The influence of coverage for high frequency mechanical impact treatment of different steel grades
The influence of coverage for high frequency mechanical impact treatment of different steel grades
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DOI：
10.1016/j.jmatprotec.2019.116437
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发表时间：
2020-03
影响因子：
6.3
通讯作者：
J. Schubnell;C. Eichheimer;C. Ernould;A. Maciolek;J. Rebelo-Kornmeier;M. Farajian
中科院分区：
文献类型：
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作者：
J. Schubnell;C. Eichheimer;C. Ernould;A. Maciolek;J. Rebelo-Kornmeier;M. Farajian
高频机械冲击（HFMI）工艺是一种全新的手动机械锤击（MHP）工艺，用于提高金属部件的疲劳性能。HFMI过程的特征在于大量的冲击，当工具以高进给速率使用时也是如此。这导致在表面层处的快速饱和和高度塑性变形。表面形貌，近表面残余应力，和加工硬化的实验研究进行HFMI处理，由S355J2，S690QL和S960QL钢级制成的平面试样，以调查表面条件的工艺参数的影响。残余应力状态，实验确定的中子衍射，补充HFMI过程的数值模拟。为此，一个弹粘塑性材料模型的实施和校准与实验测试数据。作为工艺质量的统一参数，计算了不同组工艺参数的代表性覆盖值（定义为每个参考表面积的撞击次数）。这个覆盖值也被用来比较HFMI引起的残余应力场的中子衍射技术的数值模拟和实验研究。结果表明，高覆盖率对压痕深度和低碳钢级的加工硬化效应有很大的影响。随着覆盖率的增加，工艺引起的残余应力只有轻微的变化。
The High Frequency Mechanical Impact (HFMI) process is a comparably new, manually-driven machine hammer peening (MHP) process applied to increase the fatigue performance of metallic components. The HFMI-process is characterized by a large number of impacts, also when the tool was used with a high feed rate. This leads to a fast saturation and highly plastic deformation at the surface layer. Experimental investigations of the surface topography, near-surface residual stresses, and work hardening were performed on HFMI-treated, flat specimens made of S355J2, S690QL and S960QL steel grade to investigate the influence of the process parameters on the surface conditions. The residual stress state, experimentally determined by neutron diffraction, was supplemented by the numerical simulation of the HFMI-process. For this, an elasto-viscoplastic material model was implemented and calibrated with experimental test data. As a unified parameter for the process quality, a representative coverage value, defined as the number of impacts per reference surface area, was calculated for different sets of process parameters. This coverage value was also used to compare the numerical simulation and the experimental investigations by neutron diffraction techniques of the HFMI-induced residual stress field. It is shown, that high coverage has a strong effect on the depth of indentation and in the work hardening effect for mild and medium steel grade. Only slight changes of the process-induced residual stresses could be observed with an increasing coverage.