SEM-EDS MICROCHEMICAL ANALYSIS OF THE MnS NONMETALLIC INCLUSIONS AND METAL MATRIX INTERFACE IN THE CARBURISED 20MnCrB5 STEEL
The results of investigation of 20MnCrB5 steel for carburisation and direct quenching are given in this paper. This is very important steel for motor's industry. Beside some usual factors that affect the strength and toughnes is also demanded the carburised layer depth, carbon content (% ) on the surface of carburised steel and special fracture toughnestest for this quality of the steel. Research and explanation of SEM-EDS microchemical analysis of the MnS nonmetallic inclusions and metal matrix interface in the carburised 20MnCrB5 steel was conducted in the aim of achiving demanded special fracture toughnes.
Analysis of hardenability effect of boron
AbstractThe effect of boron on the hardenability of steels depends on the contents of such elements as aluminium, titanium, nitrogen, and boron and on the austenitising temperature. An attempt has been made to calculate the solubility of boron in the presence of aluminium, titanium, and nitrogen in steels. Three systems, Ti–B–Al–N, Ti–B–N, and B–N, were derived according to the thermodynamic state of each steel and the soluble boron contents were calculated. It was found that the maximum boron factor was achieved at 0·0004–0·0005% soluble boron. The fact that aluminium content in the range 0·018–0·050 wt-% investigated in this study has little effect on the boron hardenability factor can be explained from the results of the thermodynamic calculation.MST/1025
SR topography of plastically deformed Fe-Si bicrystals - observation in situ and post mortem
SR reflection topography was applied to study the interaction of slip dislocations with the grain boundaries in Fe-4at%Si bicrystals deformed by compression. Three experimental settings with either a white or monochromatic beam were used and the corresponding orientation contrast analysed. Dislocation transmission through the grain boundary was observed in bicrystals with favourable geometry of the slip systems.