Lub hom phiaj tseem ceeb ntawm cov txheej txheem pretreatment yog tshem tawm cov roj thiab cov impurities los ntawm qhov chaw ntawm cov hlau sawb, yog li tsim cov tshuaj hloov pauv txheej ntawm cov hlau substrate los txhim kho ob qho tib si adhesion ntawm txheej thiab substrate, thiab tag nrho corrosion kuj. Cov txheej txheem pretreatment ib txwm suav nrog cov kauj ruam xws li degreasing, txhuam hniav, dej kub rinsing, deg conditioning, thib ob dej kub yaug, passivation, thiab ziab. Kev kho deg yog ib qho kev kho saum npoo ntxiv uas tau qhia ua ntej kev kho phosphate lossis chromate; Nws yuav tsum tau txau cov hlau strip nto nrog cov kua qaub tsis muaj zog uas muaj phosphate, npib tsib xee, thiab fluoride ions. Cov txheej txheem no yog txhawm rau txhim kho cov txheej txheem kev ua tau zoo thiab cov adhesion ntawm tus neeg sawv cev passivation, thaum tib lub sijhawm tshem tawm cov precipitates- xws li txhuas thiab txhuas- uas tau khaws cia ntawm cov ciam teb ntawm galvanized substrates. Cov kev kho mob rau passivation tuaj yeem siv los ntawm ntau txoj hauv kev, feem ntau txau, dipping, thiab yob txheej. Ntawm cov no, cov txheej txheem yob yuav siv cov kev daws teeb meem rau steel strip nto los tsim ib qho kev thaiv thaiv ntawm cov hlau substrate thiab cov txheej txheej tom ntej; Txoj kev no muaj qhov zoo ntawm cov txheej txheem tswj tau yooj yim, cov yeeb yaj kiab tuab tuab, thiab tsim cov kua dej tsawg tsawg, yog li ua rau muaj kev tiv thaiv ib puag ncig.
Muaj ob txoj kev tsim qauv tseem ceeb rau cov txheej txheem pretreatment layout. Thawj koom nrog kev tso npe ua ntej -tu ntu ntu ntu ntawm lub voj voog (accumulator) thiab ntu pretreatment tseem ceeb hauv qab ntawm lub voj voog; qhov kev tsim no yog dav siv los ntawm ntau tus neeg muag khoom nyob sab Europe ntawm cov xim - txheej txheej. Nws qhov txiaj ntsig tseem ceeb yog qhov muaj peev xwm ua ntej- kho thiab tshem tawm cov khoom tsis huv loj thaum cov khoom siv raw khoom tsis zoo. Qhov thib ob configuration muaj nyob rau hauv pretreatment seem nkaus xwb downstream ntawm lub looper, tsis muaj pre-tu seem nyob rau hauv upstream; Qhov kev tsim no feem ntau pom ntawm cov neeg xa khoom Asian ntawm cov xim - txheej txheej.