in fig2 has undergone a certain degree of stretching although less than the stretching that corresponds to material flow on reshaping of the bottom part 24 the aforementioned prestretched area of material is subjected to additional stretching with the result that material flows accordingly material flows in the blank 10 and the material which flows is situated closer to the axis of the blank than the material which in the blank forms the cylindrical portion 12 the material of the ring shaped transition has a smaller initial radius than the material in the cylindrical portion also indicated in the figures is a standing surface 26a and the mouth portion of the preform 27a in another version the bottom part 24 is reshaped with the material at a temperature within the thermoelastic temperature range of the material as a result the profile length of the bottom part increases in conjunction with reshaping as the thickness of the material in the bottom part decreases during simultaneous elongation of the material the equivalent to the ring shaped transition of materia1 which is stretched to flow as described in the previous paragraph consists of a ring shaped area of material stretched to flow which was formed during the passage of the blank through the draw ring and which is situated adjacent the bottom part 24 of the blank fig3 and 3a are also representative of the ring shaped area of material which is formed according to this version and which.