台阶孔锻造工艺改进相关问题综述

讨论了采用台阶孔锻造法锻造缸体锻件在生产缸体锻件时的优势，提出了对原工艺的改进方法．改进后的工艺减少了缸体锻件的锻造火次，提高了锻件的成材率，降低了生产成本，取得较好的经济效益。     

锂电铜箔阴极辊用钛筒锻件的热加工工艺研究

在传统PCB、CCL等标箔阴极辊用Φ2m和Φ1.5m两种规格钛筒锻件材料热加工工艺方法基础上,针对锂电铜箔阴极辊用钛筒锻件材料的技术要求,开展了Φ2.7m钛筒锻件材料的热加工工艺研究。经过现场取样分析及阴极辊成品使用效果证明,该工艺方案能够满足现有锂电铜箔阴极辊产品对钛筒锻件材料的使用要求。     

锻件材产生白点的原因分析

对锻钢公司生产出口材产生的白点质量异议进行分析,锻材中的白点大都是以疏松未锻合的显微空隙缺陷或密集的非金属夹杂物为核心,向基体强度弱的方向扩展的氢致裂纹缺陷。锻件材中白点的产生与其实际氢含量、内应力大小、锻件材内部的冶金质量及致密性有关。     

高压缸体锻件冲盲孔方法研究

介绍了高压缸体锻件冲深盲孔的原理,通过采用两次冲孔和煤粉“爆炸”脱模等方法实现对锻铁深盲孔的加工,此方法简单实用。可减轻高压缸体锻件重量,降低产品成本,用于类似深盲孔类锻件。     

7475铝合金大型锻件时效工艺研究

测定了7475铝合金双级时效及回归再时效（RRA）工艺状态下的常规拉伸性能和电导率，并通过标准三点弯和圆周切口圆柱试验测定各时效工艺的断裂韧性。从而研究双级时效和RRA工艺对常规力学性能，断裂韧性，电导率和微观组织的影响，结果发现回归再时效工艺并不适用于7475铝合金大型锻件的生产实践。     

Sulfides in forgings of 40KhGM structural steel

Sulfides in large forgings of 40KhGM steel containing from 0.005 to 0.023% sulfur are studied by optical and scanning electron microscopy (on fracture surfaces and polished sections) and by transmission diffraction electron microscopy (on thin foils). Several types of sulfides are found to exist in the forgings, depending on the sulfur content. Globular sulfides exist at all sulfur contents. They are located inside grains in contact with aluminum, magnesium, and silicon oxides or titanium nitride and carbide particles, which serve as substrates during sulfide solidification. At a low sulfur content, faceted manganese sulfides form in the steel; they are not in contact with oxides and are located inside grains. At 0.013–0.023% sulfur, elongated eutectic sulfides, which are located near or at the boundaries of primary grains, appear. The data obtained suggest gaps between sulfides and the matrix, and these gaps can play the role of “hydrogen traps.”     

空心钢锭镦粗过程的数值模拟

由空心钢锭锻制筒类件的过程分为钢锭倒棱、镦粗、芯棒拔长三大步骤。目前,对空心钢锭镦粗的过程研究很少。为制定准确的镦粗工艺参数并指导实际生产,应用有限元软件DEFORM-3D建立相应的分析模型,对空心钢锭镦粗过程进行了模拟,从锻件应力、应变及损伤值三个方面进行了分析对比,为确定合理的镦粗工艺提供了参考。     

35CrNi3MoV钢晶粒细化工艺的研究

通过试验研究了两种预备热处理工艺一两次高温正火工艺和临界区高温侧正火工艺以及最终热处理工艺对用于大锻件生产的35CrNi3MoV钢晶粒细化效果的影响。研究结果表明,两种预备热处理都有良好的消除组织遗传、细化晶粒的效果,最终热处理后,晶粒进一步细化。     

9%~12%Cr高中压转子材料发展历程与工程化关键技术

 高中压转子锻件因其尺寸规格和使用工况的特殊性,已成为超超临界机组技术发展过程中具有里程碑意义的关键部件。目前商业化运行的600~620 ℃超超临界机组中,广泛采用9%~12%Cr马氏体耐热钢制造高中压转子锻件。综述了近60年来9%~12%Cr高中压转子锻件耐热材料的发展历程,针对不同使用温度的高中压转子锻件,重点介绍了锻件的选材情况、化学成分和强化机制,并针对工程化制造过程中冶炼工艺、锻造工艺和热处理工艺的难点和关键点进行了简要叙述,为600 ℃及以上超超临界机组高中压转子锻件的工程化制造提供指导性建议。     

42CrMo钢曲轴锻件表面裂纹形成机理分析和工艺改进

对865℃1.5 h油淬+640℃4 h回火、水冷的42CrMo钢(/%:0.43C,0.77Mn,0.24Si,0.014P,0.007S,1.08Cr,0.17Mo,0.01Cu)曲轴锻件表面裂纹形成进行了分析。结果表明,曲轴锻件表面裂纹为淬火裂纹,回火时间不足(4 h)和锻件存在较严重的带状组织(3级)是该曲轴产生淬火裂纹的主要原因。通过将回火时间延长至5 h,控制带状组织≤2级,曲轴调质后未发现裂纹,产品合格率达100%。     

The effect of hydrogen source on crack initiation in 4340 steel

The crack initiation site and the corresponding incubation time were determined as a function of notch radius in 4340 steel for both internally and externally supplied hydrogen. The source of hydrogen was found to affect both the crack nucleation site and the incubation time. Hydrogen cracking in cathodically charged 4340 steel initiated near the elastic-plastic boundary with incubation times which exhibited a linear dependence on notch radius. Hydrogen cracking in an aqueous solution initiated near the notch surface with incubation times which were relatively independent of notch radius. Short time diffusional flow models which include a stress dependent critical hydrogen concentration were found to predict incubation times reasonably for internally supplied hydrogen. Cherepanov's solution for the diffusion at the tip of a semi-infinite linear slit when applied in the context of a finite notch root radii problem was found to predict incubation times adequately for externally supplied hydrogen.     

