High-pressure flanges are mainly used in pipeline installation. They connect pipelines or equipment with pressures higher than 10MPa. High-pressure flange connections are an important connection method for pipeline construction. They connect pipes and play a critical role in fixing pipes, fittings, or equipment onto a flange plate using bolts and gaskets. Some fittings and equipment come with their flange plates, including traditional high-pressure flanges and self-tightening flanges.
Classification By Material
Carbon Steel: ASTM A105, 20#, Q235, 16Mn, ASTM A350 LF1, LF2 CL1/CL2, LF3 CL1/CL2, ASTM A694 F42, F46, F48, F50, F52, F56, F60, F65, F70
Stainless Steel: ASTM A182 F304, 304L, F316, 316L, 1Cr18Ni9Ti, 0Cr18Ni9Ti, 321, 18-8;
Alloy Steel: ASTM A182 F1, F5a, F9, F11, F12, F22, F91, A182F12, A182F11, 16MnR, Cr5Mo,
Imported materials: [1] (nickel steel), WC5 (1.25% chromium 0.5% molybdenum steel), WC9 (2.25% chromium), C5 (5% chromium % molybdenum), C12 (9% chromium 1% molybdenum), CA6NM (4 (12% chromium steel), CA15 (4) (12% chromium), CF8M (316 stainless steel), CF8C (347 stainless steel), CF8 (304 stainless steel), CF3 (304L stainless steel), CF3M (316L stainless steel), CN7M (alloy steel), M35-1 (monel), N7M (Hastellite B), CW6M (Hastellite C), CY40 (Inconel)
The Production Standards Of High-Pressure Flanges
Ministry of Electric Power Standard GD0506~0507
Corresponding standards for flanges and tube sheets for pressure vessels: JB/T4700~4707-2000 National Standard (GB/T9112-2000)
Ministry of Machinery Standard (JB81-59, JB/T74-94)
Ministry of Petrochemical Standard (SH3406-96)
Ministry of Chemical Standard (HG5010-58, HG20592-97), etc.
USA ANSI B16.5
Japan JIS 2220
Germany DIN Standard
Introduction to Traditional High-Pressure Flanges
Traditional high-pressure flanges: They use the plastic deformation of sealing gaskets (elliptical gaskets, octagonal gaskets, lens gaskets, etc.) to achieve a sealing effect. They are connected to the ends of pipes to connect pipes to each other. There are holes on the flanges, and stud bolts connect the two flanges tightly.
Product Features Of High-Pressure Flanges
- High-pressure flanges are connected by bolts;
- Its sealing principle is plastic deformation to achieve a sealing effect;
- High-pressure flanges are generally large in size, so they are heavy and relatively difficult to install and position;
- The bolts of high-pressure flanges must withstand tension, temperature difference stress, bending moment, torque, and many other external forces;
- Traditional high-pressure flange products have relatively strict requirements on temperature, pressure, and medium, so their sealing performance is relatively unstable, and it is easy to leak.
Application Features Of High-Pressure Flanges
High-pressure flanges are mainly used in pipeline installation and are an important connection method for pipeline construction. They connect pipes by fixing them with flange plates, bolts, and gaskets. Some pipe fittings and equipment come with pre-installed flange plates, which also fall under flange connections. Performance is a key consideration for high-pressure flange products.
The ceramic composite steel pipe has a lining ceramic layer with over 95% Al2O3 content and a microhardness of HV1000-1500, providing exceptional wear resistance. Additionally, ceramics are chemically stable and neutral, offering excellent corrosion and acid resistance.
High-Pressure Self-Tightening Flange
Since its invention in the 1950s, the high-pressure self-tightening flange has been widely used in petroleum and petrochemical industries, oil and gas mining, industrial gas production, oil refining, food processing, the chemical industry, environmental engineering, minerals and nuclear power, aerospace, the shipbuilding industry, synthetic fuel processing, coal oxidation and liquefaction, and other fields.
