Understanding of Article 7, Section 8.0.2 of HG20584 regarding the heat treatment of cladded tube sheets

Thread Content

Regarding the cladded tube sheets, no mandatory requirement for heat treatment of such tube sheets can be found in the standards, nor is it mentioned in any available drawings; however, most people on forums believe that heat treatment is necessary. Have I not searched through all the standards? If so, where is the source? HG20584, Section 8.0.2, Clause 7: Thickness of the base metal layer of steel with a surfacing layer, or thickness of the base layer of austenitic stainless steel lining, or thickness of the base layer of composite steel plates. How do the experts understand this? Some views found online: View 1: Use the base layer of the tube sheet as the thickness for heat treatment. Viewpoint 2: Consider the coating on the tube sheet as the heat treatment thickness; using this approach, the vast majority of tube sheets require no heat treatment after cladding. Viewpoint 3: Interpret the heat treatment thickness specified in Article 7 of 8.0.2 of HG20584 as the thickness of the welded joint. (Point 4 is similar to Point 2 if there are no weld joints, for example, if the tube sheet has no seams.) Point 4: Interpret the heat treatment thickness specified in Article 7 of 8.0.2 of HG20584 as the thickness that manufacturers use to develop heat treatment plans. In my opinion, viewed separately, viewpoint three in Article 7 is correct; however, when considering 8.0.2 as a whole, extracting Article 7 separately creates ambiguity. Also, are there any experts from heat treatment manufacturers? Are there any methods used in the production of cladded tube sheets to ensure manufacturing quality?