A356.2铸造铝合金生产中Si偏析的影响

论述了铸造铝合金生产中不同时间和状态下采样对Si偏析的影响及Si偏析对产品的影响,并应用于指导生产实际。     

样模的外观结构对A356.2铸造铝合金中Si偏析的影响

介绍了A356.2铸造铝合金生产过程中,采用不同的样模做化学成分取样分析时,Si的偏析情况。结果显示,采用改进后的样模,液态样的分析数据结果能更准确的代表成品样的分析结果,从而有效控制A356.2铸造铝合金的生产过程。     

A356．2铸造铝合金生产中采样状态和采样时机对Si偏析的影响

本文通过试验摸索,找出规律,论述了铸造铝合金生产中不同时间和状态下采样对Si偏析的影响,并应用于指导生产实际。     

2011易切削铝合金熔炼铸造工艺

介绍了2011易切削铝合金的一些熔炼铸造工艺特点。介绍了在2011合金中加入的低熔点金属特殊的加入方式。分析了2011合金铸锭常出现的缺陷，提出了预防措施。     

高速钢辊环挤压铸造工艺研究

高速钢中各种合金元素密度差大，离心铸造时易产生偏析，为解决离心铸造高速钢辊环偏析问题，研究了高速钢辊环挤压铸造工艺，采用浇注温度1400-1450℃、压力140-150Mpa、保压时间240-300s，可获得组织致密、无偏析、加工量少、硬度高、硬度均匀性好和耐磨性好的高速钢混环。应用于高速线材轧机预精轧机架，使用寿命比高镍铬铸铁辊环提高5-8倍。     

DC铸造7075铝合金微观偏析的量化分析

采用直接水冷半连续铸造(DC铸造)工艺制备7075铝合金铸锭.利用电子探针(EPMA)观察合金元素在样品中的分布,并通过绘制元素分布图判断合金元素在基体中的分布趋势.由于合金相的形成,Zn,Mg和Cu元素易在晶界偏聚；Cr和Ti作为形核质点,易在晶粒中心偏聚.利用5种排序方法处理收集到的电子探针数据,分别绘制成分曲线....     

铝及铝合金气幕铸造工艺

本文主要介绍采用Airsol Veil^R模的铝及铝合金气幕铸造的基本大批量、设备组成、工艺参数及铸锭质量，分析了气幕铸造的工艺特点及影响铸锭质量的几个主要因素。     

A1—7Si—Mg合金的铸造和热处理参数综述

本文阐述了到目前为止所进行的与Ａ１－７Ｓｉ－Ｍｇ合金的组织和机械性能有关的铸造和热处理参数的研究工作。虽然标准技术推荐有较宽的镁含量范围和相当高的铁含量，但是，为了获得最佳和均匀的机械性能。镁的含量应控制在由要求的性能所决定的上限或者下限附近一个窄范围之内，而且铁的含量也应较低。一些研究揭示出共晶硅的变质作用略微增加合金的延性和断裂韧性，也有认为在低的铁含量情况下，变质作用效果明显。一般地说，增加     

2024铝合金气滑铸造工艺研究

介绍2024铝合金及其气滑铸造特点，研究熔体净化、铸造速度、冷却强度、空气压力、润滑油供给量等参数对熔铸工艺及铸锭表面质量的影响，确定2024铝合金气滑铸造工艺参数。     

7050铝合金薄壁管挤压工艺

介绍了7050铝合金薄壁管材的规格和质量要求、工艺路线以及主要生产设备。在大量工艺试验基础上,研究探讨了7050铝合金薄壁管材的挤压工艺、热处理工艺及矫直方法。尺寸测量和力学性能结果表明,所加工7050铝合金薄壁管材完全满足用户要求。     

挤压铸造零件沿流程方向的成分偏析及组织偏聚

采用挤压铸造(液态模锻)工艺制备了A357铝合金螺旋线试件,使用化学成分分析和金相分析方法研究了流程长度对合金成分偏析及组织偏聚的影响.结果表明:在沿流程方向上,流程的开始端和流程末端的Si元素和Mg元素含量大于流程中段的含量.合金的初始α晶粒尺寸随着流程长度的增加先增大后变小.初生固相率随着流程长度的增大呈现波动变化.造成流程成分偏析和组织变化的原因是在挤压铸造凝固阶段中补缩液相的强迫运动.     

铝硅系铸造铝合金的原位统计分布分析

The element distribution analysis for the Al-Si casting aluminum alloys has been done by metal original position analyzer(OPA). The quantitative distribution analysis results of Si, Fe, Cu, Mn and Ti have been obtained by selecting suitable spectrum reference materials and optimizing the instrumental parameters. The content results of five elements by OPA method have good coincidence with the values determined byspark source atomic emission spectrometer. The scanning analysis results show that the distribution of Si, Cu and Ti is homogeneous and some obvious segregation of Fe and Mn has been found in two real aluminum alloys and the content distributions of two elements are very similar. It can be concluded thatthere are some compound of Fe and Mn in casting aluminum alloys by the result of multi-element spectrum channel combination analysis. The conclusion also has good agreement with the results by scanning electron microscope and energy spectrum analysis.     

Fe-WC料浆浇注过程中颗粒偏析的研究

粉浆浇注过程中颗粒偏析现象是由细颗粒的堵塞效应和重力场的沉降作用共同决定的.通过深入分析粉浆浇注过程颗粒沉降运动规律,研究了颗粒偏析的本质.分析表明:粉浆浇注过程中的颗粒偏析与粉浆粘度η,液体介质流速υ0、综合沉降因子r2ρ有关;提高粉浆粘度可以有效抑制颗粒偏析;降低液体介质流速可以抑制细颗粒堵塞效应.粉末装载量和石膏...     

