Qhov kev ua tau zoo ntawm txoj kev txiav tuag yuav tsum tau ua kom cov hlau zoo sib xws, qhov sib xyaw ua ke ntawm cov hniav thiab cov hniav yog qhov tsim nyog, qhov tshwj xeeb yog qhov tseeb, thiab cov hniav yog quenched, thiab lwm yam. txiav riam feem ntau yog siab dua li ntawm cov hniav, uas tsis tsuas yog yooj yim molding, tab sis kuj muab lub neej ntev-txiav.