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Welding Procedures There are many factors
involved in the preparation of any welded joint. The detailed methods and practices used
to prepare a particular weldment are called the welding procedure. A welding
procedure identifies all the welding variables pertinent to a particular job or project.
Generally, these variables include the welding process, type of base metal, joint design,
welding position, type of shielding, preheating and postheating requirements, welding
machine setting, and testing requirements. Welding procedures are used
to produce welds that will meet the requirements of commonly used codes. The American
Welding Society (AWS) produces the Structural Welding Code that is used for the
design and construction of steel structures. Another code that is used for the
construction of steam boilers and pressure vessels is published by the American Society of
Mechanical Engineers (ASME). These codes provide a standardized guide of proven welding
practices and procedures. While you are not directly responsible for developing welding procedures, you could be assigned to a welding job that requires you to follow them. For example, when a job is assigned, it is accompanied by a set of drawings and specifications. When there is welding required for the job, the specifications normally require it to be accomplished according to a specific code requirement. For instance, if your unit is tasked to fabricate a welded steel structure, the specifications may require that all welding be accomplished according to AWS D1.1 (Structural Welding Code). The unit is then responsible for ensuring that the welders assigned to the job are qualified to produce the welds according to this welding procedure specification. Using the Structural
Welding Code, along with the project drawings and specifications, the welding
inspector develops a welding procedure specification that meets the requirements of the
job. The importance of this document is that it assures that each of the variables can be
repeated by qualified welders. Once a welding procedure
specification has been developed and qualified, welders are then required to perform a
Welding Performance Qualification test. After the test is complete, the weld specimens are
tested according to the requirements of the Welding Procedure Specification. You may use
either destructive or nonde-structive tests. One example of a destructive test is the guided-bend
test. An X-ray test is considered nonde-structive. Testing is discussed in greater
detail later in this course. NOTE
Look carefully at the notes
on the drawings and Section 5 (metals) of the specifications. If specific codes are cited,
inform the project supervisor so that you can receive the training needed to perform the
required welds.
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by SweetHaven Publishing Services Based upon a text provided by the U.S. Navy |
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