载荷对高铬铸铁磨料磨损的影响

对不同载荷作用下的高铬铸铁在耐磨实验机上进行了磨料磨损试验；对在不同的载荷作用下碳化物对基体的保护作用与碳化物的剥离进行了相关的分析。结果表明载荷在一定值以下磨损较为缓慢，当载荷超过一定值时，磨损急剧加剧，随着载荷的增加“尺寸较小”的碳化物首先剥离基体，当载荷继续增大时，“尺寸较大”的碳化物也剥离基体并有碎裂现象。因此，要求高铬铸铁中的碳化物不仅要分布均匀，而且尺寸也要合适。     

塑性形变对4340钢中氢的富集及传输行为影响

采用渗氢试验和数值计算两种方法研究．了塑性形变对金属中氢的扩散和富集的影响，讨论了４３４０钢中的氢浓度与塑性形变大小、氢扩散时间及边界条件之间的关系．     

Thermoelastoplastic and Residual Stress Analysis during Induction Hardening of Steel

A theoretical model was developed to predict the thermoelastoplastic and residual stresses developed in a round steel bar during induction hardening. For numerical analysis, a quasi- static, uncoupled thermoelastoplastic solution based on the hyperbolic sine law of Tien and Richmond was formulated. The properties of the material were assumed to be temperature dependent. The phase transformation was considered in the numerical calculation, and the results were compared with the case where phase transformation is avoided. The cylinder was heated rapidly; once the temperature of the outer surface exceeded the transformation temperature, the cylinder was rapidly cooled. Accordingly, in the numerical calculation, only the area at the vicinity of the outer surface was assumed to transform to martensite. The results showed that the compressive residual stresses at the vicinity of the outer surface were considerably higher than the tensile stresses at the center.     

应力应变顺序对应规律及其学术意义

应力应变顺序对应规律,是王仲仁教授于1979年提出的,起初在国内有一些争议,后来王仲仁教授又作了理论推导与实验验证。目前,该规律已被列入《金属塑性成形原理》全国通用教材。本文阐述此规律的提出和完善过程,并讨论其学术意义。     

钛合金带热沉钨极氩弧焊中热沉作用

采用数值模拟和实验相结合的方法研究了钛合金TC4薄板常规及带热沉的钨极氩弧焊焊接过程中温度及应力应变的分布,考察了热沉对温度场和应力应变场的影响规律,探讨了使用该技术实现应力和变形控制的机理.结果表明:带热沉的钨极氩弧焊焊接过程中,紧随热源之后热沉急冷作用使得试件形成马鞍形温度场,而热沉作用部位温度最低.热沉作用部位的急冷收缩对周围金属产生拉伸作用,使得焊缝及近缝区金属升温过程中产生的压缩塑性应变减小,冷却过程中产生的拉伸塑性应变增大,接头中不协调应变减小,残余应力降低.实验测量与有限元模拟结果吻合良好,证实了采用热沉控制应力与变形的有效性和有限元模型的正确性.     

12×4J轮辐翻边变形分析及工艺改进

将 1 2× 4J轮辐翻边的变形区看作是平面应力状态 ,从翻边高度与初始孔径变化规律及翻边变形区径向应变和轴向应变的变形规律出发 ,探讨了 1 2× 4J轮辐翻边开裂缺陷的形成原因 ,对现有的翻边成形工艺提出了改进方案。     

压缩机气缸盖螺栓断裂原因分析

对压缩机气缸盖上螺栓的断裂原因进行了分析。通过光学显微镜和扫描电镜对断口和金相组织进行了观察，分析了造成螺栓断裂的材质因素和力学因素。认为用估算螺栓工作时的最大预紧应力的方法，对防止埋头螺栓疲劳断裂再次重复发生有一定的参考价值。     

挖掘机下车架主件顶环面焊接变形的位置度研究

挖掘机下车架主件是由多条空间分布的焊缝组成的焊接结构，其顶部有40处装配孔。为保证终焊后装配，需要对顶环面装配孔的位置度提出一个指标。在此用固有应变法对下车架进行了焊接变形的有限元预测。根据预测结果，建议挖掘机下车架主件顶环面的位置度至少为0．49mm。     

6061铝合金低温快速流变行为的研究

采用圆柱体试样，在Gleeble-1500型动态热模拟试验机上进行低温快速压缩试验，研究了6061铝合金低温下快速变形的流变行为，并分析了其变形组织。结果表明，6061铝合金的流变应力随变形温度升高而降低，随应变速率提高而增大；在高应变速率下，发生了不连续动态再结晶；温升强烈地受变形程度的影响；低温快速变形可获得晶粒细小的组织。     

Stress induced magnetic field abnormality

Residual stresses in ferromagnetic material affect the direction and structure of domains and generate magnetic field abnormality on the surface.In the formation of stress induced magnetic field,the influence of geomagnetic field is unclear.Residual stress specimen was produced by tight matching of a round ring and a peg.The magnetic fields of contrast specimens,which were produced in geomagnetic field or in shielding geomagnetic field,were ingspected with 8mm lift-off.The results show that mean amplitude of magnetic field of the specimen produced in geomagnetic field is 0.85% larger than that of specimen produced in shielding geomagnetic field.So the formation of stress induced magnetic field abnormality above the surface of inspected ferromagnetic material geomagnetic field gives little contribution.