1、阀体材料选用

　　1. Valve body material selection

　　对于钢和镍合金阀体和阀盖材料的选择在ASMEB16.34表1中已经列出。这个表被分为三组：第1组是黑色金属材料;第2组是奥氏体不锈钢材料;第3组是与特殊的压力-温度等级表相关的镍合金材料。在ASMEB16.1(铸铁)、ASMEB16.24(铜合金)、ASMEB16.42(球墨铸铁)中含有其他材料。

　　The selection of steel and nickel alloy valve body and cover materials is listed in Table 1 of ASMEB16.34. This table is divided into three groups: Group 1 is made of black metal materials; The second group is austenitic stainless steel materials; The third group is nickel alloy materials related to special pressure temperature rating tables. Other materials are present in ASMEB16.1 (cast iron), ASMEB16.24 (copper alloy), and ASMEB16.42 (ductile iron).

　　对于表中涉及温度和热处理范围的注释，需要给予特别关注。通过查阅这些温度-压力表，压力-温度额定值为选择合理的满足机械强度需求提供了依据。此外材料对许多存在于过程流体流动工况中材料性能下降机理，也应该给予考虑，例如受到腐蚀、应力开裂、低温和高温、含氢工况影响等。

　　Special attention should be paid to the annotations in the table regarding temperature and heat treatment range. By consulting these temperature pressure gauges, the pressure temperature rating provides a basis for selecting a reasonable one that meets the mechanical strength requirements. In addition, the mechanism of material performance degradation in many process fluid flow conditions should also be considered, such as corrosion, stress cracking, low and high temperature, and hydrogen containing conditions.

　　2、阀门内件选用

　　2. Selection of valve internals

　　①通则 阀门内件材料的选用不只是阀座密封面材料，在API600和API602包含的内件表中对其有明确定义。通常对于所有类型的阀门其内件包括所有与过程流体接触的部件。如果没有定义特殊的要求，那么API标准要求内件材料的耐蚀性必须至少与阀体材料的耐蚀性相同。

　　① The selection of valve internal material is not only limited to the sealing surface material of the valve seat, but is clearly defined in the internal material tables included in API600 and API602. Typically, for all types of valves, the internal components include all parts that come into contact with the process fluid. If no special requirements are defined, the API standard requires that the corrosion resistance of the internal material must be at least the same as that of the valve body material.

　　②闸阀 对于闸阀，其内件为关闭件和阀座密封面以及阀杆和上密封座。正如API标准中所指出的，一个避免阀座磨损的关键因素是为与其相配合的一对密封面提供一个不同的硬度，除非两个密封面都是硬面。在参考标准中提供了内件表。某些合理内件是在一个或两个表面进行耐磨堆焊，以更好地确保密封面长期具有耐磨损性能、耐蚀性能和耐磨性能。

　　② For gate valves, the internal components include the closing element, valve seat sealing surface, valve stem, and upper sealing seat. As stated in the API standard, a key factor in avoiding valve seat wear is to provide a different hardness for the pair of sealing surfaces that match it, unless both sealing surfaces are hard surfaces. An internal component table is provided in the reference standard. Some reasonable internal components are subjected to wear-resistant welding on one or two surfaces to better ensure that the sealing surface has long-term wear resistance, corrosion resistance, and wear resistance.

　　③其他阀门内件 对于止回阀，其内件被定义为关闭件和阀座密封面。在参考标准中提供了内件表。某些合理的内件是在一个或两个表面进行耐磨堆焊，从而更好地确保阀座在长期磨损、腐蚀和磨蚀性工况使用中不会失效。

　　③ For check valves, the internal components of other valves are defined as the closing element and the sealing surface of the valve seat. An internal component table is provided in the reference standard. Some reasonable internal components are wear-resistant welded on one or two surfaces to better ensure that the valve seat will not fail in long-term wear, corrosion, and abrasive working conditions.

