Welding is more than fusing two components together. Welding is a trade, and its successful application relies upon the skill and training of the welder or weld operator. An experienced welder will have the practical experience that will often allow them to accomplish a suitable weld where other less experienced individuals might have difficulties. Welding engineers are experienced in the development and application of power supplies and welding processes.
IEC's staff is familiar with the requirements of a wide range of fabrication codes, and with the strengths and weaknesses associated with the various joining processes used in the oil and gas and electric utility industries. IEC's staff have been responsible for the design and application of welding procedures for large utility projects and for the review of vendor procedures for power boilers, structural steel, pressure vessels and piping systems. Often, understanding the impact of welding in a given application also requires an in-depth understanding of the relationship between the microstructural development resulting from the welding application and the impact of this microstructure on the properties of the weldment.
All materials, including welds, will contain imperfections; however, not all imperfections are defects, nor is their presence in a failed weld always the cause of failure. Too often failure analysts identify the presence of a weld imperfection and claim it was the failure without undertaking the supporting analysis to demonstrate the impact of the imperfection on fracture and resulting failure.
As stated in the ASME Companion Guide to the ASME Boiler and Pressure Vessel Code, Chapter 4, “Often, quality assurance personnel, company inspectors, and regulators would interpret the ASME Code incorrectly, and then force knowledgeable personnel to make changes that unnecessarily increased costs, and in some cases reduced the structural safety of the item. For example, they could reject welds that were acceptable [under the Code acceptance criteria], thus requiring weld repairs that increased residual stresses in the component.”
IEC's staff understands the microstructural evolution of the weld and how it can impact the performance of the weldment. We will advise you when a weld imperfection is a true or potential defect and similarly note when correction of an imperfection would be unnecessary, thus preventing a costly repair which may itself reduce the structural safety of the item.