NAES Power Contractors
NAES is in the business of performing scheduled maintenance on power plant boilers, as well as emergency repairs during unplanned boiler outages. This job requires adhering to very strict timelines and stringent quality standards. Failing to meet targets set by the clients will costs NAES money, hence NAES always aims to get the job done right the first time and as efficiently as possible.
In order to meet the ever-demanding schedule of boiler outage projects, NAES is always searching for ways to improve productivity without compromising on safety and weld quality.
Identifying Non-Value-Added Activities in a Jobsite
During a boiler outage, NAES welders usually have to climb into the boiler through a small hole. Once inside, the welder will climb through additional crawl spaces or up scaffolding to reach the pipes to be repaired. A typical project can involve replacing 50 to 150 boiler water wall panels.
NAES welds a lot of SA213 T11, which is 1-1/4-inch chrome boiler tube. The root pass is usually TIG welded, and the remaining passes are stick welded. Welders have to work in difficult positions and tight spaces, sometimes even lying on their backs to complete an overhead weld. Despite these challenges, the weld is still expected to meet high-quality standards and are often subject to post-weld tests.
There may be 100 welders working inside the boiler at any given point in time, but their welding power sources are typically placed outside of the boiler. After a welder completes a TIG root pass, he needs to trace the welding cable, find his machine, and then switch the cables to change the welding polarity so he can weld the stick passes. This change can take place multiple times per day per welder. Given that there are so many welders working in a confined space, the welding cables are usually tangled up like a ball of spaghetti and the welders have a very difficult time determining which cable and machine are theirs. Tracing cables and finding the right power source to make the necessary changes can take a welder anywhere from half an hour to an hour in the jobsite.
This whole process not only reduces the productivity of welders, but also significantly increases slip, trip and fall hazards for welders climbing in and out of the boiler. In addition, a welder may also accidentally make changes to the wrong machine, resulting in frustration and potential weld defects.
Switch Welding Process with the Push of a Button
NAES eliminated these non-value-added activities with the XMT 350 FieldPro (Polarity Reversing) welding system from Miller Electric. This system allows welders to stay at the weld joint and make changes to the welding process, parameters and polarity with the push of a button on the Stick/TIG remote.
Before implementing this welding system, NAES welders would typically complete 4 to 5 welds per shift. With the XMT 350 FieldPro (Polarity Reversing) welding system, welders were now able to complete 10 to 14 welds per shift. Welders were also very satisfied with the solution because it made their lives a lot easier and also helped them save time by eliminating all the unnecessary walking. In addition, the system also prevented welders from accidentally adjusting parameters on the wrong machine.
Welders also felt a lot safer at the jobsite because they no longer needed to leave the boiler to make the changes to the polarity and parameters. This significantly reduced the risks of slips, trips and falls.
Improved Arc Performance
In addition to improving jobsite safety and productivity, XMT 350 FieldPro (Polarity Reversing) welding system also offers optimized TIG and stick welding processes that have been specifically designed for open root pipe welding. For the root pass, the TIG process has a precise arc start that maintains the pipe’s root opening and prepared edge. For the subsequent passes, the stick process allows for easy arc starts and stops. This reduces the chances of porosity and minimizes stub loss.
Technology that Saves Time and Improves Safety
The power industry is very competitive. Saving one manhour per shift for every welding team in the jobsite is a tremendous amount of savings because you may have 30 to 40 welding teams working in the field at any given time. If you were to include the safety benefits related to minimizing the risks of slips, trips and falls, the XMT 350 FieldPro (Polarity Reversing) system will deliver a competitive edge to power plant contractors such as NAES.