18.2 Parts of the WPS
David Colameco, M.Ed.
This section is going to break down the WPS into sections to make it easier to explain. There is no right or wrong way to break up a WPS for explaining it. Your instructor may choose to split the WPS into even smaller pieces or even just explain the whole thing in one long discussion. This NASA WPS NASA-A36-FCAW is for FCAW of Carbon Steel.
Upper Portion of WPS
The upper portion of a WPS, Figure 18.1, typically has the company or organization’s name and address to identify who the WPS belongs to. Additional information in row 2 at the top of the WPS has the WPS number, the date, and revision of the WPS. Row 3 contains the code that the WPS is qualified to, along with the subcontractor. The next row, Row 4, has the PQR which was used to write this WPS, and the document that serves as the reference for this WPS. The last line of this Figure shows the scope of the welding as FCAW for group 1 or 2 carbon steel in a Single V-Groove joint.
AWS groups like materials into groups for the purposes of making it easier to develop WPSs. When materials weld in a similar manner and are grouped together, you don’t necessarily have to develop a whole new PQR for every metal or alloy you are welding.
Base Materials and Thickness Range Qualified
These next parts of a WPS, seen in Figure 18.2, are filled out by a qualified representative who has experience and knowledge of the welding code being used. The base materials are part of group numbers 1 or 2. A36 is a common carbon steel that is used in welding schools across the country due to its widespread structural use and ease of welding. This WPS allows for A36, which is part of AWS group 1 to be welded to groups 1 and 2. It also allows other materials in group 1 to be welded to group 1 or 2 materials, and also for group 2 materials to be welded to group 1 or 2 materials. As you can see this WPS can allow for many steel alloys to be welded together.
The thickness range qualified is for all thicknesses greater or equal to ⅛” (designated by the decimal 0.125”, which means ⅛”). This also includes all fillet welds, and pipe diameters of greater than 24”. At a certain point a large diameter pipe is similar to welding on flat plates, which is why your school usually has you weld on plates in a pipe class before welding on actual pipes.
PWHT stands for Post Weld Heat Treatment. In this case PWHT is not applicable.
Upper Portion of WPS
This portion of the WPS, Figure 18.3, lists the filler metals that can be used with this WPS. In this case a Note, D, is used to further discuss the filler metal classification. The thickness is greater or equal to ⅛” thick material in the as-welded condition. This means that the end product is welded and then no post processing such as a post weld heat treatment is used. It can be cleaned and painted or other process that does not alter the mechanical properties of the material.
Welding Procedure Portion of a WPS
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Welding Process |
FCAW (Root Pas