1. ʻO ka hōʻuluʻuluʻana
ʻO "18-8 stainless steel" ka inoa maʻamau no ka ʻohana o nā kila kuhili ʻole austenitic i hōʻike ʻia e ka 18% Chromium a 8% nickel (no laila "18-8").
ʻO ka lālā kaulana loa ʻAno 304 (US S30400 / I 1.4301). 18-8 ʻO nā hao hao ka mea hana o ka ʻenehana kuhiliʻole no ka mea ua hui pū lākou i ke kūpaʻa ʻino ākea, maikaʻi loa, paʻakikī ka paʻakikī, a me ka hana maʻalahi.
ʻAʻole lākou, Akā naʻe,, ʻO ka koho maikaʻi loa no nā kaiapuni chloride koʻikoʻi a i ʻole nā mea kolo wela kiʻekiʻe - i kēlā mau ʻano nā mea hoʻohui me ka molybdenum hou., paʻa a duplex microstructure, ʻoi aku ka maikaʻi o nā alloys nickel-base.
2. He aha ke ʻano o "18-8" - wehewehe a me ka laulā
ʻO ka "18-8" kahi mea ʻike ʻole, mea wehewehe mōʻaukala e kuhikuhi ana nā mea kanu lāʻau me aneane 18 wt.% chromium a 8 wt.% nikela—ka haku mele austenitic maʻamau i hoʻokomo ʻia i ka hoʻomaka ʻana o ke kenekulia 20.
E pili ana i ka 300-series austenitic ohana: kumu nui ʻAno 304 a me kona mau ano (304L, 304Huh), me nā māka paʻa pili (E.g., 321, 347) e kaʻana like i ka 18-20% Cr / 8-10% Ni base akā e hoʻohui i ka titanium a i ʻole ka niobium e kāohi i ka ua carbide.
Nā kiʻi nui:
- ʻO "18-8" kahi pōkole kūpono - e kuhikuhi i ka helu pololei (E.g., 304, 304L, 321) ma ke kuai ana.
- Hoʻopaʻa ʻia ka microstructure austenitic e Ni; Hāʻawi ʻo Cr i ka passivity a me ka pale oxidation.
3. Nā māka maʻamau a me nā kūlana
Hoʻohana maʻamau maʻamau 18-8 komo nā ʻano like ʻole:
- ʻAno 304 (US S30400 / I 1.4301) - maʻamau 18-8 meaʻole; Laki nui.
- Pākuʻi 304l (S30403 / 1.4306) — ʻano kalapona haʻahaʻa (≤0.03% c) e hoʻemi i ka sensitization i ka wā wili.
- ʻAno 304H (S30409 / 1.4307) — kalapona kiʻekiʻe (≈0.04–0.10%) no ka hoʻomaikaʻi ʻana i ka ikaika ma nā wela kiʻekiʻe.
- ʻAno 321 (S32100 / 1.4541) — Hoʻopaʻa ʻia ʻo Ti no ke kūpaʻa maikaʻi aʻe i ka corrosion intergranular ma hope o ka ʻike ʻia ʻana ma ka pae 450-850 °C..
- ʻAno 347 (S34700 / 1.4550) — Nb-paʻa like me 321.
Aia nā kūlana e pili ana i kēia mau māka Apono a240 / A240M (papaʻi, she wallpaper), Astm A276 (Nā BaRS), ASME/ASME II, a me EN/ISO like. E kuhikuhi mau i ka maʻamau pololei a me ka helu UNS/EN i nā kikoʻī.
