Ua hōʻoia ʻoe ua hana ʻia nā ʻāpana e like me ke kikoʻī.
ʻO ka passivation kahi hana koʻikoʻi i ka hoʻonui ʻana i ke kūpaʻa corrosion kumu o nā ʻāpana mīkini ʻaila a me nā hui. Hiki iā ia ke hana i ka ʻokoʻa ma waena o ka hana ʻoluʻolu a me ka hemahema mua.
ʻO ka passivation kahi hana ma hope o ka hana ʻana e hoʻonui ai i ka pale ʻana i ka corrosion kūʻokoʻa o nā ʻāpana kila kila e hana ai i ka mea hana.
ʻAʻohe manaʻo nui e pili ana i ke ʻano o ka hana ʻana o ka passivation. Akā, ʻike ʻia aia he kiʻi ʻoniʻoni pale ma ka ʻili o ke kila kila kila.
ʻO kahi ʻāpana kila kila maʻemaʻe, hana hou ʻia, ʻoliʻoli a pickled paha e loaʻa koke i kēia kiʻi ʻoniʻoni ma muli o kona ʻike ʻana i ka oxygen ea.
I ka hoʻomaʻamaʻa, akā naʻe, hiki i nā mea haumia e like me ka lepo hale kūʻai a i ʻole nā ​​​​mea hao mai nā mea ʻoki ʻoki hiki ke hoʻololi i ka ʻili o nā ʻāpana kila kila i ka wā o ka mīkini.
I ka wā o ka mīkini ʻana, hiki ke hoʻopau i ka mea hana a hoʻololi i ka ʻili o ka mea hana kila kila.
Pēlā nō, hiki ke hoʻopili ʻia nā ʻāpana liʻiliʻi o ka lepo hale kūʻai ferrous i ka ʻili o ka ʻāpana.
Hiki i nā sulfides i hōʻike ʻia ke pilikia. Hele mai lākou mai ka hoʻohui ʻana i ka sulfur i ke kila kila e hoʻomaikaʻi ai i ka mīkini.
I nā hihia ʻelua, koi ʻia ka passivation e hoʻonui i ke kūpaʻa kūlohelohe maoli o ke kila kila.
ʻO ke kaʻina hana ʻelua-ʻanuʻu e hāʻawi i ka pale ʻana i ka corrosion maikaʻi loa: 1. ʻO ka hoʻomaʻemaʻe, kahi hana maʻamau akā ʻike ʻole ʻia i kekahi manawa;2. Acid bath a i ʻole ka mālama ʻana i ka passivation.
Pono ka hoʻomaʻemaʻe ʻana he mea nui.
I kekahi manawa hiki i ka mea hoʻohana mīkini ke hoʻokuʻu i ka hoʻomaʻemaʻe kumu, me ka manaʻo hewa e hiki mai ana ka hoʻomaʻemaʻe a me ka passivation i ka manawa like ma ke kaomi wale ʻana i kahi ʻāpana momona i loko o ka wai ʻauʻau. ʻAʻole hiki kēia.
E ʻoi aku ka maikaʻi, ʻo ka hoʻohaumia ʻana o nā hāʻina passivation, aia i kekahi manawa ke kiʻekiʻe o nā chlorides, hiki ke hoʻoulu i ka "flashing." ʻAʻole like me ka loaʻa ʻana o ke kiʻi ʻoniʻoni i makemake ʻia me kahi ʻili ʻālohilohi, maʻemaʻe, kūpaʻa i ka ʻino, hiki i ka etching flash ke hopena i kahi ʻili nui i kālai ʻia a pōʻeleʻele paha - ka pōʻino o ka ʻili i hoʻolālā ʻia e passivation e hoʻomaikaʻi.
ʻO nā ʻāpana i hana ʻia mai ka martensitic stainless steel [magnetic, moderately resistant to corrosion, yield strength up to about 280 ksi (1930 MPa)] ua paʻakikī i nā wela kiʻekiʻe a laila hoʻomaʻamaʻa ʻia e hōʻoia i ka paʻakikī i makemake ʻia a me nā waiwai mechanical.
