大型锻件内部夹杂性缺陷产生机理研究

夹杂性裂纹是大型锻件致废的主要缺陷形式之一,为提高大型锻件的质量,研究了塑性变形过程中杂夹性缺陷的形成机理,分析了其变化过程和形成条件,探讨了其损伤和修复规律,研究表明,缺陷损伤与修现象同时存在于塑性变表过程中,是夹杂性裂纹发展和变化的两个方面,根据其成因条件不同加以控制有助于提高质量,据此提出了根治夹杂性缺陷产生了方法,并经生考证取得了满意的效果。     

高速钢锻件开裂的原因分析及防止方法

叙述了高速钢锻件中心开裂的现象，分析了开裂的原因，指出锻件缺陷是由锻造操作错误所致，提出临界单位压缩量的概念，以便于控制工艺参数。此方法已经有效地防止了锻件中心开裂。     

刚性粒子流法模拟自由锻造工艺的探索

基于网格的数值计算方法在处理自由锻造、冲压成形、高速碰撞、裂纹动态扩展等大塑性变形问题时,往往会因网格畸变和网格重构困难使得计算精度丢失甚至无法计算。针对该问题,基于连续介质力学理论和分子动力学基本原理,采用一种求解金属大塑性变形的数值模拟方法--刚性粒子流法,建立了刚性粒子流法的数学模型并探讨了初始粒子配置、粒子搜索算法、数值积分和边界条件等关键数值技术。将该方法应用到核电饼类锻件高温镦粗和大型核电封头终锻成形两个数值算例中,计算结果表明：模拟大塑性变形问题时,刚性粒子流法与实验结果能够较好地吻合,有效地解释了大型饼类锻件夹层裂纹和封头锻件层状撕裂的形成机制。研究结果为进一步采用该方法模拟变形更加复杂的自由锻造工艺提供了参考。     

汽车变速器新产品质量检测系统中关键技术研究

针对汽车变速器下线产品质量检测过程中人工检测存在的客观性差异,以及对故障定位不准确的问题,设计并开发了一种基于阶次分析理论的变速器在线质量检测系统。该系统运用阶次分析理论对振动信号进行有效的特征提取,并运用遗传搜索策略对高维特征向量进行特征选择,以提高故障判别的效率和准确率。为解决系统的通用性问题,还提出了一种通用的变速器结构建模方法。在某变速器生产企业的实际应用,验证了提出的检测方法的有效性和准确性,证明了该方法可实时按工况对变速器产品进行质量检测。对于有质量缺陷的产品,该方法可指出其故障类型和故障位置。     

大型轴类锻件的特殊锻造法

利用水平V形砧锻造法，通过有效控制锻件的纤维流向，改善轴类锻件力学性能的异向性。实现轴类锻件的等向锻造，创造普通锻造法无法达到的特殊锻造效果。定性物理模拟实验证明了水平V形砧锻造法是控制轴类锻件力学性能的有效工艺手段。     

大型轴类锻件切削性及粗加工增效措施研究

大型轴类零件毛坯经直接锻造成形,其粗加工难度很大。本文通过分析大型轴类锻件加工难点,结合目前中国一重大型轴类锻件粗加工的经验,总结出提高大型轴类零件粗加工效率的有效方法,为大型轴类锻件的加工以及强力切削刀具的改进提供了技术指导。     

AP1000核电稳压器大锻件特点及制造技术

为满足AP1000核电严格的技术要求,稳压器采用高性能大型锻件制造。介绍了AP1000核电稳压器大锻件的技术特点和制造技术。     

核电堆内构件大锻件特点及国内研制现状

介绍了1000MW压水堆核电堆内构件大锻件、AP1000项目堆内构件大锻件和高温气冷堆堆内构件的有关功能以及如何实现核电堆内构件大锻件国产化。     

锻合钢锭内部缺陷的最小锻比研究

本文从大型锻造发展趋势和质量控制、节约能源的要求出发,提出了用最小锻比或有效锻比作为制定大锻件工艺的综合性准则。用模拟试验方法确定了FM锻造法的最小锻比,并介绍了大型支承辊的锻造实例,将100t重大钢锭仅以2.25的小锻比成功地锻造出合格大锻件,节约了大量能源。     

3D measuring and segmentation method for hot heavy forging

Non-contact, three-dimensional (3D) measurements of hot heavy forgings (HHFs) are desirable for permitting real-time process control, whereas most current methods are usually inconvenient or invalid due to the difficulty in dealing with the hot heavy forgings. This paper presents a new measuring and combined segmentation approach that employs a two-dimensional (2D) laser radar with additional rotation driven by the servomotor that scans the forgings to acquire a massive 3D point cloud dataset. From this dataset, the desired forging part is roughly distinguished from the background based on the angle and distance continuity constraints, and then refined by the curvature-based border extraction method and further segmented by the hierarchical clustering analysis method. Finally, the feature points are extracted based on the normal vector variation and fitted to convey the 3D information. This novel method has been verified by experiments both in the laboratory and the forging workshop for hot heavy forging pieces, with a dimension error of less than 2%. These results indicate that the proposed approach is more practical and convenient than current methods for real-time, on-site measurements of HHFs.     

