Cov ntawv ci txhuas uas tau pleev xim ua ntej txhais tau hais tias yog xim rau saum npoo ntawm cov hlau txhuas. Vim tias kev ua tau zoo ntawm cov hlau txhuas ruaj khov heev, nws tsis yooj yim rau xeb. Feem ntau, tom qab kev kho tshwj xeeb, qhov saum npoo tuaj yeem lav tsis ploj mus tsawg kawg 30 xyoo. Ntxiv mus, vim nws qhov ceev tsawg thiab qhov nyuaj siab, qhov hnyav ib chav yog qhov sib dua ntawm cov khoom siv hlau.

Cov ntawv ci txhuas ua ntej pleev xim yog hais txog cov xim pleev xim ua ntej ntawm cov txhuas dov ua ntej txiav, khoov, dov thiab lwm yam txheej txheem tsim, nws txawv ntawm txoj kev txau (tshuaj tsuag xim tom qab molding).

Nws yog siv rau ntau txoj hauv kev tshiab los txhim kho qhov zoo nkauj ntawm cov tsev pej xeem thiab cov tsev lag luam. Hauv kev lag luam kev tsim kho tam sim no, 70% ntawm cov khoom siv hlau siv rau ntawm qhov chaw ntawm lub tsev yog ua ntej roller coated, Cov khoom yog ntsuab, tiv taus corrosion, tsis tas yuav saib xyuas thiab rov ua dua tshiab.