I kēia hihia, pono e hoʻomaʻemaʻe maikaʻi ʻia ka ʻāpana me ka degreaser a i ʻole ka mea hoʻomaʻemaʻe e wehe i nā ʻāpana o ka ʻoki ʻana i ka wai ma mua o ka mālama ʻana i ka wela. A i ʻole, ʻo ka ʻoki ʻana i ka wai i koe ma ka ʻāpana hiki ke hoʻoulu i ka oxidation nui. pale ʻana i ka rosion.
Ma hope o ka hoʻomaʻemaʻe hoʻomaʻemaʻe ʻana, hiki ke hoʻokomo ʻia nā ʻāpana kila kila i loko o ka wai wai passivating. Hiki ke hoʻohana ʻia kekahi o nā ʻano ʻekolu - ka nitric acid passivation, nitric acid me ka sodium dichromate passivation, a me ka citric acid passivation. ʻO ke ʻano o ka hoʻohana ʻana ma muli o ke ʻano o ke kila kila a me nā ʻae ʻae ʻia.
ʻOi aku ka nui o ka corrosion-resistant chrome-nickel grades hiki ke passivated in a 20% (v / v) nitric acid bath (Figure 1). E like me ka mea i hōʻike ʻia ma ka papaʻaina, hiki ke hoʻololi ʻia ke kila kila kila liʻiliʻi ma ka hoʻohui ʻana i ka sodium dichromate i kahi ʻauʻau nitric acid, e hana ana i ka hopena i ʻoi aku ka oxidizing a hiki ke hana i kahi kiʻiʻoniʻoni passive ma luna o ka metala nichromate. ʻO ka hoʻohui ʻana o ka sodium dichromate a me ke kiʻekiʻe kiʻekiʻe o ka waikawa nitric e hōʻemi i ka manawa o ka uila makemake ʻole.
ʻO ke kaʻina hana no ka passivating free-machining stainless steels (i hōʻike ʻia ma ka Figure 1) he ʻano ʻokoʻa ia mai kēlā no ka hana ʻole ʻole-machining stainless steel grades. 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 ​​​​mea āpau o ka sulfur machinable grade sulfides, e hana ana i nā microscopic discontinuities ma ka ʻili o ka mīkini.
Hiki i ka ho'oma'ema'e wai ma'amau ke waiho i ke koena waika i loko o kēia mau ho'opau 'ana ma hope o ka passivation. A laila e ho'ouka kēia 'akika i ka ili o ka 'āpana ke 'ole ia e ho'opau a wehe 'ia.
No ka hoʻololi maikaʻi ʻana i ke kila kila maʻalahi, ua hoʻomohala ʻo Carpenter i ke kaʻina AAA (Alkali-Acid-Alkali), kahi e hoʻopau ai i ke koena acid. Hiki ke hoʻopau ʻia kēia ala passivation ma lalo o 2 hola.
Ma hope o ka hoʻoheheʻe ʻana, e hoʻoheheʻe i nā ʻāpana i loko o kahi solution 5% sodium hydroxide ma 160 ° F a i 180 ° F (71 ° C a 82 ° C) no nā minuke 30. A laila holoi pono i nā ʻāpana i ka wai. A laila, e hoʻokomo i ka ʻāpana no 30 mau minuke i loko o kahi 20% (v / v) nitric acid / gal (2 oz) i loko o ka 2 dichromate acid / gal (2 dichromate acid / gal) i loko o 2 dichromate. 40°F (49°C) a i 60°C).Ma hope o ka wehe ʻana i ka ʻāpana mai ka ʻauʻau, holoi ʻia me ka wai a laila hoʻokomo i loko o ka solution sodium hydroxide no kekahi mau minuke 30. E holoi hou i ka ʻāpana me ka wai a maloʻo, e hoʻopau i ke ʻano AAA.
