高清性色生活片97,白嫩外女BBWBBWBBW,加勒比久久无码中文字幕,中出内射颜射骚妇

In centrifugal casting production, mold speed, gating system, pouring quantity, solidification under slag, metal filtration, coating application, pouring temperature and casting mold removal are the process problems that must be determined or solved, because they directly affect the quality and production efficiency of castings.

1、 Mold speed is an important process factor in centrifugal casting. Different castings and different casting processes have different mold speed. Too low mold speed will lead to poor filling of liquid metal in vertical centrifugal casting, and rain phenomenon in horizontal centrifugal casting, as well as loose, slag inclusion, uneven concave convex and concave defects on the inner surface of castings; if the casting speed is too high, defects such as cracks and segregation will easily appear on the castings, and defects such as expansion box will be formed on the outer surface of sand mold centrifugal casting, which will also make the machine appear large The vibration, wear and power consumption are increased. Therefore, the selection principle of mold speed is to select a small value on the premise of ensuring the casting quality 

2、 Gating system in centrifugal casting, the gating system mainly refers to the pouring cup and the pouring trough connected with the metal, and sometimes includes the runner in the mold. When designing the gating system, the following principles should be paid attention to:

1) When pouring long and large diameter castings, the pouring system should make the liquid metal spread evenly on the inner surface of the mold quickly 2) When pouring easily oxidized molten metal or using centrifugal sand mold, the pouring tank should make the molten metal fill the mold in a balanced way, so as to reduce the splashing of molten metal and the erosion of sand mold as much as possible 3) When casting the formed castings, the runner in the mold should be able to make the molten metal flow into the mold cavity smoothly 4) After pouring, there should be no metal and slag left in the pouring cup and pouring tank. If there is residual metal and slag, it should also be easy to remove.

3、 In order to overcome the defect of hypodermic shrinkage caused by bidirectional solidification of thick walled centrifugal casting, slagging agent and molten metal can be poured into the mold during pouring. The slag is covered on the inner surface of the casting to prevent heat dissipation from the inner surface, and the sequential solidification conditions from outside to inside are created to eliminate the subcutaneous shrinkage. At the same time, slag forming agent can also play a role in refining molten metal. The method of pouring slagging agent is as follows: the powder slagging agent is sprinkled in the pouring tank, and the molten slag is poured into the mold together with the molten metal.

4、 The inner diameter of quantitative centrifugal casting is usually determined by the amount of molten metal poured. Therefore, the amount of molten metal poured into the mold must be controlled to ensure the inner diameter. In recent years, when pouring large castings, the digital display remote control crane scale is used for quantitative pouring. Quantitative pouring pressure sensors have also been installed on the quantitative pouring ladle of centrifugal furnace.

5、 The composition of coating for centrifugal metal mold is similar to that of gravity metal mold casting. When pouring slender centrifugal casting, it is difficult to remove the residual coating on the working face of the mold, so the residual strength of the binder in the coating composition after working at high temperature should be as low as possible to facilitate the removal.

6、 Filtration of liquid metal contains some difficult to remove dregs. Some screens can be used to remove slag, such as foam ceramic filter and glass fiber filter.

7、 The pouring temperature of centrifugal casting is mostly tubular, sleeve and ring-shaped. The resistance of liquid metal filling is small, and centrifugal pressure or centrifugal force can strengthen the filling ability of liquid metal. Therefore, the pouring temperature of centrifugal casting can be 5 ~ 10 ° C lower than that of gravity casting.

8、 In order to improve the production efficiency, the casting should be demoulded as soon as possible on the premise of ensuring the quality. Sometimes, in order to prevent the casting from cracking, the casting after demoulding should be put into the holding furnace or buried in the sand pile to cool down immediately. For some castings that are not easy to demould and need slow cooling and crack prevention, the mold with casting can be removed from the centrifugal casting machine immediately after the mold stops rotating, and is buried in the sand pile for slow cooling, and the mold can be demoulded at room temperature.