4. Chempion cempition o 18-8 kila kohu ʻole
| Mua | Kaonaʻeha (MAKAINA WAU 304 ohana) | ʻO ke kuleana mua |
| Chromium (Cr) | ~17.5 – 19.5 wt.% | Hoʻokumu i ke kiʻiʻoniʻoni passive Cr₂O₃ — mea kōkua nui i ka pale ʻana i ka corrosion |
| Nickel (I) | ~8.0 – 10.5 wt.% | Mea hoʻokūpaʻa Austenite; hoʻomaikaʻi i ka paʻakikī, ductility a me ka hana ʻana |
| KālekaʻAʻI (C) | ≤ 0.08 wt.% (304); ≤0.03 wt.% (304L) | Hoʻonui i ka ikaika akā ʻo ke kiʻekiʻe C ke kumu o ka ua carbide (hōʻikeʻike) |
| Mang kāne (Mn) | ≤ 2.0 wt.% maʻamau | Kōkua i ka deoxidation a me kekahi mau austenite stabilization |
Silikino (A) |
≤ ~1.0 wt.% | Deoxididhier; hopena liʻiliʻi i ka hana kiʻekiʻe-T |
| Phoshorus (P), Sulfur (S) | Hoʻohaʻahaʻa (meheu) | Mālama ʻia ka liʻiliʻi e mālama i ka paʻakikī a me ka pale ʻana i ka corrosion |
| Titanium (No) / Nihibium (Nb) | Hoʻohui i loko 321 / 347 | Mea hoʻopaʻa kalapona; e nakinaki i ka C e pale aku i ka ua Cr carbide |
| Mybrideum (Mo) | Ka mea maʻamau 0 ma ke ano kahiko 18-8 (aia ma 316) | Hoʻomaikaʻi i ka pale ʻana i ka lua - ʻaʻohe ma kahi ākea 18-8, no laila ua kaupalena ʻia ke kūʻē lua |
5. Mechanical waiwai o 18-8 kila kohu ʻole
Hāʻawi ka papa ma lalo nei i nā waiwai mekini no ka maʻamau 18-8 ʻO nā mea kanu lāʻau austetitic (E.g., ʻAno 304 ohana) i ka solution-annealed / kahi kūlana.
| Waiwai | Waiwai makamaka (Anned 18-8 / ʻAno 304 ohana) | Nā Pono Hoʻolālā & nā hopena hana anu |
| 0.2% hoʻopau i ka ikaika hua (RP0.2) | ~ 205 mpa (≈ 30 ksi) MAKAINA WAU; Nā haʻona ~190 – 260 Mpa | Anned 304 maʻamau ~ 205 MPa. Ke hana anuanu (Kauwili, hukiʻulu) hoonui i ka hua (hiki ke keu 400-800 mpa no ka deformation kaumaha). |
| Ikaika ikaika (Rm, Us) | ~515 – 720 Mpa (maʻamau ~ 520–620 MPa) | Piʻi ka UTS me ka hana anu; hiki ke hoʻokokoke a ʻoi aku paha nā mea hana anu nui 900 MPa i nā hihia koʻikoʻi. |
| Elongation ma ka wā hoʻomaha (A, %) | ~40 – 60 % (ma ka hōʻike hōʻike maʻamau) | Kiʻekiʻe ductility ma annealed kūlana. Hāʻule ka elongation i ka piʻi ʻana o ka hana anu a me ka paʻakikī (hiki ke hāʻule i lalo 20% no ka mea hana nui). |
Hālulu (Pōhakukwell / Mau Kanaka Waiwai) |
~70 – 95 Hrb (Koho Koho. ~120 – 220 HB) | HRB annealed maʻamau ~70–95. Hoʻonui nui ka paʻakikī i ka hana anu (ʻO ka pepa paʻakikī hana hiki ke ʻoi aku ma mua o HRB 100 / HB 250+). |
| Modulus o ka elasticity, E | ≈ 193 - 200 GPA | Hoʻohana ≈ 193 GPA no ka helu ʻana i ke kūkulu ʻana/ka ʻoʻoleʻa; ʻAʻole ʻike ʻia ʻo E i ka hana anu i hoʻohālikelike ʻia me ka ikaika. |
| Shear modlulus, G | ≈ 75 - 80 GPA | Hoʻohana ~77 GPa no ka helu torsion. |
| Lakiō o Poisson, n | ≈ 0.28 - 0.30 | Hoʻohana 0.29 ma ke ʻano he waiwai hoʻolālā kūpono. |
Kaluhi (S–N) - hoʻomanawanui maʻamau |
Pili loa i ka hoʻopau ʻana o ka ʻili, ʻo ke kaumaha a me nā hemahema; alakaʻi ʻinoʻino: palena hoʻomanawanui ≈ 0.3–0.5 × Rm no ka laumania, nā hiʻohiʻona i poni ʻia | Ma nā ʻāpana maoli e hoʻomalu ʻia ke ola luhi e nā welds, kūlana ili a me ke koʻikoʻi koena. E hoʻohana i ka hoʻāʻo ʻāpana a i ʻole ka mea hoʻolako i nā pihi S–N no ka hoʻolālā. |
| Ka hopena Charpy (Cvn) | ʻO ka paʻakikī maikaʻi—CVN lumi-mehana ma'amau >> 20-30 j no ka hapanui o nā ʻano huahana annealed | Austetetitic 18-8 paʻa paʻa i nā mahana haʻahaʻa; E kuhikuhi i nā waiwai CVN inā pono ka lawelawe haʻihaʻi a haʻahaʻa paha. |
6. O ka kino & Nā'lelo Thermal
- Huakai: ≈ 7.9 g · cad.
