译文：
阐述了超高压截止阀在不同密封型式下轴向力的计算及其确定并加以论证,分析了超高压截止阀的密封机理和密封面加工精度对截止阀轴向力的影响以及密封副材料的选用。 1、概述 超高压截止阀密封副材料通常为金属对金属,为了使截止阀关闭时密封严密,必须提高密封面的加工精度和粗糙度等级,并且对密封面施加非常大的轴向密封力。然而,轴向密封力并非越大越好。有一种观点认为超高压截止阀(≥300MPa)应为塑性法密封,且大都采用锥面线性密封。所谓塑性法密封,就是密封面的密封比压等于密封副软材料的屈服极限,使结合面紧密接触,利用软材料的塑变而堵塞硬件表面的不平处,形成近似理想平面,并产生等于软材料屈服极限的反力而保持密封。 2、轴向力分析 阀杆轴向力主要取决于密封面的总作用力,阀门设计中确定密封面总作用力的关键参数是密封比压。但是在超高压截止阀的锥面线密封情况下,其轴向力Q在无介质压力关闭时所产生的密封比压q是否可以大于密封副软材料的屈服极限δs,在有介质压力关闭时的密封比压q是否一定等于δs,本文将讨论q的合适值。 3、密封面粗糙度对轴向力的影响 根据只有当密封表面间的间隙小于介质分子直径时,才能保证介质不渗漏的观点,可以认为,防止流体渗漏的间隙值必须小至0.003μm。但是,即使经过精研,金属表面上的凸峰高度仍然超过0.05μm,要达到理想平面,就必须对接触面施加一定的力,这个力的大小与密封副软材料的σs及密封面的粗糙度有关。 当密封面上的比压q<40MPa时,密封面的质量起着决定作用。例如在q=65MPa时,随着粗糙度等级的越来越高,渗透量迅速减小,也就是说在q<40MPa时,在同样一个渗漏量等级,粗糙度愈高所需要的q愈小,其轴向力越小。 但对于σs>900MPa密封副材料,在用于300MPa等级的超高压阀时,除了从线弹性断裂力学观点出发,[σ]从强度要求考虑,Ra0.05μm以上,还要从密封机理上考虑。因此,对于σs为900MPa的超高压截止阀用密封副,其密封面粗糙度必须在Ra0.05μm以上。而对于经HIP处理的WC硬质合金密封副来说,由于其性质较脆,要增大密封面上的比压来压缩密封面上的波峰,就会使轴向力增加很大,而且会使密封副产生断裂,(在Fisher公司阀门的使用中,就有因轴向力调整不当而引起阀座断裂的例子),因此,其密封面上粗糙度必须高于Ra0105μm。只有在这个范围内,才能使用式(13)的轴向力计算式。 4、结语 超高压截止阀的密封机理分狭面弹塑性密封和线密封两种型式。由于阀座(或阀瓣)密封面塑性变形后的表面冷作硬化现象,所以轴向力的增加与阀座密封面宽度的增加并不成正比关系。口径1/2in.(15mm)以上超高压阀的密封副材料以采用HIP处理的WC硬质合金为宜,密封面必须有很高的粗糙度等级,而轴向力计算公式具有一定的使用范围。

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原文：
Described high pressure valve seal types under different axial force calculation of determined and demonstrated, analysis of high pressure valve seal mechanism and the sealing surface precision axial force on the valve impact and sealing materials use. 1 Overview High pressure valve sealing materials are usually metal on metal, in order to tightly seal off valve must be sealed to improve the machining accuracy and surface roughness level, and imposed on the sealing surface of a very large axial sealing force. However, the axial sealing force is not the bigger the better. In one view, high pressure valve (≥ 300MPa) should be sealed plastic method, and the mostly linear with cone seal. The so-called plasticity seal, the seal is the sealing surface pressure is equal Sealing than the soft material yield limit, so that joint surface in close contact, use the plastic deformation of soft materials, blockage hardware uneven surface, giving rise to approximate the ideal plane, and produce equivalent soft material yield limit of the reaction and remain sealed. 2, axial force of Stem sealing surface of the axial force depends on the total force, the valve sealing surface design to determine the key parameter is the total force than the pressure seal. But in the high pressure valve and the conical sealing case, the axial force Q in the absence of medium pressure off than the pressure generated by the seal can be larger than Sealing q is the yield strength of soft δs, in a medium pressure closed q than the pressure when the seal is necessarily equal to δs, this paper will discuss the appropriate q value. 3, the sealing surface roughness effects on the axial force According to the surface only when the seal gap between the molecular diameter less than the media in order to ensure the media are not the views of leakage can be considered to prevent fluid leakage clearance value must be as small as 0.003μm. However, even after lapping, metal surface on the convex peak height still more than 0.05μm, to achieve the ideal plane, we must exert a certain force contact surface, the force size and Sealing of soft material and the sealing surface of the rough σs degrees about. When the sealing surface of the specific pressure q <40MPa, the sealing surface quality plays a decisive role. For example, when q = 65MPa, with the increasing roughness level, infiltration capacity decreases rapidly, which means that q <40MPa when a leakage in the same grade, roughness, the more the higher the required q small, the smaller the axial force. But σs> 900MPa sealing materials are used in the 300MPa grade high pressure valve, in addition to linear elastic fracture mechanics from the point of view, [σ] from the intensity required to consider, Ra0.05μm above, but also from the sealing mechanism to consider. Therefore, the high pressure σs to 900MPa cut-off valve seals, the sealing surface roughness must Ra0.05μm above. As for the WC hard alloy by HIP treatment Sealing, because of its more brittle nature, to increase the sealing surface pressure to compress the sealing surface than the peak, so that the axial force will increase considerably, and will make the valve to crack, (in the Fisher valve in the use of the company, there is a result of the axial force caused by improper seat adjustment faults example), and therefore its sealed surface roughness must be higher than Ra0105μm. Only in this context, in order to use equation (13) of the axial force calculations. 4 Conclusion High pressure valve seal mechanism of the narrow sub-surface plastic seals and sealing two types. As the seat (or valve flaps) after sealing the surface of dough deformation of cold hardening, so the increase of axial force and the valve seat sealing surface is not proportional to the increase in width. Diameter 1/2in. (15mm) or more high pressure valve sealing materials to use HIP treatment is appropriate WC carbide, sealing surface roughness must be very high level, while the formula for calculating the axial force the use of certain .