The Technical Hub
O-Ring Calculator
This interactive calculator assists engineers with selection of O-ring and hardware dimensions, and to form the basis of an O-ring installation.
Chemical Compatibility Checker
This interactive guide will help you choose a seal material based on existing compatibility test results of known chemicals and elastomers.
Interactive Engineering Calculators
Click here for volume, mass and compression set values for O-rings and rotary seal and hydraulic cylinder calculations.
Unit Converter
Our interactive conversion tools allow engineers to switch between units of measurement when preparing engineering calculations.
Engineering Tables
Our reference tables provide cross reference information for surface finish, metal hardness and polymer hardness measurement units.
Gold plated metal seals for Oil & Gas couplingsOur customer designs and manufactures hydraulic distribution products and systems used to control subsea production systems for the offshore energy industry globally.
The application
This seal application is for a range of dual resistant hydraulic couplings, designed to be suitable for make and break under full system pressure. There were three different sizes in the same design of coupling. We recommended a gold plated metal seal for this type of application. Read on to find out more about this project. The customer had been using a back-to-back elastomer O-ring arrangement, but wanted to develop a superior sealing solution in order to achieve a greater number of connect/disconnects per coupling (therefore improving the lifespan). The application itself was high pressure at 15,000 psi. The temperature range wasn’t particularly demanding compared to other Oil & Gas applications. However, because the couplings were for subsea equipment, there could be contact with well fluids and control fluids. As result the seals required NACE approval.
Our sealing solution
Our engineers recommended a metal seal for this application because of pressure and compatibility requirements with the various hydraulic fluids. The action of mating/de-mating the coupling meant this seal had to perform under a slightly dynamic movement. The seal base alloy was NACE MR0175 heat treated to obtain the standard desired properties for oil and gas specific application service; (when a material that does not comply with the NACE MR0175 heat treatment requirement is exposed to H2S, catastrophic failure can take place). Gold plating of the seal was recommended due to its malleability and suitability for slightly dynamic operation. Our metal seal solution was extensively cycle tested and the customer confirmed that the new concept metal seal solution performed under the required conditions with no leakage.
Customer Satisfaction
This sealing arrangement extended the life of the couplings by achieving 100 connect/disconnect cycles before the seals needed changing. This was substantially higher than the original sealing solution and gold plated metal seals are now supplied in production quantities. For more on our expertise in the oil & gas industry, read HERE
Why use metal seals?The use of metal seals as an engineered sealing solution is appropriate where it is not possible to use elastomeric or polymer seals due to extremely demanding application requirements. For example, these could include applications with extremely high temperatures (300°C upwards) and pressures, intense radiation, cryogenic conditions or highly aggressive chemicals.
How do metal seals work?
The metal seal concept is based on plastic and elastic deformation of the seal during compression which creates a sealing interface. The metal seal is compressed in the cavity on average about 20% of its original free height. The force generated through compression of the ring produces a high contact stress at the seal/cavity interface. This force is then supplemented by the pressure-energisation force which rises in proportion to the increase in differential pressure inside the seal cavity.
What types of metal seal are there?
There are three types of seal energisation; self, spring and pressure energisation. By design metal C-rings are self-energising due to the good spring back characteristic of the C-shaped profile. Additionally, they can be used in internal, external and axial pressure conditions. The different base material characteristics and heat treatments, along with material thickness, and cross section of the seal also determine the compressive load. This is directly related to the sealing level achieved and is known as “self-energisation”. Spring energised seals have excellent spring back properties and are typically used to improve leakage rates by increasing the load on the sealing interface. All metal seals can use system pressure to generate a hydrostatic load to obtain the highest level of sealing possible; this is known as pressure energisation. At high pressures this becomes an advantage and allows the design of metal seals for applications of 25,000 PSI and above.
Ultimate seal performance
Once the metal seal profile and material has been selected depending on the application, there are a variety of platings and coatings available. These can modify the surface properties of the seal to create a malleable outer surface layer. Typically precious metals such as gold and silver are used for plating, but many other options are available with two common ones also being Tin or PTFE. This layer ensures optimum sealing despite any mating surface imperfections. The plated or coated layer also reduces coefficient of friction so the seal can slide and bed down during initial compression. Consequently, this prevents galling. As well as providing better physical properties to the seal, coatings and platings are chosen to withstand high temperatures and aggressive (often corrosive or oxidizing) environments. There are ever changing industry demands and fast paced technology developments – particularly from customers in the Oil & Gas, Aerospace & Defence and Automotive markets. Therefore, we are challenged daily with applications where the boundaries are being pushed to the absolute limit. We have designed metal seals into F1 car exhaust systems, subsea repeaters, oil and gas production valves as a few examples; the capabilities of high performance metal seals is endless. Working with the latest developments in materials, platings and manufacturing technology; our engineering team design the sealing solutions to meet the complex specifications these types of application demand. Learn more about metal seals HERE
Tools
O-Ring Calculator
This interactive calculator assists engineers with selection of O-ring and hardware dimensions, and to form the basis of an O-ring installation.
