Effect of Shot Blasting and Shot Peening Parameters on Residual Stresses Induced in Connecting Rod

This paper investigates the effect of shot blasting and shot peening parameters on residual stresses induced in connecting rod. Compressive residual stresses are induced using shot peening to increase fatigue life of connecting rod. Shot peening is also responsible for increase in surface roughness. Surface roughness is detrimental for fatigue life of the connecting rod. This necessitates shot blasting to reduce surface roughness. Shot peening and shot blasting processes are analysed to find optimum process parameters which will induce required value of compressive residual stress on the surface of connecting rod. Compressive residual stresses induced in the connecting rod specimen have been experimentally measured using X-ray stress analyser. The experimental results have been analysed using grey relational analysis to find optimum values of process parameters for target value of compressive residual stress and surface roughness. The experimental investigation and the analysis of it have resulted in achieving the desired value of compressive residual stress, which is 10.5% higher over the existing connecting rod. Surface roughness also decreases to 3.84 Ra which is 8.5% lesser than specified value to achieve better fatigue life.     

喷丸处理对S形辐板车轮辐板表面周向残余应力变化影响的试验研究

采用X射线衍射法对喷丸处理前后车轮辐板表面周向残余应力状态的实际变化情况进行了试验研究，研究结果表明，喷丸处理有效改善精加工过程对辐板表面残余应力状态的恶劣影响，从而提高车轮的安全使用性能。     

Effects of stress‐ and/or warm peening of AISI 4140 on fatigue life

Using a new system shot peening and/or stress peening in an air blast machine at elevated temperatures is feasible. The effects of conventional shot peening, stress peening, warm peening and stress peening at elevated temperatures on the characteristics of regions close to the surface, on the stability of residual stresses and on the fatigue strength of a quenched and tempered AISI 4140 steel (German grade 42 CrMo 4) are presented. The alternating bending strength is increased by stress peening, warm peening and especially the combination of both compared to conventional shot peening. These effects are due to the residual stresses induced and the stability of the dislocation structure, which is highly affected by strain ageing effects.     

An analysis of residual stress fields caused by shot peening

In this article, the compressive residual stress field (CRSF) introduced by shot peening was studied comprehensively. The 40Cr steel, which is widely applied in industry materials, was used and shot peened under different conditions. The experimental results show that the maximum of compressive residual stress field for a given material is almost the same even under different shot peening techniques and the surface residual stress values are dependent on both the mechanical properties of target materials and peening parameters.     

Finite element simulation of shot peening of an aluminum alloy considering hardening models

Shot peening is a surface engineering process acknowledged for its potential to develop fatigue strength and erosion-corrosion resistance of metallic materials. In the present study, a 3-D finite element model is employed to predict the effective parameters through a single shot impact and the accuracy of the simulation is validated using previous literatures. In order to induce uniform compressive residual stress patterns across the specimen, processing parameters such as shot velocity, impact angle and friction coefficient should be controlled. It is observed that by increasing the shot velocity and the friction coefficient, the depth of compressive residual stress increases. Moreover, a comparative study between isotropic and kinematic hardening models is performed to evaluate the significant role of the hardening models on the compressive residual stress. It is observed that the kinematic hardening model shows better compatibility with the experimental results compared to the isotropic hardening.     

Effects of Shot Peening on Fatigue Properties of Zr-based Amorphous Alloys Containing Ductile Crystalline Particles

In this study, the fatigue properties of a shot-peened Zr-based amorphous alloy containing ductile crystalline particles were investigated, and fatigue processes were analyzed and compared with those of a non–shot-peened (as-cast) alloy. The microstructural analysis results of the shot-peened alloy surface indicated that the flexion and microstructural deformation were observed as the hot-peening time or pressure increased. However, the compressive residual stress formed on the shot-peened surface was approximately half of the ultimate tensile strength and was not varied much with shot-peening time or pressure. The fatigue limit and fatigue ratio of the shot-peened alloy were 368 MPa and 0.24, respectively, which were considerably higher than those of the as-cast alloy. This was because the compressive residual stress formed by the shot peening induced the initiation of fatigue cracks at the specimen interior instead of the specimen surface and, thus, enhanced the overall fatigue limit and fatigue life. These findings suggested that the shot peening was useful for improving fatigue properties in amorphous alloys.     

与低合金烧结钢零件形状相对应的后续处理条件最优化研究

为了扩展粉末冶金的业务,改进动态力学性能和搜集这样的数据是必要的.我们长期认为部分扩散粘结合金较适合达到较高的疲劳强度,对于在某些作业条件下的零件的确是这样.然而,现在粉末冶金零件的密度水平在提高.高密度和后续加工的最佳化相结合表明,与部分扩散粘结合金相比,预合金化的材料更适于得到高得多的疲劳强度.于是,开展了一些改善疲劳强度的研究.本文介绍了通过应用喷丸法改善疲劳强度,而且通过分析应力曲线讨论了改善疲劳强度的机制.还讨论了几何形状对应力曲线的影响,其中包括对实际的变速器齿轮的FEM分析,以此来描述每一零件的最佳后续加工方法.对于一个实际的变速器齿轮使用粉末冶金零件的可能性,在这篇论文中,通过用测量嵌进实际变速器齿轮箱中的齿轮的齿根应力计算的安全系数进行了讨论.     

干喷工艺对高速钢 M42-弹簧钢D6A 金属带锯条性能的影响

通过二元影像测量仪观察锯条干喷处理后的表面压应力、覆盖率、齿尖状况,不磨合锯切GCr15棒材的齿尖崩刃情况和锯切45^#钢和空转疲劳寿命试验研究表面处理干喷砂工艺参数（压缩空气压力0.1~0.4MPa,运行速度4~1m/min）对M42（/%:1.08C，1.5W，9.4Mo，3.8Cr，1.2V，8.0Co）-D6A（/%:0.48C，1.0Mo，1.1Cr，0.1V，0.6Ni）双金属带锯条性能的影响。结果表明,锯条经合适的参数-压缩空气压力0.3MPa和运行速度3m/min,背部表面覆盖率达到100%,干喷后,齿尖形成稳定的圆角,承受切割和振动的冲击力,以提高锯条齿尖的耐磨性,齿部的平均使用寿命提高66%,背部疲劳试验寿命提高45%~70%。     

Experimental Study on Transverse Residual Stresses of MS980 Cold-Rolled Shape With Square Section

MS980 is one of advanced high-strength steels, which has a great potential for producing square tubes. Residual stress plays a significant role in determining roll-formed members?? behavior and strength. An experimental study on transverse residual stress of roll-formed shape with square section was conducted via X-ray diffraction method. The distribution of transverse residual stresses at different position in sections was measured and studied, and influence of cold-rolled-sheet and hot-rolled-sheet, different fillet radius, different processes, and different pickling time on circumferential residual stress distribution for square section was investigated. The experimental results show the transverse residual stresses are compressive stress in the corner portion and the tensile stress in the straight edge. Fillet radius, sheet, and process have a significant impact on the distribution of residual stress, but the conventional pickling hardly affects residual stress.     

残余应力对55SiMnVB弹簧钢疲劳性能的影响

研究了５５ＳｉＭｎＶＢ弹簧钢板疲劳断口特征及裂扩展过程。结果表明，喷丸强化在表层产生的残余压应力可明显提高疲劳抗力，增强裂纹闭合效应，降低裂纹扩展速度。