Hlau yog feem ntau tau muab cais rau hauv peb pawg: carbon hlau, txheej hlau alloy, thiab stainless hlau. Txhua hom hlau yog qhov haum rau cov ntawv thov sib txawv vim nws muaj pes tsawg leeg thiab kev ua tau zoo. Carbon Steel (Carbon Cov Ntsiab Lus 0.04%) muaj cov nqi tsawg thiab ruaj khov siv hauv tsev qauv thiab kev lag luam kev lag luam kev tsim khoom lag luam thiab kev tsim ntau yam. Alloy Steel (muaj tsawg dua lossis sib npaug rau 5% chromium, thiab lwm yam) khav theeb siv zog ntxiv, ua rau nws siv cov tshuab hluav taws xob thiab cov khoom lag luam. Stainless hlau (chromium cov ntsiab lus ntau dua los yog sib npaug rau cov khoom siv kho mob thiab cov tshuaj tsuag ua kom zoo dua (cov tshuaj ntsev kom zoo dua li 96 teev).
