Carbon pipe and seamless pipe are often used interchangeably, but there are distinct differences between the two. Carbon pipe is primarily defined by its material composition, specifically the presence of carbon as the main alloying element in the steel. Carbon steel pipes are commonly used in a variety of industrial applications due to their strength, durability, and corrosion resistance.

On the other hand, seamless pipe refers to the manufacturing process rather than the material composition. Seamless pipes are made from a solid round steel billet, which is heated and then pierced through the center with a mandrel to create a hollow tube. This process results in a pipe without any seams or joints, hence the name "seamless pipe". The absence of seams provides better structural integrity and resistance to pressure, making seamless pipes ideal for high-pressure applications such as oil and gas pipelines.

In summary, carbon pipe is defined by its material composition, while seamless pipe is characterized by its manufacturing process. Both types of pipes have their unique advantages and are used in specific applications based on their properties. Carbon steel pipes offer strength and durability, while seamless pipes provide superior structural integrity and pressure resistance.