MECHANICAL CHARACTERISTICS AND CHEMICAL PROPERTIES OF ASTM A516 GRADE 70 CARBON STEEL

Abstract

Carbon steel, mainly composed of iron (Fe) and carbon (C), accounts for approximately 90% of global steel production. ASTM International (ASTM) A516 Grade 70 is a common type used in pressure vessels, boilers, and processing equipment where improved notch toughness is required. It also offers a good balance of strength and weldability, making it ideal for low- to moderate-temperature applications. Despite its widespread use in the oil and gas industry, limited data have resulted in limited understanding of its properties. Thus, this study examines the mechanical and chemical properties of ASTM A516 Grade 70, a low- to medium-carbon alloy steel. Specimens were tested for tensile strength (ASTM E8), bend resistance (ASTM E290), and hardness (ASTM E92-17). Notably, polishing was applied when necessary. Furthermore, microstructure was analyzed using a Field Emission Scanning Electron Microscope equipped with Energy Dispersive Spectroscopy (FESEM-EDS), while X-ray Diffraction (XRD) examined phase composition. In addition, FESEM-EDS confirmed the presence of Fe and C elements, whereas XRD revealed clear C peaks at 2θ values of 29.46°, 35.21°, 46.86°, 47.79°, and 60.09°. Overall, these findings are consistent with the chemical composition, with C content ranging from 0.17% to 0.28%, and are further supported by line-scan mapping. Concurrently, hardness values strongly correlated with mechanical behavior, confirming the material's suitability for structural and high-pressure applications.