What are the advantages and disadvantages of surfacing ball valves with cemented carbide and spray-welded cemented carbide?
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The thickness of the cemented carbide layer on the valve ball is relatively thick, while that obtained through spray welding is thinner, at less than 0.5 MM. Cementing is more suitable for use in environments with erosion or particle impact; please discuss other scenarios
Are there valve balls with surfacing? It seems that only the valve seat has surfacing. I hope experts can give me some advice.
The main difference between surfacing and spray welding lies in their application methods. Surfacing is primarily used on valve seats; after surfacing, mechanical machining can be carried out easily. Spray welding, on the other hand, is used for the ball portion of ball valves. If surfacing is used for the ball, it becomes difficult to perform mechanical machining, while with spray welding only final grinding is required before installation. Regarding wear caused by the medium, protection against wear does not depend solely on thickness; the material used in surfacing and spray welding is what matters most. If the hardness of the material is insufficient, even a thick sealing surface will be quickly worn away. If the material has sufficient hardness to withstand the hardness of the medium particles, then a sealing surface of moderate thickness will still have a long service life
The parts that are processed using the two methods mentioned by the original poster are different; surfacing is generally applied to the valve seat and sealing surfaces, while spraying serves a protective purpose on the ball.
This post was last edited by CXU on 2009-12-5 at 10:36. The process requirements for surfacing cemented carbide on ball valves are quite high; there is significant deformation and a large amount of machining allowance. Domestic manufacturers did not have the capability to handle this task in the past couple of years. I wonder if there have been any advances in this area recently? If any fellow travelers know, please let me know. Control in spray welding: The thickness achieved through spray welding is relatively small compared to the machining allowance, making it easier to perform grinding compared to surfacing. The thickness of the coating is particularly important in coal powder conveying and black water systems where particle erosion is severe.
The points mentioned on floors 2 and 3 are more or less the same; the ball and the seat have different quality assurance processes.
For small sizes, solid cemented carbide is currently used, while for large sizes, spraying and surfacing are still employed! The overall quality is good, but the price is high