Metallic seals are crucial machine elements in many important applications, e.g., in ultrahigh vacuum systems. Due to the high elastic modulus of metals, and the surface roughness which exists on all solid surfaces, if no plastic deformation would occur one expects in most cases large fluid flow channels between the contacting metallic bodies, and large fluid leakage. However, in most applications plastic deformation occurs, at least at the asperity level, which allows the surfaces to approach each other to such an extent that fluid leakage often can be neglected. In this study, we present an experimental set-up for studying the fluid leakage in metallic seals. We study the water leakage between a steel sphere and a steel body (seat) with a conical surface. The experimental results are found to be in good quantitative agreement with a (fitting-parameter-free) theoretical model. The theory predicts that the plastic deformations reduce the leak-rate by a factor \(\approx 8\).

在许多重要应用中，例如在超高真空系统中，金属密封件都是至关重要的机械元件。由于金属的高弹性模量以及存在于所有固体表面上的表面粗糙度，如果不发生塑性变形，则人们期望在大多数情况下，在接触的金属体之间存在较大的流体流动通道，并且存在较大的流体泄漏。但是，在大多数应用中，至少在粗糙程度下会发生塑性变形，这使表面彼此接近，从而经常可以忽略流体泄漏。在这项研究中，我们提出了一种用于研究金属密封件中流体泄漏的实验装置。我们研究了钢球和具有圆锥形表面的钢体（座）之间的漏水现象。实验结果与（无拟合参数的）理论模型具有良好的定量一致性。该理论预测，塑性变形会使泄漏率降低一个因素\（\大约8 \）。