Chemical Compatibility Checker
This interactive guide will help you choose a seal material based on existing compatibility test results of known chemicals and elastomers.
Interactive Engineering Calculators
Click here for volume, mass and compression set values for O-rings and rotary seal and hydraulic cylinder calculations.
Unit Converter
Our interactive conversion tools allow engineers to switch between units of measurement when preparing engineering calculations.
Engineering Tables
Our reference tables provide cross reference information for surface finish, metal hardness and polymer hardness measurement units.
Articles
Gold plated metal seals for Oil & Gas couplingsOur customer designs and manufactures hydraulic distribution products and systems used to control subsea production systems for the offshore energy industry globally.
The application
This seal application is for a range of dual resistant hydraulic couplings, designed to be suitable for make and break under full system pressure. There were three different sizes in the same design of coupling. We recommended a gold plated metal seal for this type of application. Read on to find out more about this project. The customer had been using a back-to-back elastomer O-ring arrangement, but wanted to develop a superior sealing solution in order to achieve a greater number of connect/disconnects per coupling (therefore improving the lifespan). The application itself was high pressure at 15,000 psi. The temperature range wasn’t particularly demanding compared to other Oil & Gas applications. However, because the couplings were for subsea equipment, there could be contact with well fluids and control fluids. As result the seals required NACE approval.
Our sealing solution
Our engineers recommended a metal seal for this application because of pressure and compatibility requirements with the various hydraulic fluids. The action of mating/de-mating the coupling meant this seal had to perform under a slightly dynamic movement. The seal base alloy was NACE MR0175 heat treated to obtain the standard desired properties for oil and gas specific application service; (when a material that does not comply with the NACE MR0175 heat treatment requirement is exposed to H2S, catastrophic failure can take place). Gold plating of the seal was recommended due to its malleability and suitability for slightly dynamic operation. Our metal seal solution was extensively cycle tested and the customer confirmed that the new concept metal seal solution performed under the required conditions with no leakage.
Customer Satisfaction
This sealing arrangement extended the life of the couplings by achieving 100 connect/disconnect cycles before the seals needed changing. This was substantially higher than the original sealing solution and gold plated metal seals are now supplied in production quantities. For more on our expertise in the oil & gas industry, read HERE
Why use metal seals?The use of metal seals as an engineered sealing solution is appropriate where it is not possible to use elastomeric or polymer seals due to extremely demanding application requirements. For example, these could include applications with extremely high temperatures (300°C upwards) and pressures, intense radiation, cryogenic conditions or highly aggressive chemicals.
How do metal seals work?
The metal seal concept is based on plastic and elastic deformation of the seal during compression which creates a sealing interface. The metal seal is compressed in the cavity on average about 20% of its original free height. The force generated through compression of the ring produces a high contact stress at the seal/cavity interface. This force is then supplemented by the pressure-energisation force which rises in proportion to the increase in differential pressure inside the seal cavity.
What types of metal seal are there?
There are three types of seal energisation; self, spring and pressure energisation. By design metal C-rings are self-energising due to the good spring back characteristic of the C-shaped profile. Additionally, they can be used in internal, external and axial pressure conditions. The different base material characteristics and heat treatments, along with material thickness, and cross section of the seal also determine the compressive load. This is directly related to the sealing level achieved and is known as “self-energisation”. Spring energised seals have excellent spring back properties and are typically used to improve leakage rates by increasing the load on the sealing interface. All metal seals can use system pressure to generate a hydrostatic load to obtain the highest level of sealing possible; this is known as pressure energisation. At high pressures this becomes an advantage and allows the design of metal seals for applications of 25,000 PSI and above.
Ultimate seal performance
Once the metal seal profile and material has been selected depending on the application, there are a variety of platings and coatings available. These can modify the surface properties of the seal to create a malleable outer surface layer. Typically precious metals such as gold and silver are used for plating, but many other options are available with two common ones also being Tin or PTFE. This layer ensures optimum sealing despite any mating surface imperfections. The plated or coated layer also reduces coefficient of friction so the seal can slide and bed down during initial compression. Consequently, this prevents galling. As well as providing better physical properties to the seal, coatings and platings are chosen to withstand high temperatures and aggressive (often corrosive or oxidizing) environments. There are ever changing industry demands and fast paced technology developments – particularly from customers in the Oil & Gas, Aerospace & Defence and Automotive markets. Therefore, we are challenged daily with applications where the boundaries are being pushed to the absolute limit. We have designed metal seals into F1 car exhaust systems, subsea repeaters, oil and gas production valves as a few examples; the capabilities of high performance metal seals is endless. Working with the latest developments in materials, platings and manufacturing technology; our engineering team design the sealing solutions to meet the complex specifications these types of application demand. Learn more about metal seals HERE
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Product Range
Our seal products range from simple static O-rings to complex and bespoke seal designs in specialist materials. Whatever your application, we have the seal product for you.
