Search academic texts

Information × Registration Number 0217U006695, 0115U000120 , R & D reports Title Establishing the corrosive-adsorption influence of the melt of lead on the degradation operational properties of ferritic-martensitic and austenitic steels popup.stage_title Head Fedirko Viktor, Registration Date 27-12-2017 Organization Karpenko Physico-Mechanical Institute of the National Academy of Sciences of Ukraine popup.description2 It has been established that for chromium steels of the ferritic and ferrite-martensitic classes at a loading speed of 51010-4 s-1 in lead melt and lead-bismuth eutectic at temperatures of 300 ... 450 ° C, the effect of liquid metal embrittlement is realized, which manifests itself in a decrease in ductility by 10 ... 20%. The maximum embrittlement effect ? 35% is typical for armco iron at a temperature of 300 ° C, doping of 11% Cr (SUH 409L) shifts the temperature to 450 ° C and reduces ductility to 13%. For an austenitic grade steel, X18H10T, no embrittlement effect is observed, and a temperature increase above 400°C promotes steel plasticization by 8%. An increase in the grain size of ferritic steel from 35 to 75 mkm shifts the embrittlement temperature from 500 to 400 ° C, and for steel of austenitic grade increasing the grain size from 90 to 160 mkm promotes the plasticization of steel by 10%. For the first time, the universality of the manifestation of the liquid metal embrittlement effect of steels of ferritic, ferritic-martensitic and austenite classes was confirmed and the temperature-deformation conditions for its realization were established. It is shown that its manifestation occurs in a certain temperature range of 350 ... 450°C and deformations of 0.8...1.0% per cycle and causes a decrease in order of durability. It was confirmed that the corrosion processes of chromium steels in lead melts are determined by the concentration of dissolved oxygen. At concentrations at the level of CO [Pb]=10-7...10-6 wt%, the predominant processes are the dissolution of the alloying elements Cr, Ni, roztvlyuvannya grain boundaries and the penetration of the melt into the matrix, as a result of intergranular corrosion. An increase in the oxygen concentration to the solubility limit of CO [Pb] =10-4 ... 10-3 wt% leads to a change in the mechanism. Determining are the oxidation processes with the formation of oxides based on iron and chromium. It is established that lead melts in the temperature range of 500 ... 600°C reduce the long-term strength, and more significantly in the melt of the eutectic. At small temporary bases, the decrease in strength is determined by adsorption processes and rare metal embrittlement. In the future, the resistance of steels to destruction is determined by the corrosive effect of melts, namely, processes realized at the grain boundaries-selective dissolution of the Cr and Ni alloying elements, oxygen diffusion and the formation of Fe-based oxides that are shaken under load and facilitate metal disintegration. Product Description popup.authors Кравчишин Тарас Миронович Кухар Іван Степановис Мельник Христина Романівна Ткачук Олег Васильович Яськів Олег Ігорович popup.nrat_date 2020-04-02 Close