Due to the application of CAD, CAM and FMS in the valve industry, the design and manufacture of butterfly valves have reached a new level. It not only comprehensively innovates the design and calculation method of valves, reduces the heavy and repetitive routine design work of professional technicians, enables technicians to have more energy to improve the technical performance of products and research and development of new products, shortens the cycle and improves labor productivity. Especially in the field of metal sealed butterfly valves, due to the application of CAD/CAM, a three-dimensional sealing pair designed by CAD and manufactured by cAM NC machining has emerged, which makes the sealing surface of the valve free of any extrusion, scratch and wear during the opening and closing process, thus improving the sealing performance and service life of butterfly valves by an order of magnitude.

Compared with other welding methods, TIG welding has the following characteristics:
(1) Argon is insoluble in metal and does not react with metal. The tetrafluoro compensator can effectively isolate the air around the welding area. During TIG welding, the arc can also automatically clean the oxide film on the surface of the workpiece. Therefore, it is possible to weld nonferrous metals, stainless steels and various alloys that are easy to be oxidized, nitrided and chemically vivid and are not easy to be welded by other welding methods.
(2) Good welding process performance. The arc can be extinguished stably even under very small welding current; No spatter, no slag, beautiful weld formation; The heat source and welding wire can be controlled separately, so the heat input is easy to adjust, especially suitable for welding thin plates and ultra-thin plates; It can stop welding at various positions and is easy to complete mechanized and automatic welding.
(3) The ability of tungsten electrode to carry current is poor. Excessive current will cause tungsten electrode condensation and evaporation, and its particles may enter the molten pool to form tungsten inclusions. Therefore, TIG welding uses low current, shallow weld penetration, low deposition speed and low consumption rate.
(4) As inert gas is more expensive and costs more than other welding methods, it is mainly used for welding products with higher requirements.
(5) The request for workpiece liquidation is high. As inert gas maintenance is used, there is no metallurgical deoxidation or dehydrogenation. In order to prevent defects such as pores and cracks, oil stains and rust on the workpiece must be removed strictly before welding.
(6) The intensity of ultraviolet ray generated by argon arc welding is 5~30 times that of shielded metal arc welding. Under ultraviolet radiation, oxygen molecules and atoms in the air collide with each other to generate ozone, which is harmful to welders. In addition, the use of radioactive tungsten electrodes in argon tungsten arc welding will also be harmful to welders. At present, the cerium tungsten electrode that has been applied is less harmful to welders.
(7) The ability to resist wind is poor, especially the ability to resist lateral wind.