ʻO ke kila kila Ferritic e pili ana i ke kila kila me ka ferrite cubic i hoʻokumu ʻia i ke kino e like me ke ʻano matrix ma ka wela kiʻekiʻe a me ka mahana maʻamau. He hao a me ka chromium ka Ferritic stainless steel i nā mea nui, ʻaʻole i loaʻa i ka nickel, a aia kekahi i kahi liʻiliʻi o ka molybdenum, titanium a i ʻole niobium a me nā mea ʻē aʻe. Loaʻa iā ia ke kūpaʻa oxidation maikaʻi, ka pale ʻana i ka corrosion a me ka chloride corrosion cracking resistance. Eia kekahi, ua loaʻa i ka ferritic stainless steel nā hiʻohiʻona o ka conductivity thermal nui, ka hoʻonui liʻiliʻi liʻiliʻi, ke kūpaʻa oxidation maikaʻi, a me ke kūpaʻa koʻikoʻi koʻikoʻi. Hoʻohana nui ʻia e hana i nā ʻāpana kū i ka lewa, ka wai wai, ka wai, a me ka corrosion acid oxidative. ʻO nā māka mākaʻikaʻi o ke kila stainless ferritic: AISI 410 (UNS S41000), AISI 420 (UNS S42000), AISI 430 (UNS S43000) e like me ka ASTM; 1.4006, 1.4021, 1.4016, e like me EN maʻamau ... etc.
Hiki ke hoʻokaʻawale ʻia ke kila kila Ferritic i haʻahaʻa chromium, medium chromium a me kiʻekiʻe chromium e like me ka chromium maʻiʻo. E like me ka maʻemaʻe o ke kila, ʻoi aku ka nui o nā mea o ke kalapona a me ka nitrogen impurities, hiki ke hoʻokaʻawale ʻia i ke kila kila ferritic maʻamau a me ka ultra-pure ferritic stainless steel. Ordinary ferritic kuhiliʻole kila i ka hemahema o ka haʻahaʻa wela a me ka lumi wela brittleness, notch sensitivity, kiʻekiʻe intergranular corrosion tendency, a ilihune weldability. ʻOiai ua hoʻomohala ʻia kēia ʻano kila ma mua, ua kaupalena nui ʻia kāna noi ʻoihana. ʻO kēia mau hemahema o ke kila kila ferritic maʻamau e pili ana i ka maʻemaʻe o ke kila, ʻoi aku ka kiʻekiʻe o nā mea interstitial e like me ke kalapona a me ka nitrogen i ke kila. I ka lōʻihi o ka haʻahaʻa o ke kalapona a me ka nitrogen i ke kila, hiki ke lanakila i nā hemahema i luna.
Hoʻohālikelike ʻia meaustenitic stainless steel, ʻoi aku ka maikaʻi o ka pale ʻana i ka corrosion, ka pale wela a me ka processability. Ma muli o ka hiki ʻole i ka pae ferrite ke hoʻoheheʻe i ke kalapona, loaʻa i ka ferrite nā ʻano palupalu a maʻalahi hoʻi e deform. E like me ke kila kila martensitic, no ka mea, ʻo ke ʻano o ka lattice he ʻano cubic i hoʻokumu ʻia i ke kino, he paramagnetic ia, no laila ʻo ke kila kila ferritic he magnetic. Austenitic kuhiliʻole kila he non-magnetic no ka mea, o kona alo-waena o ka cubic hale.
ʻO ke kumukūʻai o ke kila kila ferritic ʻaʻole ia he haʻahaʻa a paʻa, akā he nui nā hiʻohiʻona kūikawā a me nā pono. Ua hōʻike ʻia ʻo ka ferritic stainless steel he mea ʻokoʻa maikaʻi loa.
