On the application of X-ray diffraction in studying heat-transfer surfaces of steam generators

The effect of thermal cycling on the appearance of alternating stresses in the walls of tubes of perlite low-alloyed and austenitic chromium–nickel steels is studied by X-ray diffraction to develop the criteria of their compatibility. Optimal operating temperatures are estimated for the basic metals and the weld seam realized on their basis. Coincidence between experimental estimates and optimal temperatures established under long-term operation is noted. This may be considered as confirmation of the possibility of applying the stated approaches in predicting the development of hot cracks in the zone of a weld seam and the selection of operating temperatures, at which fields of internal stresses of certain value and sign are formed.