BORON-ALUMINIZING METHOD OF STEEL SURFACE Russian patent published in 2019 - IPC C23C12/00 

FIELD: metallurgy.

SUBSTANCE: method of boron-aluminizing a steel article surface relates to metallurgy and can be used in machine building for surface hardening of various steel articles. Proposed method comprises saturating surface of steel article with boron and aluminum from powder charge by heating, holding till coating is formed and cooling. Process is carried out in two stages with heating by high-frequency electromagnetic field. At the first stage borating is performed, at which steel surface is covered with a layer of charge with thickness of 2–3 mm, containing boron carbide and activator in form of flux P-0.66, with the following ratio of ingredients, wt%: flux P-0.66 15–20, boron carbide – 85–80, is heated to temperature of 1,150–1,250 °C and kept for 80–90 s. At the second step, aluminizing is carried out, where a layer of charge 1–2 mm thick is deposited on the surface of the steel article with the pre-formed boride coating, containing a compound of aluminum in form of an intermetallic compound from the group FeAl_n (where n=2, 3) and activator in form of cryolite, with following content of ingredients, wt%: cryolite 10–15, intermetallide 85-90, repeatedly heated in protective gas medium to temperature of 1,150–1,250 °C prior to the exothermic reaction, after which it is held for 5–10 s.

EFFECT: simplified process and reduced time, which reduces influence of high temperatures on mechanical properties of base metal.

1 cl, 4 dwg, 3 ex