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Welding-procedures:what to do and how.SOLUTIONS with Effective, Powerful Advice
Welding Procedures, work instructions, welding techniques, code welding, recommended practice, specifications, certifications, welding information, welding links, welding tips, joining questions needing answers: these are some of the items developed in this Site page for the benefit of interested readers. What is in here for me? In a previous page on WELDING INFORMATION, we presented the elements that a drawing should include to specify the technical requirements that guarantee the stability and functionality of the welded assembly. Here we are going to enter into some more detail to show how Welding-procedures are used to translate the information into physical objects. How is welding information transmitted to the shop in a Big organization? How one can make sure that the same successful welding method is applied time after time?
Tip!:Anyone who may fear that using Welding-procedures will make the welder a robot without will and knowledge should be reassured that this is never the case because the welder needs all his/her skill and know-how to perform successful welding time and again. How is Welding Information transmitted? The accepted way to transmit specific working INFORMATION on a given job is to use Welding-procedures. It is sometimes a code requirement. A Welding-procedure is a detailed instruction sheet which specifies in words and pictures the whole welding process for a certain production item. Good Welding-procedures are clear, understandable and complete, and do not leave space for undefined important matters to be decided by the worker to the best of his/her understanding. What are Welding-procedures? Generally, for a well organized industrial operation, Welding-procedures are manufacturing documents bearing signatures of those responsible for their preparation, check and approval, showing an issue date, a revision letter (or number) and revision date, with a documented history of introduced changes. But also smaller weld shops would profit from developing simple forms detailing as thoroughly as possible means and ways for performing welding operations. Welding-procedures are held as binding documents in a central library, much as engineering drawings. Procedures prescribe the exact steps in sequence necessary to perform successfully the job. Drawings or pictures detail the joint preparation, that is the geometric appearance of the edges to be welded, their dimensions, tolerances and surface finish and how they are to be machined. The exact call for a specific type of equipment in a simple formal document should be made clear enough, using standard terms, for everyone involved to understand. Also the way parameters are spelled out (i.e.: size of electrodes, type and current level etc.) and how auxiliary equipment is indicated, should be specified so that no mistakes occur. Commercial or institutional organizations are available, capable of undertaking, for a fee, the task of developing and of demonstrating by examination and testing the adequacy of procedures to weld difficult jobs and provide acceptable welded items. What should they include...? Welding-procedures include standard designation and condition of materials and of filler metals, thickness and form of joints, cleaning procedures, welding jigs and fixtures, tack welds, welding position, accessories like positioners or special holders, welding process, specific welding equipment or type, welding consumables, welding parameters, welding sequence, number of passes and their sequence, possible interpass cleaning and grinding stages, all these and more items of information are clearly prescribed. Welding-procedures are as simple or as complex as the welding process itself. In particular special precautions are spelled out: required additional operations like pre-heating, slow cooling if needed (by what means) or stress relieving after welding (the maximum time interval from end of welding may be prescribed) are detailed with complete description of means and parameters to be used. An Article on Stress Relieving after Welding was published in the April 2004 issue of Practical Welding Letter. To read the Article click on PWL#008. To receive regularly the Letter as it is published please Subscribe. An outstanding facility, Computer Engineering, Inc. provides software for ASME and AWS welding procedures, welder management, and welder qualifications. Visit the website where you can download and evaluate all of their software. A welding procedure is qualified to a given standard when destructive test results of a test piece demonstrate compliance of results with the standard requirements. The importance of establishing, keeping and following exact Welding-procedures is not only to meet code requirements and ensure repeatability of results, but also to provide a way to investigate possible mishaps and to improve the process if necessary by small and reckoned changes and by strictly monitoring the results. A coordinated activity originated by a common initiative of the Welding Research Council (WRC) and the American Welding Society (AWS) has resulted in the publication of a number of prequalified welding procedures, that can be adopted by industry: AWS published:
Some useful links are listed in the following: click on the underlined names: AWS - The American Welding Society And what are...? WELDING TECHNIQUES involve details of a welding operation which are controlled by the welder or welding operator within the limitations imposed by Welding-procedures. Optionally Welding-procedures may include specific welding techniques. Acceptable different welding techniques include the advancement direction of welding which may influence heat input and speed of welding: for simple joining operations the selection of the technique is left to the welder according to his/her preference and experience. Also the best angles of torch or electrode from the work surfaces and the way of feeding filler metal are details included in the technique, which the welder learn during training and become part of his/her experience to control successfully the outcome of welding operations. A number of Organizations, most notably AWS (American Welding Society), publish RECOMMENDED PRACTICES which address practical aspects of welding processes and are most useful to learn how to improve welding results.
Among them:
An Article on Welding Procedure Specifications was published (2) in the Issue 32 of Practical Welding Letter for April 2006. To read it click on PWL#032. An Article on Procedure Qualification Record was published (2) in the Issue 33 of Practical Welding Letter for May 2006. To read it click on PWL#033. Tip!: The best welding procedure cannot help a sloppy or inadequate welder to produce successful work, so that there will always be a request and a need for competent and excellent welders.
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Hardness is important, it should always be known before welding a metallic item, because it can affect the Welding-procedures. To reach a Guide to the collection of the most important Articles from Past Issues of Practical Welding Letter, click on Welding Topics.
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Welding-procedures, the correct means to convey welding information to the welder, to obtain consistent acceptable results. All clearly exposed... -
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