基于小波与双三次插值的高温锻件红外图像增强方法

提出了一种基于小波变换和双三次插值的图像处理方法,该方法利用离散小波将原图像分解成低频子带与高频子带,然后对原图像及这些子带分别进行双三次插值,同时提出增加一个中间步骤来估算高频子带,即扣除原低分辨率图像和插值后的LL子带中的相同成分而得到不同成分的图像（高频成分）,然后利用不同成分的图像对高频子带LH、HL及HH分别进行校正融合,并通过小波逆变换对这些图像进行融合重构。该方法不仅能够有效地消除图像噪声,改善细节信息,而且能够最大限度地保留边缘信息和增加图像的清晰度。最后运用该方法和传统算法分别对核电主管道高温锻件和小型高温锻件的红外图像进行增强处理,实验结果验证了该方法的可行性及优越性。     

Dimension measurement of hot large forgings with a novel time-of-flight system

The dimension measurement of hot large forgings is necessary for process control and product quality. However, the conventional technique in forging plants leads to a high scrap rate of raw materials. In order to reduce the waste and increase the productivity, this paper presents a novel measurement technique based on the pulsed time-of-flight (TOF) laser radar to measure the dimensions of hot large forgings. The system consists of a TOF, a scanning device of the two-degree-of-freedom (2-dof) spherical parallel mechanism (SPM), and two motors. Then, its measuring principle and the SPM are described. A special data-processing method is developed to extract the dimensions and the shape of a large forging by scanning for a few times. The laboratory experiments indicate that the shape and dimensions such as the diameter and length can be achieved by virtue of the TOF system. The dimension measurement in a forging plant is also conducted to verify the effectiveness of the presented system.     

An improved online dimensional measurement method of large hot cylindrical forging

The dimensional measurement of large forgings under high temperature plays an important role in product control. Cylindrical forgings belong to the important products in the forging workshop. In this paper, an improved online measurement method based on binocular vision for the dimensions of hot cylindrical forgings is proposed. Firstly, images of hot cylindrical forgings are captured by two CCD cameras, and the distorted light stripes projected onto hot cylindrical forgings can be resolved from the image by the deviated stripe model. Then, an accurate sub-pixel extraction algorithm of center points of the light stripes is developed for making the extraction of center points of the lights stripes more accurate. Moreover, for changing the field of view of cameras to measure different sections of forgings in the process of manufacturing, the fundamental matrix F is automatically calculated by matching the intersecting points of the projected light stripes in different images, without interrupting the forging process. Finally, experiments on measuring the diameters of hot cylindrical forgings in the workshop are conducted, and the experimental results indicate that the proposed measurement method is effective. Besides, an additional experiment in the laboratory verifies that the relative error of measuring diameters by the presented method is less than 0.7%.     

Cr12MoV钢锻造生产工艺

介绍一种冷冲模具钢的锻造生产工艺,执行了这种工艺,并严格遵循锻造操作要点,保证了锻件产品质量.     

基于耗散结构理论的锻造热力参数确定方法

探讨应用耗散结构理论确定鸪形材料锻造热力参数的方法，提出两个确定锻造热力参数稳定区的判据，并据此首次用图形表示出ＧＨ１６９合金和ＴＣ１１合金的锻造热力参数稳定区，从而得出对这两种合金重锻件的生产具有指导意义的若干结论。     

大型锻件扩氢效果的计算方法

本文讨论了大型锻件扩氢过程的理论基础与计算方法。对Hobson计算法进行了修正与补充。认为应当根据钢中含氢量与氢在大型锻件中的分布特征来计算锻件在各热加工过程中的扩氢效果。经在生产中广泛试用与模拟件解剖试验结果表明,采用修正后的计算方法可以给出比较准确的结果。此计算方法可在生产中应用。     

大锻件控性锻造过程的计算机模拟技术

提出能够模拟大锻件空洞型缺陷演化和微观组织演变等控性指标的数值模拟方法。基于典型体元模型建立空洞体积变化与宏观应力应变场关系的数学模型,以图从多尺度角度揭示宏观的塑性变形及其应力状态对随机分布的微小空洞的体积变化影响规律。将该模型与有限元法集成,当锻件内任意一点有空洞型缺陷(给定缺陷体积百分比)时,能够模拟得到成形过程中空洞型缺陷的体积变化,从而可被用来评估含缩孔缩松缺陷材料的压实状态。采用元胞自动机方法建立一种转子钢的微观组织演变模拟方法,根据"应变—位错密度—动态再结晶—流动应力"之间的宏微观相互影响规律,模拟出动态再结晶晶粒尺寸和完成分数。将这些模型与热力耦合有限元法相结合,构造大锻件控性锻造过程的数值模拟技术。根据大锻件增量成形的变形特点开发基于刚性区自由度凝聚技术的快速有限元法,从而为大锻件成形的工艺优化提供有效的计算工具。     

改进正火设备提高锻件正火质量

在汽车变速箱生产中，锻件的正火质量，直接影响着零件后续机加工及最终成品率；论述了对连续式正火炉的冷却系统进行改进，可以提高正火锻件的质量。     

电力驱动回转台的设计

回转台是大型锻造过程中的重要辅具,主要用于饼形锻件镦粗和圈类锻件的平头.本文通过对各种结构的回转台进行分析,设计出一个适合本单位使用的回转台     

汽车电机爪极铸锻复合近净成形及数值分析

分析了汽车电机爪极铸锻复合近净成形的技术原理和特点,进行了爪极制件的铸锻复合成形试验,设计了合理的模具结构,获得了合格的制件。同时,采用数值模拟和有限元分析的方法获得了成形过程的力能参数和相关的场量信息。研究结果表明:该技术成形汽车电机爪极成形力小、工艺流程短、锻件质量好、节能、节材,必将具有广阔的发展和应用前景。