A304不锈钢薄板激光焊工艺试验研究

研究利用激光焊接技术焊接A304不锈钢薄板的工艺.试验过程中,采用一系列激光焊参数焊接试板,然后将焊接接头制成金相试样,观察熔深、熔宽、热影响区的大小,比较连续激光和调制方波脉冲激光焊接不锈钢薄板的效果.     

埋弧焊工艺参数优化与模型建立

为快速、准确地获得埋弧焊工艺参数,本文利用单元正交多项式回归设计方法对中、薄板埋弧焊单面焊双面成形焊接工艺参数与板厚δ的关系进行了优化试验,并利用"SPSS"软件对试验结果进行了统计分析与检验,建立了焊接工艺参数与板厚δ的数学模型。该模型不仅可以用来确定中、薄板埋弧焊单面焊双面成形焊接工艺参数,而且对研究建立中、薄板埋弧焊计算机控制系统具有参考价值。     

薄板单面密集焊缝焊后弯曲变形分析

针对2 mm的316L薄板单面密集焊缝结构，采用数值模拟的方法分析了两种焊接方案下的薄板焊接弯曲变形. 利用高度测量装置建立了薄板弯曲变形测量方法，进行了两种焊接方案的工艺试验，对焊后弯曲变形进行了测量. 在此基础上，对数值模拟和工艺试验的结果进行了对比. 结果表明，薄板单面密集焊缝结构焊接后呈船形变形，拉通焊弯曲变形中心接近于板中心，而两端向中间焊弯曲变形中心偏向板的先焊位置. 两端向中间焊在长度方向弯曲变形量小于拉通焊，两端向中间焊的焊接方案较优.     

纯钛板对接焊的可焊性

钛及钛合金的焊接一般多采用惰气保护钨电极电弧焊接（TIG）、等离子焊接和激光焊接等高能量密度的焊接方法。对于纯钛板而言，焊接应变小、精度高的等离子焊接和激光焊接都是非常好的焊接方法。近年来，随着汽车的轻量化，对薄板焊接的性能和生产效率的要求日益提高。因此，探讨各种焊接方法用于纯钛薄板对接的可行性，有助于扩大其用途。     

薄板CO2焊对接间隙对焊接质量的影响

本文分析了薄板细丝ＣＯ２焊时，对接间隙对焊缝外观、强度和焊接工艺性的影响，提出了满足焊缝质量要求和易于操作的对接间隙范围。并根据试验中出现的问题，指出了薄板焊接施工中的注意事项。     

动车组铝合金厚板薄板搭接MIG焊接工艺研究

在对高速动车组铝合金车体薄板进行MIG焊时容易产生焊塌、焊穿缺陷,严重影响了车体的焊接质量.文中分析了铝合金薄板厚板搭接焊缝出现焊穿、焊塌等问题的原因,通过研究发现:采用合理的焊接电流、正确的焊接方向、适当的预热温度和合适的操作方法,可以有效防止薄板与厚板搭接MIG角焊缝焊穿、焊塌等缺陷的产生,提高了产品焊接质量,降低了生产成本.     

钨极氩弧焊在不锈钢薄板焊接中的应用

分析了不锈钢薄板焊接熔池受力情况与该工件的焊接变形，详细介绍了钨极氩弧焊焊接不锈钢薄板时的焊接工艺要领和应用。     

导入超声振动的搅拌摩擦焊性能研究

搅拌摩擦焊(FSW)技术已成功地应用于铝合金的薄板及中等厚度板的焊接,但是在焊接铝合金厚板时,被焊件焊缝深层容易出现组织疏松甚至空洞现象.为解决厚板焊接问题,扩大FSW的应用范围,提出导入超声振动能量到FSW的焊缝区.通过对2519铝合金进行对比焊接实验,并对焊缝的微观组织和力学性能进行分析比较.试验结果表明,超声振动能有效地促进焊缝底部金属材料的流动,减小流动阻力,提高焊缝力学性能,细化金相组织.     

薄板钛合金激光焊熔透稳定性临界条件的计算

钛合金薄板熔透激光焊研究发现，在一定焊接参数条件下，由于金属蒸气和光致等离子体的作用，即使焊接过程的工艺参数稳定不变，也存在全熔透不稳定过程，其特征是焊缝表面成形均匀不变，而焊缝背面出现熔透与未熔透之间交替跳跃的成形特征，这种不稳定焊接过程属于激光深熔焊过程的本征特性，主要取决于焊接过程穿孔形成的稳定性。基于小孔形成机理和孔壁能量平衡的分析，提出了小孔穿孔速度与焊接速度相匹配的熔透稳定性物理模型，将穿孔速度与激光功率密度、焊接速度、材料物理性能、板厚联系起来，并建立了熔透焊所需最小激光功率密度计算关系式，理论计算结果与试验结果基本一致。所建立的关系式可用于判断焊接工艺参数深熔焊熔透稳定性。     

薄板激光焊焊接工艺流程及不稳定性控制

针对薄板激光焊接,分析了薄板激光焊接总工艺流程,其中主要包括带头准备、带尾准备、带钢调整、焊接准备、完成焊接。研究了薄板激光焊接不稳定性控制,造成不稳定性原因有很多,主要有设备本身、工作状况和焊接工艺参数等。本文研究激光焊焊接参数:焦点位置、激光功率、焊接速度对焊接过程不稳定性的影响,建立了激光功率和焊接速度、焊缝深度和宽度的影响曲线。在焊接速度一定的条件下,建立了稳定深熔激光焊临界功率和焦点位置的数学模型,为薄板激光焊的稳定控制提供了理论依据。     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

FeCrAIW电弧喷涂层组织的致密化研究

采用激光辐照对FeCrAlW电弧喷涂层的组织进行致密化处理,借助扫描电镜和X衍射对涂层的组织进行了分析.测试了涂层的显微硬度.结果表明:涂层组织致密度提高,孔隙率明显降低.随着激光扫描速度的增加,涂层的显微硬度降低.在较低的扫描速度下,涂层与基体之间形成互熔区,涂层与基体之间产生良好的冶金结合.     

面向零件形状的计算机图形库的开发

论述了CAD技术中参数化设计的三种建模方法，重点介绍了基于特征的参数化建模原理。在此基础上，分析机械设计中的机构结构，归纳出其零件的几何特征构成。设计了机构CAD图形库，并提出了该图形库生成步骤和人机交互界面。     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.