FINITE-ELEMENT SIMULATION OF QUENCH HARDENING

In this study, an efficient finite element model for predicting the te mperature field, volume fraction of phases and the evolution of intern al stresses up to the residual stress states during quenching of axisy mmetrical steel components is developed and implemented. The temperatu re distribution is determined by considering heat losses to the quench ing medium as well as latent heat due to phase transformations. Phase transformations are modelled by discretizing the cooling cuves in a su ccession of isothermal steps and using the IT-diagrams. For diffusiona l transformations both Scheil's additivity method and Johnson-Mehl-Avr ami equation are used, while Koistinen-Marburger equation is employed for martensitic transformation. Internal stresses are determined by a small strain elasto-plastic analysis using Prandtl-Reuss constitutive equations. Considering long cylinders, a generalized plane strain cond ition is assumed. The computational model is verified by several exper imental measurements and by comparison with other known numerical resu lts. Case studies are performed with St50, Ck45 and C60 type of solid and hollow steel components. The complete data and result sets provide d for the verification examples establish a basis for benchmark proble ms in this field.