It's still the flange issue
Thread Content
I was wondering, when designing systems, what materials are used for pipe flanges when the operating pressure is quite high? For example, in the case of atmospheric-pressure vessels, or low-pressure vessels with pressures of just a few kilograms, are plate flanges used in such situations? According to pipe flange standard HG 20592, the use of sheet metal is not recommended; instead, forgings are preferred. The standard states that grade I forgings can be used, but it seems that this practice is not very common
1. I’ve been reading this discussion thread on lz for a long time but still can’t understand it. I wonder if it’s my Chinese skills that are the problem or something else? In phrases like “when the grade is not very high,” what does “grade” refer to? Does it mean the grade of the forging or the grade of the flange? 2. Please, next time you raise a problem, explain it more clearly so that everyone will be motivated to help you solve it. 3. You can check the provisions regarding Grades I to IV in JB4726/JB4727/JB4728 by yourself for your question.
I completely agree; maybe it’s because I’ve been away from school for N years, but I find the poster’s post a bit confusing – what’s the high rank about? ? Atmospheric pressure container? ? The material selection doesn’t seem to be based on this criterion; at the very least, the properties of the medium should be taken into consideration! ! ! . . . . . . . . . It seems I still need to keep working on my knowledge of culture studies!* :L
The grade is very high, and the forging grade is I – isn’t that contradictory on the part of the poster?
Regarding the selection of flanges in design, there are a few suggestions: First, as for the pressure value of the flanges, generally speaking, unless otherwise specified, plate butt weld flanges are more commonly used; the values range from 0.25 to 2.5, with 1.6 Mpa being the most common value. II. Regarding the type of flange, for applications involving high pressures or highly hazardous media, or where even minor leaks are not acceptable, butt-welded flanges are necessary. The most common type is the wafer-type butt-welded flange (WN). In situations where the requirements are not particularly strict, or where minor leaks are tolerable and the design pressure is low, slip-on flanges (SO) are also used. This choice usually depends on an individual’s design preferences. III. Regarding the grade of forged flanges, the detailed specifications are provided in the comprehensive book HG20583; grade II forged flanges are commonly used, but grade III flanges are required for media that pose extreme or high levels of hazard. No further details will be given here.
Dear friends, I’m truly sorry! One character was missing in the question; it should have read \"in cases where the level of ‘no’ is very high\". It seems that the answer given on the fifth floor was already clear enough. What I actually wanted to ask was whether plate flanges used for atmospheric pressure vessels also typically use 20Ⅱ forgings
Why are forged parts used for plate flanges? Is it quite thick? Generally, plate flanges and flange covers can be made from sheet metal
Technical specifications for steel pipe flanges HG20603-97, class P140. Note: The material for pipe flanges should generally be forged; the use of steel plates or shaped steel is not recommended. Steel plates can only be used for flange covers, lined flange covers, plate-type butt-welded flanges, ring-type loose-flange connections, and butt-welded ring-type loose-flange connections. (Original text) When the thickness of a standard plate-type butt weld flange is not large, it is best to use sheet metal, as the stress distribution is better than that in forged parts.