Aluminum melt transfer and pouring Precautions

Although the density of solid aluminum oxide similar to the density of molten aluminum, the aluminum melt entering the inside, after a sufficiently long time to sink to the bottom of the crucible accompanied. The molten aluminum is oxidized to form an alumina film, but only in contact with the aluminum alloys melt side is dense, porous side in contact with air and a large diameter 60 - 100A holes, surface area, adsorption strong, easily adsorbed moisture, anti there is a tendency to float. Thus, the oxide film and the small difference in the proportion of aluminum melt, mixing it with the melt, drifting very slowly, it is difficult to exclude from the melt, the formation of pores in the casting too inclusions. Therefore, the key transfer molten aluminum is to minimize the mixing of the molten metal, the melt to minimize contact with air.

Tilting crucible using transfer note melt, to avoid melt mixed with air, it should try to rely on the furnace ladle nozzle, and tilted so that the melt downstream along the side wall of the ladle, will not underwrite the direct impact , the occurrence of agitation, splash and so on.

Pouring the correct and reasonable approach is to get one of the important quality castings. Note the following for preventing, reducing casting defects is very effective.

(A) should be carefully checked before pouring the melt tapping temperature, ladle capacity and dryness of the surface coating layer, whether it is another tool to prepare either. Before pouring the metal pouring cup 3 - 5 minutes in a good place on the sand, when the ladle temperature not higher than the breast 150 degrees, placed premature or excessive temperature, the inner runner choked lot of gas, in pouring a risk of explosion.

(B) is not on a "Guotang Feng" in a case casting, and the strong melt oxidation, burning, produce the casting defects such as oxide inclusions.

(Three) obtained from the crucible melts, should be used to underwrite gently poke the melt surface oxide or flux layer, slowly ladle immersed in the melt, a wide mouth with ladle scooping melt , and then lift the ladle smooth.

(Four) do not end when the package palm flat, the pace should be steady, not raised too high ladle, ladle metal surface must be stable, without rope move.

(Five) about pouring should Grilled net ladle slag, slag will avoid casting, oxide, etc. into the mold.

(Six) in the casting, the melt flow to remain stable, can not be interrupted, not straight into the arms of the bottom outlet port. Gate pregnant mother to the end shall be filled from the liquid level shall not turning, casting speed should be controlled properly. Typically, the degree to slightly slower start pouring the melt filling smooth and slightly faster, and casting speed remained unchanged.

(Seven) in the casting process, ladle nozzle and the distance runner as close as possible to the extent of not more than 50 mm in order to avoid excessive oxidation of the melt. ,

(Eight) with a blocked gate arms, blocking is not reversed too early in the melt filled the gate arms, then slowly oblique aside, so as not to melt when the injection sprue vortex.

(Nine) from the bottom of the crucible 60 mm below the melt should not be pouring castings.