Butterfly valves are widely used in industrial application, part of application is general temperature and rest of application is high temperature. The materials of high temperature using butterfly valve are different from general using buterfly valve. Below main differences listed:
1, Butterfly valve stem / shaft .
At 704 ℃, the strength of austenitic steel bar decreased more than normal. If the strength is increased by increasing the stem diameter, it is beyond the valve structure, so austenitic steel is not suitable for stem material. The strength of martensitic stainless steel rod is better than that of conventional austenitic stainless steel, but the strength will also decrease under high temperature, so it is not suitable to be used as stem material. When Inconel X-750 works at 704 ℃, its strength will decrease, but the strength value of the material itself is large. According to the yield strength and durability strength, the diameter of the valve stem can meet the structural requirements of the valve. This material can be used as a material of butterfly valve for high temperature.
2, Butterfly valve stem packing .
The oxidating temperature of flexible graphite in air is 450 ℃, at which the mass of flexible graphite decreases by 1% every 24 hours. The higher the temperature is, the lower the quality and the more serious the oxidation. The highest temperature of flexible graphite packing is 650 ℃, which is only used for oxidation medium. Considering that the packing in the stuffing box is in the sealed state, only a part of the packing is exposed to the air, and the service temperature of the packing in this state is 816 ℃. so the flexible graphite.
3, Butterfly valve body and disc .
The valve design standard is ASME B16.34. According to the pressure temperature table in this standard, the pressure rating of the valve at normal temperature is the design basis, and the minimum wall thickness is calculated. In the design process, the valve body material specified in asmeb16.34 standard is also selected. Under the valve condition, the material is suitable for high temperature. After referring to a large number of butterfly valve materials used in similar conditions at home and abroad, combined with the experience of using high-temperature materials, 304H can be used as a material of valve body and disc.
ZFV ( Zhejiang zhengfeng valve co., ltd ) is a professional buttefly valve manufacturer, can produce various butterfly valves which be used for different temperature conditions.
Zhejiang Zhengfeng Valve Co., Ltd