Effect of aluminium-silicon alloy ingots on pinholes in aluminium alloys

Aluminium-Silicon, also known as 4-series aluminium alloy, is an aerospace aluminium alloy. Although we do not sell 4-series aluminium sheets at the moment, we do offer other aerospace aluminium products such as 2-series and 7-series aluminium alloys or aerospace aluminium sheets for sale. When studying the effect of aluminium-silicon alloy ingots on pinholes in aluminium alloys, it was found that pinholes did not appear when molten pure cast sand test blocks were used, and when low-organised and unqualified aluminium-silicon alloy ingots were added, the test blocks had severe pinholes and large grains. The reason for this is due to the hereditary nature of the material. Al-Si alloy and heredity increases with the increase in content surface, the amount of silicon reaches 7%, the heredity is significant. Continue to improve the silicon content to eutectic composition, heritability and slightly reduced. In order to solve the casting defects caused by the hereditary nature of the furnace material, it is necessary to use high metallurgical quality of aluminum ingots, intermediate alloys and other furnace materials. Specific standards are as follows.

(1) aluminum silicon alloy fracture should not have pinholes, pores

Pinhole should be within three levels, local (not more than 25% of the inspected area) should not exceed three levels, more than three levels must take the method of remelting to reduce the degree of pinhole. Remelting refining method is the same as general aluminium alloy melting, casting temperature should not exceed 660℃, for those ingots and alloy ingots with large original grains, a lower ingot mould temperature should be used first to make the aerospace aluminium alloy solidify quickly and refine the grains.

(2) Furnace material treatment

The furnace charge should be treated by blowing sand before use to remove rust, grease and other dirt from the surface of the aluminium-silicon alloy. The aluminum alloy ingots and metal-type furnace materials that have not been placed for a long time and have a clean surface can be treated without sand-blowing, but the iron strainers and inlays mixed in the furnace materials should be eliminated. All the furnace materials should be preheated before entering the furnace to remove the moisture attached to the surface of the aerospace aluminum plate and shorten the melting time above 3 hours.