He kila kuhiliʻole ferritic maʻamau
ʻO ia mau mea kila he haʻahaʻa, waena a me nā mea chromium kiʻekiʻe. Loaʻa i ka 11% a i ka 14% chromium ke kila kila ferritic haʻahaʻa, e like me 00Cr12 a me 0Cr13Al ma Kina. ʻAmelika AISI 400, 405, 406MF-2. ʻO kēia ʻano kila he paʻakikī maikaʻi, plasticity, deformation anu a me ka weldability. No ka mea he nui ka nui o ka chromium a me ka alumini i ke kila, maikaʻi ke kūpaʻa oxidation a me ka pale ʻana. 405 hiki ke hoʻohana 'ia e like me ka petroleum hoʻomaʻemaʻe hale kiaʻi, pahu lining, mahu turbine lau, kiʻekiʻe wela sulfur corrosion mea kū'ē, etc. 400 no ka hale a me ke keʻena lako, a pela aku. etc. Medium chromium ferritic stainless steel, ka chromium content he 14% a 19%, e like me 1Cr17 a me 1Cr17Mo ma Kina. AISI 429, AISI 430, AISI 433, AISI 434, AISI 435, AISI 436, AISI 439 ma United States. ʻOi aku ka maikaʻi o kēia ʻano kila i ka ʻele a me ka pale ʻana i ka corrosion. He liʻiliʻi kona helu hoʻoikaika paʻakikī (n≈2), a he maikaʻi kāna hana kaha kiʻi hohonu, akā maikaʻi ʻole kona ductility. Hoʻohana ʻia ʻo AISI 430 ferritic stainless steel no ka hoʻonaninani hale, ka hoʻonani kaʻa, nā lako kīhini, nā mea puhi kinoea a me nā ʻāpana o nā mea hana ʻoihana nitric acid, a me nā mea ʻē aʻe. Hoʻohana ʻia ʻo 439 e like me ka hose no nā mea hoʻomehana wai kinoea, nā lanahu a me nā pipelines kinoea, a me nā mea ʻē aʻe. ʻO ke kila kila kila kila kiʻekiʻe he 19% a 30% chromium, e like me Cr18Si2 a me Cr25 ma Kina, AISI 442, AISI 443 a me AISI 446 ma United Mokuʻāina. Loaʻa i ia mau kila ke kūpaʻa oxidation maikaʻi. Hoʻohana mau ʻia ka AISI 442 i ka lewa, ʻo 1035 ° C ka palena palena kiʻekiʻe, a ʻo ka wela kiʻekiʻe no ka hoʻohana mau ʻana he 980 ° C. AISI 446 ferritic kuhiliʻole kila i oi aku ka oxidation kū'ē.
ʻO ke kuʻi ʻoniʻoni ferritic maʻemaʻe kiʻekiʻel
Aia i loko o kēia ʻano kila ke kalapona haʻahaʻa loa, ka nitrogen; kiʻekiʻe chromium, molybdenum, titanium, niobium a me nā mea ʻē aʻe. E like me ko Kina 00Cr17Mo, 00Cr18Mo2, 00Cr26Mol, 00Cr30Mo2. Loaʻa i kēia ʻano kila nā waiwai mechanical maikaʻi (ʻoi aku ka paʻakikī), weldability, intergranular corrosion resistance, pitting corrosion resistance, crevice corrosion resistance, a me ke koʻikoʻi koʻikoʻi ke kū'ē i ka pohā. No ka laʻana, 18-2 ferritic kuhiliʻole kila he maikaʻi corrosion kū'ē i loko o ka nitric acid, acetic acid, NaOH, pitting corrosion kū'ē i loko o 3% NaCl a FeCl3 ua like me 18-8 austenitic kuhiliʻole kila, 26CrMo kila ma ka nui media Corrosion kū'ē. , ʻoi loa i loko o nā ʻakika organik, nā waikawa oxidizing, a me nā alkali ikaika. Loaʻa iā ia ka pale corrosion pitting maikaʻi i loko o ka medium chloride ikaika. ʻAʻole hiki i ka chloride, ka hydrogen sulfide, ka waikawa sulfuric nui a me ka alkali ikaika. ʻO 30Cr-2Mo ka mea ʻoi aku ka nui o ke kūʻē ʻana i ka pitting corrosion a me ka crevice corrosion me ka mālama ʻana i ke kūpaʻa koʻikoʻi.
