupalu loa e hala i nā ʻāpana maikaʻi ʻole.
ʻOi aku ka maikaʻi o ka loiloi ʻana i nā kila kila kila 400 series precipitation hardening a me nā kila kila free-machining i loko o kahi keʻena i hiki ke mālama i ka 100% humidity (laʻana pulu) no 24 mau hola ma 95°F (35°C). ʻO ka ʻāpana kea pinepine ka ʻili koʻikoʻi loa, ʻoi aku hoʻi no nā māka ʻoki manuahi. ʻO kekahi kumu no kēia, ʻo ia ka hoʻolōʻihi ʻia o ka sulfide i ke kuhikuhi mīkini, e hui pū ana me kēia ʻili.
Pono e kau ʻia nā ʻili koʻikoʻi i luna, akā ma 15 a 20 degere mai ke kū pololei e ʻae ai i ka nalowale ʻana o ka makū. ʻAʻole e popo ka mea i hoʻoneʻe pono ʻia, ʻoiai hiki ke hōʻike iki ʻia kekahi kala.
Hiki ke loiloi ʻia nā pae kila kila Austenitic ma o ka hoʻāʻo ʻana i ka haʻahaʻa. Ke hoʻāʻo ʻia pēlā, pono e loaʻa nā kulu wai ma luna o ka ʻili o ka hāpana, e hōʻike ana i ka hao manuahi ma ke alo o kekahi ʻōpala.
Pono nā kaʻina hana like ʻole no ka passivating i nā kila kila ʻokiʻoki manuahi a me nā kila kila ʻokiʻoki ʻole i hoʻohana pinepine ʻia i loko o nā hopena citric a nitric acid paha. Hāʻawi ke Kiʻi 3 ma lalo nei i nā kikoʻī e pili ana i ke koho ʻana i ke kaʻina hana.
(a) E hoʻoponopono i ka pH me ka sodium hydroxide. (b) E nānā i ke Kiʻi 3 (c) Hōʻike ʻo Na2Cr2O7 i 3 oz/galani (22 g/l) sodium dichromate i loko o 20% nitric acid. ʻO kahi koho ʻē aʻe i kēia hui ʻana he 50% nitric acid me ka ʻole o ka sodium dichromate
ʻO kahi ala wikiwiki e hoʻohana ai i ka hopena ma ASTM A380, "Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems." ʻO ka hoʻāʻo ʻana, ʻo ia ka holoi ʻana i ka ʻāpana me kahi hopena keleawe sulfate/sulfuric acid, e mālama ana iā ia i ka pulu no 6 mau minuke a nānā i ka uhi keleawe. Ma ke ʻano he koho ʻē aʻe, hiki ke hoʻokomo ʻia ka ʻāpana i loko o ka hopena no 6 mau minuke. Inā heheʻe ka hao, hana ʻia ka uhi keleawe. ʻAʻole pili kēia hoʻāʻo i nā ʻili o nā ʻāpana hana meaʻai. Eia kekahi, ʻaʻole pono e hoʻohana ʻia no 400 series martensitic a i ʻole nā ​​​​​​kila ferritic chromium haʻahaʻa no ka mea hiki ke loaʻa nā hopena maikaʻi ʻole.
I ka wā ma mua, ua hoʻohana ʻia ka hoʻāʻo pīpī paʻakai 5% ma 95°F (35°C) e loiloi i nā laʻana passivated. He paʻakikī loa kēia hoʻāʻo no kekahi mau papa a ʻaʻole pono e hōʻoia i ka pono o ka passivation.
E hōʻalo i ka hoʻohana ʻana i nā chloride keu, hiki ke hoʻoulu i nā hoʻouka kaua flash ʻino. Inā hiki, e hoʻohana wale i ka wai kiʻekiʻe me ka emi ma mua o 50 mau ʻāpana no ka miliona (ppm) chloride. ʻO ka wai piula wai ka mea maʻamau a hiki ke ʻae i kekahi mau haneli ppm chloride i kekahi mau hihia.
