words from precipitation hardened ferritic pearlitic steel such as case hardened steel 38mnvs6 for example however any other suitable steel can be used such as tempered steel 42crmo4 for example in this connection production of the lower piston part 4 takes place in conventional manner by means of casting or hot forging the upper piston part 3 is produced by means of the method of hot forming in this connection a piece of afp steel that is shaped to fit into the drop forging machine intended for the upper piston part 3 is heated to 1200 u00b0 c to 1300 u00b0 c and subsequently formed or preformed in multiple forming stages in other words forging processes in the same drop forging machine the scale that forms during forging is removed by means of blasting subsequently the finished forged upper part blank is cold calibrated at room temperature whereby all the surfaces of the upper piston part 3 are pressed at room temperature in order to achieve the final dimensions alternatively to this the pre formed upper part blank can also be brought into its final shape by means of cold forming at room temperature it is advantageous in this case if an annealing process is still carried out before blasting in order to reduce the tendency to form cracks during cold forming furthermore other processes can also be used for production of the pre form such as the method of cold forming of semi hot forming or of milling for example thus the pre form.