夹杂物对超高强度钢应力应变场的影响

非金属夹杂物对钢性能的影响与夹杂物的特征参数密切相关.首先分析拉伸和疲劳载荷下超高强度钢中TiN夹杂物导致裂纹萌生的扫描电镜原位观察结果,采用MSC Marc有限元分析软件对夹杂物及周围基体的应力场进行计算,然后对拉伸载荷下不同特征参数的TiN夹杂物及周围基体的应力应变场进行模拟.结果表明,有限元法能够解释并预测夹杂物及周围基体的力学行为.三角形夹杂物尖角附近的应力集中最严重.矩形夹杂物内部高应力区的位置受夹杂物与外载荷方向夹角的影响.随邻近夹杂物间距的增大,基体内的最大应力由夹杂物外侧移至夹杂物之间.近表面夹杂物使得基体自由表面附近出现高应力区,基体内最大应力的位置受夹杂物与自由表面距离和尺寸的影响.

Influence of inclusion on stress and strain fields in ultra-high strength steel

The influence of non-metallic inclusion on the performance of steels is closely related to the characteristic parameters.The in-situ scanning electron microscope (SEM) observation results of the crack initiation induced by TiN inclusion under tensile and fatigue loads in the ultra-high strength steel were analyzed.The stress fields of the inclusions and nearby matrix were then calculated using the MSC Marc finite element analysis software.Subsequently, the stress and strain fields of the TiN inclusions with different characteristic parameters and the nearby matrix were simulated.The results show that the mechanical behavior of the inclusions and the nearby matrix can be explained and predicted by finite element method.The maximum stress concentration is located around the sharp angle of a triangle inclusion.The position of the high-stress region in a rectangle inclusion is affected by the angle between the inclusion and the load direction.The position of the maximum stress in the matrix changes from the outer-inclusion region to the inter-inclusion region with the increase of the inter-inclusion distance.The high-stress region near the free surface results from the sub-surface inclusions, and the position of the maximum stress is affected by the distance from the inclusion to the free surface and the inclusion size.