Sulphur diffusion and distribution study in St 3 and 12Kh18N9 steels

The effect is studied of annealing upon the distribution of sulphur at the interfaces between the following welded pairs: iron-steel St3, iron - steel 12 Kh 18N9, and steel St3 - steel 12Kh18N9. Homogenized samples of low-carbon iron (to 0.003% of C) and steel St3 were welded with samples of iron, steels St3 and 12Kh18N9 using a diffusion welding installation. Then the welded samples were annealed at 1,000 deg, 1050 deg, 1,100 deg, and 1,150 deg C. The change in sulphur content in the zones parallel to the welding plane has been determined by the layer-by-layer radiometric analysis. It has been shown that after annealing the sulphur concentration in the welding zone increases. The sulphuric diffusion coefficient have been determined and their temperature dependence has been found for the steel St3 in the γ -region