Strengthening technology and mechanism for semi-solid die casting of aluminum alloy

Combined with theoretical evaluation, an optimized strengthening process for the semi-solid die castings of A356 aluminum alloy was obtained by studying the mechanical properties of castings solution treated and aged under different conditions in detail, then, the semi-solid die castings and liquid die castings were heat treated with the optimized process. The results show that the mechanical properties of semi-solid die castings of aluminum alloy are superior to those of the liquid die castings, especially the strengthening degree of heat treated semi-solid die castings is much greater than that of liquid die castings with the tensile strength more than 330 MPa and the elongation more than 10%, and this is mainly contributed to the non-dendritic and more compact microstructure of semi-solid die castings. The strengthening mechanism of heat treatment for the semi-solid die castings of A356 aluminum alloy is due to the dispersive precipitation of the second phase（Mg2Si） and formation of GP Zone.

Performance of Semi-solid Slurry Produced by Twin-screw Stirring Mixer and Rheo-diecasting Process of AZ91D Alloy

The microstructure of semi-solid slurry of AZ91D alloy, which was produced by twin-screw stirring mixer under the different parameters, was investigated.Rheoforming by cold chamber die casting process was performed thereafter. The results indicate that with decreasing of the barrel temperature of the mixer and the pouring temperature of molten Mg alloy, the solid fraction of semi-solid slurry increases and the size of non-dendritic grains becomes smaller. While the shear rate increases, the solid fraction of semi-solid slurry decreases. The tensile strength and elongation of metal rheoformed by die casting are higher by about 37% and 44% respectively than those produced by conventional liquid die casting.

Heat shock behavior of permanent die during non-solid near-net forming process

Heat shocks caused by alloy melt and coat spraying are the main reason of die plastic deformation and early fracture. Based on theoretical analysis of heat shock phenomenon, two characteristic parameters of die damage caused by heat shock were proposed, which are heat shock plastic deformation index (HSPI) and heat shock crack index (HSCI). The effect of heat shock on die plastic deformation and fracture behaviors was described quantitatively by these two parameters. HSPI represents approaching of heat shock stress to die yield stress. Plastic deformation will happen on a die if this index reaches 1. HSCI represents approaching of heat shock stress to die tensile strength. Die fracture will happen if this index reaches 1. According to theoretical analysis of heat transfer, theoretical models of HSPI and HSCI were established. It is found that, the smaller the interfacial thermal resistance (ITR) is, the higher the pouring temperature and die temperature are before heat shock, and the greater the HSPI and HSCI are, which can be fitted as exponential curves, linear and cubic curves.

基于SolidWorks配置功能的冲模标准件的参数化造型

以提高冲模设计效率为目的,结合具体实例,介绍了使用SolidWorks的配置功能实现冲模标准件参数化造型的方法。该方法简单易行,不需要进行二次开发,有较好的应用价值。

Solidworks在锻模设计中的应用

本文介绍了三维CAD/CAM/CAE集成化机械设计软件Solidworks的功能、特点,并利用此软件对变速叉锻件进行了三维实体造型及锻模设计。

基于匀加速料筒孕育半固态压铸制备薄壁复杂空腔手模的研究与实践

随着全球节能减排、碳达峰、碳中和的发展需求,各行业零部件轻量化、绿色化成为必然发展之路。生产医疗用橡胶、丁腈手套所需要的手模一直以来都采用陶瓷型,虽能满足功能性要求,但其存在能耗大、易破损、无回收等缺点。改用易回收的金属材料成为研究热点,铝合金以其质轻成为研究首选。由于手模部件具有薄壁、内腔复杂等特点,并需要与挤压成型部件进行焊接,采用铝型材冲压制备成本高,普通压铸存在复杂内腔难以成形和铸件不能焊接等难题。本研究基于自主开发的匀加速料筒孕育半固态压铸技术,通过数值模拟分析优化压铸工艺,采用优选的树脂砂芯,成功制备出铝合金复杂空腔手模压铸件。开发出的产品满足了项目要求,也为复杂空腔压铸件研发提供了很好的技术实例和参考。

基于Solid Edge的参数化设计建立三维冲模标准件库

主要介绍了基于SolidEdge的参数化设计,利用VB6.0对SolidEdge进行二次开发,实现三维冲模标准件库的建立,从而提高冲模的设计效率.

