Grey hlau peev castings yog cov khoom lag luam casting los ntawm poob ciab peev casting txheej txheem ntawm cov hlau foundry. Grey hlau (los yog grey cam khwb cia hlau) yog ib hom hlau-carbon alloy (los yog Ferrum-Carbon Alloy) uas muaj graphite microstructure. Nws yog lub npe hu ua grey xim ntawm lub pob txha tawg nws cov ntaub ntawv. 
