The Effect of Heat Treatment Parameters on the Mechanical and Microstructural Properties of an ASTM A860 WPHY 65 Pipe Fitting: An Experimental Investigation

This study focused on investigating the influence of quenching and tempering temperatures on the mechanical properties and microstructure of ASTM A860 Gr-WPHY 65 hot-formed 30-inch elbow steel, commonly utilized in high-strength low-alloy (HSLA) pipelines for oil and gas applications. Experimental methods were employed, involving variations in soaking temperatures at 960, 1000, and 1050 °C, followed by water quenching at 20 °C and subsequent tempering at 670 and 700 °C. Through an experimental design approach, the optimal heat treatment conditions were determined. Results indicated that the most favorable treatment parameters for achieving higher mechanical strength were soaking at 1050 °C and tempering at 700 °C. Microstructural analysis unveiled that the heat treatment procedure yielded finer grain sizes and successfully restored the microscopic structure, characterized by acicular ferrite, of the base material.