EASY TREATED STRUCTURAL CHROME-NICKEL STEEL Russian patent published in 2015 - IPC C22C38/40 

FIELD: metallurgy.

SUBSTANCE: steel has the following chemical composition, wt %: carbon 0.09-0.15, silicon 0.17-0.37, manganese 0.30-0.60, chrome 0.40-0.70, nickel 0.50-0.80, bismuth 0.08-0.13, calcium 0.002-0.003, aluminium 0.005-0.015, iron - rest. Steel contains following substances as impurities, in wt %: copper - max. 0.25, phosphorus - max. 0.025, copper - maximum 0.25. Ratio of calcium and aluminium is from 0.20 to 0.40.

EFFECT: increased steel machinability by cutting upon keeping of the required metal mechanical properties, and improved ecological situation during production due to reduced aggression of harmful discharges to atmosphere as result of reduced quantity of added high toxic components.

3 cl, 2 tbl, 11 ex