Microstructure and mechanical properties of Gas tungsten arc welded High Strength Low Alloy (15CDV6) steel joints

15CDV6 is a high strength low alloy (HSLA) steel being extensively used in aerospace applications, particularly in manufacturing of solid rocket booster motor cases because of its excellent strength to weight ratio and good weldability. The present investigation was carried out by Gas Tungsten Arc Welding (GTAW) process using L9 orthogonal array. The welding trials were conducted with different welding parameters such as current, voltage, welding speed and gas flow rate. The dimensions of the plates used in this work are 150x300x3.7mm. The 8CD12 filler wire of diameter 2.6 mm was used by GTAW process with DCEN polarity. The weld coupons were heat treated for hardening at 975 degrees C followed by air quenching and tempering at 650 degrees C. Bead geometry (Reinforcement, bead width) and hardness were measured as performance characteristics. Technique for Order Preference by Similarity to Ideal Solution Method (TOPSIS) was used for the optimization of multi performance characteristics. ANOVA was used to predict the influence of welding parameters on the multi performance characteristics. The metallurgical characterization of optimized weld is discussed briefly. (c) 2017 Elsevier Ltd. All rights reserved.