大型锻件用钢的回火脆性

讨论了回火脆性的产生原因和合金元素及杂质对钢的回火脆性的影响，介绍了目前国际上测定与判别回火脆性的方法，几种典型大锻件有钢的回火脆化倾向以及这种脆化倾向的工艺途径。     

大型锻件热处理过程的数值模拟研究

在对大型锻件传热分析的基础上,建立了大型锻件的物理模型,对其温度场的变化规律进行了模拟计算,同时将模拟结果和实验结果进行了对比分析,并通过实例说明了热处理过程数值模拟方法的准确性和优越性,为进一步分析此类工件的组织转变和应力应变等奠定了基础.     

沸水淬火对铝合金锻件组织与机械性能的影响

铝合金锻件在冷水中淬火时由于冷却速度快，残余应力集中，机械加工成　成品后应力释放，往往发生不良　　　　变　形，造成零件尺寸超差。作者研究分析了铝合金锻件在沸水中淬火后的残余应力、机械性能、抗腐蚀性及金相组织，认为在生产条件下铝合金锻件沸水淬火在技术上是合理的，可以明显减少残余应力。     

Interaction between Rotating Elliptic Cylinder and Fixed Circular Cylinder

The general planar motion of an elliptic cylinder through an inviscid and incompressible fluid in the vicinity of a fixed circular cylinder is investigated analytically. The velocity potential is derived by using the successive-image method and the perturbation method, and it is used to determine the hydrodynamic interactions between them. In a relative coordinate system moving with the uniform flow, the kinetic energy of the fluid is expressed as a function of 15 generalized added masses due to the motion of these two cylinders. The generalized added masses are then employed to determine the translational and rotational motion of the elliptic cylinder based on the dynamic equations of motion that are obtained from Lagrange's equations of motion. Numerical results show that the initial configuration of the elliptic cylinder greatly affects its subsequent motions.     

Transition to Self-Similarity of Diffusion of Tracer in Turbulent Patch

A mixing of a passive tracer inside a turbulent patch generated by a localized short-time perturbation is studied numerically and analytically. Two kinds of an initial distribution of a tracer are considered: two-layer and continuous with constant gradient. For the turbulent patch shaped as a layer, it is shown that, regardless of details of initial distributions of a turbulent energy and dissipation, a tracer concentration evolves to self-similar regimes as time elapses. Analytical self-similar solutions to turbulent diffusion equations are found for three symmetric shapes of a turbulent patch: layer, cylinder, and sphere. Distributions of the concentration inside a patch are found to be substantially nonuniform, with a typical ratio of a concentration gradient in the middle of a patch to its initial value of about 0.5.     

Developing regimes for the heat treatment of tool steel 1.2344 with a specific structure

A regime for heat-treating forgings of steel 1.2344 (the analog of steel 4Kh5MF1S) has been developed, tested, and optimized to ensure that the structure of the forgings meets the requirements of the NADCA standard and specification SEP 1614. A study was made of the microstructure of forgings of steel 1.2344 after annealing and normalizing under different conditions. It was found that the structure of the forgings made in the forging-extrusion shop at Spetsstal’ meets the NADCA standard and specification SEP 1614 when the forgings are subjected to normalizing and tempering.     

Quantification of hydrogen diffusion and trapping in 2.25Cr-1Mo and 3Cr-1Mo-V steels with the electrochemical permeation technique and melt extractions

The electrochemical permeation technique was used to investigate the effect of microstructure, hydrogen activity, and stationary dislocations generated by tensile straining on the permeation and degassing of hydrogen. A conventional 2.25Cr-1Mo steel, with which the existing hydrotreating reactors are made, and a 3Cr-1Mo-V steel, which is a candidate material for the future generation of reactors, were selected for this study. The effective diffusion coefficient of hydrogen derived from permeation and degassing transients shows a slower diffusivity in the V-containing steel at room temperature, regardless of the hydrogen activity. A large plastic deformation obtained by tensile straining in the homogeneous deformation domain only leads to a moderate decrease of the hydrogen diffusivity in both steels. The results are compared with the literature data on hydrogen permeation in iron and ferritic steels. On the other hand, the hydrogen content was measured with the melt extraction method after cathodic charging and subsequent aging at room temperature for different times to determine the diffusible (lattice+reversibly trapped) hydrogen concentration. It was shown that the latter is larger in 3Cr-1Mo-V steel, which contains, in addition, a large fraction of “strong reversible” traps. A good concordance was found between the diffusible hydrogen concentration values computed from steady-state permeation measurements and from graphical integration of decay transients. The validity of the quantification, from permeation experiments, of the diffusible hydrogen concentration in materials with complex microstructures is discussed.     

大型精锻件CAPP系统的开发和应用

针对大型锻件工艺设计的复杂性、特殊性以及传统手工设计方法的缺点,对大型锻件CAPP系统的关键技术进行了研究与分析,开发了大型锻件精密锻造的CAPP系统.该软件通过输入精锻机的简单参数,由计算机自动生成工艺卡片和锻造的CAM卡片,将CAM卡片输入精锻机程序,可实现大型锻件精密锻造的智能化,并给企业技术人员节省了大量的时间.