Regarding the local heat treatment of patch welding
Thread Content
It is a horizontal tank made of 16MnR material. It was supposed to undergo overall heat treatment after being welded to the pre-welded parts, but the manufacturer carried out the heat treatment without first welding those parts. Now, it is intended to weld the pre-welded parts back in place and then perform local heat treatment – how should this process be carried out? What measures need to be taken for the newly welded area and the surrounding areas? Such as heat preservation, etc
Reference can be made to the method of segmented heat treatment specified in the code, Article 73, 2: Local heat treatment may be applied to the circumferential weld joints that have been repaired, as well as to the weld joints connecting the nozzles to the cylinder or head. For welds that have undergone local heat treatment, the entire weld shall be included. The heating width on each side of the weld shall be not less than 2 times the thickness of the base material; when joining a pipe to a shell, the heating width shall be not less than 6 times the greater of the thicknesses of the two materials. The casing near the heating area should be insulated to prevent large temperature gradients from occurring.