リング圧縮試験における潤滑条件下の摩擦せん断応力の評価 : 超音波測定の適用
1994 年 60 巻 577 号 p. 3171-3176
詳細
1994 年 60 巻 577 号 p. 3171-3176
This paper describes an estimation of frictional shearing stress τc acting on the real contact area of lubricated conditions in the upsetting of an aluminum ring. The transition of the contact ratio between a tool and a workpiece could be obtained by applying ultrasonic examination. In addition to measuring the relative expanding velocity of outer diameter of the ring as well as forging load and stroke, the varying frictional conditions could be discussed in detail. In our experiment, the results show that τc for lubricant of higher viscosity has a tendency to become high and τc decreases gradually with the progress of deformation. The value of τc for each viscosity corresponded well to the roughness and the topography of flattened contact area of deformed asperities. It has also been suggested that the method is very useful for estimating τc during a process.
