Lub log hlauyog ib hom log ua los ntawm hlau thiab hlau, thiab nws tseem yog cov khoom siv log tsheb thaum ub, uas muaj cov yam ntxwv ntawm tus nqi qis, lub zog siab, kev tiv thaiv zoo thiab kev siv tshuab yooj yim, nws tseem siv dav hauv txhua hom tsheb niaj hnub thiab tsheb thauj khoom qis. Nws qhov tsis zoo tseem ceeb yog qhov zoo thiab kev zoo nkauj tsis zoo. Qhov kev xaiv tseem ceeb ntawm cov khoom siv log hlau yog cov hlau carbon, hlau ductile, thiab lwm yam khoom siv hlau. Feem ntau ntawm cov log hlau carbon yog siv rau hauv cov tsheb ua haujlwm fais fab dav dav, nws lub zog qis, tsis kam rau sab nraud, nres cua sov ntawm lub tsheb cua sov dissipation kev ua tau zoo yog txwv, nws nyuaj rau ua cov qauv zoo nkauj ntawm qhov chaw ntawm cov hlau carbon, tab sis nws tus nqi pheej yig dua, thiab nws yog thawj qhov kev xaiv rau ntau cov khoom siv log tsheb qis. Log Hlau Ductile muaj cov khoom siv kho tshuab zoo dua li lub log hlau carbon, tab sis nws nyuaj dua los tswj cov duab dua li lub log hlau carbon thaum lub sijhawm ua haujlwm, yog li tus nqi ua haujlwm siab dua thiab kev lag luam tsis zoo. Nyob rau xyoo tas los no, lwm cov ntaub ntawv hlau xws li qee cov hlau alloy tau siv ntau dua thiab ntau dua li cov ntaub ntawv log tsheb, nws muaj qhov zoo ntawm lub zog siab dua, qhov hnyav sib dua, cua sov zoo dua, kev ua tiav zoo thiab kev ua pwm, yooj yim rau weld thiab lwm yam, thiab tau txais kev nyiam los ntawm feem ntau ntawm cov chaw tsim khoom tsheb.