铝挤压机模拟等温挤压控制系统

为了提高铝挤压制品的质量和产量,提出了模拟等温挤压控制.介绍了铝挤压机模拟等温挤压电气控制系统的系统构成、控制原理及程序设计,对铝型材挤压具有重要意义.     

基于串级控制的铝型材等温挤压系统建模与仿真

等温挤压技术对提高铝型材的质量与产量均具有重大影响,是我国铝型材业界一直存在的一个难题.采用Matlab仿真技术,基于挤压过程中实测到的速度与温度的关系,针对等温挤压过程中的温度控制问题,提出了一种简单有效的串级控制的方法,它能克服挤压过程中的干扰因素.仿真结果表明,该系统可使铝挤压制品的出口温度保持恒定,波动范围在±5℃之内.     

实现铝合金等温挤压的主要方法与关键技术

简要阐述铝合金等温挤压的特点、技术效果,介绍铝合金挤压过程的温度变化及实现等温挤压的主要方法与关键技术措施。     

铝型材挤压模具设计及制造工艺

介绍了常用的铝型材挤压模具的制造工艺.通过对铝型材零件的机构分析,阐述挤压模具采用分体设计便于制造.分析了铝型材挤压模具的机加工、电加工及热处理和部分工艺参数选择的重要性.最后通过试模后,该模具能够挤压出完全合格的铝型材.     

铝型材挤压模具抛光用珩磨膏的分析研究

本文介绍了国内铝型材挤压模具抛光用珩磨膏的研制及使用情况,着重介绍了珩磨抛光的加工原理以及对珩磨膏的要求,并且通过对进口珩磨膏的分析研究,提出了铝型材挤压模具抛光用珩磨膏的研制方法。实验结果表明,这种国产珩磨膏适合用于铝型材挤压模具的珩磨抛光。     

铝型材挤压模的制造工艺

介绍了常用的铝型材挤压模的制造工艺.通过对挤压模的制造工艺分析,详细叙述了铝型材模的机加工、电加工及热处理和部分工艺参数的选择.     

铝型材挤压模的制造工艺

介绍了铝型材挤压模加工工艺编制过程,着重叙述了各工艺参数的选择原则,提出了有待改进的几个问题。介绍的工艺方法是目前铝型材挤压模较先进的制造方法,具有代表性和参考价值。     

铝型材挤压模具抛光用珩磨膏的分析研究

本文介绍了国内铝型材挤压模具抛光用珩磨膏的研制及使用情况，着重介绍了珩磨抛光的加工原理以及对珩磨膏的要求，并且通过对进口珩磨膏的分析研究，提出了铝型材挤压模具抛光用珩磨膏的研制方法，实验结果表明，这种国产珩磨膏适合用于铝型材挤压模具的珩磨抛光。     

240活塞铝裙等温挤压工艺条件的选用及特点

介绍了变形温度，应变速率，润滑剂的使用对ＬＤ１１等曙挤压的影响，在２４０活塞铝裙等温挤压生产中对上述工艺参数进行了选用及控制，同时就该件等温挤压工艺的特点与热模锻工艺进行了初步比较。     

工业铝型材等温挤压技术的研究进展

介绍铝合金等温挤压的原理及在国内外应用现状;分析不同等温挤压方法的特点;阐述等温挤压的关键技术.     

Isothermal extrusion speed curve design for porthole die of hollow aluminium profile based on PID algorithm and finite element simulations

The isothermal extrusion process of hollow aluminium profile was investigated using incremental proportional–integral–derivative (PID) control algorithm and finite element simulations. The range of extrusion speed was determined by considering the maximum extrusion load and production efficiency. By taking the optimal solution temperature of the secondary phase as the target temperature, the extrusion speed–stroke curve for realizing the isothermal extrusion of the aluminium profile was obtained. Results show that in the traditional constant extrusion speed process, the average temperature of the cross-section of the aluminium profile at the die exit rapidly increases and then slowly rises with the increase in ram displacement. As the extrusion speed increases, the temperature difference at the die exit of the profile along the extrusion direction increases. The exit temperature difference between the front and back ends of the extrudate along the extrusion direction obtained by adopting isothermal extrusion is about 6.9 °C. Furthermore, the heat generated by plastic deformation and friction during extrusion is balanced with the heat transfer from the workpiece to the container, porthole die and external environment.     

基于有限元技术的大型6061无缝管挤压温度变化规律研究

分析了铝锭坯在挤压容室的热量变化情况,采用有限元软件对大型6061无缝管材挤压过程进行了三维热力耦合数值模拟,得到了不同挤压速度下力与行程的关系曲线以及铝管在模具出口处的温度和挤压行程的关系曲线.在模拟的基础上提出了将挤压速度沿挤压行程分段,通过挤压制品出口温度反馈,采用比例调节系统闭环调节挤压速度,实现特大铝型材等温挤压的新方法.在100MN油压双动铝挤压机上采用模拟的参数进行了生产验证.     

