Influence of lead and Pb−Bi eutectic melts on the mechanical properties of 20Kh13 ferritic–martensitic steel

We have investigated the influence of a liquid-metal medium on the mechanical properties of 20Kh13 ferritic–martensitic steel in the temperature range 300–600°С. It is shown that lead and lead−bismuth eutectic melts facilitate a decrease in the ultimate strength of 20Kh13 steel by 10–20% against that in vacuum, and with increase in temperature, this effect is enhanced. We have found the influence of the liquid-metal medium on the plastic deformability of 20Kh13 steel at elevated temperatures. It has been established that 20Kh13 steel is susceptible to liquid-metal embrittlement in the temperature range 350–450°С, which manifests itself weaker in lead and more substantially in the lead−bismuth eutectic. The decrease in the percentage elongation against that in vacuum depends on the medium: it is equal to 11% in Pb at a temperature of 450°С, and ranges from 15 to 30% in the Pb−Bi eutectic melt in the temperature range 350−400°С.