This article will deal with step by step guide for preparation of Weld Map, Shop Weld Plan, WPS, PQR & WPQ as per ASME SEC IX for a Static Pressure Vessel designed in accordance with ASME SEC VIII DIV I for non-lethal Service.
The Reader must be wondering from where this requirement of Weld Map and Weld Plan arises which is very common thinking when one (Welding Engineer) is making them for the first time as many a times it is mandatory as per customer/client specification and also if a company is ISO 9001 certified along with U stamp designator holder as per ASME SEC VIII DIV I so to enable inspector and customer of knowing what was approved, what was followed and as built information communication both Weld Map and Shop Weld Plan are required.
Weld Map: A document which include but not limited to a Sketch of the equipment locating all the welds along with a table with all the details (Material, thickness, welding process, WPS, PQR etc…) required for getting customer/client/TPI approval.
Shop Weld Plan: A document prepared on the basis of weld map & drawings approved by customer which mentions specific seam no with WPS parameters, WPQ etc., which is issued to shop for the fabrication activities.
WPS: It stands for welding procedure specification which is a document directing welding personnel (supervisors, welders, operators) for details like the Type of Joints, Base metals, Filler metals, Position, Preheat, PWHT, Gas(es), Electrical characteristics and Technique to be used for joining of metals. The WPS will include all the variables like Essential, Supplementary Essential and Non-Essential Variables (To learn more about WPS, Please click here).
PQR: It stands for procedure qualification record and it documents all the essential variables and additional details recorded during its qualification, the testing’s (Nondestructive and destructive) carried out and signed by Welding Engineer and in most of the cases reviewed/witnessed by TPI (Third party inspector) depending on the customer/client requirements. The Non Destructive testing (NDT) may include: Visual, LPT, MPI, RT, UT etc. and the destructive tests (DT) may include: Fracture (Room temp Tensile, Bend, Impact), Fatigue (CTOD etc..), Corrosion (HIC, SSC, IGC etc.…), Creep (Hot Tensile, S-N Diagram), Embrittlement (Temper Embrittlement – Step Cooling etc…).
We shall now discuss the step by step procedure for creation and approval of the Weld Map;
The sketch of a Static Pressure Vessel, designed as per ASME SEC VIII DIV-I is as below;
Note: Every effort was being made so that our pressure vessel (PV) design seems compliant to ASME SEC VIII DIV I, however author accepts no responsibility whatsoever in this regard.
Bill of Materials is as mentioned below:
Note: The author has not considered the base ring below the skirt and the RF Pad for man way, earthing lug of ASS, Lifting Lug and any other internal or external attachment for making it easier for the reader to understand.
From above, the author will utilize GTAW & SMAW process (as per ASME SEC IX) for procedure and performance qualification and considering the minimum design metal temperature (MDMT) of the Vessel to be 0 °C there is no impact requirements applicable (Refer UCS -66) and also the governing thickness (Refer UW-40 for details) is less than 38 mm there is no need to carry out post weld heat treatment (PWHT).
The material combination utilized, will be SA 516 Gr 70 and SA 516 Gr 60 as a smart welding engineer will be able to utilize it for welding of P1 G2 and P1 G1 (Note: P1, G1 & G2 are parent metal grouping, to learn more about metal grouping, please click here) when there is impact test requirement.
After having the above information, proposed Weld Map and WPS are made, considering this is the first Job to be executed by Company Name: Welding and NDT for approval of customer/client/TPI a sample of both are attached below:
Proposed WPS No : GS-001 (Click here to download the proposed WPS)
Proposed WPS No : S-001 (Click here to download the proposed WPS)
Proposed WPS No : G-001 (Click here to download the proposed WPS)
Considering above situation the Welding Engineer needs to plan the welder qualification (WPQ) too, as the above WPS after qualification will be utilized for Welder qualification.
Proposed Welder List for Qualification
- Proposed WPQ for GTAW welder: Please click here to download
- Proposed WPQ for SMAW Welder: Please click here to download
Shop Weld plan will be prepared once WPS and WPQ gets qualified and may or may not require customer/Client approval but may require inspector approval.
(Note: Purpose of this article is to give a general guideline to the readers and it shall not be considered as a substitute of code. For full terms and conditions please read ASME Section VIII DIV I 2017 & ASME SEC IX 2017 edition).
This article is written and published by;
MR. SANDEEP SINGH PARMAR
(Ex. GE, ISGEC & ESSAR)
IWE (IN/IWE/41700026); B Tech (Mechanical); AMIIW (Welding Technology)
ISO 9001:2008 Internal Auditor; ISO 9001:2015 Lead Auditor ;
NDE L-II (UT, LPT, MPI, RT); Lean Six Sigma Green Belt;
MWeldl IEng; MIE C Eng(Ind) ; M.I.Inst.W ; LM IIM