Metal Gasket Research Articles

An Analysis on copper corrosion SUS304 corrugated metal gasket electroplating

The objective of this study was to examine the corrosion characteristics on the copper coating on SUS 304 corrugated metal gasket electroplating. The corrosion process on the gaskets coating surface generates an oxide coating which affects the gasket quality both in the decorative aspect and the performance of the SUS 304 corrugated metal gaskets. The experiment method was used in this study. The objects involved consisted of five variants of copper coating thickness of 10, 15, 20, 25, and 30 µm. Each variant consisted of three samples. Analysis on the corrosion was done through the experiment and reference review. The findings show that the 10 µm thickness variant has a near perfect or flawless coating result. The oxide coating formed from the corrosion is not significant. On gaskets with 15 and 20 µm coating thickness variants, copper (I) oxide or Cu2O is formed with a reddish hue characteristic. Meanwhile, on gaskets with 25 and 30 µm coating thickness, two types of oxide coating, namely Cu2O and CuO are formed with a blackish grey hue. The corrosion level is a result of inadequate electroplating process.

Sealing Performance Layered Metal Gasket Based on the Simulation Method

Studies for corrugated metal gaskets are still ongoing to improve its performance. This is considered to be a single gasket with SUS304 material when contact with flanges that have greater surface roughness, reduced contact width and plastic deformed contact surfaces are incomplete and cannot fill the surface roughness of flanged flanges. The use of softer material than the base material as a surface covering material is used to improve the performance of the gasket. In this study, therefore the effect of modulus of elasticity ratio and thickness ratio on contact width and contact stress, 25A three-layer metal gasket was investigated using Finite Element Analysis. The results showed that the material with tangent modulus, Ehal = Eal / 150 had the highest slope for contact width. While the contact width of the plastic mode gasket is higher than the elastic mode gasket.

Plate-style recuperator for a solar Brayton cycle using high-temperature sealant

A large, efficient recuperator is required for high cycle efficiency in a solar Brayton cycle (STBC) with an open-cavity solar receiver and air as working fluid. A recuperator often requires complex and costly manufacturing methods. In this work, a clamped plate-type recuperator with a metal gasket is investigated, together with a low-cost high-temperature sodium silicate-based sealant. Experimental investigations were performed to validate a mathematical model using a novel bone-shape design as well as a wide-channel design. The high-temperature sealant worked well on the bone-shape recuperator; however, a leak occurred on the hot-side header tube of the wide-channel recuperator. For the recuperator core of the wide-channel test rig, a cold-side effectiveness of 82.5% and a total pressure loss of 24.9 kPa were found at an average mass flow rate of 0.74 g/s per channel. The validated mathematical model was used in a parametric study to analyse the performance of the recuperator in an STBC by taking the stress and deflection of the plates into consideration. Results show that, for a total mass flow rate of 0.06 kg/s, a cold-side effectiveness of 90% and total pressure loss of less than 5% could be achieved, if a spacer is implemented to prevent deflection.

Optimum Design of Laminated Corrugated Metal Gasket Using Computer Simulation

Previous studies on corrugated metal gaskets using single material SUS 304 was clarified. However, the corrugated metal gasket for elastic model in contact with flange having high surface roughness was still leaking due to only partial contact occurs. Besides that, for gasket contact with another surface roughness of flange still need high axial force. Further development is needed to improve gasket perform. The basic problem of single material SUS 304 is lower of contact width. The contact stress is larger enough to reduce the internal pressure effect of piping. To increase the contact width between flange and gasket, it needed surface layer in the both outside of gasket. The layer materials should softer than base material. The layer material will stick on the outer surface of flange. The optimization analysis using simulation analysis. Simulation analysis using finite element method based on contact width and contact stress. The Taguchi method used to determine the optimum design. The optimum design of laminated corrugated metal gasket has been obtained. The dimension of laminated corrugated metal gasket is pitch 1 is 4.5mm, pitch 2 is 3.4 mm, pitch 3 is 4 mm, thickness of based material is 1,5 mm, radius is 1,5 mm, height is 0.35 and thickness of surface material is 0.1 mm. This gasket is better than corrugated metal gasket without laminated.

