【摘要】：隨著社會經(jīng)濟(jì)的不斷發(fā)展以及工業(yè)化程度的快速提高,鋁合金已經(jīng)被廣泛的應(yīng)用于航空、航天、船舶、建筑、橋梁等行業(yè)中,復(fù)雜的鋁合金零件也得到了廣泛的開發(fā)應(yīng)用。相比于傳統(tǒng)的鋁合金制造工藝,冷擠壓技術(shù)以其特有的成形精度高、綜合性能好、節(jié)約成本等優(yōu)點逐漸受到人們的關(guān)注。本文以5A06鋁合金錐形件的冷擠壓成形為研究對象,介紹了冷擠壓的原理、金屬流動規(guī)律及影響擠壓的因素;利用UG三維造型軟件對錐形件建模;計算和確定了冷擠壓工藝中的相關(guān)參數(shù)。通過有限元理論以及DEFORM模擬軟件分析了擠壓過程中的速度、載荷、應(yīng)力、應(yīng)變以及成形規(guī)律,并通過實驗分析了擠壓過程中產(chǎn)品的力學(xué)性能以及顯微組織變化,從而驗證模擬結(jié)果的正確性。本論文的主要結(jié)論有:(1)采用四個工序擠壓成形,錐形件成形狀況良好,金屬流線清晰均勻。隨著凸模的壓下,模頭位置金屬的流動速度逐漸減小,上部分的金屬流動速度逐漸增加,中間位置金屬的流動速度隨著坯料尺寸的增加逐漸增大,在最后一次擠壓的終了階段,速度在中間位置達(dá)到最大,約30mm/s。擠壓載荷均呈現(xiàn)規(guī)律性增大過程,其中第二次擠壓初期模具需要較大的壓力壓入坯料,固初期載荷增加較快,隨后穩(wěn)定增加至最大值。擠壓過程等效應(yīng)力以及等效應(yīng)變分布相對均勻,且變化趨勢一致,擠壓終了階段最大等效應(yīng)力值約為386MPa。(2)沿著成形件擠壓方向,金屬的變形量以及顯微組織變形程度逐漸增大。底部型壁處金屬變形程度最大,顯微組織沿著擠壓方向明顯被拉長,呈現(xiàn)明顯的纖維狀;在擠壓凸模未壓入的成品件尾端,金屬受到較大的擠壓力作用,流線分布較為均勻,但是組織變形量相對較小。(3)對原材料進(jìn)行熱處理(310℃保溫1小時,空冷),材料的抗拉強度和硬度降低,減小了變形抗力,增加了塑性以及原材料的可擠壓性。對成形件進(jìn)行顯微硬度分析發(fā)現(xiàn),在錐形件頭部由于金屬的變形量大,顯微硬度值達(dá)到最高,平均為132.2HV,靠近擠壓成型件的尾部,由于在擠壓前進(jìn)行了退火,在擠壓過程中變形量較小,金屬的顯微硬度相對較低,平均為119.6HV。
[Abstract]:With the continuous development of social economy and the rapid improvement of industrialization, aluminum alloy has been widely used in aviation, aerospace, ships, buildings, bridges and other industries, the complex aluminum alloy parts have been widely developed and applied. Compared with the traditional aluminum alloy manufacturing process, cold extrusion technology has attracted more and more attention due to its high forming accuracy, good comprehensive properties and cost saving. In this paper, the cold extrusion forming of 5A06 aluminum alloy conical parts is studied, the principle of cold extrusion, metal flow law and factors affecting extrusion are introduced, and the conical parts are modeled by UG 3D modeling software. The relevant parameters in cold extrusion process are calculated and determined. The velocity, load, stress, strain and forming law of the extrusion process were analyzed by finite element theory and DEFORM software. The mechanical properties and microstructure changes of the products during extrusion were analyzed by experiments. The correctness of the simulation results is verified. The main conclusions of this paper are as follows: (1) the tapered parts are well formed and the metal streamline is clear and uniform. With the pressing of the punch, the flow velocity of the metal at the die head decreases gradually, the flow velocity of the metal in the upper part increases gradually, and the flow velocity of the metal in the middle position increases with the increase of the blank size, and at the end of the last extrusion stage, The speed is the highest in the middle position, about 30 mm / s. The extrusion load increases regularly, in which the die needs a large pressure to press into the blank at the beginning of the second extrusion, and the initial load increases rapidly, and then increases to the maximum value. The distribution of equivalent stress and strain during extrusion is relatively uniform, and the variation trend is the same. The maximum equal effect force at the end of extrusion is about 386MPa. (2) along the direction of extrusion, the amount of metal deformation and the degree of microstructure deformation increase gradually. The metal deformation at the bottom wall is the largest, the microstructure is obviously elongated along the extrusion direction, showing obvious fibrous shape, and at the end of the finished product which is not pressed into the extrusion punch, the metal is subjected to greater extrusion force, and the streamline distribution is more uniform. However, the amount of microstructure deformation is relatively small. (3) the tensile strength and hardness of the raw materials are reduced by heat treatment (310 鈩，

本文編號：2259609