The problem is that almost nobody in the US has PED compliant WPS and also many Notified Bodies require witnesses of the WPS and WPQ coupons by the manufacturer.
Does anyone know of a US based manufacturer capable of making welded (not seamless) pipe, elbows, tees, etc. 12" and down that are compliant with the PED (stainless steel)? The main problem is the welding procedures; no one in the US has PED approved WPS. There are many manufacturers of...
Prex,
The geometry I am considering is a relatively thick walled cylinder (welded to another thick structure) and I would naturally consider lines not a single line through a cross-section of interest. The loading is such that the maximum stresses will definitely occur on the same plane as the...
TGS4, thanks for the reply. I'm familiar with 4-136 and the related methodologies outlined at:
http://ped.eurodyn.com/jrc/jrc_design.html
However, the problem is that I've got potentially dozens of different sizes/thicknesses of equipment to design and each of these might require a few...
There has been a bit of discussion of the merits/methods, etc. of stress linearization through a section of interest to extract equivalent membrane and membrane + bending stresses to compare to ASME Sec. VIII Div. II allowable values.
Someone had suggested looking at the stress intesity at...
Our firm (in Florida) is PED certified (Module H) to manufacture "CE-Stamped" pressure equipment. ijzer is incorrect; no agent is required within the EC. Seeker88, feel free to contact me directly if you have any questions regarding the PED or if you need a quotation on a piece of equipment.
I agree. This is what I was trying to say in my previous post, but you have put it in a very concise and detailed format. Thanks. In an older post on this topic, someone had erroneously stated that one should add the six components.
Chris
Upon further delving into Section VIII Div. 2 App.4 and WRC 429 (p. 112 to be exact), it seems that one should compute the membrane stress intensity based on the largest difference of the linearized principal stress components and compare this value to Sa. The same should be done on the inner...
Prex,
Wouldn't implementation of "Step 4" result in a sort of stress classification plane rather than "line" and permit you to get some sort of average M, M+B for the structure in this area? With certain loading and structures I think it's pretty hard to equilibrate external loads (e.g., the...
When interpreting solid models in Ansys in relation to allowable stesses of Sec. VIII Div. I, is the following methodology reasonable for primary stresses?
1. Excluding discontinuiies in the structure, locate the section that appears to have the highest stress by a Stress Intensity or von Mises...
Steve,
I think you could picture it as ring in the horizontal double welded with fillet welds to a vertical cylinder or vessel. There are four vertical point loads applied normal to the ring. They are usually 90 deg from each other and several inches away from the shell. It could be a...
I guess what you're saying is that even though we are talking about a sustained load on the ring, that the stresses in the shell are self-limited due to the ring's resistance to the bending moment/torsion? That does sound reasonable. Couldn't this computation in certain cases be conservative if...
It depends greatly on the Notified Body that you use, how they interpret PED. Our PED weld procedures (and WPQ) are compliant with ASME IX but also with much (not all) of EN 287/288. Reason is that I do not believe there is a "harmonzied" welding standard yet, although if you were good to EN...
Dar,
Yes, you will need PED weld procedures and with all of the paperwork and witnessing by AI's involved, it is a very expensive investment. (I've written many in the last year or so) We are a PED shop (ASME U Stamp, ISO 9001: 2000, Pressure Equipment Directive 97/23/EC: Module H) and can...
As someone mentioned in a different, similar post it probably wouldn't be a good practice to allow a welder to qualify on mild carbon steel (P-1) and then go weld 9% Cr material (P-5b), which is obviously a much more difficult material to work on.
