Tua hlauyog cov hlau uas tau deoxidized tag nrho los ntawm qhov sib ntxiv ntawm tus neeg sawv cev ua ntej casting xws li tias tsis muaj kev hloov pauv ntawm cov roj thaum lub sij hawm solidification. Nws yog tus cwj pwm los ntawm qib siab ntawm tshuaj lom neeg homogeneity thiab kev ywj pheej los ntawm cov pa porosities.

Semi-tua steel feem ntau yog deoxidized steel, tab sis cov pa roj carbon monoxide tawm blowhole hom porosity faib thoob plaws hauv lub ingot. Lub porosity tshem tawm cov yeeb nkab uas pom nyob rau hauv cov hlau tua thiab ua kom cov qoob loo nce mus txog 90% los ntawm qhov hnyav. Semi-tua steel feem ntau yog siv rau cov qauv hlau nrog cov ntsiab lus ntawm 0.15 thiab 0.25% carbon, vim nws yog dov, uas kaw lub porosity.

Rimmed hlau, tseem hu ua kos duab zoo hlau, muaj me ntsis rau tsis muaj deoxidizing tus neeg sawv cev ntxiv rau nws thaum lub sij hawm casting uas ua rau carbon monoxide evolve sai los ntawm lub ingot. Qhov no ua rau lub tshuab me me hauv qhov chaw uas tom qab raug kaw hauv cov txheej txheem kub dov. Feem ntau cov rimmed steel muaj cov ntsiab lus carbon qis dua 0.25%, manganese cov ntsiab lus qis dua 0.6%, thiab tsis yog alloyed nrog aluminium, silicon, thiab titanium.Vim qhov tsis sib xws ntawm alloying ntsiab nws tsis pom zoo rau kev siv kub ua haujlwm.