纤维增强铝合金复合材料凝固偏析的数值模拟

根据凝固过程中的守恒原理,建立了铝合金复合材料凝固过程的数学模型.根据所建立的模型对Al2O3f/Al 4 5Cu复合材料进行数值模拟,模拟结果表明:Al2O3短纤维周围有低熔点物质及溶质富集;随冷却速度增大,复合材料基体偏析加剧;随复合材料中纤维体积分数增大,基体中偏析减小.     

Effects of continuous casting process parameters on carbon segregation degree of 38CrMoAl steel big round billet

The effects of continuous casting process parameters (superheat degree, casting speed and F- EMS) on the carbon segregation of round billet with diameter 600mm of 38CrMoAl steel were investigated by industrial experiments and numerical simulations. The results show that the equiaxed crystal rate and solidification structure both affect the carbon segregation. When the superheat is low, shrinkage tends to occur, and the shrinkage is often accompanied by severe segregation. When the superheat is high, the equiaxed grain ratio is lower, carbon segregation is also severer, so the superheat degree is controlled at 30??. With the increasing of casting speed?? it can obviously spur the growth of columnar crystals and formation of central pipe; both columnar crystals and central pipe are the major cause of segregation, so the suitable casting speed is 0. 19m/min. Final electromagnetic stirring has the effect of uniform liquid steel composition and temperature, which increases the density of solidification structure, and reduces the central shrinkage hole, thereby reducing carbon segregation, but the electromagnetic stirring effect is greatly affected by the installation position. Based on comprehensive consideration of the production and quality in practical production, the suitable process parameters are established: the optimal superheat is 30??, casting speed is 0. 28m/min, the combination of electromagnetic stirring is M- EMS+S- EMS+F- EMS, and the corresponding electromagnetic stirring parameters are M- EMS of 101A/2Hz??S- EMS of 200A/8Hz??F- ME of 900A/8Hz. Under the above process conditions, it will be more reasonable for the F- EMS installation position to move 0. 4-0. 5m toward the meniscus.     

Effects of low-frequency electromagnetic field on the surface quality of 7050 aluminum alloy ingots during the hot-top casting process

To improve the quality of 7050 aluminum alloy ingots, low-frequency electromagnetic (LFE) field was applied during the conventional hot-top casting process. Macrostructures and microstructures of the ingots by the conventional and LFE hot-top casting processes were studied. The experimental results show that when the LFE field is turn off during the hot-top casting process, cold folding appears, and the as-cast structure becomes very coarse. Additionally, the thickness of the shell zone is much thinner during the low-frequency electromagnetic hot-top casting process than that during the conventional hot-top casting process. Some reasons for low-frequency electromagnetic field improving the surface quality, refining the structure of the ingot, and minimizing the thickness of the shell zone have been studied.     

压力对A380铝合金的铸造组织和力学性能的影响

对A380铝合金进行了挤压铸造成型和传统重力铸造成型,并制得试样.采用偏光显微镜、扫描电镜、定量金相分析、拉伸性能测试等手段,研究在不同压力下挤压铸造A380铝合金的铸造组织和力学性能.结果表明:当压力在0~75 MPa范围内时,随着压力的增加,一次枝晶臂尺寸和气孔率得到大幅下降,共晶组织体积分数增加;二次枝晶臂间距减小;针状富铁β-Al₅ FeSi相尺寸大幅度减小,同时有部分汉字状α-Al₈(Fe,Mn)₃Si₂相生成.当压力在75~100 MPa范围内时,压力继续增加对合金组织细化、第二相形貌改善和力学性能提高的作用不明显.挤压铸造试件与重力铸造试件相比,气孔率减小,显微组织细化,力学性能显著提高.当压力为75 MPa时,挤压铸造A380铝合金的铸态抗拉强度和伸长率分别比重力铸造提高19%和65%.     

超声铸造7050铝合金的微观组织和宏观偏析规律

采用不同功率超声对铝熔体进行处理,研究超声场对7050铝合金凝固组织和宏观偏析的影响规律.结果表明:超声振动产生的空化效应和声流效应影响熔体的凝固过程,合理功率的超声能有效细化晶粒、优化组织及改善宏观溶质分布.当超声功率达到170 W时,铸锭径向宏观偏析的弱化效果最好,Zn、Mg和Cu的偏析指数分别为0.0593、0.0565和0.0319;超声功率超过170 W,溶质元素在中心区域富集量显著提高,宏观偏析程度增大.     

双源超声辅助铸造相位差对铝合金细晶效果的影响

建立双源超声铝合金铸造熔池模型,利用fluent软件模拟相同频率与不同频率下相位差对熔池声场的影响。仿真结果显示,相同频率下,相位差显著影响熔池声场的分布,随相位差增大,熔池空化域变小;不同频率下,相位差对熔池声场的分布无影响。通过不同相位差双源超声铸造试验发现,同频率振动下,相位差对双源超声铸造边部及超声辐射区的晶粒细化效果影响很小,心部晶粒细化效果随相位差变大效果变差;不同振动频率作用下,相位差对铸锭细晶效果无影响,心部晶粒细化效果与同频率相位差为90?时接近。同频率相位差0?超声作用下,铸锭心部晶粒尺寸较常规不同频率双源超声作用下心部晶粒尺寸大幅减小。     

连铸坯动态轻压下的压下参数分析

简述了连铸坯动态轻压下技术,介绍了该技术的关键工艺参数即压下区间、压下量和压下速率.通过对近年来国内外对压下模型研究结果的分析和讨论,预测了动态轻压下压下模型的研究方向.