254SMO vs 654SMO Super Austenitic Stainless Steels: Qhov kawg Chloride Corrosion Resistance

 

Dab tsi yog lawv cov ntsiab lus tseem ceeb thiab kev ua tau zoo?

254SMO (UNS S31254) muaj 19.5–20.5% Cr, 17.5–18.5% Ni, 6.0–6.5% Mo, thiab 0.18–0.22% N, khav theeb Pitting Resistance Equivalent Number (PREN) ntawm ~ 42. Nws ua tau zoo nyob rau hauv dej hiav txwv, brine, thiab acidic chloride daws, siv rau desalination cog Cheebtsam thiab offshore pipeline systems.654SMO (UNS S32654) nta 24.0–26.0% Cr, 21.0–23.0% Ni, 7.0–8.0% Mo, thiab nrog 0.0%–PR, thiab 0.040% N. 55-qhov siab tshaj ntawm kev lag luam qib austenitic. Nws resists pitting nyob rau hauv boiling 20% ​​NaCl kev daws teeb meem thiab yog zoo tagnrho rau subsea wellheads thiab acidic tshuaj reactors.Ob qib yog tag nrho austenitic, tsis-sib nqus, thiab muaj zoo weldability piv rau duplex stainless hlau.

Yuav ua li cas lawv corrosion resistances txawv nyob rau hauv huab chloride ib puag ncig?

254SMO ua tau zoo nyob rau hauv seawater thiab raug brine daws, withstanding pitting thiab crevice corrosion ntawm kub txog li 60℃.654SMO txuas lub peev xwm no mus rau qhov kub siab tshaj 100℃thiab nyob rau hauv concentrated chloride tov (piv txwv li, 20% NaCl), qhov twg 254SMO tej zaum yuav pib .In cov tshuaj tiv thaiv corrosion hauv zos (cov kua qaub ntau hauv zos. H2SO4 + NaCl sib tov), 654SMO's siab dua chromium thiab molybdenum cov ntsiab lus tsim kom muaj cov yeeb yaj kiab ruaj khov dua, tiv thaiv corrosion tsis sib xws txawm tias muaj ntau qhov siab.

Thaum twg yog 654SMO qhov kev xaiv tsuas yog siv tau tshaj 254SMO?

654SMO yog yuav tsum tau rau subsea roj thiab cov khoom siv roj ua hauj lwm nyob rau hauv qhov tob tshaj 1000 meters, qhov twg siab thiab chloride concentration ua ke los tsim ultra- tej yam kev mob hnyav.Nws tseem yuav tsum tau rau cov tshuaj ua cov nroj tsuag tuav concentrated acidic chloride tov, xws li siv cov kua qaub rov qab systems thiab pulp bleaching khoom.Rau daim ntawv thov qhov twg kev tiv thaiv tsis ua hauj lwm yuav ua rau catastrophic. 654SMO qhov kev ntseeg siab zoo tshaj plaws ua rau nws tus nqi siab dua.

Tus nqi thiab kev ua lag luam yog dab tsi - tawm ntawm ob qib?

654SMO tus nqi 50–80% ntau dua 254SMO vim nws cov ntsiab lus alloy siab dua thiab cov txheej txheem ntau lawm.While ob qib muab cov weldability zoo heev, 654SMO yuav tsum muaj kev sib txuam siab- alloy muab tub lim (piv txwv li, NiCrMo-3), ntxiv cov nqi tsim khoom ntxiv.Rau qhov tsis tshua muaj huab cua zoo li cov ntug dej hiav txwv fais fab nroj tsuag, 2 MO desalin kev ua tau zoo. tus nqi qis dua ntawm kev ua tswv cuab.

Cov txheej txheem fabrication dab tsi ua kom muaj kev ua tau zoo rau cov qib no?

Ob qib yuav tsum tau qis - cua sov input welding kom tsis txhob muaj qoob loo loj hlob thiab khaws cia corrosion kuj; GTAW (TIG) yog txoj kev nyiam tshaj plaws rau cov ntawv thov tseem ceeb.Post- vuam tu (pickling thiab passivation) yog qhov yuav tsum tau tshem tawm cov cua sov- cuam tshuam thaj chaw oxides thiab rov ua kom cov yeeb yaj kiab tsis zoo.Machining yuav tsum muaj cov cuab yeej ntse carbide thiab txiav nrawm nrawm- siab kub tuaj yeem ua rau cov cuab yeej ua kom tiav, ua haujlwm tsis zoo.