It is known that the strength of metals depends on their grain size. Would you then expect

strength to influence the R value of sheet metals? Explain. It seen from the Hall-Petch Eq. (3.8) on p. 92 that the smaller the grain size, the higher the yield strength of the metal. Since grain size also influences the R values, we should expect that there is a relationship between strength and R

values.

2.Equation (7.23) gives a general rule for dimensional relationships for successful drawing without a blankholder. Explain what would happen if this limit is exceeded. If this limit is exceeded, the blank will begin to wrinkle and we will produce a cup that has wrinkled walls.