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1.
差压铸造在航空航天、国防和汽车工业领域具有广泛的应用前景.应用工程流体力学理论,解析法建立了真空差压铸造过程中铸造罐内压力变化的数学模型,分析了各参数对铸造罐内压力变化的影响,这对真空差压铸造设备的工程设计和控制具有理论及实际的指导意义.  相似文献   

2.
《铸造技术》2015,(5):1281-1283
根据当前真空差压铸造控制系统控制功能薄弱的不足,运用工控机为控制中心,使用PCI总线技术,设计了一种真空差压铸造控制系统,介绍系统的整体结构,阐述系统的硬件与软件设计方法。真空差压铸造控制系统的应用,实现了真空差压铸造工艺的精确控制,提高真空差压铸造工艺水平。  相似文献   

3.
论述了真空差压铸造技术在国内外的理论研究情况及其控制系统的发展,分析了真空差压铸造所具有的优点,指出了其发展趋势和良好的开发前景。  相似文献   

4.
基于铝合金铸件差压铸造各种原始数据积累,结合差压铸造理论,阐述了差压铸造对于装备轻量化的重要作用。  相似文献   

5.
陈竺 《铸造技术》2014,(12):3033-3034
为了改进当前真空差压铸造控制方法的不足,运用计算机控制技术设计了一种真空差压铸造控制系统,介绍了系统的硬件组成,压力检测电路,开关信号检测电路的设计,阐述了监控软件的功能与使用VC++与SQL Server技术实现的监控软件的方法,真空差压铸造控制系统的应用,实现了真空差压铸造工艺的精确控制,提高真空差压铸造工艺水平。  相似文献   

6.
刘明黎 《铸造技术》2014,(8):1857-1858
针对差压铸造的加压过程,分析了铸造生产加压曲线,确定了压力控制方案,利用微机控制气阀的动作实现了对差压铸造过程中的压力控制,对进一步提高差压铸造水平有重要的意义。  相似文献   

7.
大量的薄壁铸件广泛应用于航空航天和国防领域,而真空差压铸造因具有良好的充型和凝固条件,被用于生产高质量的复杂薄壁铸件。目前真空差压铸造薄壁件引起了国内外研究者的广泛关注,为此对真空差压铸造控制系统、薄壁铸件充型以及凝固等方面的研究进展作了介绍,详述了真空差压铸造分级变压控制系统、薄壁铸件充型流态模型、凝固组织与补缩能力,并就目前该研究中存在的问题及今后的发展方向提出了建议。  相似文献   

8.
张庆玲  陈世仓 《铸造技术》2014,(12):3048-3050
采用铸造仿真软件对铝合金舱门盖的铸造过程进行仿真模拟,设计差压铸造模具,优化差压铸造工艺参数,从而消除其铸造缺陷。实验结果表明:仿真结果与试制结果相吻合,采用该差压铸造工艺制得的铝合金舱门盖无缺陷,其力学性能显著提高,具有320330 MPa的抗拉强度和5%330 MPa的抗拉强度和5%6%的伸长率。  相似文献   

9.
利用低压铸造和差压铸造两种工艺制取了A357试样,分别在150、165、180和200℃温度下,研究了不同时效温度下硬度随时间的变化趋势.结果表明,铸态下,低压铸造试样和差压铸造试样硬度均值相差不大,但差压铸造试样硬度分布较为均匀.固溶处理后,两者的硬度均下降20%左右.人工时效开始后,铸造工艺对硬度的影响在铸件上显现出来,差压铸造试样的测试结果均高于低压铸造试样;而且,在165和200 ℃人工时效温度下,低压铸造试样和差压铸造试样硬度随时间的变化趋势有所不同.  相似文献   

10.
为了提高真空差压铸造过程中压力的控制精度,本文研究了基于模糊PID控制的反重力真空差压铸造工艺优化。首先,对真空差压铸造工艺进行分析,确定优化对象;然后,设计以STM32为核心的硬件控制系统,对铸造过程中压力值进行实时采集;最后,将模糊PID控制算法耦合到控制系统中,以实现对铸造过程中压力值的精确控制,从而实现对真空差压铸造工艺的优化。  相似文献   

11.
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.  相似文献   

12.
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.  相似文献   

13.
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.  相似文献   

14.
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.  相似文献   

15.
韩磊 《腐蚀与防护》2015,36(1):84-90,94
综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。  相似文献   

16.
Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.  相似文献   

17.
The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.  相似文献   

18.
On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes' collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.  相似文献   

19.
The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.  相似文献   

20.
正Harbin General Hydraulic Machinery Works Co.,Ltd.of Yilin Hydraulic Group is the most professional production base of large-scale metallurgy oil cylinder and oil machinery cylinder in the Northeast of China.The main products include metallurgy cylinder,swell-shrink cylinder,rotating injection device,lifting cylinder,main lifting jack,front lifting jack,engineering oil cyl-  相似文献   

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