The sealing surface of steel valves (DC341X-16 Double flanged eccentric butterfly valve) is generally manufactured by (TWS valve )surfacing welding. The materials used for valve surfacing are divided into 4 major categories according to the alloy type, namely cobalt-based alloys, nickel-based alloys, iron-based alloys, and copper-based alloys. These alloy materials are made into electrodes, welding wires (including flux-cored wires), fluxes (including transition alloy fluxes) and alloy powders, etc., and are surfacing by manual arc welding, oxyacetylene flame welding, tungsten argon arc welding, submerged arc automatic welding and plasma arc welding.
The selection of valve sealing surface surfacing materials (DC341X3-10 Double flanged eccentric butterfly valve body sealing ring) is generally based on the use temperature, working pressure and corrosiveness of the valve, or the type of valve, the structure of the sealing surface, the sealing specific pressure and the allowable specific pressure, or the production and manufacturing conditions of the enterprise, the processing capacity of the equipment and the technical ability of the surfacing and the requirements of users. Optimized design should also be adopted, and the sealing surface material with low price, simple production process and high production efficiency should be selected under the condition of satisfying the performance of the （D341X3-16 Double flanged concentric butterfly valve )valve.
Some of the materials used for surfacing of valve sealing surfaces have only one form, or electrode or welding wire or alloy powder, so only one surfacing method can be used. Some are made into welding rods, welding wires or alloy powders in various forms, such as stellite l 6 alloy, both welding rods (D802), welding wires (HS111) and alloy powders (PT2102), then manual arc welding, oxy2acetylene flame welding, tungsten argon arc welding, wire feeding plasma arc welding and powder plasma arc welding and other methods can be used for surfacing welding. When selecting the surfacing materials for the valve sealing surface, we should take into account the selection of the surfacing method with mature technology, simple process and high production efficiency of the enterprise, so as to ensure the realization of its performance in the surfacing manufacturing of the sealing surface.
The sealing surface is the key part of the valve (D371X-10 Wafer butterfly valve ), and its quality directly affects the service life of the valve. Reasonable selection of the material of the valve sealing surface is one of the important ways to improve the service life of the valve. Misunderstandings should be avoided in the selection of valve sealing surface materials.
Myth 1: The hardness of the valve (D371X3-16C) sealing surface material is high, and its wear resistance is good.
Experiments show that the wear resistance of valve sealing surface material is determined by the microstructure of the metal material. Some metal materials with austenite as the matrix and a small amount of hard phase structure are not very hard, but their wear resistance is very good. The sealing surface of the valve has a certain high hardness to avoid being injured and scratched by hard debris in the medium. All things considered, the hardness value HRC35~45 is appropriate.
Myth 2: The price of valve sealing surface material is high, and its performance is good.
The price of a material is its own commodity characteristic, while the performance of the material is its physical characteristic, and there is no necessary relationship between the two. The cobalt metal in cobalt-based alloys comes from imports, and the price is high, so the price of cobalt-based alloy materials is high. Cobalt-based alloys are characterized by good wear resistance at high temperatures, while when used in normal and medium temperature conditions, the price/performance is relatively high. In the selection of valve sealing surface materials, materials with low price/performance should be selected.
Myth 3: If the sealing surface material of the valve has good corrosion resistance in a strong corrosive medium, it must adapt to other corrosive media.
The corrosion resistance of metal materials has its own complex mechanism, a material has good corrosion resistance in a strong corrosive medium, and the conditions change slightly, such as temperature or medium concentration, the corrosion resistance is changed. For another corrosive medium, the corrosion resistance varies greater. The corrosion resistance of metal materials can only be known through experiments, and the relevant conditions must be understood for reference from relevant materials, and must not be blindly borrowed.
Post time: Mar-01-2025
