nyab xeeb thiab txhim khu kev qha

Cov kav dej tooj liab yog cov kav ntev
Tooj liab muaj cov khoom siv ruaj khov, thiab sib txuas ua kom txias, tiv thaiv tshav kub, ua haujlwm siab, tiv thaiv corrosion thiab hluav taws kub (tooj liab muaj qhov taw tes melting txog li 1083 degrees Celsius), thiab tuaj yeem siv tau ntev hauv qhov chaw sib txawv. Lub neej kev pab cuam ntawm cov kav dej tooj liab tuaj yeem ntev npaum li lub neej ntawm lub tsev, lossis ntev dua. Piv txwv li, cov kav dej tooj liab tau teeb tsa hauv Peking Union Medical College Tsev Kho Mob hauv xyoo 1920s tau zoo rau ntau tshaj 70 xyoo. Nws tuaj yeem pom tau tias cov kav dej tooj liab yog cov kav dej uas tau sim ua tiav los ntawm ntau tshaj li ib puas xyoo ntawm lub sijhawm thiab kev ua haujlwm.
Cov kav dej tooj liab muaj kev nyab xeeb thiab txhim khu kev qha
Cov kav dej tooj liab sib xyaw ua ke qhov zoo ntawm cov kav hlau hlau thiab cov kav dej tsis yog hlau. Nws yog ib qho nyuaj tshaj li cov kav dej yas thiab muaj lub zog siab ntawm cov hlau dav dav (lub zog ntawm cov kav dej txias txias yog sib npaug rau cov kav hlau steel nrog tib lub phab ntsa tuab); Nws yog qhov yooj yim rau khoov dua li cov hlau dav dav, muaj qhov zoo toughness thiab siab ductility, thiab muaj kev co zoo heev, cuam tshuam tsis kam thiab Frost heave kuj.
Cov kav dej tooj liab tuaj yeem tiv taus qhov txias txias thiab kub kub, nrog rau ntau yam kev siv los ntawm -196 degrees mus rau 250 degrees, thiab tuaj yeem hloov kho qhov kub thiab txias (-high temperature-low temperature-high temperature). Qhov kev ua tau zoo yuav tsis raug txo vim kev siv mus ntev thiab kev hloov pauv kub, thiab yuav tsis tsim kev laus. Qhov no yog dhau qhov ncav cuag ntawm cov kav dej zoo tib yam.
Lub linear expansion coefficient ntawm cov kav hlau yog me me, uas yog 1/10 ntawm cov kav dej yas, thiab tuaj yeem tiv taus qaug zog. Thaum qhov kub thiab txias hloov, yuav tsis muaj ntau thermal expansion thiab contraction, uas yuav ua rau muaj kev ntxhov siab qaug zog tawg.
Cov yam ntxwv no ua rau daim ntawv thov ntawm cov kav dej tooj liab hauv qhov chaw txias tau zoo heev. Qhov sib txawv ntawm qhov kub thiab txias thaum sawv ntxov thiab yav tsaus ntuj nyob rau hauv qhov chaw txias txias yog qhov loj, thiab cov kab hluav taws xob nthuav dav ntawm cov kav dej zoo tib yam yog qhov loj thiab lub zog tsawg, uas yooj yim heev los tsim kev ntxhov siab qaug zog tawg los ntawm thermal expansion thiab contraction. Ib txhia hais tias tsis nkig ntawm -20 degrees, tab sis qhov tseeb lawv tsis tuaj yeem tiv taus kev ua haujlwm siab, thiab lawv lub neej kev pabcuam luv luv, uas tsis muaj qhov tseem ceeb. Txawm hais tias kev ntsuas rwb thaiv tsev tuaj yeem siv tau, nws yuav tsum tsis txhob ntsib qhov kub thiab txias thaum lub sijhawm thauj mus los, khaws cia thiab kev teeb tsa, thaum qhov kev ua haujlwm ntawm cov kav dej tooj liab zoo ib yam ntawm -183 degrees thiab chav tsev kub.