- Modulus o ka elasticity (E): ≈ 193–200 GPa.
- Ka HōʻaʻO Kokua: ʻano haʻahaʻa no kahi metala, ≈ 14–16 W·m⁻¹·K⁻¹ a 100 ° C (hāʻule me ka mahana).
- Ka maikaʻi o ka hoʻonuiʻana i ka: ≈ 16–17×10⁻⁶ K⁻¹ (20-100 ° C) — oi aku mamua o ke kila kalapona, mea nui no ka hoʻolālā hui ʻana.
- Hoʻohemo melū: SoUDUS ~ 1375-1400 ° C, wai ~ 1400-1450 ° C (pili i ka haku mele).
- ʻO ke ʻano mākēneki: mea nui non-magnetic i ke kūlana annealed; ʻO ka hana anu a i ʻole ka hoʻokumu ʻana o martensite e hāʻawi i ka ferromagnetism māmā.
Nā palena lawelawe wela: hoʻohana mau a hiki i ~400–800 °C hiki ke pili i ka alloy a me ke kaiapuni; e makaala i ka sensitization zone (~425–850 °C) a me ka carburization / oxidation ma nā wela kiʻekiʻe.
No ka ikaika kiʻekiʻe-T mau e noʻonoʻo i ka 304H, 309, 310 a i ʻole nā huila wela kiʻekiʻe.
7. ʻO ka hana ʻino - nā ikaika a me nā palena
Nā ikaika
- ʻO ke kū'ēʻana o ka'ōpū i loko o nā ea ea a me nā kemika he nui (nā ʻakika/base) i nā mahana ambient.
Hāʻawi ke kiʻiʻoniʻoni passive Cr₂O₃ i ka pono ākea i ka meaʻai, hale kūkulu hale a me nā kaʻina hana he nui. - Maʻemaʻe maikaʻi a maʻemaʻe, ʻo ia ke kumu 18-8 hoʻohana nui ʻia i ka meaʻai, mea inu a me nā mea lapaʻau.
PAHUI
- Pitting and crevice corrosionion ma chrloudes: me ka Mo, 18-8 hiki ke hoʻouka ʻia i ka hoʻouka ʻia ʻana i loko o ka media chloride-bearing media (Ke wai wai, palaualelo) ʻoi aku ka nui ma nā mahana kiʻekiʻe a i ʻole ma nā māwae.
Inā loaʻa nā chloride, ʻAno 316 (me Mo) koho pinepine ʻia nā ʻāpana duplex. - ʻO ke kūleʻaʻana o ke kalaʻana (SCC): Austetetitic 18-8 hiki i nā kila i ka SCC i hoʻokomo ʻia i ka chloride ma lalo o ke koʻikoʻi tensile a me ka wela kiʻekiʻe; pale i ka hui pū ʻana o ka tensile stress + chrlodes + keka ao.
- Intergranur corrosior (hōʻikeʻike): hiki ke loaʻa ma hope o ka ʻike ʻana i 425–850 °C ke ʻole ka haʻahaʻa-C (304L) a i ʻole nā māka paʻa (321/347) hoʻohana ʻia.
- Kahiki Galvaniko: i ka wā e hui pū ʻia ai me nā ʻāpana ʻoi aku ka maikaʻi, 18-8 Hiki iā ia ke hana ma ke ʻano he anode i kekahi mau electrolytes - hoʻolālā e pale i ka pilina metala ʻokoʻa a hāʻawi i ka insulation.
Ka lula koho pono: No ka lawelawe maʻamau i loaʻa nā chloride a i ʻole nā kūlana hoʻohaʻahaʻa kaumaha, loiloi 316 (Mo), super-austenitics, Duplex Oole nickel alloys.
