Seven-series aluminum alloy small piece and die casting method thereof

Abstract

The invention discloses a seven-series aluminum alloy small piece and a die casting method thereof. The die casting method of the seven-series aluminum alloy small piece is used on a horizontal cold chamber die casting machine and sequentially comprises the steps of a low-speed injection stage, a high-speed injection stage, a pressure maintaining stage when an injection punch stops, a delay extrusion stage for extruding an extrusion package in a die and a cooling stage with continuous dwell pressure; the extrusion pressure of the delay extrusion stage is 130-150 bar, and the extrusion time is2.5-3s, and the delay extrusion stage is delayed by 0.05s compared with the pressure maintaining stage; as the extrusion package of the forming die adopts a delay extrusion method, no filler is neededduring pressure maintaining, and the filler which is not completely solidified in a cavity is extruded in volume through the extrusion package of the die, so that the core structure of the aluminum alloy small piece is denser, the die casted aluminum alloy small piece avoids the situation that structural looseness occurs at the core part position with thicker wall thickness, and defects such as local cracks, cracks, pore expansion, voids and shrinkage cannot occur after the later heat treatment; and the heat-treated aluminum alloy small piece is indeed much higher in strength than materials using traditional die casting materials.

Description

technical field [0001] The invention relates to the field of seven-series aluminum alloy small pieces and processing methods thereof, in particular to a seven-series aluminum alloy small piece and a die-casting method thereof. Background technique [0002] At present, most of the aluminum alloy structural parts that exist in 3D form in smartphones and their accessories are manufactured by aluminum alloy stamping, aluminum forging, aluminum die casting, and full CNC machining. [0003] The aluminum alloy stamping process is mainly used for most products with the same thickness, and it is difficult to produce products with different thicknesses; and it is generally used for the production of thin parts, and is not suitable for structures with higher strength requirements. [0004] The aluminum forging process has a long process and requires multiple forging dies. After each forging process is completed, heat treatment is required to eliminate the influence of residual stress. ...

AI Technical Summary

Problems solved by technology

[0008] It can be seen from the figure that the middle part of the aluminum alloy small piece has an arched structure, and the wall thickness varies greatly in the longitudinal and transverse directions. The wall thicknesses at the wings d and e on both sides are relatively thin, and the core The wall thickness of a and b along the longitudinal direction of the part is relatively thick, while the wall thickness of c is relatively thin; therefore, the product not only has a complex shape and structure, but also has problems with different wall thicknesses in many places. At the same time, the product is also There is a need for higher intensity

[0009] Obviously, the traditional die-casting process is prone to loose structure in the core of the product, especially in the thicker part, and after heat treatment, pores will expand, cracks, cracks, voids, shrinkage and other defects will appear locally, resulting in a significant decline in the overall strength of the product

[0010] Therefore, the existing technology still needs to be improved and developed

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