Insulation ring form
Thread Content
Article 5.7.3 in HG20652 "When the carbon steel insulation ring should not be welded to the tower body (heat treatment tower, cryogenic tower), a detachable insulation ring connected by bolts should be used." Please tell me: Why should we not weld carbon steel insulation rings to the tower body in heat treatment towers and low-temperature towers? We must use detachable ones.
It may be because carbon steel is not suitable at this temperature (high or low temperature). If it is wrong, please correct me!
There are not one or two thermal insulation support rings, but many. If they are installed directly on the heat treatment tower, there will be inconvenience during heat treatment. You can weld the backing plate first, and then weld the support rings after the heat treatment. There are many contraindications to cryogenic equipment, and it is important to avoid excessive constraints. So this may be the reason why they cannot be welded directly.
Thank you for your answers. If the tower is subject to external pressure, can the reinforcing ring be made detachable? A complete ring must be used.
How can I reinforce the reinforcing ring if it is made detachable? The reinforcing ring does not have to be a full circle, but there is a requirement for the length of the break.
Regarding the reinforcement ring, there are specific regulations in GB150. For the insulation ring, if the insulation ring is welded directly to the equipment, the weld is too long and unnecessary welding residual stress is easily generated. This should be avoided in heat treatment equipment and low-temperature equipment.； After being made into a detachable part, there will be much fewer welds, which can effectively reduce welding stress in the manufacturing process.
If the temperature is too high, the material properties of the support ring may change, such as creep. Low temperatures may cause it to become brittle! My personal opinion is wrong, please correct me
After the heat-treated equipment arrives at the site, welding is generally not allowed on the body. If necessary, local heat treatment must be performed after welding. Therefore, at the beginning of the redesign, it was considered that the skirt or skirt pad, platform ladder support pad, insulation support ring pointing pad, nameplate bracket pad, etc. were all installed and welded and then heat treated as a whole before going to the site. The thermal insulation support rings are installed on site and are not shipped together with the equipment (not conducive to transportation), so the general manufacturer is not responsible for the support rings.
But if it is shown on the equipment diagram, the manufacturer should be responsible for welding and installation. If it is welded at the manufacturer, is it necessary to make it a detachable structure?
I suggest the poster take a look at HG20652_24 pages of 98 tower design technical regulations.
1: There will be temperature difference stress 2: Welding issues of non-carbon steel as the main material