STRUCTURAL STEEL FOR VOLUME-SURFACE HARDENING Russian patent published in 2012 - IPC C22C38/58 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: steel contains components at the following ratio, wt %: carbon 0.15 - 1.2, manganese 0.005 - 1.8, silicon 0.005 -1.8, chrome 0.005 - 1.8, nickel 0.005 - 1.8, molybdenum 0.0001 - 0.5, tungsten 0.0001 - 1.5, boron 0.00001 - 0.007, copper 0.001 - 0.3, aluminium 0.03 - 0.1, nitrogen 0.0001 - 0.1, titanium 0.001 - 0.4, vanadium 0.001 - 0.4, zirconium 0.001 - 0.4, niobium 0.001 - 0.1, tantalum 0.001 - 0.1, calcium 0.001 - 0.03, sulfur 0.0001 - 0.035, phosphorus 0.0001 - 0.035, iron and unavoidable admixtures - balance.

EFFECT: production of steels of lower and regulated hardenability with finer austenite grain, more stable level of hardenability at considerably smaller dispersion of ideal critical diametre of hardening and depth of a hardened layer, produced directly on parts exposed to strengthened volume-surface hardening, and also the possibility to process thinner and finer parts with volume-surface and through strengthening.

3 cl, 4 tbl, 3 ex