Investigation of Stainless Steel Obtained by Additive Technology as Applied to the Operating Conditions of Liquid Metal Heat-Exchange Systems

The properties of stainless steel grade GP1 obtained by additive technology (AT) by the method of selective laser melting (SLM) in relation to the operating conditions of liquid metal heat-exchange systems of power plants (vacuum density, corrosion effect of eutectic sodium and potassium alloy Na–K at temperature 700 ± 5°С) are investigated. The microstructure of GP1 steel has a fine structure with a characteristic size of structural components from 2 to 3 μm. The results of local chemical analysis of the identified structural components of the material showed a high degree of material homogeneity. The material is sealed, the flow of helium into the sample made by AT was no more than 4 × 10–10 (Pa m3)/s. Under the conditions of the tests performed, the corrosive effect of Na–K on the material is observed in the surface layers with a thickness of no more than 2 μm. The corrosion rate of the test material under test conditions was less than 0.01 mm/year, which, according to the existing classification of corrosion resistance, makes it possible to assign the test material under test conditions to the resistance group of extremely resistant. The results give grounds to continue research on a larger time base and in conditions close to the operating conditions of the heat-exchange systems of power plants (non-isothermal dynamic conditions), as well as to conduct research on other steels obtained by AT, for example, chromium-nickel corrosion-resistant steel of austenitic class with a high level of corrosion resistance in the environment of the liquid metal coolant Na–K of eutectic composition.