During the welding process of the condenser titanium tube, it was found that the weld seam was more oxidized and had more pores. During the coloring inspection, there were many pores and cracks. During the water filling inspection, there were more than 50 leaks. Since the titanium tube plate is relatively Active metal has poor repairability and should not be repaired more than three times according to the instructions.
Repair welding of cracks:
The key is to clear the cracks down to their roots. After cracks are discovered, you should first use a forward grinder and a reamer head to completely remove the cracks. Otherwise, the deep cracks after repair welding may slowly extend to the surface after a few hours, causing new cracks. crack. The cracked area after repairing should be inspected by PT, and repair welding can only be carried out after confirming that it has been completely removed: before repairing welding, it should also be rinsed with internal ketone; welding wire should be added after repairing welding. The key to crack repair welding is to control the temperature to prevent oxidation and overburning of the titanium tube. After the repaired welding joint has been completely cooled, PT inspection should be performed, and PT inspection should be performed again after 24 hours to determine whether there are delayed cracks. of production.
Repair welding of pores:
The generation of pores is mainly caused by the presence of impurities between the titanium tube and the tube sheet. The main focus should be on cleaning the tube sheet before welding, so that the generation of pores can be effectively avoided. Repair of pores generally does not require adding welding wire. During repair welding, the operation must be steady. The tip of the tungsten electrode is directly aimed at the pore area to start the arc. After the pores are melted, the arc is stopped immediately. When the arc is stopped, the decay time should be greater than 4s, arc stop/T; do not take away the argon arc handle immediately, and use argon. Use gas to cool down the repaired solder joint for a few seconds and then take away the argon arc handle. The parts after repair welding should be bright white with metallic luster. If the color changes to blue or silver gray, it indicates that the temperature during repair welding was too high, and crack defects are easy to be found during PT inspection.
