Cylindrical deep drawing piece
The application of stretch pieces is very extensive, and we can often see it in our life. Drawing parts manufacturers need to understand the drawing characteristics of drawing parts during stamping, so as to better control production. Cylindrical strip is a common metal stamping strip. Next, Zhejiang Baifudu Precision Stamping introduces the tensile characteristics of the cylindrical stretch piece. 1. Tensile coefficient and tensile time of cylindrical tensile parts. Tensile coefficient m refers to the ratio of cylinder diameter (or semi-finished product diameter) before and after stretching to the blank diameter (or semi-finished product diameter).
2. The partially stretched stamp can only be formed once, and its stamping coefficient is the ratio of the diameter of the cylindrical portion of the stamp to the diameter D of the blank.
3. Some stretch pieces need to be punched several times before forming. The tensile coefficient can be used to indicate the degree of deformation of the material during stretching. The smaller the value of the tensile coefficient m, the greater the degree of deformation.
4. From the point of view of reducing production costs and improving economic benefits, the better the stretching time, the lower the stretching coefficient of each stretch. However, the smaller the m value, the greater the deformation, and the greater the pmax value. When m decreases to a certain value, the pmax value will reach the tensile strength of the dangerous area σ b. This will lead to the rupture of the hazardous area. In deep tension, the tensile coefficient corresponding to the condition that the dangerous area is at the edge of the tensile crack is called the ultimate tensile coefficient (or the lower limit of the tensile coefficient), which is recorded as min. The value of the ultimate tensile coefficient depends on the upper limit of tensile stress in the force transfer area of the cylinder wall and the strength of the dangerous part. Any factor that can reduce the upper limit of tensile stress in the force transmission area of the cylinder wall or increase the strength of the dangerous part will help reduce the ultimate pullout coefficient.
5. The higher the material strengthening rate ( σ s/σ The smaller the b ratio, the greater the value of n and D), and the smaller the value of the ultimate tensile coefficient. The greater the thickness of the anisotropy index, the smaller the ultimate tensile coefficient.