ʻO ke kūpaʻa ʻino o ke kila kuhili ʻole ferritic
(1) ʻAi like ʻole.
ʻO Chromium ka mea maʻalahi loa i ka passivate. I loko o ka lewa, ka hao-chromium alloy me ka chromium maʻiʻo o ka oi ma mua o 12% hiki ke ho-passivated. I loko o ka oxidizing medium, hiki ke passivated ka chromium content inā ʻoi aku ia ma mua o 17%. I kekahi mau mea corrosive, hiki ke hoʻohui ʻia ka chromium kiʻekiʻe a me ka molybdenum, nickel, keleawe a me nā mea ʻē aʻe e loaʻa ai ke kūpaʻa maikaʻi.
(2) Intergranular corrosion.
ʻO nā kila kuhili ʻole Ferritic, e like me nā kila kulika austenitic, e ʻeha i ka ʻino intergranular, akā ʻo ka mālama ʻana i ka sensitization a me ka mālama wela e pale aku ai i kēia corrosion he ʻokoʻa wale nō. Ferritic stainless steel mea prone i intergranular corrosion mai ka hooluolu wikiwiki ma luna o 925 ° C, a me ka moku'āina (sensitized state) i susceptible i intergranular corrosion hiki ke hoʻopau 'ia ma hope o ka pōkole manawa o ka tempering ma 650-815°C. ʻO ka corrosion intergranular o ke kila ferritic ka hopena o ka pau ʻana o ka chromium ma muli o ka ua carbide. No laila, ʻo ka hōʻemi ʻana i ka ʻike o ke kalapona a me ka nitrogen i ke kila a me ka hoʻohui ʻana i nā mea e like me ka titanium a me ka niobium hiki ke hōʻemi i ka maʻalahi o ka corrosion intergranular.
(3) ʻAi ʻana i ka lua a me ka māwae.
ʻO Chromium a me molybdenum nā mea ʻoi loa e hoʻomaikaʻi ai i ka pitting a me ka crevice corrosion resistance o ke kila kila. Ke piʻi aʻe ka ʻike chromium, piʻi pū ka ʻike chromium i loko o ke kiʻi oxide, a piʻi ka paʻa kemika o ke kiʻiʻoniʻoni. Hoʻopili ʻia ka Molybdenum ma ka ʻili metala ikaika ma ke ʻano o MoO4, ka mea e pale ai i ka hoʻoheheʻe ʻana o ka metala, hoʻoikaika i ka repassivation, a pale i ka pōʻino o ke kiʻiʻoniʻoni. No laila, ʻo ka chromium kiʻekiʻe a me ka molybdenum ferritic stainless steel he kūpaʻa maikaʻi loa i ka pitting a me ka crevice corrosion.
(4) Ke kū'ē i ke koʻikoʻi ka pohā ʻino.
Ma muli o nā hiʻohiʻona o ka hoʻonohonoho hoʻonohonoho ʻana, ʻo ka ferritic stainless steel he corrosion-resistant i loko o ke kikowaena kahi austenitic stainless steel e hoʻopuka ai i ke koʻikoʻi koʻikoʻi.
Mechanical waiwai o ferritic kuhiliʻole kila
ʻAʻole hiki ke hoʻoikaika ʻia ke kila stainless Ferritic e ka mālama wela no ka mea ʻaʻohe hoʻololi ʻāpana. ʻO ka maʻamau, hoʻohana ʻia ma hope o ka hoʻopili ʻana ma 700-800 ° C. Ma muli o ka nui o ka atomic like o ka hao a me ka chromium, he liʻiliʻi ka hopena hoʻoikaika ikaika, ʻoi aku ka kiʻekiʻe o ka ikaika a me ka ikaika tensile o ka ferritic stainless steel ma mua o ke kila kalapona haʻahaʻa, a ʻoi aku ka haʻahaʻa o ka ductility ma mua o ke kila kalapona haʻahaʻa. .
