X-ray inspection plays a vital role in the manufacturing of silica sol investment casting process (also known as lost-wax casting or precision casting), it particularly uses in Quality Control and Process Optimization.
X-ray inspection is reflected in the following aspects:
A)Detection of Internal Casting Defects is the primary use of X-ray. Although silica sol investment casting can produce castings with extremely complex shapes and high surface finish, internal defects may still occur during solidification.
B)Typical Detectable Defects Includes gas porosity and pinholes,the voids formed by trapped gas failing to escape completely during solidification. Appear as round or oval low-density (darker) areas on X-ray images.
C)Detection shrinkage cavities and porosity, the voids formed due to insufficient feeding during metal contraction (shrinkage cavities) or areas of fine, dispersed pores (microporosity/shrinkage porosity). Typically occur at thick sections, hot spots, or below riser necks. Appear as irregularly shaped, potentially dendritic-edged, low-density areas on X-ray images.
D)Found the Inclusion defects which caused by non-metallic materials such as mold material (sand grains, incompletely removed silica sol), slag, or oxides becoming entrapped in the molten metal. Appear as variably shaped areas of abnormal density on X-ray images – higher density than the base metal (brighter) or lower density (darker, e.g., low-density slag).
E)Detectetion cold shuts and pour shorts which Incomplete fusion of converging metal streams (cold shuts) or failure to completely fill the mold cavity (pour shorts). Appear as linear or discontinuous-edged low-density areas on X-ray images.
F)Cracks detection by X-ray, it can find Internal hot tears or stress cracks formed during solidification or cooling. Appear as thin, usually linear, low-density streaks on X-ray images.
G)The greatest advantage of X-ray inspection is its non-destructivenature. It can clearly reveal the internal structure of a casting without destroying it, determining product acceptability and avoiding costly destructive testing.
