METAL HARDENING MEDIUM Russian patent published in 2001 - IPC

FIELD: metallurgy; hardening media on base of water-soluble polymers used for heat treatment of carbon and alloyed steels and other metals. SUBSTANCE: medium contains aqueous solution of carboxyl-containing polymer; medium includes copolymer of acrylamide, methacrylic acid and acrylonitrile of the following formula: m where, m is acrylamide n is methacrylic or acrylic acid: p is acrylonitrile; Me-H and/or cation of alkali metal at the following content of monomeric components, mas. %: acrylamide, 25-90; methacrylic acid, 10-55; acrylonitile, 0-30 at concentration of copolymer in working solutions, 0.1-5.0. EFFECT: ecologically pure, non-toxic medium; reduced losses of polymer; absence of alkaline corrosion due to neutral pH value of concentrate and working solution, thus making it possible to use medium non-ferrous metals. 7 tbl