What distinguishes NQT steel from QT steel used in cargo tank construction?

The distinction between NQT (Normal Quenching and Tempering) steel and QT (Quenching and Tempering) steel lies primarily in their mechanical properties and how they respond to thermal treatment. NQT steel is indeed more ductile compared to QT steel. Ductility refers to the ability of a material to deform under tensile stress, which means it can be stretched into a wire or manipulated without breaking. This property is critical in applications like cargo tank construction, where materials must withstand various stresses during transportation and handling.

In contrast, QT steel typically undergoes a more aggressive heat treatment resulting in a harder but less ductile material. While QT steel offers superior strength, it may not perform as well under conditions where flexibility and ductility are required. This makes NQT steel a suitable choice in situations where some degree of deformation is anticipated without compromising structural integrity.

Understanding the differences in ductility is crucial for engineers and technicians in selecting the appropriate material for specific applications, ensuring safety and reliability in the transportation of hazardous materials.