Is heat treatment performed after flange surfacing?
Thread Content
The existing flanges are DN900, made of 16Mn grade III + S30403 with surfacing; is heat treatment performed after the surfacing? The manufacturer welds a transition layer on the flange; after the cladding is applied, precision machining is carried out without any heat treatment. The reason is that the equipment is a complete heat treatment system. However, in my opinion, if heat treatment is to be carried out, a transition layer should first undergo heat treatment, followed by the deposition of a cladding layer, and then final machining ； If the equipment is a complete heat-treatment unit, it is possible to weld a transition layer first and then directly weld the coating layer; however, precision machining is still required after heat treatment, taking into account the deformation caused by stress relief in the flange surface as a result of heat treatment. I’m not sure how everyone approaches the heat treatment for flange surfacing; I’d like to ask for some advice!
All measures are for quality!
In my personal opinion, the surfaced flanges should be heat-treated. It has nothing to do with the heat treatment of the entire device. . .
Before machining, the forgings must undergo normalizing (failing to do so will cause various cracks during welding; it’s cracks, not fissures). After depositing the surfacing layer, stress relief treatment is carried out, followed by the application of the corrosion-resistant layer. No further heat treatment is done after welding the corrosion-resistant layer, in order to avoid chromium depletion.
You mean the sealing surface, right?
Heat treatment should be carried out after the transition layer welding, right?
Heat treatment is not necessary for the flange surfacing of this material.
Take a look at what page 331 of 150 says. Don’t form opinions on your own.
Fine machining still requires heat treatment, taking into account the deformation caused by stress relief in the flange surface as a result of heat treatment.
In my opinion, stress-relief heat treatment should be carried out after the transition layer welding is completed； No treatment is required after surfacing welding ；