多杆连续挤压下的铝合金扩展与焊合成形机理研究

In continuous extrusion process, the combination method of multiple billets extrusion and extending forming is especially suitable for extrusions of flat profile with high width. Compared with conventional extrusion, continuous extrusion exhibits the advantage of energy conservation. But during multiple billets extrusion the problem of solid phase welding with oxides arises; the big extending forming will induce the metal flow, organization and property uneven; the big extending forming will weaken the welding pressure; and the extrusion force is big. These problems restrict the application of the technology. The continuous extrusion of 6063 Aluminium Alloy with double billets is taken as breakthrough point to grasp the extending and welding mechanism in the continuous extrusion process with multiple billets. And then the force, welding pressure and temperature theoretical calculation models will be built by the theoretical calculation. .On the basis of the testing performance and the microstructure observation results, the microstructure evolution of the Aluminium Alloy and the aluminium oxide on the outer surface of the rods will be analysed. The essence of the solid phase welding mechanisms will be revealed. And the continuous extrusion welding criterion will be established. The effects of the expansion forming on the uniform of the microstructure and the properties of product will be analysed through the simulation and experimental methods. The relationship of extending forming and welding quality will be established. The size of the product and the welding strength of the welds will be improved by optimizing the cavity structure and the temperature control conditions. The research results will provide a theoretical basis for exploring the continuous extrusion of Aluminium Alloy with multiple billets.

采用多杆连续挤压扩展焊合成形技术，可以以较卧式挤压更合理的能量消耗挤压大宽度壁板产品。但多杆挤压中存在着杆与杆之间有氧化物参与的固相焊合，大扩展成形使金属流速、产品组织性能不均匀，大的扩展比会削弱杆与杆之间的焊合强度，挤压变形力大等问题，制约了该技术的应用。本项目以6063铝合金双杆连续挤压为突破口以掌握多杆挤压中的扩展、焊合成形机理。通过理论计算构建力能及焊合压力、温度计算模型；结合微观组织观察及产品性能测试，研究铝合金组织及杆料外表面氧化铝的演变过程，并揭示有氧化物介入的固相焊合本质，建立铝合金多杆挤压焊合判据；通过模拟和实验手段研究扩展成形方式对产品组织、性能均匀性的影响机制；建立连续挤压扩展成形与焊合之间的协调关系；通过优化型腔结构、温度控制条件提高可挤压的产品尺寸及焊合强度。该研究成果为探索利用多杆连续挤压方法生产大宽度壁板提供理论基础。

采用多杆连续挤压扩展焊合成形技术，可以以较卧式挤压更合理的能量消耗挤压大宽度壁板产品。本项目以6063铝合金双杆连续挤压为突破口以掌握多杆挤压中的扩展、焊合成形机理。通过理论计算构建力能及焊合压力计算模型，为合理选择机器设备和工模具材料提供理论依据；结合微观组织观察及产品性能测试，掌握铝合金组织及杆料外表面氧化铝的演变特点，揭示焊缝形成机制；通过有限元模拟和实验手段掌握扩展成形方式对产品组织、性能均匀性的影响机制；利用正交试验进行模腔结构的优化设计，提出既有利于扩展成形、又利于焊合成形的工模具结构；通过有限元模拟和实验相结合的方法，掌握各工艺参数对焊合质量的影响规律，并构建由焊合条件决定的焊合判据，在此基础上通过理论计算构建以产品尺寸为变量的焊合判据的数学模型，达到有效预测产品焊合质量的目的。该研究成果为探索利用多杆连续挤压方法生产大宽度壁板提供理论和实验基础。