AUSTENITIC AND AUSTENITIC-FERRITIC STEEL PROCESSING METHOD Russian patent published in 2017 - IPC C21D8/00 C21D6/00 C21D7/06 B24B39/04 

FIELD: metallurgy.

SUBSTANCE: method includes ultrasonic non-abrasive steel surface treatment and final surface plastic deformation. Sonication austenitic steels tratement is carried out with the tool pressing force to the surface of 10-12 N and oscillation frequency of 15-20 kHz, forming the surface layer of a two-phase structure with a dislocation density⋅ of 2.5-3.01010 cm-2 consisting of 78-83 % deformation martensite and 17-22 % austenite, and ferrite-austenite steels - with a pressing force to the surface of 15-20N and ultrasonic oscillations frequency 20-25 kHz forming in the surface strengthened layer of a three-phase structure with a dislocation density⋅ of 5.5-6.0 10¹⁰ cm^-2 comprising 47-53 % ferrite, 40-43 % deformation martensite and 7-10 % austenite. Austenitic steel finish deformation is carried out with compression, providing a hardening depth 70-80 % of the strengthened layer thickness after ultrasonic treatment and forming on the surface of the two-phase structure with the dislocation density⋅ of 6.5-7.0 10¹⁰ cm^-2 consisting of 84-90 % deformation martensite and 16-10 % austenite, and ferrite-austenite steel - three-phase structure with the dislocation density⋅ of 9.0-9.5 10¹⁰ cm^-2 comprising 47-53 % ferrite, 44-48 % deformation martensite and 3-5 % austenite.

EFFECT: increased steel structural strength.

3 cl, 4 dwg, 4 tbl, 7 ex