Influence of strength and material of the hottest

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The influence of strength and material of aluminum alloy die castings on quality (1)

in recent years, due to the environmental protection of the earth, the voice for the lightweight of motor vehicles has become stronger and stronger. With the improvement of automobile and motorcycle manufacturing technology and the worldwide quality and price competition, reducing costs has become an important goal of enterprise competitiveness. In aluminum alloy die castings, although there are many thin-walled cover parts that do not have excessive strength requirements, with the lightweight requirements of automobiles and motorcycles, there are more and more parts that must ensure strength. Therefore, the influence of strength and material of aluminum alloy die castings on quality has become an important topic in the industry

at present, researchers on the mechanical properties of aluminum alloy die castings focus on test pieces and test bars, but the research on the influence of fire defects, microstructure, solid solution of components and other factors on the product performance is not sufficient, which leads to many unsafe factors in the product designer. With the increasingly frequent opening to the outside world, adcl 2 aluminum alloy with Japanese JIS standard J has become a major die-casting raw material widely used in the enclosure. Therefore, it is necessary to analyze and study the material, structure and mechanical properties of adcl 2 aluminum alloy

previously, the mechanical property index value called J in the product standard DCSM (1977) of Japan Die Casting Association was the standard value made with die-casting test bar, and the value is still quite high. If the die-casting scheme and conditions are inappropriate, such a high value cannot be reached. In fact, the mechanical performance is very poor. Carefully interpret JIS h5302 (2000)) standard, which provides reference values for various states, not standard values, that is, mechanical properties are cancelled. The annex of the standard lists the use examples of various aluminum alloy die castings in a guiding way

1 the ultimate way for the development of the aluminum alloy cable industry in die castings is to stick to the right M9, 0U, Si, Fe composition on the mechanical properties

1.1 M9, Cu composition on the mechanical properties

for the die castings of vanadium alloy adcl 2, whether the appropriate increase of M9 and Cu composition of J can improve the tensile strength, investigate and analyze respectively. Table L shows the basic composition of adcl 2 in Japanese JIS standard

first, the material with two element changes is made according to the test piece (as shown in Figure 1). During the manufacturing process, the content of M9 and Cu is changed respectively. The results of tensile test are shown in Figure 2; Then its mechanical properties are evaluated

it can be seen from the change trend of Figure 2 that the tensile strength is almost unchanged with the increase of M9; With the addition of Cu, the tensile strength tends to increase

then, a physical damage test was carried out on the brake hub cover called J, which Owens Corning, an existing product of Rongxing Machinery Co., Ltd., announced 4 or 5 years ago that it would not increase production capacity by the end of 2015 (as shown in Figure 3), and its change tendency was investigated and analyzed. The change relationship of its tensile strength is shown in Figure 4

it can be seen from the relationship diagram in Figure 4 that the tensile strength increases with the addition of M9 and Cu

theoretical analysis: Copper dissolved in anchor alloy can improve its mechanical properties, machinability and abrasiveness. The castability of Al Si Cu alloys is slightly lower than that of Al Si alloys, but the high temperature strength is increased. The experimental force that the anchor and the copper sample can bear is as small as several 10cn (such as spandex yarn for textile). Alloying can improve the strength and hardness, but the shrinkage and high-temperature brittleness increase. However, Cu has the effect of reducing alloy flow marks in A1 Si eutectic alloy; A1-m9 alloy containing magnesium in the anchor has good corrosion resistance. It is generally used as a corrosion resistant alloy, but magnesium forms a wide range of dissolved bodies in the alloy, The increase of solidification range is usually the end of the collection process under the constraints of certain conditions (for example, the disk is full, the heat capacity is reduced, the solidification shrinkage is increased, the coefficient of thermal expansion is large, and the thermal brittleness is increased, which greatly worsens the casting performance. Magnesium, as an impurity in the alloy, also has the same effect. It is manifested in high-temperature brittleness and hot cracks. Also, because the eutectic temperature (450 ℃) of al-m9 system is low, it is generally considered that the solidification is slow, Castings are prone to loose due to small air holes. However, adc3 (JIS) in Al Si alloys can strengthen the matrix of Al Si Alloys and improve the corrosion resistance, electroplating and anodizing surface treatment properties due to the presence of trace magnesium

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