基于Solid Edge的不锈钢圆筒形件拉深模具设计的研究

分析了不锈钢在拉深中存在的工艺问题和如何选用模具材料以延长模具的寿命。并基于SolidEdge平台,采用参数设计技术和VisualBasic工具,开发了一个圆筒形零件拉深模具系统,该系统能够全参数化进行零件设计并生成零件图、模具虚拟安装并生成模具装配图。

基于Solid Edge的冲模标准件库系统研究

针对模具设计需大量重复使用标准件的特点,以VB为开发工具,对三维CAD软件Solid Edge进行二次开发,开发出了冲模标准件库系统,使标准件的调用实现自动化,减少了设计中大量重复性工作,简化了设计,提高了效率。研究证明,使用VB编程技术操纵Solid Edge变量表建立标准件库的方法是可行的,开发的冲模标准件库系统不再仅仅局限于某个零件,还可扩展到装配体,为复杂模具标准件库系统的开发提供了思路,研究成果对建立相关行业标准件库有一定指导意义。

基于Solid Edge的塑料管材挤出机头零件参数化设计

采用VisualBasic编程语言工具,对三维造型软件SolidEdge进行二次开发,实现了对塑料管材挤出机头的主要零件参数化设计。按照用户选择或输入的不同参数,得到不同尺寸零件的三维实体和相应的变量表,扩展了SolidEdge的功能。

基于Solid Edge/SDK的覆盖件拉延模快速设计系统研究

采用Solid Edge/SDK技术针对某汽车覆盖件模具制造企业的设计工作,开发了基于Solid Edge/SDK的汽车覆盖件拉延模快速设计系统。该设计系统根据模具设计流程及设计数据控制Solid Edge软件的运行,生成覆盖件拉延模各零件以及装配模型。该系统可以有效地提高同类模具的设计效率,特别适用于大型模具的上下模座、压边圈等主要零件的设计。

铝合金左悬置支臂半固态压铸技术研究

研究了铝合金左悬置支臂半固态压铸技术,对铸件结构设计、半固态压铸工艺及台架试验等进行分析,对样件产品质量进行检测。半固态压铸左悬置支臂样件通过台架试验,与重力铸造产品相比,减重10%以上。

基于Solid Edge V17的轴承盖级进模设计

Solid Edge软件系统功能强大,应用广泛,在模具设计和制造行业具有很大的优势。主要叙述了基于Solid Edge V17平台实现轴承盖级进模三维设计的过程。

Interfacial heat transfer behavior at metal/die in finger-plated casting during high pressure die casting process

Heat transfer at the metal-die interface has a great influence on the solidification process and casting structure. As thin-wall components are extensively produced by high pressure die casting process(HPDC), the B390 alloy finger-plate casting was cast against an H13 steel die on a cold-chamber HPDC machine. The interfacial heat transfer behavior at different positions of the die was carefully studied using an inverse approach based on the temperature measurements inside the die. Furthermore, the filling process and the solidification rate in different finger-plates were also given to explain the distribution of interfacial heat flux(q) and interfacial heat transfer coefficient(h). Measurement results at the side of sprue indicates that qmax and hmax could reach 9.2 MW·m^(-2) and 64.3 kW ·m^(-2)·K^(-1), respectively. The simulation of melt flow in the die reveals that the thinnest(T_1) finger plate could accelerate the melt flow from 50 m·s^(-1) to 110 m·s^(-1). Due to this high velocity, the interfacial heat flux at the end of T_1 could firstly reach a highest value 7.92 MW·m^(-2) among the ends of T_n(n=2,3,4,5). In addition, the q_(max) and h_(max) values of T_2, T_4 and T_5 finger-plates increase with the increasing thickness of the finger plate. Finally, at the rapid decreasing stage of interfacial heat transfer coefficient(h), the decreasing rate of h has an exponential relationship with the increasing rate of solid fraction(f).