Research on the Optimization Design of Metallic Gasket Based on DOE Methodology

In the present study, the method of simulation and Statistical Design of Experiment (DoE) combined approach has been applied to investigating the influence of metallic gasket, flange and bolt on sealing performance. In order to analyze the influence of wavy shape, bolt distribution, wavy height, gasket thickness, top flange thickness, top flange material, gasket materials and bottom flange material, the contribution degree of each factor to the bolt axial force and pressure distribution was taken as the evaluation index. Research results show that the corrugated shape and bolt distribution have the greatest influence on the pressure distribution of gasket and the range of the bolt axial force.

Engineering Development and Application of Hydrodynamic Mechanical Seal of Reactor Coolant Pump

The shaft seal of reactor coolant pump (RCP) consists of three same hydrodynamic mechanical seals in series. It is the heart of RCP and its leakage directly determines the normal operation of the RCP. This paper introduces a new extruding deformation lapping method to manufacture the hydrodynamic mechanical seal. The stationary ring is deformed by using the extruding deformation tool and metallic gasket, and nine waveform grooves are produced on the seal end face. The function test showed that the low-pressure (LP) leakage meets the design requirement of the shaft seal under the examination pressure. Meanwhile the impact examination under the saltation pressure showed that the liquid film between new hydrodynamic mechanical seal friction pair was intact, and no failure occurred on the seal. The operation of this hydrodynamic mechanical seal in the nuclear power plant shows that the operation performance agrees well with the function test results, and proves that this new hydrodynamic mechanical seal is with a high reliability in engineering application.

Influence of dies type for gasket forming shape

Performance of metal gasket influenced by the final design of the forming result. Good shape of the gasket will give optimal leakage performance. It is difficult to produce good shape because of the spring back effect. In this study, we investigated the forming process of metal gasket 400MPa-mode for two types of dies which are open dies and closed dies. The finite element method employed to analyze the effect of different types of dies on the final design of the corrugated metal gasket. The simulation shows corrugated metal gasket 400MPa-mode with closed dies result in better final shape than open dies.

The metal gasket sealing performance of bolted flanged with fem analysis

There is a wide variation of flange style and configuration, but only four types of facing are widely used, which are raised face, flat face, ring joint facing and lap joint flange. Corrugated metal gaskets 400MPa-mode has better performance than gaskets 0Mpa-mode for flat face flange type. In this study we investigated the performance of corrugated metal gasket 400MPa-mode for three types of flange facing which are raised face, flat face and combination raised-flat face. The finite element method employed to analysis the effect of different types of flange on contact width and contact stress in relation with axial force of corrugated metal gasket. The result shows corrugated metal gasket 400MPa-mode give good performance for all type of flange face.

An analysis of changes in flange surface roughness after being used to tighten a corrugated metal gasket

A corrugated metal gasket is not reusable once the plastic deformation has occured. Meanwhile, flange might be reusable if it has not corroded. This research aimed to find out the surface roughness and contour shape of the flange after being used to tighten the gasket. This study employed a method of measuring the surface roughness before and after the first, second, third, and fourth tightening. The flange used had a surface roughness of Ra 3.5µm, Ra 2.5 µm and Ra 1.5 µm. The measurement of surface roughness was based on the standard of JISB0601-2001. The findings show that no significant change occured on the flange surface roughness. However, the corrugated contour shape did occur in the surface roughness after use.