In the Chinese market, such products depend entirely on imports, and no domestic company can design and produce them. Until 2005, Chengdu Zhiyuan Machinery Technology, a domestic company, broke this situation. It produced China’s high-pressure self-tightening flange, ZY-LOC.
High-pressure self-tightening flange: This is a new type of high-pressure flange that is more conducive to pipeline connection under harsh working conditions, such as high pressure, high temperature, and high corrosion.
Traditional flanges rely on the plastic deformation of the sealing gasket to achieve the sealing effect, which is a soft seal. The core of the high-pressure self-tightening flange is a unique new type of seal; that is, the elastic deformation of the sealing lip (T-shaped arm) of the sealing ring forms a seal, which is a hard seal.
The combination of the sleeve ribs, the ferrule, and the sealing ring forms a strong, rigid body, making the connection part far greater than the strength of the pipe base material itself. When under pressure, the ribs and lips provide strength and create a self-tightening seal.
But also strengthen the pipeline, greatly enhancing the overall strength of the connection. In this field, progress is epoch-making!
Product structure of high-pressure self-tightening flange: Generally, each set of high-pressure self-tightening flange consists of a ferrule, a sleeve, a sealing ring, and a bolt.
- Metal sealing ring: The sealing ring is the core of the high-pressure self-tightening flange, and its cross-section is similar to a “T” shape.
- After the flange is assembled, the ribs of the sealing ring are clamped by the end faces of the two sets of HUBs to form a whole with the mother pipe, which greatly improves the strength of the connection part; the two arms of the “T”-shaped section, namely the sealing lips, form a sealing area with the internal conical surface of the sleeve and extend freely under the action of external force (within the yield limit range) to form a seal.
- Hub: After the ferrule clamps the two hubs, they press on the ribs of the sealing ring, and the sealing lip deviates from the internal sealing surface of the hub. This deviation elastically returns the load of the internal sealing surface of the hub to the lip of the sealing ring, forming a self-enhanced elastic seal.
Ferrule: The ferrule can be freely adjusted in 360° direction during installation, which is convenient for installation.
- Four sets of ball bolts: Generally, each set of high-pressure self-tightening flange only requires four sets of tangential high-pressure ball bolts to complete the overall firmness.
Product Features Of High-Pressure Flanges
- Sealing method: The core of the high-pressure self-tightening flange is a unique, new metal-to-metal seal, that is, the elastic deformation of the sealing lip (T-shaped arm) of the sealing ring is used to form a seal, which is a hard seal; and then the ribs of the hub, ferrule, and sealing ring are combined to form a strong rigid body so that the strength of the connection part is far greater than the strength of the pipe base material itself. When under pressure, the ribs and lips play the role of strength and sealing respectively, which can not only self-tighten and seal, but also strengthen the pipeline, greatly enhancing the overall strength of the connection part
- Tensile resistance: In most cases, the high-pressure self-tightening flange in the connection can withstand tensile loads better than the pipeline itself; destructive tests have proved that after the pipeline fails under tensile load, this flange is still intact and leak-free.
- Bending resistance: Many tests have shown that this flange will not leak or loosen when subjected to large bending loads. Actual test: DN15 high-pressure self-tightening flange welded on the pipeline has undergone multiple cold bends, and the high-pressure self-tightening flange connection does not leak, and the bolts do not loosen.
- Compression resistance: In normal pipeline applications, high-pressure self-tightening flanges are not subjected to overload compression. When higher compression loads occur, the pipeline’s ultimate strength determines the maximum load on the flange.
- Impact resistance: The geometric dimensions are small and compact, and the flange can withstand impact forces that traditional high-pressure flanges cannot; the unique metal-to-metal sealing structure greatly enhances its impact resistance.
Corrosion resistance: Different material selections make its corrosion resistance meet the special anti-corrosion requirements of different use environments.
Product Application Of High-pressure flanges
Petroleum and petrochemical, chemical, military, metallurgical, electric power, shipbuilding, nuclear, and aerospace industries.
