H.R." stands for Hot Rolled pipes. Hot rolling is a manufacturing process where steel is heated to high temperatures and then passed through rollers to shape it into the desired pipe form. H.R. pipes tend to have a rough surface and are less precise in terms of dimensions compared to C.R. pipes. They are often used for applications where surface finish is less critical, such as structural and industrial applications.

C.R." stands for Cold Rolled pipes. Cold rolling is a manufacturing process where steel is processed at room temperature, resulting in a smoother and more precise finish. C.R. pipes are known for their smoother surface and tighter dimensional tolerances. They are often used in applications where a precise size and a smoother appearance are required, such as automotive components, furniture, or architectural elements.