Cast iron castings often have various casting defects. How to prevent these defects has always been the concern of casting manufacturers. This paper introduces the author’s knowledge and practical experience in this field. Characteristics of casting porosity: porosity in casting refers to the smooth pores with different sizes existing...
Casting porosity This is a small cavity formed by the gas which can not escape during the solidification of metal. The inner wall of the cavity is smooth and contains gas. It has a high reflectivity to the ultrasonic wave. However, because it is basically spherical or ellipsoidal, that...
Porosity is usually the most common defect in cylinder block castings, which often takes the first place in the scrap castings. How to prevent porosity is a permanent problem for foundry workers. The air holes in the cylinder block are mostly found on the outer surface corresponding to the...
Features: in the thick section of the casting, hot spot or axis and other places of the final solidification, rough holes are formed on the surface, and more or less with dendrite crystal. The large and concentrated holes are called shrinkage cavities, and the small and scattered holes are...
Features: Invasive pore: the pore size is generally large, in the shape of round, ball or pear; the pear shaped small head points to the direction of the external gas source; the pore wall is smooth, and the pore wall is blue when the composition of the invasive gas...
Features: Shrinkage cavity: the hole with large volume, rough wall surface and irregular shape in the casting Shrinkage porosity: a large number of irregular shaped micro holes or fissured holes are distributed on the casting section Causes: A. The location or size of the riser is unreasonable. During the...
1 Casting porosity (1) Features and inspection methods: After dissection, appearance inspection or flaw detection showed that the pores had smooth surface and round shape. (2) Causes: ① The introduction direction of the alloy liquid is unreasonable or the flow speed of the metal liquid is too high, resulting...