It is difficult to determine specifically which industries use S235JR or DX51 steel without more information about their properties and application. However, both S235JR and DX51 steel are commonly used in various industries, including construction, automotive, manufacturing, and infrastructure. S235JR steel is often used for general structural purposes and components, while DX51 steel is typically used for galvanized applications. The choice of steel will depend on the specific requirements of the project or application.