(1) Lub tshuab hluav taws xob siv hluav taws xob, lub zog huv tshaj plaws. Lwm qhov chaw siv hluav taws xob xws li thee, coke, roj crude, nkev roj, thiab lwm yam yuav inevitably coj cov impurity nrog rau hauv cov txheej txheem metallurgical. Tsuas yog lub tshuab hluav taws xob tuaj yeem tsim cov hlau huv tshaj plaws.
(2) Hluav taws xob yog tib lub zog hluav taws xob uas tuaj yeem tau txais kev kub ntxhov siab.
(3) Lub tshuab hluav taws xob hluav taws xob tuaj yeem yooj yim paub txog cov txheej txheem thermodynamic xws li oxygen ib nrab siab thiab nitrogen ib feem siab xav tau los ntawm ntau yam kev cuam tshuam metallurgical xws li txo qis, kho kom zoo thiab nitriding.