In the early 1980s, Ningbo, Zhejiang, took the lead in developing a manufacturing process, changing the history of long -term use of cast iron valves in China. In the manufacturing process, the sand casting process was first adopted, and the forging process was changed in the early 1990s. In the early 20th century, China has developed into the world's copper valve manufacturing center.
Zhejiang Yuhuan, where it is the most important production base with copper valve.
In the early 1980s, Ningbo, Zhejiang, took the lead in developing a manufacturing process, changing the history of long -term use of cast iron valves in China. In the manufacturing process, the sand casting process was first adopted, and the forging process was changed in the early 1990s. In the early 20th century, China has developed into the world's copper valve manufacturing center.