Effect of preliminary heat treatment on the formation of a boronized layer on steel 35

Abstract

1. Preliminary heat treatment of specimens leading to refinement of the austenite grain helps increase the thickness of the boronized layer on steel 35. The greatest thickness of the boronized layer is attained after HC, and this layer is thicker than the layer obtained without preliminary treatyment. 2. Preliminary normalization and HC affect the formation of the phase components of the boronized layer. Normalization reduces the content of α-phase in the layer by 40%, and HC by 60% in comparison with the initial state of the steel. After pendulum normalization the phase composition of the layer does not change. 3. The microhardness of the boronized layer depends on the quantitative ratio of the phases in the layer; the highest microhardness is attained after HC.