Steel Casting Features High Melting Point
Casting steel casting system characteristics Cast steel characteristics of high melting point, Steel Casting poor mobility, shrinkage, easy oxidation, the requirements of metal liquid fast and smooth filling.
The pouring system has the following characteristics: ⑴. Cast steel body shrinkage, casting easy to produce shrinkage, shrinkage, cracks and deformation defects. Steel Casting Thick and thick wall thickness of the castings with the principle of directional solidification set up the riser system, the liquid flow through the riser into the cavity, to strengthen the riser of the filling capacity; for easy to produce cracks, deformation of the shell castings, The inner runner should be distributed in the thin wall of the casting and minimize the mechanical obstruction of the runner to the casting.
Cast steel casting temperature is high, easy to oxidize, usually using packet leakage. Leakage bagging slag effect is good, the pouring system slag effect is not high, Steel Casting so the pouring system cross-sectional area is large open, do not need high slag function, but should be fast and smooth full of mold. Drain the pouring pressure, Steel Casting easy to rush the runner, therefore, the casting system should strive to simple structure, strong impact resistance. Large and medium castings of the sprue and steel flow more than 1T of the runner and runner, should be composed of refractory brick. Small cast steel casting system can be used water glass, Steel Casting resin sand or all the use of sand composition, and to ensure adequate strength.
Casting in the production process often occur in a variety of casting defects, Steel Casting how to prevent these defects, casting manufacturers have been concerned about the issue. This article mainly introduces some understanding and practical experience in this field.
In the long-term production, found that the main cast steel casting defects, trachoma, sticky sand, pores, holes, sand sand scar, swelling sand, and so on, the main production of the original wet sand casting process.
In the casting, the surface or near the surface, Steel Casting there are different sizes of smooth holes, the shape of a round, long and irregular, there are single, but also gathered into a piece. The color is white or with a layer of dark, sometimes covered with a layer of oxide. Due to the different sources and causes of gas formation, the manifestations of stomata are also different, with invasive porosity, precipitation porosity and reactive stomata.
Invasive porosity larger, Steel Casting similar shape pear-shaped, often appear in the upper part of the casting near the core wall or pouring position, mainly due to the sand core gas generated in the metal can not escape, pear-shaped small holes The position indicates that the gas enters the cast member from there.
Precipitation stomatal and scattered, generally located in the casting surface, often the same furnace casting almost all occur, mainly due to the metal in the melting process of the absorption of the gas before the solidification failed to all precipitation,Steel Casting in the casting to form many scattered small pores.
The reactive pores are due to the chemical reactions of the metal-to-mold interface, which are also known as subcutaneous stomata due to their uniform distribution and often occurring at 1-3 mm below the skin of the casting (sometimes under a layer of scale). And because the pores are mostly elongated pinholes, Steel Casting the long axis and casting surface perpendicular, but also can be called pinholes.