1) ʻO ka brittleness wela o ke kila ferritic maʻamau.
Pilikia ke kila kuhiliʻole ferritic maʻamau i nā notches, a ʻoi aku ka mahana o ka hoʻololi brittle ma luna o ka wela o ka lumi koe wale nō ka haʻahaʻa chromium ferritic kila. ʻO ke kiʻekiʻe o ka chromium maʻiʻo, ʻoi aku ka nui o ka brittleness anu. Keia anu brittleness pili i ka interstitial mea e like me ka carbon a me ka nitrogen i loko o ke kila, a me ka ultra-maemae ferritic kila i loa haʻahaʻa kalapona maʻiʻo i interstitial mea e like me kalapona a me ka naikokene, no laila, hiki ke loaʻa ka maikai toughness, a me ka brittle hoʻololi. Hiki ke hoʻemi ʻia ka mahana ma lalo o ka mahana wela.
2) Kiʻekiʻe wela embrittlement o maʻamau ferritic kuhiliʻole kila.
Hoʻomaʻamaʻa ʻia ke kila kila ferritic maʻamau ma luna o 927 ° C a laila hoʻomaʻalili wikiwiki i ka lumi wela, hoʻemi nui ʻia ka plasticity a me ka paʻakikī. ʻO kēia embrittlement wela kiʻekiʻe e pili ana i ka ua wikiwiki o nā pūhui kalapona (nitride) ma nā palena palaoa a i ʻole nā dislocations ma kahi mahana o 427-927 °C. ʻO ka hoʻemi ʻana i ke kalapona a me ka nitrogen maʻiʻo o ke kila (me ka hoʻohana ʻana i ka ʻenehana ultra-pure) hiki ke hoʻomaikaʻi nui i kēia brittleness. Eia kekahi, i ka wā e wela ai ke kila ferritic ma luna o 927 ° C, e hoʻohaʻahaʻa ʻia ka nui o ka palaoa, a e hoʻohaʻahaʻa ka palaoa i ka plasticity a me ka paʻakikī o ke kila.
3) Hoʻokumu ʻia o ka σ-phase.
Wahi a ke kiʻikuhi iron-chromium phase, ke mālama ʻia ma 500-800 ° C, ʻo ka huila i loaʻa ka 40% -50% chromium e hana i hoʻokahi māhele σ, a ʻo ka alloy i loaʻa ma lalo o 20% a i ʻole 70% chromium e hana ʻia. he α+σ lua-pālua. ʻO ka hoʻokumu ʻana o ka σ-phase e hoʻemi nui i ka ductility a me ka paʻakikī o ke kila. No laila, ʻaʻole pono e hoʻohana ʻia ka ferritic stainless steel no ka manawa lōʻihi ma 500-800 °C.
4) ʻAha ma 475°C.
ʻO ka chromium kiʻekiʻe (> 15%) ke kila ferritic e hoʻopau ikaika ʻia ke mālama ʻia ma 400-500 °C. ʻOi aku ka pōkole o kēia ʻano embrittlement ma mua o ka ua o ka māhele σ. No ka laʻana, ke mālama ʻia ka 0.080C-0.4Si-16.9Cr ferritic stainless steel ma 450 ° C no 4 mau hola, ʻaneʻane hāʻule ka paʻakikī o ka lumi wela i ka ʻole. Hoʻonui ka pae o ka embrittlement me ka piʻi ʻana o ka maʻi chromium, akā hiki ke hoʻihoʻi ʻia ka paʻakikī ma hope o ka mālama ʻana ma luna o 600 °C. ʻO ka embrittlement ma 475 ° C ka hopena o ka ua o ka māhele alpha waiwai chromium. Pono ia kila e pale i ka wela ma kahi o 475°C.
Ka manawa hoʻouna: Mei-02-2023