Cylinder Head Gasket Fretting Simulation for High Horse Power Engine

<div class="section abstract"><div class="htmlview paragraph">The head gasket of an internal combustion engine acts as a critical seal between its cylinder block and heads. Typically, and ideally, a high horse power engine head gasket will be composed of elastomer fluid sealing elements in a carrier and combustion seal body composed of aluminum, brass, carbon steel, copper, nickel, and/or stainless steel etc. The head gaskets purpose is to seal high pressure combustion gases, coolant, and oil and to ensure no leakage of gases or fluids out of the block to head joint.</div><div class="htmlview paragraph">Three major failure modes [<span class="xref">1</span>] for cylinder head gasket joint are; 1. Fluid or gas leakage due to low sealing pressure. 2. Head gasket (bead) cracking due to high gap alternation and 3. Gasket scrubbing/fretting due to pressure and temperature fluctuations causing relative movement in the joint. During engine operation, the head gasket design should be robust enough to prevent all failure modes and provide acceptable performance. Sealing analysis method to address low sealing pressure failure mode is well developed and common within the industry. This paper is focused on the development and utilization of an analytical method for the 3<sup>rd</sup> failure mode mentioned above i.e., scrubbing/fretting. Single layer metal gasket is considered during the scope of mentioned method. Single layer metal gasket gets locally yielded due to the design feature provided on the cylinder liner, called as bite ring.</div><div class="htmlview paragraph">During the scope of work, head gasket fretting mechanism is investigated. Based on the understanding of the fundamental fretting mechanism, considering Ruiz model [<span class="xref">2</span>], an analysis procedure is developed and finite element analysis results are correlated with actual failures and measured data. Finite element analysis results shows very good correlation in terms of relative sliding magnitude and failure location prediction. Commercial software ANSYS is used here. Actual gasket crushing is simulated by using 3D solid elements with non-linear material and geometric non linearity captured.</div></div>

Prediction of Leakage Rates Through Sealing Connections with Metallic Gaskets

According to fractal theory, the leakage model of metallic gaskets was developed in order to predict leakage rate of metallic gasket sealing connections. The relationship among the leakage rate, the fractal dimension, the compressive stress and the scale coefficient obtained by experiment, is approximately the same as that by the sealing model of metallic gaskets, which indicates that the sealing model of metallic gaskets established in this paper is reasonable. The research results not only are helpful for the development and application of metallic gaskets, but also contribute to the establishment of the design criterion and the design method of metallic gasket connections.

Stress and thickness calculation of a bolted flat cover with double metal sealing rings

The design of a bolted flat cover is extremely important for the structural integrity of pressure vessels. The present design codes provide the thickness calculation equations for a bolted flat cover with single metal gasket. However, the rules for a bolted flat cover with double metal sealing rings are not developed to date. In the study, a new thickness calculation equation for the bolted flat cover with double metal sealing rings is proposed. First, the theoretical stress solution for bolted flat cover with the double metal sealing rings is obtained, based on the theory of simply supported circular plate and then verified using the results from finite element analyses. The results indicate that the influence of double metal sealing ring on the stress of the flat cover is more serious compared to single metal gasket. Second, a more accurate and reasonable equation is proposed to calculate the thickness of bolted flat cover with double metal sealing rings based on the derived theoretical equations of maximum stress. Finally, the influence of linear load and the spacing between rings on the thickness are discussed. Subsequently, a few suggestions are provided to design low-pressure or atmosphere pressure vessels. The study provides a theoretical foundation to develop design codes of pressure vessels in nuclear reactors.

Simulation Analysis of 25A-Size Corrugated Metal Gasket Coated Copper to Increase Its Performance

Previous study, researchers investigated on 25A-size corrugated metal gasket using material SUS304 and it modified. The elastic model design of corrugated metal gasket still leakage and need high axial force for tightening process. The purpose of this study is to analyze coated corrugated metal gasket by FEM simulation. Experimental result used for validating the data. The characteristic of coating material should softer than base material. The coating material will stick and fill in the surface roughness of gasket. The simulation result shows that contact width increase and contact stress decrease after the gasket coated by copper. It mean that the gasket performance increase to stop the leakage.

Study on Seal Characteristics of Laminated Metal Gasket Using Spring Effect

Study on Seal Characteristics of Laminated Metal Gasket Using Spring Effect

Comparison of permeation of atmospheric gases through Viton O-ring gaskets for different initial conditions

Viton O-ring gaskets are frequently used in high vacuum for demountable flange and vacuum valve seals. Atmospheric gases, particularly water vapor from humid air, permeate through Viton gaskets and thus limit the lowest attainable pressure level in vacuum systems. In this work, a comparison of a vacuum degassed Viton O-ring gasket and a gasket fully saturated with atmospheric gases was performed. A reference measurement with an alternative soft metal gasket for Klein Flange type flanges was also made. The permeation rate of each individual gas from the atmosphere (water vapor, N2, O2, Ar, and CO2) through the Viton O-ring was measured using quadrupole mass spectrometry. The partial gas flow curves Q(t) were also modeled using finite difference modeling (FDM). Using FDM, one can determine the diffusion constant, permeability, and solubility of the gas in the material.

