30Cr3钢形变热处理工艺研究

30Cr3SiNiMoVA(以下简称30Cr3钢)是超高强度合金钢,主要作为某型号发动机壳体(以下简称壳体)材料,传统的工艺方法是壳体先旋压成形,然后整体淬火强化,壳体的最终性能主要靠热处理强化获得。该工艺过程的缺点是壳体经整体淬火后变形较大,尤其对大长径比、薄壁壳体更为突出。通过工艺研究,采用先调质后旋压形变热处理工艺方法,取得了很好的效果,为相似超高强度钢的簿壁细长筒体的精密成型,提供了一种更合理的工艺途径。     

某壳体零件加工工艺设计

介绍了采用分体、旋压、焊接合成等工艺手段,解决了某超高强度钢薄壁壳体高要求零件的制造工艺难题.     

高强度承力梁零件加工技术研究

高强度承力梁零件(材料牌号16Co14Ni10Cr2Mo)是某型号科研生产过程中制造难度最大、加工风险最高的梁类结构件。该材料经热处理淬火后会产生明显变形,同时因为承力梁零件属典型高长细比梁类零件,缘条高而薄,筋条结构繁多,导致该零件在淬火后产生了扭曲、孔位窜动和伸长缩短等变形情况。为解决型号研制过程中承力梁的热处理淬火变形问题,开展了超高强度钢淬火变形规律统计、淬火前余量设置原则以及淬火后精加工工艺方案等一系列研究工作,应用多学科相互补偿的变形控制方法解决超高强度钢承力梁零件强化热处理变形大而导致零件无法合格交付的问题,实现了高强度承力梁零件的优质高效稳定批产加工。     

W9Mo3Cr4V刀具的热处理工艺

W9Mo3Cr4V(以下简称W9)钢是含钼高速钢,该新钢种尚未列入国家有关标准和热处理手册。现就我们在用该钢种制造刀具时,所摸索出的热处理工艺方法作一简单介绍。一、初定淬火温度区间     

超高强度钢的发展及展望

结合超高强度钢在航空领域的广泛应用,介绍了航空用超高强度钢的发展现状,总结了国内外超高强度钢的发展思路及特点。目前,300M钢以及AerMet100钢以其较高的强度及韧性,应用于飞机的起落架和联接螺栓等关键部件上。阐述了当前的热处理加工方法,与传统的淬火-低温回火(Q-T)热处理工艺相比,采用淬火-碳分配(Q-P)以及淬火-碳分配-回火沉淀(Q-P-T)工艺,将获得更加细小的晶粒以及更高的强韧性。分析了超高强度钢今后的大致发展方向。     

3Cr13钢低温水淬工艺的研究

3Cr13钢为我国应用较多的不锈轴承钢之一。通过合适的热处理工艺可充分发挥钢的内在潜力,改善性能,大幅度提高其使用寿命和耐蚀性。近年来,该钢的热处理工艺取得明显进展,但对淬火温度与冷却条件的研究较少,尤其是降低淬火温度,提高冷却强度的淬火工艺尚未见报道。 试验用钢3Crl3由于含有大量的合金元素Cr,     

40Cr钢亚温淬火后的力学性能

亚温淬火热处理是亚共析钢在Ac1～Ac3温度之间进行加热淬火的一种热处理工艺。40Cr钢是我国目前用量最大的合金调质钢，广泛应用于轴类、连杆、螺栓和重要齿轮等零件的制造。本文通过对40Cr钢在常规热处理、亚温淬火热处理工艺和性能方面的研究，进一步探讨了40Cr钢亚温淬火后的力学性能，并研究了它的强韧化机理，     

提高012AI冷冲模寿命途径（连载二）

四、锻热调质预处理,提高冷冲模寿命 锻热淬火利用模具钢坯高温形变锻后余热仍高于该钢Ac3（或Acm）临界温度迅速冷却淬火,获得淬火马氏体组织方法。实质是高温形变强化与相变强化及热处理强化三结合工艺方法。     

3OCrMnSiA钢燃烧室的热处理工艺试验

为解决30CrMnSiA钢燃烧室旋压成形件等温淬火后硬度偏高时,可否采用回火的方法降低硬度的意见分歧,对这种燃烧室作了等温淬火、油淬＋回火、等温淬火＋回火3种不同热处理状态下材料机械性能的对比试验.试验结果表明：这种材料的燃烧室在等温淬火后,若硬度偏高不合格,采用回火的方法降低硬度后,其材料的冲击韧性将会大幅度下降,将远低于有关材料标准的要求.因此,对于安全系数不太高的30CrMnSiA钢燃烧室,不能允许以回火的方法来降低硬度,而应采用其他的工艺方法来降低硬度.而且不能笼统地认为燃烧室材料的抗拉强度和伸长率都合格,其冲击韧性也一定会合格.     

3Cr2W8V热冲模热处理工艺的改进

我厂的热冲模是采用3Cr2W8V钢制造。原热处理工艺为:1100℃淬火,560℃三次回火,处理后硬度为HRC52。每个模具平均使用寿命为4000模次左右,模具主要损坏形式是磨损和开裂。为解决模具使用寿命问题,我们改用安徽工学院热处理教研室提出的碳氮共渗——低温淬火强韧化处理工艺。经该工艺处理后的3Cr2W8V钢的模     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...