METHOD FOR MEASURING SHEAR FRICTION FACTOR USING BACKWARD EXTRUSION

摘要

PURPOSE: A detecting method of a shear friction factor is provided to conveniently measure a shear friction factor occurring in the volume formation applicable to wide range friction condition and to reproduce the friction condition of a complex process. CONSTITUTION: An extrusion material(30) is placed on the upper face of a lower die. The material has a columnar shape, and the diameter of the material is the average of the diameter of a punch(21) and the inner diameter of an outer die(11). The center of the extrusion material is aligned with the centers of the punch and the outer die. If an extruding load is applied to the material by lifting down of the punch, the material is sequentially deformed. Then a typical formed product is produced by the shapes of the outer die and the punch. A sharp peak(33) of the formed product has a triangular sectional shape, and the upper apex of the triangle is spaced apart from the inner face of the outer die by a specific vertical distance(d). The vertical distance(d) is a factor determining friction condition.