1. Chemical composition:
The alloy grades of aluminum foil for heat exchange fins mainly include 1100, 1200, 8011, 8006, etc. From the perspective of use, air conditioners do not have strict requirements on the chemical composition of aluminum heat exchange fins. Without surface treatment, 3A21 aluminum alloy has relatively good corrosion resistance, high mechanical properties such as strength and elongation, and high hardness. The choice of alloy depends primarily on the final mechanical properties the material can achieve and the ease of the ant process. For example, the 1 100 aluminum alloy with higher purity is easier to roll, while the 8011 alloy is more difficult.
2. Mechanical properties:
Mechanical properties mainly refer to the tensile strength, elongation and cupping value of aluminum foil. From the perspective of use, it is hoped that these three indicators are as high as possible, but in terms of the material itself, these three indicators are contradictory, that is, when the tensile strength of the aluminum foil is relatively high, the elongation index will decrease; When the elongation of the aluminum foil is increased, the tensile strength will decrease. Therefore, in practical applications, the intermediate value of the mechanical properties is generally taken, and the specific strength and plasticity values are related to the punching die during the processing of the heat exchange fin. Generally, the punching process of heat exchange fins is divided into two types: stretching type and non-stretching type. The mold for stretch punching requires better plasticity of the aluminum foil, that is, the elongation is higher, and the relative strength value can be slightly lower; while the non-stretch mold requires higher strength of the aluminum foil, and plasticity is a secondary indicator. There are many factors affecting the mechanical properties of aluminum foil, mainly the chemical composition and processing technology of aluminum foil. As far as the strength and plasticity of aluminum foil are concerned, by adjusting the chemical composition or changing the processing process and parameters, the plasticity or strength of the material can be changed within a certain range while keeping one side unchanged. That is to say, through the adjustment of chemical composition and processing technology, the matching value of aluminum foil strength and plasticity can be changed limitedly.
According to the different requirements for mechanical properties of heat exchange fins, there are currently three main use states of aluminum foil: H22, H24, and H26. Each state corresponds to a certain range of strength and plasticity. Judging from the current situation of the domestic aluminum processing industry, there is no unified standard for the range of mechanical properties of each state. At the same time, in practical application, the range of mechanical properties of each state is too wide, and the mechanical properties of the product cannot be well controlled to satisfy the user.