The equipment flanges are made of 16Mn forgings, with a thickness of over 38 mm; is post-weld heat treatment required?
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The equipment flanges are made of 16Mn forgings, with a thickness of over 38 mm; is post-weld heat treatment required? If post-weld heat treatment is required, then the flanges of most of those equipment pieces are over 38 mm!
It refers to types A and B flanges of 47020
Annealing is required; otherwise, it will definitely deform after processing.
The welds that connect type A and type B flanges to tube sections differ from those of butt-welded flanges; the thickness of the welds that require heat treatment is not determined based on the thickness of the flange. As determined by GB150, post-weld heat treatment is generally not required.
The heat treatment thickness is not necessarily the same as the flange thickness
The heat treatment of equipment flanges should be carried out section by section. For example, in the case of heat exchanger tube box flanges that are equipped with partition plates, heat treatment is necessary. Since these partition plates are welded to the tube box, the flanges may deform unevenly, which can affect the sealing performance. Therefore, heat treatment is required after welding the partition plates in order to eliminate welding stresses and prevent flange deformation ； For cylinder flanges, unless there are special requirements, heat treatment is generally not necessary.
Mentioning 38mm specifically refers to the corresponding standard value, right? The determination of the thickness requirements for heat treatment can be clarified by referring to 8.2.1 in GB150.4 in conjunction with the specific structure
Assess the understanding of the concept of “post-weld heat treatment thickness”. For standard flanges of types A and B, the thickness for post-weld heat treatment at the welded area is determined in accordance with clause GB150.4 8.2.1 (d): the thickness of the pipe neck at the joint is used, unless the flange and the pipe form a fully penetrated structure (i.e., as shown in GB150.3 Figure 7-1g), in which case the thickness of the flange is used instead.