The invention discloses a 300-meter
water depth jacket S420 high-strength steel
welding construction method which is characterized in that preheating treatment is carried out in the processes of plate
cutting and blanking, plate pre-bending, reel
pipe closing, transition groove
cutting and longitudinal
seam welding, and during pre-bending, a multi-time slow pressing and pre-bending mode is adopted, so that mechanical indentations can be prevented from occurring in the pre-bending process; during
pipe rolling,
pipe rolling and opening closing are completed in a multi-rolling slow forming mode, and rolling'dead bending 'can be avoided; in the process of
cutting and
grinding the transition groove, the workpiece is synchronously heated, so that defects can be avoided in the
grinding process, and the influence on subsequent
welding is avoided; in the longitudinal
seam welding process, the requirement for the preheating temperature is improved, only
electric heating can be adopted during preheating, the
welding process is strictly controlled, and after-heating
hydrogen elimination treatment is conducted after welding, so that the
hydrogen content is reduced, and cracks are avoided; the construction quality of the second sea foundation is better guaranteed, the potential safety
hazard of offshore operation of the jacket is reduced, and it is guaranteed that the main structure meets the service requirement.