Aluminum alloy quality control is important for aluminum melting. Melting and pouring of aluminum alloy is the main link in casting production. Strict control of the whole process of melting and casting plays an important role in preventing casting defects such as pinholes, inclusions, under casting, cracks, pores and shrinkage porosity. Due to the high tendency of hydrogen absorption, strong oxidation ability and easy dissolution of iron, simple and cautious preventive measures must be taken in the melting and casting process to obtain high quality castings.
Aluminum Alloy Quality Control
In order to melt high quality aluminum melt, the qualified raw materials should be selected first. Raw materials must be scientifically managed and properly treated, otherwise the quality of the alloy will be seriously affected. The production practice has proved that if the raw materials (including metal materials and auxiliary materials) are not strictly controlled, the castings will be scrapped in batches.
Raw materials must have qualified chemical composition and organization, and the specific requirements are as follows:
In addition to the analysis of the main components and impurity contents, the microstructure and fracture surface of the alloy ingots entering the factory are also examined. It has been proved by practice that it is difficult to obtain dense castings by using liquid aluminum containing severe shrinkage, pinholes and bubbles, and even the whole furnace and batch of castings will be scrapped.
It has been found that there is no pinhole in the pure casting sand mold test block when the molten aluminum silicon alloy ingot is used to study the influence of aluminum silicon alloy ingot on the pinhole of aluminum alloy.
When the low structure and unqualified aluminum silicon alloy ingot are added, the pinhole of the test block is serious and the grain size is large. The reason is the heredity of the material. The heritability of Al-Si alloy increases with the increase of Si content. When Si content reaches 7%, the heredity is obvious. The heritability decreased slightly with increasing silicon content to eutectic composition. In order to solve the casting defects caused by the heredity of charge, it is necessary to select aluminum ingot, metal alloy additive, and other charge with high metallurgical quality.