Corrosion tsis kam ntawm ferritic stainless hlau

(1) Uniform corrosion. Chromium yog qhov yooj yim tshaj plaws rau passivate. Nyob rau hauv ib puag ncig atmospheric, hlau chromium alloys nrog chromium cov ntsiab lus siab tshaj 12% tuaj yeem ua tus kheej passivate. Hauv oxidizing media, passivation tuaj yeem ua tiav thaum cov ntsiab lus chromium siab dua 17%. Hauv qee qhov kev tshaj tawm corrosive, siab chromium ua ke nrog cov ntsiab lus xws li molybdenum, npib tsib xee, thiab tooj liab tuaj yeem ua tau zoo corrosion kuj.
(2) Intergranular corrosion. Ob leeg ferritic stainless hlau thiab austenitic stainless hlau undergo intergranular corrosion, tab sis rhiab heev kev kho mob thiab kev kho cua sov kom tsis txhob xws corrosion yog raws nraim qhov opposite. Ferritic stainless hlau yog feem ntau cuam tshuam rau intergranular corrosion thaum txias txias siab tshaj 925 degree, thiab lub xeev (sensitized xeev) uas nquag mus 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 deficiency tshwm sim los ntawm carbide nag lossis daus. Yog li 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 rhiab heev rau intergranular corrosion.
(3) Pitting thiab crevice corrosion. Chromium thiab molybdenum yog cov ntsiab lus zoo tshaj plaws los txhim kho kev ua haujlwm ntawm stainless hlau rau pitting thiab crevice corrosion. Raws li 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 adsorbs ntawm cov hlau ua haujlwm nyob rau hauv daim ntawv ntawm MoO4, inhibiting hlau dissolution, txhawb re passivation, thiab tiv thaiv zaj duab xis puas. Yog li ntawd, siab chromium thiab molybdenum ferritic stainless hlau muaj zoo heev tiv taus pitting thiab crevice corrosion.
(4) Ua rau kev ntxhov siab corrosion tawg. Vim yog cov yam ntxwv ntawm nws cov qauv tsim, ferritic stainless hlau yog corrosion-resistant nyob rau hauv nruab nrab qhov kev ntxhov siab corrosion cracking tshwm sim nyob rau hauv austenitic stainless hlau.