Numerical Simulation to Determine Design Factors V-Block of Fluid Control System for Semi-Conductor Manufacturing Lines

Worldwide semi-conductor market has been growing from long time ago. Manufacturing lines of semi-conductors needs to handle several kinds of toxic gases. Especially, they have to be significantly accurately controlled in real time. This kind of toxic gas control system consists of many different kinds of part, for example, fittings, valves, tubes, filters and regulators. These parts obviously have to be precisely manufactured as well as corrosion resistant because they have to keep on controlling high pressure gases without any leakage. For this, surface machining and hardening technologies of metal block and metal gasket have to be studied. This study unfortunately depends upon various factors, for example, geometric shapes, part materials, surface hardening method and gas pressures. This study presented in the paper strongly concerned on a series of simulation processes about the differences between inlet and outlet pressures under considering several different fluid velocities, tube diameters, V-angles. In fact, it can be expected that this study will very helpful to determine important design factors as well as precisely manufacture these parts. For this, “Fluent” was used and simulation results were analyzed.

Theoretical investigation of the compression limits of sealing structures in complex load transferring between subsea connector components

This paper provides a theoretical method for calculating the compression limits of a subsea connector's sealing structure to prevent natural gas leakages. The amount of compression deformation is related to the compressive load between contact surfaces. Because of the different compressive loads on the gasket under preloading and operation conditions, the amount of compression will change. Therefore, the load transmission relations between subsea connector components are first analyzed under different working conditions, and the relationship between the sealing contact load and the locking force is obtained. Secondly, a contact model between the lenticular gasket ring and hubs is established on the basis of Hertz contact theory. An analytical equation for the amount of compression is deduced. Considering the demands for sealing and strength, compression limit equations are put forward. In order to apply the compression limits equations, an optimization model is built for a locking mechanism, and the structure design parameters of one certain subsea connector are optimized. This study provides a theoretical method and guidance for the structural design of subsea connectors with a metallic lenticular gasket.

Analysis of Contact Width and Contact Stress of Three-Layer Corrugated Metal Gasket

Analysis of Contact Width and Contact Stress of Three-Layer Corrugated Metal Gasket

Enhancement of Real-Time THz Imaging System Based on 320 × 240 Uncooled Microbolometer Detector

A real-time terahertz (THz) imaging system was demonstrated based on a 320 × 240 uncooled microbolometer detector combined with a 2.52 THz far-infrared CO2 laser. On the top of micro-bridge structure (35 × 35 μm2), a 10 nm nickel-chromium (NiCr) thin film was deposited to enhance THz absorption, which was fabricated by a combined process of magnetron sputtering and reactive ion etching (RIE). By mechanical simulation using design of experiment (DOE) method, the minimum deformation was optimized to 0.0385 μm, and a measured deformation of 0.097 μm was achieved in the fabrication. The fabricated micro-bridge pixel was used for THz detection, and a responsivity of 1235 V/W was achieved with a noise equivalent power (NEP) of 87.4 pW/Hz1/2. THz imaging of metal gasket covered by label paper, paper clip in an envelope, and watermark of a banknote was demonstrated by a combination of histogram equalization (HE) and linear enhancement algorithm.

Gamma Ray Measurements at OMEGA with the Newest Gas Cherenkov Detector “GCD-3”

Initial results from the newest Gas Cherenkov Detector (GCD-3) are reported demonstrating improved performance over previous GCD iterations. Increased shielding and lengthening of the Cherenkov photon optical path have resulted in a diminished precursor signal with increased temporal separation between the precursor and the primary DT Cherenkov signal. Design changes resulted in a measured GCD-3 sensitivity comparable to GCD-1 at identical 100 psia CO2 operation. All metal gasket seals and pressure vessel certification to 400 psia operation allow for a GCD-3 lower Cherenkov threshold of 1.8 MeV using the fluorinated gas C2F6 as compared to the 6.3 MeV lower limit of GCD-1 and GCD-2. Calibration data will be used to benchmark GEANT4 and ACCEPT detector models. The GCD-3 acts as a prototype for the Super GCD being fielded at the National Ignition Facility (NIF) as part of the National Diagnostics Plan and will be installed at NIF in early 2016.