Last Updated on May 17, 2022
Welding Procedure Specifications (or WPS) are documents comprising all relevant information/ instructions a welder needs to start (and finish) their welding procedure. These documents contain everything from the materials that need to be used, the technique that needs to be used, the kind of weld required – basically, everything a welder (or team of welders) needs to know to get through with a certain project.
If you’ve ever come across a WPS, though, you probably know how scary and mean-looking those documents can appear. This is especially true if you have no welding experience or have never worked using a WPS before. However, despite their unappealing appearance, these documents are useful for welders. In fact, without this document guiding welders (even the most experienced ones), there is a good chance that they will make an error at some point or the other throughout the process that will require additional costs to amend.
Given that WPS is of such great importance in the ambit of welding, anyone who is related to this field in any way should be aware of what this document is, what purpose it serves, where it is needed, and how to write it. To save you the trouble of surfing all over the internet and navigating your way among the different recommendations you’ll find out there, we decided to assemble all the must-knows about WPS in this article. So, stick with us, and we’ll teach you the basics about WPS in this quick read.
What is The Difference between a PQR, WQR, and WPS?
Each time a WPS needs to be drafted, a PQR (or Procedure Qualification Record) must also be drafted. The only exception to this rule is when the application is already using prequalified techniques. Other than that, though, PQRs are considered to be just as important as WPS documents since it supports the welding procedure with tested findings.
The main outcomes of PQR testing include chemical and mechanical tests to see if the desired outcome will be achieved – This means that essentially everything listed in the WPS, i.e., the iterations of amps, voltages, and raw materials, are all tested to see if the procedure will move forward as expected. The results acquired from such testing form the basis for the parameters that are set for each variable in the WPS.
In short, a WPS outlines how best to produce a high-quality weld, whereas PQR will show the actual tests that show the results of going through with welds of those parameters.
One other that occasionally supplements a WPS is a WQR (or a welder qualification record). This document demonstrates whether a welder has passed the relevant tests and is competent to perform certain kinds of welds. This document is sometimes a necessary demand for certain welding codes, and it is usually a requirement for welding jobs that are sensitive to error.
How to write a WPS?
Drafting a WPS requires considerable analysis and research to verify that the information presented is appropriate for the application. To do this, there are multiple resources that can assist you. Consider these three suggestions while writing a WPS.
1) Determine what you want to get out of the welding job.
Determine what you want to get out of the welding job. To draught your WPS correctly, you need to have your objectives clear. Ask yourself questions like: Is it true that mechanical characteristics are the essential factor? Is low-temperature hardness, for example, a necessity? If this is the case, it may be preferable to specifically state the tradename of filler metal on the welding technique rather than merely the classification to guarantee that criteria are followed consistently. This practice of clearing out the objectives of welding inside your head will help you decide the correct course of action and hence will result in you drafting a more accurate WPS.
Manufacturer guidelines like data sheets that lay out the filler metal requirements should be followed. These may be used to generate excellent beginning parameters by indicating the parameters of an approved range. However, you shouldn’t just depend on datasheet ranges; a thorough WPS necessitates parameter testing in order to confirm that they are appropriate for the application and environment. Check the certificate of compliance for a filler metal, which will include the gas listing and other parameters utilized, as well as joint designs in addition to other considerations.
3) Lab Work
First and foremost, it’s essential to evaluate and assure satisfactory performance across the welding procedure across the range. If the performance is poor, reduce the range somewhat. Then, with the help of the floor crew, figure out the ideal mix of productivity and baseline welder skillset.
Weld cross-sections should also be examined to verify that proper fusion and satisfactory bead profiles are produced. Although an operator may weld at fast deposition rates, they may not be achieving adequate root fusion or an overall cross-section. With slight changes to welding settings, borderline root fusion might result in the absence of root fusion. Ascertain that the WPS has solid ranges and no margin for error.
4) Final Touches
Some additional considerations can go a long way in improving the quality of your WPS. Using a consistent format and flow is one such consideration. It will allow the reader to be able to understand the already complex WPS better.
Detailing past sequence requirements is another step that clears up any ambiguity. Welders may use this information to calculate proper trip speeds, placement of wires, and weave width. Wire location isn’t usually specified in a normal welding method specification form, although it might be crucial in certain automated applications. In these situations, recording wire location and oscillation parameters might save a lot of time if the robotic programming fails.
Sample WPS Template Recommendations
To put things more concretely, we decided to add a recommendation for a good WPS format. Use this structure as a guide to making your own WPS template. If you don’t want to do that, you could always get one from the internet.
A Good Structure of a WPS report would include the following information:
- Information about the contractor, the contract, and the date.
- Type of welding process
- Type of Weld
- Type of Joint (with details)
- Technique of welding
- Characteristics of Electricity
- Base Metal
- Filler Metal
- Type of Shielding
- Pre Heat parameters
- Welding parameters
Of course, if you end up making your own template, you can always switch a few things around here and there. However, we strongly advise that you don’t miss out on any of the aforementioned headings to ensure that you don’t leave anything important out of your WPS document.
WPS is a document that is used to maintain high-quality work throughout a welding operation. WPS works by identifying all the raw materials and instructions for the welders so that it is easier for them to do their job correctly.
To draft a good WPS, remember to:
- Determine the clear objectives of your work
- Do the due research
- Spend a lot of time lab testing everything
- And add some additional touches to help your WPS become more reader-friendly