Discussion on the materials of valve body, valve core, valve seat, and valve stem
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Discussion on the materials of the valve body, valve core, valve seat, and valve stem. Taking ball valves as an example, Question 1: Must the materials of the valve body, the valve core, and the valve seat be the same? Especially high-temperature media, above 400 degrees. Can a 304 valve body with a 316 valve core and seat be used? Question 2: For hard-sealed valves, must the stem material be 17-4PH?
The materials for the valve core, valve seat, and valve stem are selected based on the structure of the valve and the properties of the medium; there is no requirement for them to be identical. Generally, the valve stem must have high hardness, while the valve seat and valve core need to take into account issues such as erosion, so their surfaces must be reinforced, for example by welding in hard alloys. 304/316 can be used in high temperatures without any problem.
17-4PH has higher hardness than 316, but its corrosion resistance is lower than that of 316. The choice should be based on the actual conditions on site; if the torque requirements are not high, it is recommended to use 316.