8. Huahuai: hana, Machimen, wiliwili a hui
Hana
- Maikaʻi loa i ke kūlana annealed ma muli o ka ductility kiʻekiʻe. E hoʻohana i nā mea hana kūpono e helu ai i ka springback (kiʻekiʻe ma mua o ke kila māmā) a me ka hana ikaika o ka hana.
- Huki kaha & Ka pāpaleʻana mea maʻamau no nā ipu kuke a me nā ipu pā lahilahi.
Machimen
- Kaulana ʻo "gummy" hoʻohālikelike ʻia me ke kila kalapona; austenitic stainless steels hana-paʻakikī i ka ʻoki, ka mea e hoʻonui ai i ka lole paahana. ʻO ka hana maikaʻi loa:
-
- E hoʻohana i nā mea hana paʻa, mea paahana rake carbide.
- E hoʻohana i nā māmā ʻoki haʻahaʻa, ʻai kiʻekiʻe no ka hoʻoulu ʻana, a me ka mea hoʻoluʻu nui e pale aku i ka lihi i kūkulu ʻia a me ka wela.
- E hoʻohana i nā ʻaoʻao ʻoi aku a me nā mea haki.
Welding & hui pū
- Maikaʻi loa ma nā ʻano maʻamau (Gtaw, Kāmaʻa kikomua, Smaw, Pcow). Nā kiʻi nui:
-
- E hoʻohana i ke kalapona haʻahaʻa (304L) no nā hui welded kahi e hopohopo ai ka sensitization post-weld.
- E hoʻohana i nā metala hoʻopiha kūpono (E.g., 308L/308 mea hoʻopiha kulika no 304 metala kumu) e hoʻohālikelike i ka chemistry a pale i ka pohā wela.
- Hoʻoponopono i ka hoʻokomo wela & wela waena; hoʻomāhuahua ka wela nui i ka ʻāpana sensitized.
- ʻO ka anneal hopena ma hope o ka weld (1050-1100 ° C) hiki ke hoʻihoʻi i ka pale ʻana i ka corrosion ma kahi kūpono; ʻaʻole hiki ke kūpono no nā hale i hui ʻia.
HE MAU NUI, e hoʻohana i nā māka haʻahaʻa-C a i ʻole i hoʻopaʻa ʻia e pale i ka pono o PWHT. - E makaʻala i ka haki ʻana o ka paʻa ʻana i kekahi mau hoʻonohonoho weld - e hahai i nā WPS kūpono a me nā kaʻina hana prequalified.
ʻO nā hui ʻē aʻe
- Mohaihala, nā loina, hoʻopaʻa paʻa hoʻohana ʻia me nā flux kūpono a me nā hoʻomākaukau ʻili. Pono pinepine ka hoʻopili ʻana i ka ʻili o ka ʻili (Flame, plasma, kiʻi kemika).
9. ʻO ka hana wela & hana wela
- ʻAʻole hiki ke paʻakikī ma ke kinai & huhū (Austetetitic 18-8 ʻAʻole hana i ka martensite ma o ka mālama ʻana i ka wela e like me nā kila kalapona).
- Hoʻoholo i Airnaal: maʻamau ma 1010–1120 °C ukali ʻia e ke kinai wikiwiki (wai) e hoʻoheheʻe i nā carbide a hoʻihoʻi i ke kūpaʻa corrosion a me ka ductility. Hoʻohana ʻia ma hope o ke kuʻi ʻana/ka hana anu nui inā hiki.
- ʻO ka anneal hoʻomaha pilikia: pōmaikaʻi palena ʻole; ina hanaia, pale i nā mahana ma ka laulā o ka sensitization ke ʻole e ukali ʻia e ka anneal solution.
- ʻEhā: ʻike lōʻihi i ka 475 ° C (475 °C embrittlement) i kekahi hao-nickel-chromium alloys hiki embrittle ka mea - 'aʻole typical no 304, aka, e akahele i na hoike loihi ana.
10. Ke hoʻopauʻana, ka hoʻomaʻemaʻe a me ka hoʻomaʻemaʻe
- Hoʻopau mīkini: 2Na B, BA, No.1, No.4 (pua) etc. E koho i ka pau no ka noi: i poniia no ka ma'ema'e, matte no ka hale hana.
