Metallurgy and radiation stability of steel for reactor pressure vessels

The procedure of the forging of ingots weighing up to 200 tons consists in the purposeful combination of steel metallurgy in an open-hearth furnace and an electric arc furnace and ingot vacuum casting. The choice of a suitable batch (pig iron and precast ingots) will make for a very low content of impurities. The values are given of the mechanical properties of steel 15Kh2MFA showing negligible scatter. The content of arsenic, antimony and tin is much below maximum permissible levels. The content of copper and phosphorus is higher than the threshold values for radiation embrittlement but is still below limit value. The experiments show that as concerns purity the manufacture of steel for reactor pressure vessels has been mastered with sufficient reliability and reproducibility. (J.B.)