The invention discloses a wall thickness difference
cupronickel and
beryllium copper foil transition
welding method for a CT
bulb tube. The method comprises the following steps that S1, materials are pretreated; s2, assembling is conducted, specifically, a
copper foil sheet is placed at a
ray window in the side wall of the
cupronickel tube shell, the inner side and the outer side of the
copper foil sheet are both coated with
welding flux, a
beryllium sheet is placed on the outer side of the
copper foil sheet, the
beryllium sheet and the
copper foil sheet are the same in size and
radian, a
welding tool is placed on the outer side of the beryllium sheet to fasten the
copper foil sheet and the beryllium sheet, and assembling of a to-be-welded
assembly is completed; and S3, welding. Through high
thermal conductivity and low yield strength of the copper foil, uniform distribution of heat and stress buffering are realized, on one hand, excessive heat gathered by thin-wall
cupronickel can be quickly conducted to thick-wall cupronickel, and overall
heat distribution is balanced through the heat storage capacity of the
thick wall; and on the other hand, the uniform
thermal conductivity of the copper foil can reduce the local
temperature difference of a welding seam area,
micro cracks or air holes generated due to uneven
thermal expansion and cold contraction are avoided, and the welding
air tightness is improved fundamentally.