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
|
Welding Process |
FCAW (Root Pass) |
FCAW (Following passes) |
|---|---|---|
|
Type |
Semi-Automatic |
Semi-Automatic |
|
Minimum preheat/interpass temperature (°F) |
320°F (See Note E) |
320°F (See Note E) |
|
Maximum Interpass Temperature (°F) |
500°F |
500°F |
|
Tungsten Size |
N/A |
N/A |
|
Tungsten Size |
N/A |
N/A |
|
Filler Metal Size (in) |
0.045 – 0.052 |
0.045 – 0.052 |
|
Layer Number |
Root |
2 -Cap |
|
Position of Groove |
(See Note G) |
(See Note G) |
|
Weld Progression |
N/A |
N/A |
|
Current/Polarity |
DCEP (See Note F) |
DCEP (See Note F) |
|
Amperes |
N/A |
N/A |
|
Volts |
24.5-30 |
24.5-30 |
|
Travel Speed (in./min) |
5 – 12 ipm |
8 – 20 ipm |
|
Maximum Heat Input (kj/in) |
N/A |
N/A |
|
DC Pulsing Current |
N/A |
N/A |
|
Shielding Gas Type |
Argon/CO2 – 75%/25% |
Argon/CO2 – 75%/25% |
|
Shielding Flow Rate |
30-60 CFH |
30-60 CFH |
|
Trailing Gas Type |
N/A |
N/A |
|
Trailing Flow Rate |
||
|
Backing Gas Type |
N/A |
N/A |
|
Backing Flow Rate (cfh) |
||
|
String or Weave |
String or (Weave ≤= ⅝”) |
String or (Weave ≤= ⅝”) |
|
Orifice/Gas Cup size |
⅜” – ¾” |
⅜” – ¾” |
|
Multi/Single Pass per Side |
Multiple (See Note C) |
Multiple (See Note C) |
|
Weld Deposit Chemistry |
||
|
Notes: Contact Tube to Work Distance – ½” to 1”. Single Electrode |
Note: From Compliance is Mandatory, John C. Stennis Space Center, Flux Cored Arc Welding of Carbon Steel for ⅛-inch to Unlimited Plate Thickness, National Aeronautics and Space Administration
The welding procedure portion of a WPS, Table 18.1, contains the settings you will use to perform the welding. Notice that the left most common lists the parameters such as preheat, filler metal size, volts, shielding gas, etc. The columns to the right are for the root and then the following passes including the cap pass.
Have you welded using the FCAW process before? If so, do the machine settings such as voltage and electrode size look familiar? If you haven’t welded FCAW before, do these look like machine settings you would need to know?
Page 2 Upper Portion of WPS including Base Metals
The upper portion of Page 2 of this WPS, Figure 18.4, contains additional information about Base Metals. This part of the form begins with the WPS Record Number. In this case it is NASA-A36-FCAW-AWS. The date of the form is repeated as is the revision number, B. This indicates xyz. The second line of this page includes which welding code, AWS D1.1, this WPS is made to. Finally, the company name of Syncom Space Services (S3) is listed.
Following the identification information, the Base Metals requirements are listed.
The first piece of information is about peening. Notice that peening is not allowed. Peening is a technique of hammering a surface to reduce residual stresses. Imagine if you were baking bread or making a pizza and you had a ball of dough on the table in front of you. If you punched it into the table you would squish the dough down and out to the sides. Your fist is circular like a ball peen hammer or other peening devices. Therefore, in a metal that is contracting while cooling will build up stresses, peening will counteract those forces pulling the weld apart by applying a force similar to punching the dough ball.
The line after peening is called surface preparation. This form reads, “joint prep – Flame cut and light grinding on surfaces to be welded.
On the next line, labeled Initial/Interpass Cleaning, additional information about preparing the surface and cleaning between weld passes is given. This form reads, “Grinding, Power Brush.”
