Stainless Steel Casting Too Much Deviation
The casting condition of alloy steel castings is unreasonable: the process setting of pouring filling type is too long, it is caused by the low temperature of pouring molten steel in pouring process, Stainless Steel Casting especially the increase of casting wall thickness, Stainless Steel Casting the solidification speed of pouring molten steel is slow, the liquid phase-solid stay time is longer, which leads to the increase of the action time of molten steel and the pyrolysis product of the shape, The carburizing and carbon content of cast steel were increased.
In the production of alloy steel castings, the carbon content in the smelting ingredients is not strictly controlled, especially in all kinds of scrap steel and the existence of other alloy components in various scrap steels is unknown.
The pouring system of alloy steel castings is unreasonable: in particular, the vacuum system and pouring sand box or casting molding process of the configuration is unreasonable, Stainless Steel Casting resulting in casting in the pouring process, pouring sand box of the vacuum degree, the deviation is too large, or the actual vacuum degree is insufficient, and the vacuum pressure gauge display is in line with the technical parameters of the wrong number, The thermal decomposition product of the appearance cannot quickly and rapidly discharge the pouring cavity, resulting in the carburizing or carbon deposition of the castings.
Due to the unreasonable design of the gating system, Stainless Steel Casting the filling speed of the metal liquid is larger than that of the foam gasification and the gas discharging speed, which leads to the filling-type frontier that the gasification residue is clamped in the metal liquid to form the inner wall smoke black.
The connection between the pouring cup and the sprue and the pouring system is not good, Stainless Steel Casting especially the connection between the sprue and the pouring cup is not good, it is easy to form the sand and blowhole under the action of negative pressure, which can be calculated and explained by Bernoulli equation.
The granularity of the sand is too fine, the dust content is high, the air permeability is poor, the negative pressure distortion is caused by the internal blockage of the pressure pipe, Stainless Steel Casting so the negative pressure around the cavity is far below the indicated negative pressure, and the gasification material can not be discharged in time to form the blowhole or wrinkle skin.
Low pouring temperature, filling the front of the metal liquid can not make the foam fully gasification, the remaining material is not decomposed too late to float to the riser and solidification in the casting to form pores.
Deoxidation of molten steel, stove, inside and inside of the furnace, Stainless Steel Casting the slag is not clean, the sedation time is too short, the slag is not good in pouring process, and the pouring process is unreasonable to cause slag hole.
The position of the inner runner is unreasonable and the dead area is formed when filling. Because of the gas pressure in the cavity, the gasification residue accumulates in the dead corner to form the blowhole, Stainless Steel Casting the inner runner area is too large, so the filling speed is larger than the foam gasification yield, the foam is swallowed up in the alloy, and the gas cannot be discharged to form the blowhole.