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
Hardenability effect of boron on carbon steels
AbstractAn attempt has been made to investigate the effects of aluminium, titanium, nitrogen, and boron on the hardenability of boron-bearing medium-carbon steels. It was found that not only titanium but also boron had the scavenging effect for dissolved nitrogen. A parameter designated as boron potential (Bp = xB−11/14(xN−14/47·9XTi), where xB, xN, and xTi are the total boron, nitrogen, and titanium content, respectively) was chosen to evaluate and predict the boron hardenability effect. From the results of this study, boron potential is a parameter useful in discerning the optimization of contents of titanium, nitrogen, and boron for the development of boron steels having excellent hardenability.MST/655