Cov hlau tsis muaj tsw zoo yog cov nquag muaj: (1) Brittleness ntawm chav tsev kub. Cov khoom siv hluav taws xob tsis yooj yim rau lub pob taws yog nkag siab tsis zoo, thiab qhov kev hloov brittleness yog qhov siab tshaj chav nyob hauv chav tshwj tsis yog muaj chromium tsawg (xws li 405). Tus nqi ntau ntawm cov chromium, ntau dua qhov txias txias. Lub khaub thuas txias no cuam tshuam nrog cov khoom sib txawv xws li carbon thiab nitrogen hauv cov hlau. Txawm li cas los xij, ultra-pure ferritic steels muaj cov ntsiab lus carbon tsawg heev hauv cov khoom sib txawv xws li cov pa roj carbon thiab nitrogen, thiab tuaj yeem tau txais cov tawv zoo, thiab cov kev sib hloov ntawm cov cua sov tuaj yeem txo qis dua chav sov.
(2) Cov kub ua kom muaj zog embrittlement. Cov txheej txheem ua kom tsis muaj steel hlau tau raug kub kom siab dua 927 ° C thiab tom qab ntawd txias txias rau chav tsev kub, thiab nws cov yas thiab tawv yog txo qis. Qhov kub siab embrittlement no muaj feem xyuam nrog cov dej nag sai sai ntawm cov pa roj carbon (nitrogen) sib txuas rau ntawm cov ciam teb lossis thaj av ntawm qhov kub ntawm 427 txog 927 ° C. Txo cov pa roj carbon thiab nitrogen cov ntsiab lus nyob rau hauv cov hlau (siv ultra-pure technology) tuaj yeem txhim kho qhov no brittleness. Tsis tas li ntawd, thaum hlau ferritic yog rhuab mus rau saum toj no 927 ° C, lub peev xwm nplej tau coarsened, thiab cov coarse nplej yuav vau qhov yas thiab toughness ntawm cov hlau.
(3) Kev Tsim ntawm σ-theem. Raws li daim duab hlau-chromium theem daim duab (saib Daim Duab 1), yog hais tias kub tau khaws cia ntawm 500 ～ 800 ℃, cov xaim nrog 40% ～ 50% chromium yuav tsim ib theem σ, thiab cov alloy nrog chromium tsawg dua 20% lossis ntau dua 70% yuav ua α + σ Lub koom haum Biphasic. Kev tsim ntawm σ-theem yuav txo qhov ua kom cov yas thiab cov tawv ntawm cov hlau. Yog li hom hlau no yuav tsum tsis txhob siv ntev ntev ntawm 500 ～ 800 ℃.
(4) Brittleness ntawm 475 ° C. High chromium (GG gt; 15%) ferritic steel yuav ruaj khov ua pa thaum khaws cia ntawm 400 ～ 500 ℃. Qhov embrittlement no yuav tsum siv sijhawm luv dua li cov nag lossis daus ntawm the theem. Piv txwv li, thaum 0.080C-0.4Si-16.9Cr steel khaws cia ntawm 450 ° C rau 4 teev, chav nyob hauv chav sov yuav tsum ua rau tawv yuav luag poob rau xoom. Cov degree ntawm embrittlement nce nrog nce ntawm chromium cov ntsiab lus, tab sis cov tawv tawv tuaj yeem kho rov qab los ntawm kev kho mob siab dua 600 ℃. Embrittlement ntawm 475 ° C yog los ntawm cov nag lossis daus ntawm chromium-nplua nuj α' theem. Xws li cov hlau yuav tsum zam kom tsis txhob muaj cua sov ze 475 ° C.