By Spencer O. Luke Feature Reviewing Welding Procedures Here’s a look at some of the mistakes commonly found in Welding Procedure Specifications and how to avoid them A competent review of welding procedures is an essential safeguard that can help ensure production welding (e.g., by the fabricator, contractor, subsuppliers, and erector) is in compliance with the requirements of the construction code and any additional requirements imposed by a contract specification and applicable industry standards. Imagine the consequences if any of the following occurred: • Grade 91 (9Cr-1Mo-V) piping for critical steam service was welded with B3 consumables (2¼Cr-1Mo). • Austenitic stainless steels for corrosive service were welded using plain carbon steel welding consumables. • Piping or vessels for cryogenic service were welded with a welding procedure qualified without the required Charpy impact tests. • Gas tungsten arc welding occurred using an argon/oxygen shielding gas mixture. • ASME code work took place using AWS D1.1 welding procedures. These are just a few examples of glaring errors found during welding procedure reviews. The list of errors (and omissions) goes on and on — from minor, inconsequential errors and typographical errors to major critical errors. Just because a Welding Procedure Specification (WPS) or Procedure Qualification Record (PQR) has been “certified” by the manufacturer or contractor as being in conformance 26 Inspection Trends / July 2013 with code requirements, does not mean that is actually the case. In some instances, nothing could be further from the truth. Common Mistakes Experience after many years and reviews of thousands of welding procedures has shown there are a few common mistakes of which both writers and reviewers should be made aware. A large percentage of errors is due to the writer failing to do the following: • Proofread the document • Do a variable-by-variable code check • Fail to ask him- or herself if the procedure makes good welding common sense. Most errors seem to be due to a lack of attention to detail, so here’s a quick checklist that will help eliminate a lot of errors. • Check the code. • Check the contract. • Check for special service requirements. • Proofread. As with writing any formal document, it’s advisable to draft the procedure, walk away from it for a day or two or even longer when possible, and then come back to it again and review it for technical content and accuracy. Whenever possible, ask another competent individual to review the document. Also consider asking an experienced welder to look at the procedure. A review by independent organizations or third-party insurers who have welding experts generally helps to ensure the documents are properly qualified, written, and certified. Using Software to Write Procedures Writing procedures using available welding procedure software programs does help ensure that all the required variables are properly addressed; however, the writer may still need to address any special items such as mandatory preheat or postweld heat treatment (PWHT) requirements, and special contract requirements. The person qualifying the procedure still needs to do so using appropriate filler metals and be knowledgeable enough to specify appropriate welding parameters. Before overriding any item within the software program, the user must know whether or not it will violate any code requirement. It’s not uncommon to find an electronically produced WPS or PQR (such as created in MS Word or Excel) that was apparently created by modifying another electronic WPS or PQR. The writer duplicated the existing WPS or PQR in order to modify it and generate a new WPS or PQR; however, the person failed to update all the necessary fields. One of the most common errors of this type is where the filler metal on the new WPS
Inspection Trends | Summer 2013
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