On Dec. 3, 2015, the theme of "China Fusion Processing Technology, Leading Processing Future; Focusing on Technology and Achieving Win-Win" was held in Harbin. The conference was jointly organized by Shanghai YiMao Business Development Co., Ltd and China Nonferrous Metals Industry Association, and Harbin Dongsheng Metal Material Co., Ltd. As the sole communication platform for the industry, the conference brought together experts and scholars and technical experts, Production technology to explore and jointly promote the casting industry, technological upgrading, promote the development of the industry.

Northeastern University Associate Professor Wang Xiangjie at the meeting published "aluminum alloy casting test technology and its application" keynote speech. (The original speaker for the aluminum Limin Co., Ltd. technical director of the Department of Engineering Luo Xiao Xiong, because of their failure to attend). The contents of the lecture include the influence of melt quality, factors affecting melt quality, impurity classification, how to judge the quality of melt quality, the evaluation method of inclusions in melt.

First, the melt quality

Pure melt is to improve the quality of aluminum common technical base, but also enhance the quality of aluminum key technologies. The presence of gas and non-metallic inclusions in the melt has a significant effect. Mainly include: the subsequent processing of blank forming properties, the final product physical properties, mechanical properties, corrosion resistance, structural integrity and appearance quality.

Second, the impact of melt quality factors

1. External materials: quality of raw and auxiliary materials, types of waste and the proportion of added;

2. Melting and on-line processing:

Melting temperature, standing time, furnace refining, slag operations, cleanliness of the furnace, aluminum converter / pouring, health and drying tank, the degree of drying tools;

In addition to gas, filtration, refinement additives;

3. Casting process: distribution bags, metal flow, metal temperature, the operation is not standardized.

Third, impurity classification

1. Gas impurities: H2

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

3. Non-metallic impurities: usually said inclusions

Al2O3, spinel, MgO, FeO, MnO;

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

MgCl2, NaCL2, CaCl2 salts;

4. Liquid impurities: low melting point chlorides, fluoride and their mixtures.

Fourth, how to determine the quality of the melt is good or bad

1. High-quality products must be to reduce or eliminate non-metallic inclusions in aluminum melt as the ultimate goal;

2. Domestic and foreign melt treatment means very much, but how to deal with the effect of the need for an accurate evaluation system;

3. In-melt inclusion evaluation is a comprehensive evaluation and analysis of the melt treatment system used. Based on the comprehensive and systematic analysis of the whole process melt treatment, the evaluation criteria are established. The selection of the filter And the use of more scientific, to seek the most economical and reasonable way to achieve the aluminum filter performance optimization.

5, melt inclusion evaluation method

1. The current main evaluation methods to off-line analysis, that is, after the melt before and after sampling, determination of inclusion content and comparison, conventional methods, including quantitative metallographic, chemical analysis, image scanning (IA), volumetric method, scanning electron microscopy (SEM), laser diffraction particle size analysis (LDPSA), nondestructive ultrasonography (CUS), laser microprobe mass spectrometry (LAMMS), X-ray diffraction (XPD), photoelectric scanning, Auger electron Spectroscopy (AES), and the like. Off-line analysis, although the accuracy is high, but the test results lags behind the casting process, can only express the sampling time of the filtration efficiency, can not track the low filtration efficiency changes and make adjustments.

2. Western developed countries for high-end aluminum products to the strict quality requirements, the development of a variety of production sites for the new evaluation techniques.

11LiMCA11 liquid metal cleanliness analyzer, invented by the ABB company in Canada.

22PoDFA device, invented by the Canadian Aluminum Corporation;

33LAIS method, invented by United Carbide Corporation;

44Prefil-Footprinter device, invented by the ABB company in Canada.