Warm Precision Forging on Extruded AZ61 Magnesium Alloy

温精锻造是塑性成形中直接获得成品形状和高尺寸精度的综合生产工艺，受到人们的重视。本研究对具有高塑性可加工性和高强度的AZ61镁合金挤压坯温精锻进行了研究。本研究旨在寻找生产T形精锻件的最佳工艺条件，并对其力学性能和织构进行分析。此外，还对AZ61挤压坯的温轴向顶锻能力进行了评价。这对于实际应用广泛的T形锻件尤其有用，如汽车零件、管接头、阀体等。对于T形锻件，研究了润滑剂、温度和背压条件。还研究了AZ61挤压方坯的轴向温镦粗作为锻造工艺的基础数据。分析了AZ61挤压铸坯在温轴向压缩过程中的变形行为和不稳定变形。结果表明：(1)对于T形锻件，在成形温度为463K、成形速度为14 mm/min的条件下，获得了背压为250kN的无断裂锻件；(2)在锻造能力方面，在温轴向镦粗过程中出现了垂直方向的不对称变形，这与其择优取向有关。在483K下，铸态镁合金的锻造速度是挤压坯料的3倍以上。由于锻造后的硬度和抗压强度都很好，因此采用铸造镁合金的锻造工艺是可取的。

Warm precision forging is receiving attention as integrated producing process to directly obtain finished product form and high dimensional accuracy in the plastic forming In this research warm precision forging of an AZ61 Magnesium alloy extruded billet with an expected high plastic workability and high strength was investigated. This research aims to find the best condition for producing T-shaped precision forging, and to analyze the resultant mechanical properties and texture. In addition, warm axial upset ability of AZ61 extruded billet is also evaluated. This is particularly useful for T-shaped forging, which have broad practical application, such as automobile parts, pipe joints, valve bodies, etc. For T-shaped forging, the lubricant, temperature and backpressure condition were investigated. Warm axial upsetting of an AZ61 extruded billets is also investigated as the base date of a forging process. Deformation behavior and unstable deformation of AZ61 extruded billets during warm axial compression are also analyzed. Obtained results are as follows:(1)For T-shaped forging, at forming temperature of 463 K, and velocity of 14 mm/min, fracture-free forging with an applied backpressure of 250kN were obtained(2)For upset ability, asymmetrical deformation in the vertical direction was appeared in warm axial upsetting, and is related to the prefer orientation. This phenomenon occurs prior to deformation caused by crystal rotation in the upper loaded region of the billet.(3)By using cast magnesium alloy, T-shaped forging were obtained at the speed three times or more the extruded billets, at 483K. As the both of hardness and compression strength after forged is excellent, forged technology that used the casting magnesium alloy is expected.