- Pickling & hoʻolauna: hoʻopau ʻia ka ʻili wela a me ka hao i hoʻokomo ʻia; hoʻolauna (nā lāʻau nitric a i ʻole citric acid) hoʻihoʻi a hoʻoikaika i ka kiʻiʻoniʻoni passive-koʻikoʻi ma hope o ka wili a hana ʻana paha.
Hoʻonui ʻia ka passivation acid citric no ka palekana a me nā kumu kaiapuni. - Uilaiauliwi: e ho'ēmi ana i ka 'ilikai a hoʻomaikaʻi i ka pale ʻana i ka corrosion (pono i nā ʻoihana lāʻau/meaʻai).
- ʻO ka hoʻomaʻemaʻe: pale i nā mea hoʻomaʻemaʻe chlorinated; makemake i nā mea hoʻomaʻemaʻe alkaline ʻoluʻolu a i ʻole nā mea hoʻomaʻemaʻe ma hope o ka holoi ʻana i ka wai inu. No ka hoʻohana maʻemaʻe koʻikoʻi, hōʻoia i ka hana hoʻomaʻemaʻe.
11. Nā noi maʻamau o 18-8 kila kohu ʻole
- ʻO ka lawelawe meaʻai a me nā lako hana: sinks, kaniulail, nā pahu - hygienic, hoʻomaʻemaʻe maʻalahi.
- Nā ʻili a me ka ʻokiʻoki: piha, hoʻopau pale-corrosion.
- Nā waiwai o ka hale: kā mākou kā'ā, kuʻina, nā panela mea hana.
- Mea hana kaʻina hana kemika (nā lawelawe mālie): Piping, nā pahu hopu no nā kaiapuni non-chloride.
- Nā mea paʻa, punawai (ke anu-hana), Kākau: hoʻohana i ka hana-paʻakikī no ka hana mechanical.
- Nā mea lapaʻau a me nā implants (koho i nā māka, hana hoʻomalu): ma muli o ka biocompatibility a me ka sterilizability (ʻaʻole naʻe a pau 18-8 ʻO nā ʻano like ʻole he lāʻau lapaʻau).
12. Hoʻohālikelike i nā Alloys pili
| Waiwai / Kālā | 18-8 Kila kohu ʻole (ʻAno 304 ohana) | ʻAno 316 (18-10 + Mo) | Hoʻopaʻa ʻia 18-8 (321 / 347) | Duplex 2205 |
| Nā mea koʻikoʻi o ka haku mele | ~ 18% cr, ~8–10% Ma | ~17–18% Cr, ~10–14% Ni, 2-3% mo | 18–20% Cr, ~8–10% Ma + No (321) Oole Nb (347) | ~22% Cr, ~5–6% Ni, ~3% Mo, N |
| ʻOhana huila | ʻO kahi kila kila Austetetitic | ʻO kahi kila kila Austetetitic | ʻO kahi kila kila Austetetitic (hoʻopaʻa ʻia) | ʻO ka kila kila fuplex (austentes + ferrite) |
| Kūʻē lua (pili pili) | Loli | Hoʻomaikaʻi vs 304 (Mo-hoʻonui) | E like me 304 | High (ʻoi aku ka maikaʻi ma mua o 304/316) |
| Kū'ē i ka chloride SCC | Ua kaupalena ʻia i nā kaiapuni chloride wela | ʻOi aku ka maikaʻi 304, akā hiki nō ke SCC | E like me 304 (pili ka stabilization i nā welds, ʻaʻole SCC) | Kūpono - ke kū'ē ikaika i ka chloride SCC |
| MAKAINA WAU 0.2% ka ikaika (Anned) | ~190–260 MPa | ~185–260 MPa | ~190–260 MPa | ~400–500 MPa |
ʻO ka ikaika maʻamau (Anned) |
~515–720 MPa | ~515–700 MPa | ~515–700 MPa | ~620–880 MPa |
| Kumaikalua / ewangantion | Kūpono (≈40–60%) | Kūpono (e like me 304) | Kūpono | Maikaʻi—maikaʻi (haʻahaʻa ma mua o nā māka austenitic) |
