Effect of technological parameters of laser and laser-plasma alloying on properties of 38KhN3MFA steel layers

Abstract

The results of investigations of structural-phase conditions in surface layers of structural steel 38KhN3MFA and their changes under different modes of strengthening by laser and laser-plasma alloying are given. Experimental investigations were used as a basis for analytical evaluation of differential input of all structures being formed in strengthening and their parameters (chemical composition, grain and subgrain structures, dislocation density, volume fraction of phase precipitates etc.) in change of strength characteristics of alloyed layers, conditions of crack formation promoted by formation of local internal stress concentrators, i.e. zones of nucleation and propagation of cracks, as well as mechanisms for relaxation of such type of stresses. 12 Ref., 6 Figures.

Strengthening phases, structure and properties of low-alloy steel modified welds

“…The calculation methods of estimation of the internal stresses in local structural zones, based on experimental data of fine structure analysis [13,14], allowed determining that the maximum local internal stresses are concentrated along the boundaries of upper bainite (welds «Ti», «SiC» and «TiC») and are the potential sources of nucleation and propagation of cracks, i.e. processes of crack formation (magnitudes of these values is approximately 2-3 times higher than in lower bainite structures (Figure 6)).…”