The next line is for the back gounding method. Back gouging is used with code welds where welding is occurring from both sides of a weld joint. Back gouging removes metal from the side where the remaining welding is going to occur to ensure that the root of the follow on welds will penetrate into the weld metal of the original root pass of the welding from the other side. Back gouging is very important to do to ensure sound quality welds. If you are performing a code weld from both sides of the material in a joint, ask if back gouging is needed. It is much better to take a minute to ask a question than to have to grind out a days or weeks worth of welding because it was not done properly. This form indicates that no backgouging is required.
Following the Base Metals heading on the form, there is a heading for Postweld Heat Treatment. This section of the form includes temperature, time and temperature, and other. In the case of this WPS, all three lines are marked, “None.”
Page 2 Notes of WPS
The notes section of this WPS, Figure 18.5, contains general information to clarify what is contained in the WPS. This form includes the following notes:
- AWS D1.1, Table 3.1, Groups 1 and 2 (Refer to both backing and retainers.)
- Any Group 1 to any group 1; any Group 2 to any Group 1; any Group 2 to any Group 2.
- Maximum Pass Thickness: ≤ ½” (13mm)
- AWS No. A5.20, A5.29 or A5.36 (Class) E71T1
- Maintain 320 degrees F for 2 ½ hours. Continuous or special heating, where applicable, should be recorded. Immediately after final pass is completed, slow cool to ambient temperature.
- Power Supply; CV (Constant Voltage)
- Welded in flat position 1G or 1F (Fillet) weld only.
Page 2 Signature Block of WPS
This portion of the WPS, Figure 18.6 contains the signatures of those organizational members who have reviewed and are approving the WPS. This form includes the engineer’s name, the quality name, the customer reviewer name, and a blank space for the customer’s name. The engineer, quality control officer, and customer reviewer have all signed the form. Under each person’s name is a space for the date, which for this form is June 1, 2019.
Joint Designs of this WPS
The next page of this WPS has sketches of weld joints. This WPS is on Revision B, and this 3rd page is likely the original from Revision A. Revision B may have replaced the weld joint designs of Revision A on Page 3, with a new attachment. Figure 18.7 contains the obsolete joint designs which are still cool to look at, while Figure 18.8 contains new joint designs for this WPS.
The first two pages of this WPS are standard information. Joint designs and other information can be attached to a WPS to help the welder by providing information they need to weld in one document. WPSs are similar to blueprints in that they can look very different from company to company but they contain similar information in a format that is similar enough that you can generally Figure it out as you read more and more blueprints or WPSs.
Attributions
- Figure 18.1: Compliance is Mandatory John C. Stennis Space Center Flux Cored Arc Welding of Carbon Steel for ⅛-inch to Unlimited Plate Thickness by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
- Figure 18.2: Compliance is Mandatory John C. Stennis Space Center Flux Cored Arc Welding of Carbon Steel for ⅛-inch to Unlimited Plate Thickness by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
- Figure 18.3: Compliance is Mandatory John C. Stennis Space Center Flux Cored Arc Welding of Carbon Steel for ⅛-inch to Unlimited Plate Thickness by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
- Figure 18.4: Compliance is Mandatory John C. Stennis Space Center Flux Cored Arc Welding of Carbon Steel for ?-inch to Unlimited Plate Thickness by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
- Figure 18.5: Compliance is Mandatory John C. Stennis Space Center Flux Cored Arc Welding of Carbon Steel for ⅛-inch to Unlimited Plate Thickness by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
- Figure 18.6: WPS Signature Block by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
- Figure 18.7: Compliance is Mandatory John C. Stennis Space Center Flux Cored Arc Welding of Carbon Steel for ⅛-inch to Unlimited Plate Thickness by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
- Figure 18.8: Compliance is Mandatory John C. Stennis Space Center Flux Cored Arc Welding of Carbon Steel for ⅛-inch to Unlimited Plate Thickness by National Aeronautics and Space Administration, John C. Stennis Space Center in the Public Domain; United States government work
a person picked by company management with authority to speak and do things for the company