Titanium flange sealing surface 7 kinds of form comparison: FF/RF/MFM/TG/RJ/LM/convex once clear
Published by Engineering Team, Shaanxi Qianyi Tuoda Technology Co., Ltd on 2026-08-06
Titanium flangeMaterial selection Many customers only pay attention to material grade and pressure grade, For example, choose TA2 material, PN2.5 pressure rating, However, the type selection of sealing surface is ignored.Once the sealing surface selection error, even if the material is qualifiedTitanium flangeThere may also be a media leakage problem within 1 to 2 years.Shaanxi Qianyi Tuoda has many years of titanium non-standard parts processing experience, Customer body materials are often encountered in project docking, Pressure parameter selection is correct, But the sealing surface selection error, Eventually, the pipeline leaked and shut down.This article explains 7 categories in detail
Titanium Flangestructural characteristics of sealing surface, combined dielectric properties, Pressure rating and engineering case, Help engineering and procurement staff to completeTitanium flangeAccurate selection of sealing surfaces.
One or seven.Titanium flangeDetailed explanation of sealing surface structure characteristics
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FF Full-plane sealing surface, The whole end face of flange is sealing contact surface, Used with full flat gasket, Low processing difficulty.Uniform stress on sealing surface, Not easy to crush lining equipment, Mostly for low pressure, Non-toxic medium condition, Low pressure rating, Not suitable for high pressure, Strong corrosive medium.The disadvantage is that the gasket pressure area is large, requiring greater bolt pre-tightening force, and the sealing anti-fluctuation ability is weak.
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RF raised sealing surface, The most widely used sealing form in industry, A ring of convex sealing ring exists on the flange end face, Bolt pressure is concentrated on the ring belt, Improve gasket compaction effect.A wide variety of adapter gaskets, Non-metallic flat pad, spiralwound gasket, All coated gaskets can be used, PN2.5 This kind of low pressure caustic soda, Seawater pipeline, RF salient surface is preferredTitanium flange。Strong versatility, moderate processing cost, chemical industryTitanium flangeGeneral selection.
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MFM Concave-convex sealing surface, A convex flange and a concave flange are used in pairs, the space is placed inside that concave surface, can effectively prevent the gasket from being pressed and extruded, and that medium scour resistance is bet than that of the RF convex surface.Suitable for medium pressure, slightly fluctuating corrosive medium, heat exchanger inlet and outlet pipelines often choose MFMTitanium flange;The disadvantage is that the flange must be paired and processed, and cannot be exchanged with ordinary RF flanges.
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TG groove face sealing face, Divided into tenon surface and groove surface, The gasket is completely embedded in the groove body, Gasket extrusion failure is almost impossible, High sealing reliability.Suitable for toxic, flammable and explosive, high-purity media and vacuum conditions. The gasket only contacts the media in the tank and is less subject to external interference.The processing cost is high, and the disassembly and maintenance have high requirements for field operation.
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RJ ring connection surface (RTJ), Flange end face processing trapezoidal annular groove, Metal-to-metal seal by means of metal ring gasket, Outstanding high temperature and high pressure resistance, Mostly used for high temperature and high pressure, Severe corrosion conditions, Such as high pressure chemical reaction lines.Strong sealing stability, thermal cycle shock;The disadvantage is that the processing accuracy is high, the metal ring pad is mostly disposable, and the procurement cost is higher.
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LM Large concave convex, An upgraded version of the MFM bump, Greater bump contact area, Higher tolerance for machining tolerances, Mostly used for pressure vessel equipment nozzle.Reduce the risk of seal failure due to misalignment, Suitable for large titanium equipment barrel connection, Pressure stability is better than conventional MFM concave surface.
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convexity, which is commonly referred to as a single convex surface., Flanges on one side only with raised seal ring, the other flange is flat, Multi-use for equipment pre-fabricated supporting scenes, Relatively limited usage scenarios, Generally not used alone for long distance pipelines.
II. Principles of medium matching and pressure grade selection
According to the characteristics of the medium divided into five categories of working conditions, clear water, Low pressure salt water is a non-corrosive medium., Priority FF or RFChlorine ion corrosive media such as caustic soda and seawater, RF is selected for normal working conditions, and MFM is selected for large pressure fluctuation;TG mortise surface is recommended for toxic and volatile medium;High temperature and high pressure corrosion medium is RJ ring connection surface;For large pressure vessel equipment nozzle, LM large concave convex surface is preferred.
Pressure rating is divided into five sections: low pressure PN≤2.5, priority FF, RF;Medium voltage PN4~PN16, RF, MFM recommended;Medium and high voltage PN25~PN63, MFM or TG selected;HV PN≥100, RJ ring connection surface;Large pressure vessel nozzle, LM large concave convex surface selected according to equipment design.
Combined with 5 real engineering cases simple reference: caustic soda low pressure circulation pipeline, TA2 PN2.5Titanium flangeRF salient surface is selected for long-term stable operation;Inlet and outlet of seawater desalination heat exchanger, pressure fluctuation is large, MFM concave and convex surface is selected;Fine chemical toxic medium rectification tower pipeline, TG mortise surface;RJ ring connection surface shall be selected for outlet pipeline of high temperature and high pressure titanium reactor;Large titanium tank nozzle, LM large concave convex.
Selection needs attention,Titanium flangeAfter the sealing surface processing is completed, it should be well protected, Avoid titanium sealing surface collision scratch, Small scratches can cause gasket seal failure.TA2 titanium flange processing sealing surface, need to control the surface roughness, ensure gasket fit.It is strictly prohibited to mix different types of sealing surfaces directly, for example, RF flanges cannot be directly butted with TG groove flanges.
Relying on the advantages of Baoji China Titanium Valley Industrial Cluster, Shaanxi Qianyi Tuoda Technology Customizable TA 2, TA10 and other materials all kinds of sealing surface titanium flange, Support non-standard size processing, Flange processing strictly follows titanium related standards, Material inspection report can be provided, Adapting chemicals, Marine Engineering, Environmental protection equipment and other corrosion conditions of pipelines and equipment.
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data sources, HG/T 20592 Standard for Steel Pipe Flanges, Titanium flange processing engineering experience, Specification for flange type selection of chemical equipment
disclaimer, Titanium flange sealing surface selection needs to be combined with the project medium, temperature, Integrated pressure assessment, It is recommended that the flange of special pressure equipment be designed and selected by professional engineers.