1. Features and Advantages of Medium-pressure Seamless Steel Pipes:
- Seamlessness: Compared to welded steel pipes, medium-pressure seamless steel pipes offer superior load-bearing capacity and pressure resistance because they lack welds on both the inner and outer surfaces, eliminating the potential weaknesses associated with weld defects.
- High Strength: Due to the manufacturing process, seamless steel pipes achieve a denser grain structure, resulting in higher strength and hardness, enabling them to withstand greater pressure and impact.
- Corrosion Resistance: By utilizing various alloying elements or surface treatments, medium-pressure seamless steel pipes can exhibit excellent corrosion resistance, maintaining stable operation even in harsh environments.
- Variety: Medium-pressure seamless steel pipes can be made from a variety of materials, such as carbon steel and alloy steel, to meet diverse application requirements.

2. Applications of Medium-pressure Seamless Steel Pipes:
- Oil and Gas Industry: Medium-pressure seamless steel pipes are widely used in oil fields and natural gas pipelines, fulfilling the critical tasks of both transportation and pressure bearing. 
- Chemical Industry: Medium-pressure seamless steel pipes are a common material in chemical equipment and piping systems, highly favored for their excellent corrosion resistance.
- Mechanical Manufacturing: In the mechanical equipment manufacturing sector, medium-pressure seamless steel pipes are widely used in the manufacture of components such as high-pressure cylinders and drive shafts, ensuring safe and reliable operation of the equipment.

3. Manufacturing Process of Medium-Pressure Seamless Steel Pipes:
- Piercing: Appropriate billets are selected and processed into tube blanks in a cold state using a piercing machine.
- Rolling: The tube blanks undergo hot and cold rolling processes before being processed into seamless steel pipes using a rolling mill to ensure the uniformity of the steel pipe wall and dimensional accuracy.
- Heat Treatment: Through heat treatment processes such as quenching and annealing, the microstructure of the steel pipe is adjusted to enhance its strength and hardness.

The importance of medium-pressure seamless steel pipes is self-evident. They carry out important tasks across various industries and provide solid support for the development of modern industry. In the future, with the continuous advancement of technology and the continuous expansion of demand, medium-pressure seamless steel pipes will undoubtedly usher in broader development opportunities, injecting strong impetus into the development of various industries.