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COMMON ALUMINUM PROBLEMS - QUESTIONS AND ANSWERS
QUESTION: I have a welding shop that manufactures small to medium-sized welded structures. I have been acquiring some larger contracts lately in both steel and aluminum structures. Some of my larger steel customers have requested that we have welding procedures and qualified welders for some of the structural steel work. We have used AWS D1.1 Structural Welding Code – Steel, to qualify our procedures and welders for steel.
I am currently trying to increase the amount of aluminum fabrication business and think that I should consider the possibility of producing welding procedures and qualifying my welders for aluminum. Is there a welding code like AWS D1.1 that can be used for aluminum? If so can I transfer my D1.1 procedures and performance qualifications from steel to aluminum?
ANSWER: First, before I answer your questions, I would like to say that I think you are extremely sensible to have considered welding procedures and welder performance qualifications for the various types of welding work in which you are engaged. In general terms, working with a welding code or standard designed for any material, in my opinion, has merit.
I have to believe that the use of welding codes and standards are an opportunity for the welding fabricator to control quality and improve the reliability of their product. If we consider the move by more manufacturing organizations toward the implementation of quality management systems, such as ISO 9000, and the requirement of such systems for process control, we must consider welding as a special process and, consequently, its formal control.
Welding codes and standards can be used by the welding fabricator to assist with the development of their process control system. If we examine the major elements of process control, as specified by such standards for quality systems, we will recognize those same elements as being addressed within most welding codes or standards. The first requirement for process control is to have documented procedures defining the manner of production. For welding, this is the welding procedure specification (WPS). The second requirement is criteria for workmanship, which shall be stipulated in the clearest practical manner. For welding, this may be the code or standard quality acceptance criteria. The third requirement is qualification of personnel. For welding, this is addressed by the code or standard welder performance qualification test.
In adopting a welding code or standard, we can acquire these three main elements of a welding control system, along with the reassurance that our fabricated product has been manufactured in accordance with a nationally recognized standard, which is invaluable if we should ever have to defend the integrity of our welded product.
From a much more specific standpoint, and in direct answer to your questions, yes, there is a welding code like AWS D1.1 that can be used for welding aluminum, and no, you cannot transfer your procedures and performance qualifications from steel to aluminum.
The welding code for aluminum is AWS D1.2 Structural Welding Code – Aluminum, and in many ways this code is similar to the AWS D1.1 document. However, the similarity of D1.2 to D1.1 is only in format, which has been chosen to match D1.1 for its simplicity of use, particularly for personnel who employ both of these codes in practice. Because of the totally different characteristics of steel and aluminum relating to their metallurgical structure and related reactions during welding, method of welding, design criteria, and inspection and testing requirements, these two codes are completely independent. If you desire to qualify welding procedures and welders for aluminum welding, you will have to start from scratch, so to speak, and perform this qualification totally independent of your current steel qualifications.
The AWS D1.2 Structural Welding Code – Aluminum is an excellent document to use for welding procedure and welder performance qualification for aluminum structural welding.