Addressing Welding of Grade 91 (9Cr-1Mo-V) Chromium-Molybdenum Steel’s Challenges

On Tuesday, April 25, Mr. Charles W. “Pat” Patrick will explain how the gas tungsten-arc welding (GTAW) process can produce welds of high quality; however, manual welding is extremely expensive and labor-intensive, requiring skilled welders with extreme hand-to-eye coordination and dexterity. TIP TIG has changed how P91 can be welded for either shop or field fabrication by introducing a semiautomatic GTAW hot wire welding system. TIP TIG’s system is cost-effective and can be used for the entire weld from root to cap while producing high quality welds that the industry expects from the GTAW process. Charles will also talk about power piping systems using Grade 91 materials and will explain the reason for low impact values of weld metal produced by some semiautomatic hot wire processes. He will explain how the dynamics of the weld pool during deposition and the heat flow during solidification play an important role in the resulting mechanical properties of the weld metal.


Charles will also talk about the results of a study that shows that the TIP TIG semiautomatic GTAW hot wire welding system is capable of producing impact values comparable to or exceeding manual GTAW and that the process provides an attractive alternative for welding P91 root and hot passes or the entire weld from root to cap.

Charles is a Director of Technical Services, ALS Maverick Testing Laboratories, Inc. His technical expertise spans 54 years of welding, engineering and consulting on major projects, both domestically and internationally.