|KORBÁŠ Martin||VÍTKOVICE HEAVY MACHINERY a.s.|
|Spoluautoři ČAMEK Libor, KURKA Vladislav|
The paper presents research of possibilities of optimisation of production of tool steel of X40CrMoV5-1 grade for forging on the rapid forging machine, which was directed on conditions of casting with focus on macro-porosity and micro-porosity in the ingot body. Metallographic analyses of ingot structures prove that internal discontinuities in ingots may be formed as a result of volume changes of liquid and solid phases, of carbidic segregations and micro-cracks in segregations. Assuming similar conditions and parameters for casting of X40CrMoV5-1 steel grade, numerical simulations of casting, solidification and cooling of two types of identical shape of cross-section, of similar diameter and taper of the forging ingot from the melt without rejects and with occurrence of rejects from the final forged piece were performed in MAGMA program. Design of new shape of ingot mould was created after evaluation of the achieved parameters and numerical simulation of casting with modified taper of the forging ingot was performed with preservation of other original parameters.