I would like to ask about the sealing materials for stop valves – what is the difference between H and Y?
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Requirements: 425°C, 2.5 MPa; medium is water and steam. What sealing material should be chosen? Can H-stainless steel seals be used? Are there any chemical valve manufacturers in Jiangsu Province that offer valves of reasonable price and reliable quality (electric and manual globe valves, control valves, etc.)? Please recommend some
You can check the valve manual. . . Inside, there are specifications regarding the operating medium, temperature, and pressure for various valves; if needed, I have an electronic version available
H should be Cr13. Y refers to welded Stellite cemented carbide; it is not recommended to use martensitic stainless steels of the H Cr13 series. The temperature of 425°C is a bit high – domestic standards such as GB/T20801 specify that martensitic stainless steels should not be used in environments where the temperature exceeds 370°C. This temperature and pressure can be represented by Y.
The H sealing surface is commonly used in media at normal temperatures that are non-corrosive and free from erosion, while the Y cemented carbide material can be used in corrosive, high-temperature media; I am a valve manufacturer.
Cr13: t≤425°C (theoretical value; however, GB-T20801-2006 states that due to the brittleness of martensite, this material is not suitable for use at temperatures above 370°C). Cemented carbide: -30°C–425°C. When considering the temperature of the medium, it’s not possible to focus solely on the sealing surface – what about the valve body? It can’t be that the valve body is at 100°C while the inside of the valve is at 1000°C. Use cemented carbide
Regarding J941Y-25, for this model, does the letter Y refer to the material of the sealing surface or the material of the valve body? Can the valve body made of WCB withstand temperatures of 425°C?
This post was last edited by Dipel NDIV on 2017-1-12 at 13:11. For electric globe valves, the letter Y denotes the sealing surface. The material of the valve body is not specified for this model; WCB can theoretically operate in temperatures ranging from -29°C to 427°C. However, WCB cannot be used for long periods at temperatures above 400°C as it tends to deform, and stainless steel is generally chosen for applications involving temperatures above 400°C!
Considering the departments where it is used on-site, if the temperature does not exceed 400°C, what consequences will arise from the phase change of WCB? Generally speaking, is the material selection for the sealing surface more demanding (have higher requirements) than that for the valve body?
At temperatures above 427 degrees, the carbide phases in WCB steel transform into graphite. For the sealing surfaces of valves, especially those with tight seals, factors such as scratch resistance, erosion resistance, hardness, oxidation resistance, high-temperature tolerance, and the coefficient of linear expansion matching that of the valve body material must be taken into consideration. For various issues related to sealing surfaces, you can refer to: http://bbs.hcbbs.com/thread-1664355-1-1.html