Because the stainless steel casting cross-section is too thick, precision casting plant led to metal type casting poorly produced shrinkage holes. Precision casting stainless steel castings wall thickness is not proportional, in the wall thickness of a part of the hot section at the cause of shrinkage or shrinkage loose. Hebei casting factory details because the stainless steel plate cast hole diameter is too small to produce cast holes in the sand core was heated by high temperature alloy liquid, long-term sex in high temperature situation, reducing the solidification rate of the metal material on the surface of the stainless steel plate cast hole, at the same time the sand core for the vapor or atmospheric pressure gives a wireless channel, resulting in the hole edge caused by shrinkage and embroidered pine.
Stainless steel castings of the concave angle arc half through the small, so that the oblique angle at the type of sand heat transfer capacity is reduced, precision casting defects at the corner of the solidification rate is reduced, at the same time because the oblique angle at the type of sand encounter heat efficacy, hair gas pressure is too large, for precipitation of vapor can be to the unconsolidated metal material liquid penetration to, resulting in casting parts caused by gas shrinkage holes. Smelting level cause: stainless steel plate liquid metal containing gas supply is too high, resulting in stainless steel castings cooling the whole process of precipitation in the form of vapor bubbles, blocking the adjacent liquid metal to the point of mobility to carry out metal type casting, resulting in shrinkage or shrinkage pine.
When the gray cast iron carbon equivalent is too low, will make the iron solidification carbide high-purity graphite precipitation less, reducing the effectiveness of graphitization pescado, so that the solidification gathered to enhance, and at the same time also reduce the flow of iron. Recognise and reduce the self-replenishing shrinkage capacity of the molten iron, so that casting parts are very easy to cause shrinkage holes or shrinkage loose. When the phosphorus or sulphur content of the molten iron is high, the phosphorus is the element that expands the solidification temperature range, and at the same time produces a lot of low soluble point phosphorus carbide, which reduces the metal casting ability when solidifying.
Sulphur is the element that blocks graphitization, and sulphur can also reduce the flow of iron. At the same time the iron air oxidation is more serious, also reduce the liquid metal circulation, so that the workpiece caused by shrinkage or shrinkage loose. Create pig iron or ductile iron castings before demoulding to silica iron and other inoculants to carry out the creation of solutions, if the creation of poor, will cause the iron to solidify when the precipitation of a lot of pearl body, and thus make the solidification of the collection of elevated, resulting in shrinkage of the part of the shrinkage hole will certainly occur shrinkage loose, resulting from the same principle.