| Haʻahaʻa-mehana paʻakikī | Kūpono, paʻa paʻakikī i ka laulā cryogenic | Kūpono | Kūpono | Maikaʻi loa, akā, haʻahaʻa i nā kila austenitic piha |
| ʻO ka hoʻomauʻana | Loli; 304H makemake ʻia no ka wela kiʻekiʻe | Loli; 316H loaʻa | Kūʻē maikaʻi i ka sensitization | Ua kaupalena ʻia no ka lawelawe kolo lōʻihi |
| Wawahua | Kūpono; haʻahaʻa pilikia me 304L | Kūpono; 316L hoʻohana mau ʻia | Maikaʻi loa no nā hui welded | Maikaʻi akā pono nā kaʻina hana i hoʻomalu ʻia |
NoMame |
Maikaʻi ka huki hohonu a me ke anu | Maikaʻi loa | Maikaʻi loa | Kūpono; ʻO ka ikaika kiʻekiʻe ke kumu o ka springback |
| ʻO ke ʻano mākēneki | Non-magnetic (Anned) | Non-magnetic (Anned) | Non-magnetic (Anned) | Māmā ʻāpana |
| Nā noi maʻamau | Meaʻai meaʻai, Matapili, nā ipu koʻikoʻi, Piping | Mary Ples, Ke kālepaʻana, nā mea hana wela | Kōkua, Nā'ōnaehana exhaust, ʻāpana kaomi welded | Of 3Ikeha, Hoʻohanaʻoihana, pono & aila, nā lāʻau kanu lāʻau |
| Koina pili waiwai | Haʻahaʻa-haʻahaʻa | ʻOluʻolu-kiʻekiʻe | Loli | High |
13. Hopena
18-8 kila kohu ʻole ʻo ia kekahi o nā ʻōnaehana mea kaulike a i hoʻohana nui ʻia i ka ʻenekinia hou.
Ma ka hui ʻana ma kahi o 18% chromium a 8% nickel, loaʻa ia i kahi microstructure austenitic paʻa e hāʻawi i kahi hui kūʻokoʻa o ke kūʻē ʻana i ka corrosion, ʻO ka hilinaʻi koʻikoʻi, NoMame, a me ka wellingbility.
Hōʻike kēia mau hiʻohiʻona i kona noho aliʻi lōʻihi ma ka hana ʻai, Nā lako hana, hale kūkulu hale, nā ipu koʻikoʻi, a me nā noi ʻoihana maʻamau.
FaqS
He aha ka manaʻo o "18-8" i ke kila kila?
ʻO ka "18-8" e pili ana i ka hoʻohui inoa kemika o kahi 18% chromium a 8% nickel.
Hoʻopaʻa kēia haku mele i kahi ʻano austenitic, hāʻawi ʻana i ka pale ʻana i ka corrosion, kumaikalua, a me ka hana non-magnetic i ke kūlana annealed.
Oe 18-8 kila kila e like me Type 304?
ʻAno 304 ʻo ia ka papa maʻamau maʻamau i loko o ka 18-8 ohana.
ʻOiai ʻo "18-8" kahi huaʻōlelo ʻoihana maʻamau, ʻAno 304 (a me kona mau ʻano like me 304L a me 304H) hōʻike i kahi kikoʻī i wehewehe pono ʻia ma lalo o nā kūlana honua.
Oe 18-8 kila kuhiliʻole magnetic?
I ke kūlana hoʻonā-annealed, 18-8 ʻo ke kila kuhiliʻole ka mea nui ʻole-magnetic. Akā naʻe,, Hiki i ka hana anu ke hoʻoulu i ka hoʻololi martensitic hapa, ka hopena i ka pane magnetic liʻiliʻi.
He aha nā pōmaikaʻi nui o 18-8 kila kuhiliʻole ma luna o nā kila kuhiliʻole duplex?
18-8 ke kila kuhiliʻole hāʻawi ʻoi aku ka maikaʻi formability, maʻalahi ka wiliwili, ʻoi aku ka ikaika haʻahaʻa haʻahaʻa, a haʻahaʻa i nā kumu kūʻai a me nā kumu hana.
Hāʻawi ka Duplex stainless steel i ka ikaika kiʻekiʻe a me ka hoʻomaikaʻi ʻana i ka pale chloride akā ʻoi aku ka koi i ka hana.