He mea nui e hoʻololi pinepine i ka ʻauʻau i ʻole e nalowale ka hiki ke passivation, hiki ke alakaʻi i nā hahau uila a me nā ʻāpana i hōʻino ʻia. Pono e mālama ʻia ka ʻauʻau i ka mahana kūpono, no ka mea, hiki i nā mahana holo ʻole ke hana i ka pala kūloko.
He mea nui e mālama i kahi papa hana hoʻololi hoʻonā kikoʻī loa i ka wā o ka holo ʻana o ka hana kiʻekiʻe e hōʻemi i ka hiki ke haumia. Ua hoʻohana ʻia kahi hāpana kaohi e hoʻāʻo i ka pono o ka ʻauʻau. Inā hoʻouka ʻia ka hāpana, ua hiki i ka manawa e hoʻololi i ka ʻauʻau.
E ʻoluʻolu e kuhikuhi aku he hana kila kila wale nō kekahi mau mīkini; e hoʻohana i ka mea hoʻalili makemake like e ʻoki i ke kila kila, koe naʻe nā metala ʻē aʻe a pau.
Hoʻokaʻawale ʻia nā ʻāpana o ka ʻūpā DO e pale aku i ka hoʻopili ʻana o ka metala-i-ka-metala. He mea nui loa kēia no ka hana ʻana i ke kila kila kila, no ka mea, pono nā hopena passivation a me nā hoʻoheheʻe wai e kahe ana e hoʻolaha i nā huahana corrosion sulfide a pale aku i ka hoʻokumu ʻia ʻana o nā ʻeke waikawa.
Mai hoʻopau i nā ʻāpana kila kila carburized a nitrided paha. Hiki ke hoʻemi ʻia ke kūpaʻa ʻana o ka pala o nā ʻāpana i mālama ʻia a hiki i kahi e hoʻouka ʻia ai lākou i loko o ka ʻauʻau passivation.
Mai hoʻohana i nā mea hana hao i loko o kahi hale hana i maʻemaʻe ʻole. Hiki ke pale ʻia ka ʻōpala kila ma ka hoʻohana ʻana i nā mea hana carbide a i ʻole keramika.
Mai poina e hiki ke pala i loko o ka ʻauʻau passivation inā ʻaʻole i mālama pono ʻia ka ʻāpana i ka wela. Pono e hoʻopaʻakikī ʻia nā papa martensitic chromium kiʻekiʻe no ke kūpaʻa ʻana i ka pala.
Hoʻopau pinepine ʻia ka passivation ma hope o ka hoʻomāinoino ʻana ma hope me ka hoʻohana ʻana i nā mahana e mālama ai i ke kūpaʻa i ka corrosion.
Mai hoʻowahāwahā i ka nui o ka waikawa nitric i loko o ka ʻauʻau passivation. Pono e hana i nā nānā manawa me ka hoʻohana ʻana i ke kaʻina hana titration maʻalahi i hāʻawi ʻia e Carpenter. Mai passivate i nā kila kila ʻoi aku ma mua o hoʻokahi i ka manawa. Pale kēia i ka huikau pipiʻi a pale i nā hopena galvanic.
E pili ana i nā mea kākau: He loea noiʻi a me ka hoʻomohala ʻana ʻo Terry A. DeBold i ka hoʻohuihui kila kila a ʻo James W. Martin he loea hao pā ma Carpenter Technology Corp. (Reading, PA).
I loko o kahi honua o nā kikoʻī hoʻopau ʻili e paʻakikī nei, he mea pono nō nā ana "roughness" maʻalahi. E nānā kākou i ke kumu he mea nui ke ana ʻana o ka ʻili a pehea e hiki ai ke nānā ʻia ma ka papahele hale kūʻai me nā ana lawe lima akamai.
Ke maopopo nei iā ʻoe ua loaʻa iā ʻoe ka mea hoʻokomo maikaʻi loa no kēia hana hoʻohuli? E nānā i ka chip, ʻoiai inā waiho ʻia me ka nānā ʻole. Hiki i nā ʻano o ka chip ke haʻi iā ʻoe i nā mea he nui.