Industrial development of gas induced semi-solid process

The gas induced semi-solid(GISS) is a rheocasting process that produces semi-solid slurry by applying fine gas bubble injection through a graphite diffuser.The process is developed to be used in the die casting industry.To apply the GISS process with a die casting process,a GISS maker unit is designed and attached to a conventional die casting machine with little modifications.The commercial parts are developed and produced by the GISS die casting process.The GISS die casting shows the feasibility to produce industrial parts with aluminum 7075 and A356 with lower porosity than liquid die casting.

Research and development of gas induced semi-solid process for industrial applications

Several rheocasting processes are developed or applied worldwide in the metal forming industry.One of the new rheocasting processes is the gas induced semi-solid(GISS) process.The GISS process utilizes the principle of rapid heat extraction and vigorous local extraction using the injection of fine gas bubbles through a graphite diffuser.Several forming processes such as die casting,squeeze casting,gravity casting,and rheo-extrusion of the semi-solid slurries prepared by the GISS process have also been conducted.The GISS process is capable of processing various alloys including cast aluminum alloys,die casting aluminum alloys,wrought aluminum alloys,and zinc alloys.The GISS process is currently developed to be used commercially in the industry with the focus on forming semi-solid slurries containing low fractions solid(< 0.25) into parts.The research and development activities of the GISS process were discussed and the status of the industrial developments of this process was reported.

Research and Applications of Semi-solid Processing

It has been more than ten years since the semi-solid processing (SSP) technique was put into commercial applications in the world. A lot of work on semi-solid metals (SSM) including their preparation, reheating and semi-solid forming has been done in China. In order to produce the high quality die-casting, a novel innovation that modifies the present machines based on the SSP technique was proposed. Semi-solid die-casting on modified casting machines can manufacture parts with more excellent quality than those produced by squeeze casting. It was found that the defects such as 'elephant foot' and 'periphery liquid metal loss' during reheating could be avoided through controlling the non-dendritic structure of billets and optimizing the reheating process. The processing parameters and mold designs of semi-solid die-casting are fairly different from those of liquid die-casting.

基于Solid Edge的节流阀体压铸模CAD/CAM

为了实现以产品为中心的设计,以节流阀体为例,采用CAD/CAM集成技术,利用SolidEdge软件完成了模具的三维实体造型和计算机辅助数控工艺设计,实现了该模具CAD/CAM集成设计和制造;运用设计计算对浇铸系统、冷却系统进行了设计验证,优化了模具的设计;同时压铸过程中对压铸工艺参数进行了优化设计。

Semi-solid Thixoforming Simulation of Al-Cu-Mn-Ti Alloy Parts via AnyCasting

The software AnyCasting was used to simulate the thixotropic die-casting process of semi-solid Al-Cu-Mn-Ti alloy slurry to form the parts of a particular shape, especially on how the in-gate size of die and injection speed affect the process. The results showed that the die cavity can be filled well with the semi-solid slurry in form of laminar flow under conditions that the temperature of the semi-solid slurry is 640℃ and that of die 200-240℃, thickness of in-gate is 11 mm and, more important, the injection speed should be changed from 0.1 to 1.0 m/s when 60% of die cavity has been filled. The simulation result is highly proved in conformity to the actual die-casting specimens in accordance to the filling process as simulated. Moreover, the hardness of the specimens is up to 116.6 HV after the treatment of solid solution plus underaging, i.e. 45.7% higher than that in conventional ones.

Solid Edge在模具设计中的应用

对Solid Edge软件的安装、实体建模的基础过程以及在设计塑料管材胀口模具工作中的运用进行了简要介绍。