Abstract
The distribution of tramp elements in the enriched layer and the scales produced by oxidization while heating was minutely investigated by spectrographic and chemical analyses. The results obtained were as follows:—(1) When steel is heated in oxidizing atmosphere, Cu, Sn, Ni, As and S contained in steel are enriched on the surface of steel. (2) A linear relationship is observed to exist between the depth from the surface of steel and the logarithm of the concentration of each enriched element contained in the layer. (3) In the case the scaling loss of steel is constant, the surface concentration of enriched Cu and Sn is decreased while that of S is increased with rising h ating temperature, and the surface enrichment of each element is also affected by the oxidizing velocity and the coexisting elements. (4) The diffusion constants of Cu and Sn in steel are determined by measurement of the enriched depth at various temperatures, and the following were the values obtained: & D_Cu^- 12700 exp(-48700/RT) cm^2/day
& D_Sn^- 4570 exp(-45600/RT) cm^2/day(5) The concentrations of Cu and Sn in scales are less than those in the steel matrix, and usually depend on the degree of scaling loss.
