Lub shrinkage tus nqi ntawm cam khwb cia hlau feem ntau yog hais txog qhov loj me me ntawm volumetric contraction tshwm sim thaum lub sij hawm solidification thiab txias txheej txheem. Vim muaj cov pa roj carbon ntau thiab silicon cov ntsiab lus hauv cov cam khwb cia hlau- thiab qhov tseeb tias graphite nag lossis daus muab ib qib ntawm "expansion them nyiaj"-nws tag nrho cov shrinkage tus nqi qis dua cov hlau cam khwb cia.
Feem ntau, cov kab shrinkage tus nqi rau grey cam khwb cia hlau castings yog nyob ib ncig ntawm **0.7% rau 1.0%**. Cov hlau ductile, muaj ib qho microstructure ze rau ntawm cov hlau, nthuav tawm qhov qis dua me ntsis, feem ntau nyob rau hauv thaj tsam ntawm ** 1.0% txog 1.3% **. Cov txiaj ntsig no txawv nyob ntawm seb yam xws li casting geometry, phab ntsa thickness, thiab txias txias.
Hauv kev tsim khoom, tus nqi shrinkage tsis yog tus nqi tas li tab sis tus qauv tsim uas yuav tsum tau hloov kho raws li cov txheej txheem casting tshwj xeeb. Piv txwv li, tuab-walled castings txias dua maj mam, uas ua rau cov shrinkage ruaj khov; conversely, nyias-walled castings txias sai heev thiab yog nquag mus rau lub zos shrinkage concentration, yuav tsum muaj xws li ib tug shrinkage nyiaj pub rau hauv pwm tsim los them.
Cov yam ntxwv xws li qhov kub thiab txias, kev kho inoculation, thiab tus nqi cua txias tag nrho cuam tshuam tus cwj pwm shrinkage. Kev tswj tsis raug tuaj yeem ua rau muaj qhov tsis xws luag xws li cov kab noj hniav shrinkage lossis porosity. Yog li ntawd, thaum lub sij hawm tsim casting theem, tus nqi shrinkage ua lub hauv paus tseem ceeb rau kev txiav txim siab qhov ntev thiab tsim cov txheej txheem pub mis.
