Cutting of S355J2H seamless steel pipe:
After the S355J2H seamless steel pipe is straightened, the first inspection and soot blowing shall be carried out to determine the length of the cutting head and tail. The purpose of S355J2H seamless steel pipe cutting is to remove the ends with cracks, knots, scars, tears and uneven wall thickness, so as to obtain the required fixed length S355J2H seamless steel pipe. In addition, defects that are difficult to be saved after inspection are removed, such as internal fold, internal scar, serious wall thickness nonuniformity, etc. Generally, the former is cut off on the operation line, while the latter is cut off offline.

Control of heat preservation time of S355J2H seamless steel pipe during heat treatment:
During the heat treatment of S355J2H seamless steel pipe, the heat preservation time shall ensure that the steel pipe in the furnace can be completely burned through, the temperature is uniform, and the proper structure transformation is completed, so as to obtain uniform structure and performance. Generally, increasing the heating temperature can shorten the holding time properly. In the process of low temperature annealing (including softening, stress relief and recrystallization annealing), the closer the annealing temperature is to the lower critical point A1, the faster the recovery of S355J2H seamless steel pipe will be, and the more complete the effect of eliminating work hardening will be. Therefore, the holding time can also be appropriately shortened.