Thaum lub sij hawm vuam txheej txheem ntawm kauv steel kav, cov pa roj tej zaum yuav muaj nyob rau ntawm qhov chaw ntawm lub vuam los yog nyob rau hauv lub weld nws tus kheej. Qhov teeb meem no yog hu ua porosity. Qhov laj thawj tseem ceeb ntawm qhov tsis xws luag yog qhov tsis huv ntawm qhov vuam, uas yuav muaj cov dej noo los yog xeb. Thaum lub sij hawm vuam, nyob rau hauv lub siab ntawm vuam kub, impurities xws li ya raws pib evaporate. Vim qhov qeeb evaporation ntawm noo noo los yog xeb, kab noj hniav tsim nyob rau hauv cov hlau molten. Cov kab noj hniav no sawv cev rau qhov tsis xws luag hauv cov txheej txheem vuam. Tshwj xeeb tshaj yog thaum groove welding, kev tu tsis tiav ntawm qhov zawj tuaj yeem yooj yim ua rau muaj roj tsis xws luag. Lub xub ntiag ntawm cov roj tsis xws luag cuam tshuam rau cov vuam zoo ntawm vuam, vim nws txo qhov ntim uas yuav tsum tau welded, ua rau cov vuam hlau tsis ua tiav cov vuam, yog li txo qhov vuam lub zog thiab ua rau nws yooj yim tawg.
Yuav kom daws tau qhov teeb meem porosity zoo dua nyob rau hauv kauv hlau yeeb nkab vuam, nws yog ib qho tsim nyog los kho qhov chaw vuam raws li kev nkag siab ntawm kev tsim porosity. Qhov no tuaj yeem tshem tawm qhov cuam tshuam ntawm impurities xws li ya raws thiab xeb ntawm npuas tsim. Los ntawm kev xav ntawm vuam, nws tseem yuav tsum tau kho qhov vuam tsis zoo kom cov vuam tam sim no thiab vuam ceev ua tau raws li qhov xav tau ntawm vuam, yog li txo qhov tshwm sim ntawm qhov porosity tsis xws luag. Tsis tas li ntawd, tag nrho cov txheej txheem vuam yuav tsum tau kuaj xyuas. Pib los ntawm kev tuaj txog ntawm cov khoom siv raw, kev khaws cia thiab kev khaws cia yuav tsum tau ua. Txoj kev khaws cia yuav tsum tau txais kev pom zoo raws li cov yam ntxwv ntawm cov vuam hlau daim hlau kom ntseeg tau tias lawv tau khaws cia rau hauv ib puag ncig zoo, yog li tsis txhob muaj qhov tshwm sim xws li xeb. Ua tib zoo tshuaj xyuas cov txheej txheem steel phaj, tshwj xeeb tshaj yog cov chaw vuam, uas yuav tsum tau soj ntsuam ntau qhov tob. Los ntawm kev tshuaj xyuas, cov teeb meem muaj peev xwm tuaj yeem txheeb xyuas thiab kho tam sim ntawd, txhim kho kev huv ntawm qhov chaw vuam thiab ua kom tsis txhob muaj qhov tshwm sim ntawm npuas tsis xws luag.
