Dear All
A conical section with half apex angle of 15 degrees is going to be joined to a cylinder of different thickness. The difference in thickness is 20 mm. Is there any requirements for a tapered transition as per UW-9 or UW-13 for this joint? In tapered transition requirement is there any...
Dear All
I am running an elastic-plastic analysis of an equipment as per ASME BPVC VIII-2 Ed. 2021. I have some questions hope you could help me.
1- I am using Ansys workbench. As I understand in material properties for FEA true plastic strain vs true stress shall be the input data. Based on...
Dear all
Please help me understand this issue regarding forming of heads fabricated from more than one piece.
ASME BPVC VIII-1 UG-79, regarding weld thickness reduction due to forming, reads:
Does this mean that for head fabrication, if the head is fabricated by forming a blank which has a...
Dear all
I am reviewing an elastic stress analysis of legs to shell junction for protection against plastic collapse. The vendor wants to show that the stress results for the analysis are free from mesh size. First he has reduced the mesh size from 100 mm to 50 mm and the maximum stress has...
Dear all
How would you categorize stresses in an elbow due to internal pressure?
Is it ok if I take membrane stresses as primary and bending stresses as secondary?
I am talking about a ninety degree elbow with stresses considered at the 45 degrees section. The elbow is attached at both sides...
Dear All
I was reading API 934 C for a new project in our company and I have some doubts with which you might help me.
API 934 C Ed.2008: 7.3.1 All base metals shall be heated to a minimum of 300 °F (150 °C) during all welding, rolling, forming, pressing operations, thermal cutting, and gouging...
Dear All
I want to know what is the difference between class 1 and class 2 in SA-387. As per the specification, there is no difference in chemical composition of these two classes. However, there is difference between the two classes in terms of their mechanical strength.
In table3 of the...
Dear All,
If I am the manufacturer of a pressure vessel and I want to outsource fabrication of heads (which have seam welds) to another vendor, can I give them my own WPS & PQR and they follow it or should they prepare their own?
Where in the code can I find the answer to this question?
Warm...
Dear All,
Which one of the following weld details is preferred for nozzles with and without reinforcement.
I want to know about fabrication and mechanical design aspects of choosing between one of these.
Warm Regards
Dear All
In the engineering spec of a project it is mentioned that for hydrogen service equipment, the plates shall be normalized and as-rolled normalizing is not acceptable.
Can you please help me understand the difference between the two and why normalized is the preferred for hydrogen service.
Dear All,
Our factory cannot fabricate an elliptical head with especial dimensions and we have outsource it.
They have sent us a contract in which they have included all prices and one of them is PWHT of the head after forming.
The whole vessel is going to be PWHT'ed so I thought this PWHT of...
Dear All
I want to know what welds are to be included in welding maps. Is it true that all pressure parts welds shall be included and others are not necessary?
For the following welds can we say none of them are required to be included in the welding map:
1-Wear plates to shell in a horizontal...
Dear All
Please help me understand something regarding SPWHT of SA-516 70.
In the engineering spec. of the project it is mentioned that where PWHT is required the mill certificate is required for three cycles of PWHT. Does this mean that I have to sent test coupons to a laboratory and ask them...
Dear all
I wonder if I have fully understood the taper design as per ASME BPVC VIII.
in VIII-1 it says the length of the taper shall not be less than 3 times the thickness offset.
then it says the length of the taper may include the width of the weld.
I wonder if the weld taper detail in the...
Dear All
I have heard contradictory comment on the future of Division 1 of ASME BPVC Sec. VIII.
Is it the intent of the code to put the VIII-1 aside and use VIII-2 instead?
If it is a possibility will it replace the VIII-1 in its entirety or just selected parts will undergo changes?
Regards
Dear All,
I want to know about the taper detail as shown in Fig. UW-13.1 j & k. My question is for a hemispherical head is it necessary that the tangent line crosses the center of the hemisphere?
It seems from the figure that the taper starts exactly from the tangent line. Can I start the bevel...
Dear All,
I am a mechanical engineer and have problem understanding something related to metallurgy so please help me.
Is there a mechanism based on which a carbon steel becomes harder and harder as time goes by?
I mean suppose that I have a steel with yield stress 250 MPa and I put it aside in...
Dear all
A supplier of carbon steel plates says that the product conforms to both SA-516 60 & SA-516 70. Am I allowed to consider the allowable stress to be that of SA-516 70 and for UCS-66 consider the exemption curve to be that of SA-516 60 in the design of the same equipment as per VIII-1...
Dear All,
(For vessels fabricated as per ASME BPVC VIII-1)I have seen many datasheets indicating joint efficiency for a cylindrical shell to be 0.85 corresponding to spot radiography. What is the reason for that? I mean is radiography so expensive that increasing shell thickness is a preferred...
TGS4, Please help me.
I want to know how to take thermal cycles into account when doing a fatigue exemption screening. My question is how can I understand the temperature distribution throughout the vessel. Is it my responsibility to somehow calculate the temperature distribution all over the...