Hoʻonui nui ʻia ka passivation acid citric me nā mea hana e makemake e pale i ka hoʻohana ʻana i nā ʻakika mineral a i ʻole nā ​​​​mea e loaʻa ai ka sodium dichromate, a me nā pilikia hoʻokuʻu a me nā pilikia palekana e pili ana i kā lākou hoʻohana.
ʻOiai ke hāʻawi nei ka citric acid passivation i nā pōmaikaʻi kaiapuni, makemake paha nā hale kūʻai i kūleʻa me ka passivation acid inorganic a ʻaʻohe pilikia palekana.
ʻO ka passivation i loko o ka ʻauʻau citric acid ua ʻike ʻia he mea pono no ka nui o nā mea kila kila, e like me ka mea i hōʻike ʻia ma ka Figure 2. e pale aku i ka "flashing" i wehewehe mua ʻia.
ʻOkoʻa ka mālama ʻana i ka passivation e like me ka ʻike o ka chromium a me nā ʻano mīkini o kēlā me kēia papa.
Ua hōʻike ʻia nā hoʻokolohua Laboratory e ʻoi aku ka maʻalahi o ka citric acid passivation kaʻina "flashing" ma mua o ka nitric acid process.Factors contributing to this attack include too high bath temperature, long soak time, and bath contamination.Citric acid products loaʻa nā corrosion inhibitors a me nā mea hoʻohui ʻē aʻe e like me ka wetting agents i loaʻa i ke kūʻai aku a hōʻike ʻia e hoʻemi i ka corrosion.
ʻO ka koho hope loa o ke ʻano passivation e hilinaʻi ʻia i nā koina ʻae i kau ʻia e ka mea kūʻai. E ʻike iā ASTM A967 no nā kikoʻī.
Hoʻohana pinepine ʻia nā hoʻāʻo e loiloi i ka ʻili o nā ʻāpana passivated. ʻO ka nīnau e pane ʻia, "E hoʻoneʻe anei ka passivation i ka hao manuahi a hoʻopaʻa pono i ka pale ʻana o ka ʻoki manuahi?"
He mea nui ke ʻano o ka hoʻāʻo ʻana e like me ka papa e loiloi ʻia nei. ʻO nā hoʻāʻo ʻoi loa e hāʻule i nā mea maikaʻi maikaʻi loa, aʻo nā hoʻāʻo ʻole ʻole e hele i nā ʻāpana maikaʻi ʻole.
400 series precipitation hardening a me ka noa-machining kuhiliʻole steels ua maikaʻi loiloi 'ia i loko o ka aha Kuhina hiki ke mālama i 100% humidity (kahi laʻana pulu) no 24 hola ma 95 ° F (35° C). O ke kea pauku pinepine i ka loa koʻikoʻi ili, oi aku no ka noa-okiʻoki grades.
Pono e kau ʻia nā ʻili koʻikoʻi i luna, akā ma 15 a 20 degere mai ke kūpaʻa e ʻae ai i ka nalowale o ka makū.
Hiki ke loiloi ʻia nā māka kila kila Austenitic ma ka hoʻāʻo ʻana i ka haʻahaʻa. Ke hoʻāʻo ʻia, 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.
ʻO nā kaʻina hana no ka passivating maʻamau i hoʻohana ʻia i ka ʻoki manuahi a me ka ʻoki ʻole ʻole i ka ʻokiʻoki ʻole i ka citric a i ʻole ka nitric acid solution e koi i nā kaʻina hana like ʻole.