Optimisation of flow balance and isothermal extrusion of aluminium using finite-element simulations

There is significant demand to reduce variations in the shape and mechanical properties of the aluminium extrusion process to meet tighter tolerance requirements. To reduce variations, the flow and temperature evolution in the container and die must be controlled. To study how the process parameters influence the temperature evolution and the material flow, the effects of ram speed, initial temperature distribution in the billet and container cooling rate have been studied. This work is divided into three parts which examine the different aspects of the extrusion process. (1) To minimize the radial variations of temperature and velocity fields over multiple press cycles. (2) To obtain isothermal extrusion of aluminium. (3) To understand and formulate the effect of an undesired lateral temperature gradient in the billet on the exit velocity of the aluminium sections. In each part, the effect of different process parameters on the flow balance and temperature evolution of the extruded sections is shown and discussed.     

国外铝挤压技术及其装备的进展

介绍了国外挤压机在工艺、机械、液压和自动控制方面的技术发展,着重叙述等温挤压、高速挤压、挤压工艺参数优化和反向挤压等先进技术以及为实现等温挤压和高速挤压所采取的铸锭梯温加热、挤压减速控制、模具冷却等措施。对先进挤压机的结构、计算机控制系统等作了简要介绍。     

基于有限元的铝合金反向挤压技术研究

根据铝合金反向挤压技术特点,分析了反向挤压时铝合金挤压出口温度的变化趋势,采用有限元数值模拟的方法模拟了铝合金反向挤压过程,得到了不同挤压速度情况下铝合金挤压出口温度的变化趋势,根据出口温度的变化情况,提出了采用挤压速度逐渐减小的速度曲线来实现反向挤压的等温挤压技术路线。     

Ram speed profile design for isothermal extrusion of AZ31 magnesium alloy by using FEM simulation

In the conventional hot extrusion of metallic materials,the temperature of the workpiece varies during the whole extrusion process,leading to the non-uniformity of the product dimension,microstructure and properties.In the present research,a simulation model based on the principle of PID control was developed to establish ram speed profiles that can suppress the temperature evolution during the process to allow for isothermal extrusion.With this simulation model,the real-time extrusion ram speed was adju...     

FE analysis of extrusion defect and optimization of metal flow in porthole die for complex hollow aluminium profile

To solve the defects of bottom concave appearing in the extrusion experiments of complex hollow aluminium profiles, a 3D finite element model for simulating steady-state porthole die extrusion process was established based on HyperXtrude software using Arbitrary Lagrangian–Eulerian (ALE) algorithm. The velocity distribution on the cross-section of the extrudate at the die exit and pressure distribution at different heights in the welding chamber were quantitatively analyzed. To obtain an uniformity of metal flow velocity at the die exit, the porthole die structure was optimized by adding baffle plates. After optimization, maximum displacement in the Y direction at the bottom of profile decreases from 1.1 to 0.15 mm, and the concave defects are remarkably improved. The research method provides an effective guidance for improving extrusion defects and optimizing the metal flow of complex hollow aluminium profiles during porthole die extrusion.     

Al—Cu—Mg系硬铝型材挤压淬火研究

研究了高强度Al-Cu-Mg系硬铝型材挤压淬火的温度－速度制度、挤压比对稳态自然时效后力学性能的影响。指出,在合适的挤压温度－速度下,对Al-Cu-Mg系硬铝实施挤压淬火是可行的,其力学性能与普通淬火相当。分析认为,这是由于挤压淬火产生高密度位错细小亚结构的增强作用所致。     

AZ80镁合金塑性变形行为及等温挤压过程仿真

在温度为400℃～450℃、应变速率为0.01s-1～50s-1变形条件下,研究了AZ80镁合金的塑性变形行为,讨论了变形温度及应变速率对该合金热变形行为的影响,分析了该合金管材等温挤压的有限元模拟。研究发现,AZ80镁合金晶粒大小随温度的升高而增大,随应变速率的升高而减小;在高温变形时,发生连续动态再结晶,再结晶组织相对较均匀;通过调整挤压速度2mm/s～1mm/s,使该合金挤压出口温度维持在400℃～430℃较小范围内波动,从而保证制品的组织性能和尺寸精度的稳定。     

In718合金杯形件等温挤压成形数值模拟

应用有限元法对In718合金的杯形件挤压成形过程进行了数值模拟，着重分析了不同挤压温度和不同凸模形状下的金属流变行为和应力应变分布，对模拟结果进行了对比分析，得出了比较合理的等温挤压工艺参数，为高温合金的生产和实验研究提供了科学的理论依据。