　　对于球阀，其关闭件被定义为阀门的内部金属件，例如球体、阀杆和金属阀座或阀座支撑圈。这些件都可以具有与壳体相同的名义化学成分，以及具有与壳体材料相似的力学性能和耐蚀性能。

　　For ball valves, their closing components are defined as the internal metal parts of the valve, such as the ball, stem, and metal valve seat or seat support ring. These components can have the same nominal chemical composition as the shell, as well as mechanical and corrosion resistance properties similar to the shell material.

　　对于蝶阀，所有与过程流体接触的材料都应遵循制造商的标准，除另有规定外。蝶阀内件被定义为阀体阀座密封面、蝶板、蝶板与轴连接件(例如键、销、螺钉等)和全部与过程流体接触的内部紧固件。轴和轴套的材料与内件材料的腐蚀性能相似。

　　For butterfly valves, all materials in contact with the process fluid should comply with the manufacturer's standards, unless otherwise specified. Butterfly valve internals are defined as the valve body seat sealing surface, butterfly plate, butterfly plate and shaft connecting components (such as keys, pins, screws, etc.), and all internal fasteners in contact with the process fluid. The corrosion resistance of the materials of the shaft and sleeve is similar to that of the internal components.

　　对于旋塞阀，要求旋塞和阀杆材料的耐蚀性至少与阀体材料相同。

　　For plug valves, it is required that the corrosion resistance of the plug and stem materials be at least the same as that of the valve body material.

　　对于截止阀，其内件见API602中定义。3、阀座密封面——软阀座　　球阀和蝶阀经常使用带有弹性的、非金属的阀座来提供密封。API608和API609中包含带有压力-温度额定值规定的PTFE和增强型PTFE材料。其他软阀座材料的压力-温度额定值，经购买者和制造商商定。PTFE阀座的使用温度范围往往是177～225℃(350～400℉)。对于一些用于液体工况中的软阀座球阀，应该考虑中腔泄压要求。4、阀杆密封——逸散性排放

　　For globe valves, their internal components are defined in API602. 3. Seat sealing surface - Soft seat ball valves and butterfly valves often use elastic, non-metallic seats to provide sealing. API608 and API609 contain PTFE and reinforced PTFE materials with pressure temperature ratings specified. The pressure temperature ratings of other soft seat materials shall be agreed upon by the purchaser and manufacturer. The operating temperature range of PTFE valve seats is often 177-225 ℃ (350-400 ℉). For some soft seat ball valves used in liquid working conditions, the requirement for pressure relief in the middle chamber should be considered. 4. Valve stem seal - fugitive emissions

　　通常用于工艺管道中的阀杆填料为一种柔性石墨。新阀门填料典型设计方法是：放置几个压制成形的几道填料环，填料环上面放置一个编织材料环以及在堆叠填料的底部放置一个编织材料环。这种编织材料“擦拭环”有助于防止压制填料环被挤出填料函。与先前使用的石棉材料相比，目前阀门填料技术有效地阻止了轻烃泄漏(逸散性排放)。影响柔性石墨填料材料性能的关键因素有：碳的百分含量、填料密度和耐蚀/氧化剂。为提高阀杆填料性能，MSS SP-120中对用于升降阀杆阀门的柔性石墨填料系统进行了很好的讨论。API622的填料应予以考虑。

　　The valve stem packing commonly used in process pipelines is a type of flexible graphite. The typical design method for new valve packing is to place several compressed packing rings, place a woven material ring on top of the packing rings, and place a woven material ring at the bottom of the stacked packing. This woven material 'wiping ring' helps prevent the compressed packing ring from being squeezed out of the packing box. Compared with the previously used asbestos materials, the current valve packing technology effectively prevents light hydrocarbon leakage (fugitive emissions). The key factors affecting the performance of flexible graphite filler materials include the percentage of carbon content, filler density, and corrosion/oxidation agents. To improve the performance of valve stem packing, MSS SP-120 provides a good discussion on the flexible graphite packing system used for lifting valve stem valves. The packing of API622 should be considered.

