Fig. 3 — Typical of the stresses on the weld encountered during installation. cases, welders and helpers work as a team so if the welder moves to another job, so does the helper. The volatility of the welding labor force can cause problems with respect to the expected production schedule. In addition to labor availability, the quality and consistency of the welds being produced can often be less than satisfactory. Of course, this is directly related to the individual welders, but it is still a factor that is hard for the contractor to control. Observing Other Possibilities Prather recognized the problems associated with the standard solution for welding short run pipelines and wondered if there was another way to build them. From pipelines on the North Slope to having spent years in the pipe and fabrication arena, he had the opportunity to visit many job sites and fabrication shops and see many different potential solutions to the joining of pipes and tanks. One important observation continued to come to mind as he considered a different way to approach this next project. In nearly all of the fabrication shops he had visited, he recognized he had very rarely seen a weld being made with a covered electrode. The standard practice in these shops was that nearly all welds were made using either gas tungsten arc welding (GTAW) or a wire-fed process such as submerged arc welding (SAW) or gas metal arc welding (GMAW) or gas-shielded flux cored welding (FCAW-G). In many cases the root pass was made with GTAW and the fill and cap passes were made with one of the wire-fed processes. This was particularly true if the pipe or tank could be rolled as the weld was made. But even if the part remained in a stationary position, the fill and cap passes were rarely performed with shielded metal arc. The GTAW process, while producing a very high-quality weld, was just too slow to work on a pipeline. How could one of these wirefed processes be used on the pipe projects in the field? Finding a Process that Fit the Application The question was asked, “If these wire-fed processes were working successfully in the shop, why was no one using them in the field?” Change is hard and comes very slowly, particularly in the welding industry. The pipeline welding segment is certainly not unique in its resistance to change. In some cases, that resistance could be warranted. The pipeline industry faces uncertain terrain and daily concerns presented by the weather. Those challenges did exist, but they did not appear to be unsurmountable. The welding of the root pass is well accepted as the most critical portion of a pipe weld. While there are other methods, it was understood and accepted that it would still be necessary to make that root pass in the traditional manner with SMAW. To go to another process would require a considerable amount of training and development, and probably a long time to realize. The fill and cap passes appeared to present an opportunity to try another approach, but there were limitations. One does not just take a GMAW welding machine to the field and have success. First, there needed to be some sort of enclosure as these processes required protection from wind and other environmental concerns. This problem was readily solved because contractors already used welding shelters mounted to side-boom pipe layers. These shelters were most often used in harsh environments of extreme cold or wind, but they could easily be used in any kind of weather. 46 WELDING JOURNAL / NOVEMBER 2016
Welding Journal | November 2016
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