P235GH and S235JR are two different types of steel that have distinct characteristics and applications. Here are the key differences between them:

1. Composition: P235GH is a non-alloy quality steel primarily used for high-temperature applications such as pressure vessels and boilers. It has a defined chemical composition, including higher concentrations of elements like carbon (C), manganese (Mn), and silicon (Si). On the other hand, S235JR is a structural steel with a wider range of applications, including general structural engineering and construction. It has a different chemical composition compared to P235GH, with lower carbon content.

2. Strength and Tensile Properties: P235GH is designed for high-temperature applications and possesses good mechanical properties at elevated temperatures. S235JR, being a structural steel, is characterized by its excellent formability, but it doesn't possess the same high-temperature strength as P235GH.

3. Usage: Due to its specific alloying elements, P235GH is predominantly used in the production of pressure vessels, boilers, and heat exchangers. S235JR, on the other hand, finds extensive use in general structural applications, including building frames, bridges, and machinery.

4. Certification: P235GH is typically certified according to the European standard EN 10216-2, while S235JR is certified under the European standard EN 10025-2.

In summary, P235GH is a specialized steel for high-temperature applications, while S235JR is a versatile structural steel used in various general applications.