　　虽然石墨材料在温度高于343℃(650℉)时易氧化，但是其已经被成功地用于使用温度大于等于538℃(1000℉)的阀门中。

　　Although graphite material is prone to oxidation at temperatures above 343 ℃ (650 ℉), it has been successfully used in valves with temperatures greater than or equal to 538 ℃ (1000 ℉).

　　动加载和超时工况中的填料，由于“填料压实”可能会导致其密封性能降低。这使压盖载荷减小，导致填料泄漏。这种“动加载”的过程可能是合理的选择，包含由碟形弹簧加载的填料压盖，从而提供了一种维持填料压盖载荷的方法以帮助延长填料有效使用时间。

　　The sealing performance of fillers in dynamic loading and timeout conditions may be reduced due to "compaction of fillers". This reduces the load on the gland, resulting in packing leakage. This "dynamic loading" process may be a reasonable choice, including a packing gland loaded by a disc spring, providing a method to maintain the packing gland load to help extend the effective use time of the packing.

　　某些1/4旋转阀门的阀杆可能会用弹性O形圈密封。这些密封圈的使用温度范围可能会低于PT-FE。

　　The stem of some 1/4 rotary valves may be sealed with an elastic O-ring. The temperature range for the use of these sealing rings may be lower than that of PT-FE.

　　波纹管密封阀门已经被用于蒸汽和某种有危险/有毒的工况中，从而减少潜在的填料泄漏。在API 602中阀门的公称尺寸为NPS1/2～2。API602除传统填料外还包括波纹管阀杆密封的设计方法和试验细节。

　　Bellows sealed valves have been used in steam and certain hazardous/toxic conditions to reduce potential packing leaks. The nominal size of valves in API 602 is NPS1/2 to 2. In addition to traditional packing, API602 also includes design methods and testing details for bellows valve stem seals.

　　5、阀盖垫片

　　5. Valve cover gasket

　　API 600提供了几种阀盖垫片的选择类型：金属环形垫、金属包复垫片、柔性石墨复合金属齿形垫片(仅仅适用于150磅级)，环连接，缠绕式(大于等于300磅级)和增强型柔性石墨垫片其仅仅适于150磅级(买方批准时)。这种阀盖垫片在-29～538℃(-20～1000℉)温度中使用时是合理的。

　　API 600 provides several types of valve cover gasket options: metal ring gasket, metal clad gasket, flexible graphite composite metal toothed gasket (only applicable to the 150 pound class), ring connection, wrap around (greater than or equal to the 300 pound class), and reinforced flexible graphite gasket, which is only suitable for the 150 pound class (when approved by the buyer). This type of valve cover gasket is reasonable for use at temperatures ranging from -29 to 538 ℃ (-20 to 1000 ℉).

　　API 602要求阀盖法兰垫片类型为填充柔性石墨的缠绕式垫片，另有规定除外。设计要求防止垫片的过度压缩。

　　API 602 requires that the valve cover flange gasket type be a wound gasket filled with flexible graphite, unless otherwise specified. Design requirements to prevent excessive compression of the gasket.

　　API 603阀盖垫片设计与API 600相似。带有压缩限制和柔性石墨填料缠绕式垫片(压力等级≥300磅级)是被允许的。API 603没有定义一个更高的温度要求。

　　The design of API 603 valve cover gasket is similar to API 600. Compression limited and flexible graphite filler wrapped gaskets (pressure rating ≥ 300 pounds) are allowed. API 603 does not define a higher temperature requirement.

　　本文由 良工阀门代理  友情奉献.更多有关的知识请点击  http://www.jnlgvf.com/   真诚的态度.为您提供为全面的服务.更多有关的知识我们将会陆续向大家奉献.敬请期待.

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