Experimental investigation on the effect of heat treatment parameters on the mechanical and microstructural properties of an ASTM A860 WPHY 65 pipe fitting

Abstract

In order to optimize the heat treatment process following hot induction forming, our study focused on investigating the impact of quenching and tempering temperature on the mechanical properties and microstructure of ASTM A860 Gr WPHY 65 hot formed 30-inch elbow steel, which is utilized in high strength low alloy (HSLA) pipelines for oil and gas applications. The desired properties for these steels include high mechanical strength, toughness, ductility, and weldability. Our experimental approach involved varying the soaking temperatures at 960 °C, 1000 °C, and 1050 °C, and subsequently cooling the samples in water at 20 °C, followed by tempering at 670 °C and 700 °C. Through the use of experimental design techniques, we determined the optimal heat treatment parameters. The results indicate that soaking at 1050 °C and tempering at 700 °C were the most effective treatment conditions in terms of mechanical strength. Furthermore, microstructural analysis revealed that heat treatment not only restored the microscopic structure of the base material, but also resulted in finer grain sizes.

Keywords

• HSLA
• Hot forming
• Microstructure
• Heat treatment