International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The article presents a comparison of different computational approaches used to study the surface treatment of a NiCrMoV steel with 0.55% Carbon content by a plasma jet. Metallographic observations show formation of martensite layer due to high cooling rate by heat transfer into the bulk steel. Heat affected zone (HAZ) was 1 mm deep and 10-12 mm wide. The treated surface maximum hardness was measured at 763 HV0.1 whereas untreated steel was at 210 HV 0.1. The computation indicates a hardening sink near the surface that went undetected in the experimental observations. The ability of the different computational approaches to explore the process related phenomena and to give reliable results is put into discussion.

An coupled analytic-numerical model for calculation of distortions arising by welding fabrication is introduced. Target of the analytical model is the calculation of the inherent strains after the local thermal-mechanical influence of the welding or thermal straightening process. Following the fabrication processing chart the strains are loaded on an elastic FE-model of the structure and the residual stresses and distortions of the whole structure are calculated. The consideration of welding and thermal straightening scenarios, inclusively the assembling stages, is done by taking into consideration the intermediate variation of the strain state in the FE-model of the structure at every processing step. The important physical relations are demonstrated. The model is intended to be used for solving industrial tasks, i.e. intending acceptable precision and calculation time as well as low simulation costs.

An coupled analytic-numerical model for calculation of distortions arising by welding fabrication is introduced. Target of the analytical model is the calculation of the inherent strains after the local thermal-mechanical influence of the welding or thermal straightening process. Following the fabrication processing chart the strains are loaded on an elastic FE-model of the structure and the residual stresses and distortions of the whole structure are calculated. The consideration of welding and thermal straightening scenarios, inclusively the assembling stages, is done by taking into consideration the intermediate variation of the strain state in the FE-model of the structure at every processing step. The important physical relations are demonstrated. The model is intended to be used for solving industrial tasks, i.e. intending acceptable precision and calculation time as well as low simulation costs.