Mass fraction of elements not more than, %: Carbon (C) 0,90-1,05; Silicon (Si) 0,10-0,40; Manganese (Mn) 0,80-1,10; Chromium (Cr) 0,90-1,20; Molybdenum (Mo) up to 0,30; Tungsten (W) 1,20-1,60; Nickel (Ni) up to 0,35; Copper (Cu) up to 0,3; Phosphorus (P) up to 0,03; Sulphur (S) up to 0,03.