CORROSION RESEARCH ROUND‐UP

Abstract

U.S.S.R. Scale removal at high temperatures. In pickling steels for scale removal, acid solution is now largely used with additions of acid corrosion inhibitors, but this often proves ineffective at temperatures of 50°C. or higher. Some of the literature is surveyed. In the present work the use of the (Russian) ChM as an additive in the pickling baths for different marks of Russian steels is described (the steels are in the U1A class—tabulated analyses). The identity of this material is not disclosed. Figures are tabulated showing time of removal of scale at temperatures of 15 to 70° using 15% sulphuric, and this with either 4 g./1. of ChM or 0.5 g./1. of stannous sulphate. There appears to be little difference: at 15° time is 82 min. for acid alone and 84 to 86 min. for the others; at 70° it is 9 min. for acid alone and 8 min. with additive. Other figures show that the protective action of ChM sharply declines e.g. from 87% at 15° to 12% at 70°; whereas with a metal sulphate there is little change. Further experiments are described and discussed, and it is generally concluded that tin is the most effective inhibitor. A film of this at 70° and over is much more effective than ChM at 35°; the carbon content of the steel is less important; at the higher temperatures there is less risk of damage to steel articles; and it is easier to control time of treatment in pickling bath through practically complete cessation of hydrogen separation when scale removal is finished. Twelve references.—(B. S. Krasikov, etc., Jnl. Appl. Chem., 1957, (7), 993–997.)

Citation

(1958), "CORROSION RESEARCH ROUND‐UP", Anti-Corrosion Methods and Materials, Vol. 5 No. 6, pp. 198-200. https://doi.org/10.1108/eb019459