分流模挤压铝合金焊合研究

发布时间：2018-06-03 22:14

本文选题：分流模 + 焊合　；参考：《天津理工大学》2015年硕士论文

【摘要】：平面分流模具的工作原理是采用实心铸锭,在挤压力作用下,使铸锭在经过分流孔时被分为几股金属流,然后在高温、强挤压力和真空的环境下,在焊合室内被重新焊合在一起,最后通过符合型材断面尺寸要求的定径带流出,从而形成了符合一定尺寸、形状的空心型材。分流模挤压的生产效率高,生产周期短,并能生产断面复杂、壁厚差大的型材,在生产管材、空心型材中得到了广泛的应用。但是,平面分流模挤压同样存在一定的缺陷,即分流后的几股金属流在焊合室内焊合后存在焊缝,铝合金结构型材的强度较差的位置一般就在焊缝处。所以,提高平面分流模挤压工艺的焊合质量对型材质量有着至关重要的影响。分流模挤压的焊合研究,首先通过研究一个多孔铝合金扁管的挤压工艺来引入。该铝合金管主要应用于汽车空调散热器中,其特点在于超薄、轻量及其良好的散热性与耐腐蚀性。研究改进了挤压该超薄铝合金管的模具结构,效仿蝶形模具的结构形式,将分流桥的前后端设计为“弓形”,并使用有限元模拟技术对管材挤压过程进行模拟。Deform-3D的模拟结果表明,“弓形”结构减小了坯料分流时的突破挤压力,加快了桥后金属的流动速度,增加了备料区的金属量,有利于金属焊合。文章还着重对分流比的选择进行了详细地分析。对12组不同的分流比K值分别进行了建模、有限元模拟分析,进而进行对比,找出了最佳的分流比K值。经过研究,分流比值选择16时挤压模拟结果最佳。文章对三角孔超薄铝合金管的挤压也进行了研究,通过增加分流比,减小摩擦,减慢挤压速度,提高挤压温度等方法,最终在模拟结果中实现了金属比较好的焊合。而针对平面分流模挤压工艺的特点,采用一个静态挤压实验来探索铝合金在高温、强压力下实现高质量焊合的条件。实验是在高温、强挤压力下,将两个完全相同的3003铝合金锭坯挤压为一体,并讨论焊缝变化的情况。实验的结果表明,挤压焊合的焊缝质量与温度、挤压速度、压力等参数均有关联。而具有侧向流动的金属芯部层,其焊缝的质量更高。最后,设计了一种分流模成型管材挤胀组合模具,包括分流挤压模具部分和胀形模具部分。设计的初衷是利用该挤胀组合模具进行胀形实验,以检验铝合金管焊合带质量。
[Abstract]:The working principle of the plane split die is to adopt solid ingot, under the action of extrusion force, the ingot is divided into several metal flows when passing through the shunt hole, and then in the environment of high temperature, strong extrusion pressure and vacuum. After being welded together again in the welding chamber, the hollow profile with certain size and shape is formed through the flow of the sizing strip which meets the requirements of the section size of the profile. The extrusion of split die has high production efficiency, short production cycle, and can produce sections with complex section and large wall thickness difference. It has been widely used in the production of pipe and hollow profile. However, there are some defects in the extrusion of plane split die, that is, there are weld lines after welding in the welding chamber, and the position where the strength of the aluminum alloy structure profile is poor is generally located at the weld seam. Therefore, it is very important to improve the welding quality of the extrusion process. Firstly, the extrusion process of a porous aluminum alloy flat tube is studied. The aluminum alloy tube is mainly used in automobile air conditioning radiator, which is characterized by super thin, light weight and good heat dissipation and corrosion resistance. The die structure of extruding the ultra-thin aluminum alloy tube is studied and improved, and the front and rear end of the shunt bridge is designed as "bow", following the structure of butterfly die. The finite element simulation technique is used to simulate the tube extrusion process. Deform-3D simulation results show that the "bow" structure reduces the breakthrough extrusion pressure when the blank is divided, accelerates the metal flow rate behind the bridge, and increases the metal content in the material preparation area. It is favorable for metal welding. The selection of shunt ratio is analyzed in detail. The K value of 12 groups of different shunt ratio was modeled and simulated by finite element method, and the best value of K value was found out. Through the research, the best result of the 16:00 extrusion simulation was chosen as the shunt ratio. The extrusion of ultra-thin aluminum alloy tube with triangle hole is also studied in this paper. By increasing the flow ratio, reducing friction, slowing down extrusion speed and increasing extrusion temperature, the welding bonding of metal is realized in the simulation results. According to the characteristics of the extrusion process of the plane split die, a static extrusion experiment was used to explore the conditions of high quality welding of aluminum alloy under high temperature and high pressure. Two identical 3003 aluminum alloy ingot billets were extruded under high temperature and strong extrusion pressure, and the change of weld seam was discussed. The results show that the welding quality is related to temperature, extrusion speed and pressure. The weld quality of the core layer with lateral flow is higher. Finally, a split die forming tube extrusion die is designed, including the split extrusion die part and the bulging die part. The original intention of the design is to test the quality of welded strip of aluminum alloy pipe by means of bulging test.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG379

【参考文献】