Accession Number : AD0710685

Title :   THE REMOVAL OF HEAT TREATMENT SCALE FROM TWO VERY STRONG STEELS (3% Cr-Mo-V STEEL AND 18% Ni-Co-Mo-Ti. STEEL),

Corporate Author : MINISTRY OF TECHNOLOGY LONDON (ENGLAND) MATERIALS DIV

Personal Author(s) : Duffin,R. A.

Report Date : MAY 1970

Pagination or Media Count : 27

Abstract : Experiments on anodic pickling in sulphuric acid solutions showed that the most effective acid concentration corresponds to maximum conductivity (S. G. 1.36). Wetting agents did not improve scale removal and promoted absorption of hydrogen into the steel. A proprietary inhibitor, 'Corinex', manufactured by Berk Ltd., was advantageous in reducing smut formation and uptake of hydrogen. Raising the temperature of the solution to 70C was advantageous. Interruption of the anodic current for a few seconds allowed much lower current densities to be used, and pretreatment of scale on 3% Cr-Mo-V steel and maraging steel in an alkaline solution of sodium gluconate prior to anodic pickling further reduced the current density required. Sustained load tests on 3% Cr-Mo-V steel at 170 hbar and 18% Ni. maraging steel at 200 hbar tensile strength, loaded to 90% NTS, gave no failure even of specimens anodically pickled in uninhibited acid with interrupted current. (Author)

Descriptors :   (*PICKLING, *STEEL), MARAGING STEELS, CHROMIUM ALLOYS, MOLYBDENUM ALLOYS, VANADIUM ALLOYS, COBALT ALLOYS, SULFURIC ACID, SOLUTIONS(MIXTURES), GREAT BRITAIN

Subject Categories : Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE