Abstract： By analyzing the S690 high strength steel's chemical composition, carbon equivalent, temperature control, hydrogen content and stress condition, the reason of cold cracks appearance is found, and then the weld repair control measures such as clearing dirties, ensuring preheating temperature, and carrying out post heat treatment immediately for eliminating hydrogen and releasing stress are proposed. In this way, all the defective welds are repaired successfully and the inspection result is acceptable. The results show that the strict quality control precautions are the key factors to get a successful repair work for S690 high strength steel cold cracks.
