On Increasing Powder Carbon Steels Properties Using Activating Additives

In this paper, the possibility of increasing powder carbon steels properties by activation of carbon diffusion into the iron base during sintering process due to the introduction of the thermally split graphite (TSG), macromolecular compounds (MC) and sodium bicarbonate was investigated. It was found that the introduction of these additives allows obtaining homogeneous structures at a sintering temperature of 100–200 °C lower than that traditionally used for sintering of powder carbon steels. Such structures provide increased mechanical properties of powder carbon steels. The addition of sodium bicarbonate increases the diffusion rate of carbon into iron at a temperature of 950 C by 1.8 times, at 1000 °C by 1.5 times, and at 1100 °C by 1.2 times.

Determination of the limiting values of the laser parameters to heat treatment of powder carbon steels surface

The microstructure and microhardness of the surface layer of powder steels PA-ZhGr with different porosity are studied in comparison with cast steel U10 after laser treatment (LT) with a 1 kW fiber laser in argon. Using thermal modeling, the geometric dimensions of the laser exposure zones formed in the area of the laser exposure were calculated and experimentally confirmed, and the mechanisms of their formation were proposed. The boundary values of the integral criterion for the parameters of laser influence for the heat treatment of carbon powder steels are established.