(1) Uniform corrosion. Chromium yog qhov yooj yim tshaj plaws rau passivate. Nyob rau hauv ib puag ncig atmospheric, hlau-chromium alloys nrog cov ntsiab lus chromium ntau dua 12 feem pua tuaj yeem ua rau nws tus kheej passivated. Hauv qhov nruab nrab oxidizing, cov ntsiab lus chromium tuaj yeem dhau mus thaum cov ntsiab lus ntawm chromium ntau dua 17 feem pua. Hauv qee qhov nruab nrab hnyav, siab chromium thiab molybdenum, npib tsib xee, tooj liab thiab lwm yam khoom tuaj yeem tau txais kev tiv thaiv corrosion zoo.
(2) Intergranular corrosion. Ferritic stainless hlau raug kev txom nyem los ntawm intergranular corrosion zoo li austenitic stainless hlau, tab sis rhiab heev kev kho mob thiab kev kho cua sov kom tsis txhob no corrosion yog qhov opposite. Ferritic stainless hlau yog feem ntau cuam tshuam rau intergranular corrosion thaum quenched saum 925 degree, thiab lub xeev (sensitized lub xeev) cuam tshuam rau intergranular corrosion yuav raug tshem tawm los ntawm lub sij hawm luv luv tempering ntawm 650 ~ 815 degree. Lub intergranular corrosion ntawm ferritic hlau kuj yog qhov tshwm sim ntawm chromium tsis zoo vim carbide nag lossis daus. Yog li ntawd, txo cov pa roj carbon thiab nitrogen cov ntsiab lus hauv cov hlau thiab ntxiv cov ntsiab lus xws li titanium thiab niobium tuaj yeem txo qhov cuam tshuam rau intergranular corrosion.
(3) Pitting corrosion thiab crevice corrosion. Chromium thiab molybdenum yog cov ntsiab lus zoo tshaj plaws los txhim kho pitting thiab crevice corrosion kuj ntawm stainless hlau. Thaum cov ntsiab lus chromium nce, cov ntsiab lus chromium hauv oxide zaj duab xis kuj nce, thiab cov tshuaj lom neeg ruaj khov ntawm cov yeeb yaj kiab nce. Molybdenum yog adsorbed rau ntawm cov hlau ua haujlwm nyob rau hauv daim ntawv ntawm MoO4, uas inhibits kev tawg ntawm cov hlau, txhawb kev rov ua dua, thiab tiv thaiv kev puas tsuaj ntawm zaj duab xis. Yog li ntawd, high-chromium thiab molybdenum ferritic stainless hlau muaj zoo heev tiv taus pitting thiab crevice corrosion.
(4) Kev nyuaj siab corrosion cracking kuj. Vim yog cov yam ntxwv ntawm cov qauv, ferritic stainless hlau yog corrosion-resistant nyob rau hauv nruab nrab qhov twg austenitic stainless hlau tsim kev ntxhov siab corrosion cracking.
