Penetration detection in precision casting is a method to check the surface defects of castings. It can be used not only for the detection of magnetizable metal castings, but also for the detection of non-magnetized metal (such as austenitic alloy steel) castings.

The principle is: on the surface of the cleaned workpiece, a permeant is placed, which penetrates into the cracks on the surface of the casting; Then the remaining permeant is removed and a thin layer of developer or fluorescent substance is applied. The permeant in the crack is sucked out by capillary. If the choice of developer, in the light of the flash must be the color, such as penetration agent for red dye, the defect flash out of red. If the fluorescent substance is involved, it will flash a bright greenish-yellow precision casting under ultraviolet irradiation.

    Compared with the two methods, the defects on the casting surface can be easily detected by the fluorescence method involving fluorescent substances. In the dark field, 0. The hole of 01mm meter, or the width is 0. The sensitivity of 01mm crack is higher than that of coloring method. However, the choice of the coloring agent used in the equipment is brief, do not need power, strong adaptability.

Photo of penetration detection of valve steel castings. Since fluorescence cannot be captured with a normal camera, color the casting defects with a marker pen. In the precision casting, in the selection of its methods, should be considered, mainly for the adaptability of the method, and, whether can be through equipment, such as the selection of advanced molding or core technology, to advance the work efficiency. As for the casting of ferrous metals, they can be precisely cast. Moreover, according to the characteristics of the casting, it can be used to produce some thin-wall casting.