Aluminum Alloy Melting Casting and Slagging Technology and Application

A melt quality effect

Pure melt purification is a common technical foundation for improving the quality of aluminum materials, and it is also a key technology for improving the quality of aluminum materials. The presence of gas and non-metallic inclusions in the melt has a significant effect. Mainly include: the subsequent processing and forming properties of the blank, the physical properties of the final product, mechanical properties, corrosion resistance, structural integrity and appearance quality.

Two factors that affect the quality of the melt

1 External materials: quality of raw and auxiliary materials, type of waste, and proportion of added materials;

2 smelting and online processing:

Melt temperature, standing time, furnace refining, slag slag operation, furnace cleanliness, aluminum liquid converter / pouring, flow tank hygiene and drying degree, degree of tool drying;

Degassing, filtration, refinement of additives;

3 casting process: distribution bag, metal flow, metal temperature, operation is not standardized.

Three impurity classification

1 gas impurities: H2

2 basic impurities: Na, Ca, Li and so on.

3 non-metallic impurities: commonly referred to as inclusions

Al2O3, spinel, MgO, FeO, MnO;

AlN, TiB2, (Ti, V) B2, Al4C3;

MgCl2, NaCL2, CaCl2 salts;

4 liquid impurities: low melting point chlorides, fluorides and mixtures thereof.

How to determine the quality of the melt

1 High-quality products must have the ultimate goal of reducing or eliminating non-metallic inclusions in the aluminum melt;

2 There are many methods for the treatment of melt at home and abroad, but the effect of the treatment needs an accurate evaluation price system;

3 The assessment of inclusions in the melt is a comprehensive judgment and analysis of the used melt treatment system. The evaluation criteria are established on the basis of a comprehensive and systematic quantitative analysis of the entire process melt treatment, so that the selection of the filter The use of more scientific, seeking to optimize the performance of aluminum products with the most economical and reasonable filtration.

Five melt inclusions evaluation method

1 At present, the main evaluation methods are mainly off-line analysis. After the melt is sampled before and after filtration, the inclusion content is measured and compared. The conventional methods include quantitative metallography, chemical analysis, image scanning (IA), volumetric method, and scanning electron microscopy. (SEM), Laser Diffraction Particle Size Analysis (LDPSA), Nondestructive Ultrasound (CUS), Laser Microprobe Mass Spectrometry (LAMMS), X-ray Diffraction (XPD), Photoelectric Scanning, Auger Electron Spectroscopy Law (AES) and so on. Although the accuracy of off-line analysis is high, but the detection results lag behind the casting process, it can only express the filtration efficiency at the sampling time, and can not track the low-efficiency changes of filtration efficiency and make adjustments in time.

2 Western developed countries have developed a variety of new evaluation techniques for production sites in response to the stringent requirements for the quality of high-end aluminum products.

11LiMCA11 liquid metal cleanliness analyzer, invented by Canadian ABB company.

22PoDFA device, invented by Canadian Aluminum Corporation;

33LAIS Act, invented by United Union Carbide Corporation;

44Prefil-Footprinter device, invented by Canadian ABB company.

(Associate Professor of Northeastern University: Wang Xiangjie)