(a) Hoʻololi i ka pH me ka sodium hydroxide.(b) E nānā i ke Kiʻi 3 (c) Na2Cr2O7 e hōʻike ana i 3 oz/galani (22 g/l) sodium dichromate i loko o 20% nitric acid. ʻO kahi mea ʻē aʻe i kēia hui ʻana he 50% nitric acid me ka sodium dichromate
ʻO ke ala wikiwiki ka hoʻohana ʻana i ka hopena ma ASTM A380, "Hoʻomaʻamaʻa maʻamau no ka hoʻomaʻemaʻe, hoʻomaʻemaʻe, a me ka passivation o nā ʻāpana kila kila, nā lako, a me nā ʻōnaehana." ʻO ka hoʻāʻo ʻana ʻo ka holoi ʻana i ka ʻāpana me kahi solution copper sulfate/sulfuric acid, e hoʻomau i ka pulu no 6 mau minuke a me ka nānā ʻana no ka hoʻopaʻa ʻana i ke keleawe. ʻAʻole pili kēia ho'āʻo i ka ʻili o nā ʻāpana hana meaʻai. Eia kekahi, ʻaʻole pono e hoʻohana ʻia no 400 series martensitic a i ʻole chromium ferritic steels no ka mea e hiki mai ana nā hopena maikaʻi ʻole.
Ma ka mōʻaukala, ua hoʻohana ʻia ka hoʻāʻo ʻana o ka paʻakai 5% ma 95°F (35°C) no ka loiloi ʻana i nā sample passivated. He paʻakikī loa kēia hōʻike no kekahi mau māka a ʻaʻole pono e hōʻoia i ka maikaʻi o ka passivation.
E hōʻalo i ka hoʻohana ʻana i nā chlorides keu, hiki ke hoʻoulu i nā hoʻouka uila.
He mea nui e hoʻololi i ka ʻauʻau i nā manawa a pau i ʻole e nalowale ka passivation hiki ke alakaʻi i ka uila a me nā ʻāpana ʻino.
He mea nui ka mālama ʻana i kahi hoʻololi hoʻololi kikoʻī kikoʻī i ka wā o ka hana kiʻekiʻe e hoʻemi i ka hiki ke hoʻohaumia. Ua hoʻohana ʻia kahi laʻana mana e hoʻāʻo ai i ka pono o ka ʻauʻau.
E ʻoluʻolu e hoʻomaopopo i ka hana ʻana o kekahi mau mīkini i ke kila kuhili wale;e hoʻohana i ka mea hoʻoluʻu like ʻole e ʻoki i ke kila kila, me ka ʻole o nā metala ʻē aʻe.
Hoʻokaʻawale ʻia nā ʻāpana rack DO i mea e pale aku ai i ka hoʻopili metala.
Mai hoʻokaʻawale i nā ʻāpana kila kuhili ʻole i ka carburized a i ʻole nitrided. Hiki ke hoʻemi ʻia ka pale ʻana o nā ʻāpana i mālama ʻia a hiki i kahi e hoʻouka ʻia ai lākou i ka ʻauʻau passivation.
Mai hoʻohana i nā mea hana ferrous i loko o kahi hale hana i maʻemaʻe ʻole.
Mai poina e hiki mai ka corrosion i loko o ka ʻauʻau passivation inā ʻaʻole mālama pono ʻia ka ʻāpana.
Hoʻohana pinepine ʻia ka passivation ma hope o ka hoʻohana ʻana i nā mahana e mālama ai i ke kūpaʻa corrosion.
Mai haʻalele i ka manaʻo o ka waika nitric i loko o ka ʻauʻau passivation. Pono e hana ʻia nā loiloi manawa me ka hoʻohana ʻana i ke kaʻina hana titration maʻalahi i hāʻawi ʻia e Carpenter.
E pili ana i nā mea kākau: ʻO Terry A. DeBold he mea noiʻi a me ka hoʻomohala ʻana i ke kila kila kila a ʻo James W. Martin he mea hoʻokele pahu ma Carpenter Technology Corp. (Reading, PA).
I loko o ka honua o nā kikoʻī hoʻopau ʻili, pono mau ke ana ʻana o ka "ʻeleʻele".
ʻIke paha ʻoe i ka mea hoʻokomo maikaʻi loa no kēia hana hoʻololi?