抄録
A new estimating method of the depth of surface affected layers is proposed. In this method, the depth is numerically estimated by vectorizing the digital images of boundary flow in metal structure and carrying out a rotary operations of these vectors. As the results of these operations, the depth of surface affected layers can be estimated quantitatively. It is confirmed that the boundary flow of metal structure can be indicated numerically. These operations take only three minutes and it is clarified that reliable estimation of the depth of surface affected layers can be realized.