Effect of TMCP Parameters on Microstructure and Mechanical Properties of Cargo Oil Tanks Steel

Abstract

The effect of TMCP parameters on the microstructure and mechanical properties of cargo oil tanks (COT) steel is investigated. The microstructure characteristics are performed by optical microscope, and the mechanical properties are researched by tensile test at ambient temperature and impact test at different temperatures (-20°C, -40°C). The results show that the microstructures of COT steel are a mixed microstructure consisting of ferrite, granular bainite and pearlite, which are resulted from the special TMCP parameters. The COT steel has good comprehensive mechanical properties by analyzing the experimental data, satisfying the international standard. Furthermore, impact fracture surfaces appear small dimples and a few of large ones, most of the dimple with a certain direction, and the inclusion with the fracture is mainly composed of MnS, CaS and Al2O3 composite product.