| 摘要 |
PURPOSE:To prevent much elution of chromium and to obtain a degree of freedom for printing time in a sulfur printing method of a special steel contg. >=10% chromium. CONSTITUTION:A special steel contg. >=10% Cr is subjected to sulfur printing by using an aq. soln. of a hydrochloric acid with which the elution of Cr is small, i.e., 3-10% (vol) hydrochloric acid. A sharp print is obtd. with 3-5% concn. of the hydrochoric acid and adequate printing time is 2-3min. The immersion time of photographic paper varies in an adequate range with the concn. of the hydrochoric acid, and is adequately 2-4min if the concn. of the hydrochloric acid is 3% and 0.5-1.5min of the concn. is 5%. The sharp sulfur print of the special steel is thus obtd. without receiving the adverse influence of Cr existing much in the steel and therefore this method is effective in process and quality control of steel materials. |
