This system is specially designed for welding on the inner walls of valves and pipe fittings. It is suitable for workpieces made of carbon steel, stainless steel and other metal and alloy materials, and can be used for welding on their sealing surfaces and outer surfaces. Suitable for workpieces with a diameter of 40 - 1200mm and a weight not exceeding 5000kg. The system is equipped with HMI touch screen controller, workpiece servo turntable and cross operating machine. It is easy to operate, has high control accuracy and process repeatability.