In the oil, gas, chemical and power industries, the safety and reliability of pipeline connections are of paramount importance.ASTM A105 lap joint flange has become the preferred connectors for high-pressure pipeline systems due to their unique structural design and excellent material properties.
The ASTM A105 lap joint flange is a state-of-the-art connection designed specifically for high-pressure piping systems and is made of carbon steel forgings that meet the requirements of the ASTM A105 standard. This flange is unique in its “loose fit” design – the flange ring is free to rotate while the weld ring is fixed to the pipe and the two are bolted together. This innovative construction solves many of the problems associated with traditional flange installations, and is particularly suited to piping systems that require frequent disassembly or alignment adjustments.
What Is a Lap Joint Flange?
Lap Joint flange is mainly composed of two parts: a stub end and a lap joint flange ring. The flange ring has bolt holes, which can be connected with another flange pair; the flanging or butt-welding ring is welded at the end of the pipe, which serves as the supporting structure of the flange ring, so that the flange ring can be free to rotate on the pipe.The design of this flange construction allows the flange ring to be separated from the stub end, providing flexibility in installation and removal, especially for pipe connections that require frequent disassembly or lined piping systems. Lap joint flanges are commonly used in the petroleum, chemical, and pharmaceutical industries for their ability to reduce material costs and simplify maintenance, as well as for their good corrosion resistance and adaptability.
Specification of Lap Joint Flange:
| Size Range | 1/2″ – 24” / DN15 – DN600 |
| Pressure Rating | Class 150, 300, 600, 900, 1500, 2500lb |
| Standard | ASME B16.5, EN1092-1 |
| Carbon Steel | ASTM A105 / A105N |
| Low Temp Carbon Steel | ASTM A350 LF2 / LF3 |
| Pipeline Steel | ASTM A694 F42 / 46 / 56 / 60 / 65 |
| Alloy Steel | ASTM A182 F11 / 12 / 5 / 9 / 91 / 92 |
| Stainless Steel | ASTM A182 F304/304L/304H, 316/316L, 310S, 317,347,904L |
| Duplex Stainless Steel | ASTM A182 F51, F53, F44 |
ASTM A105 Lap Joint Flange Material Analysis:
Chemical Composition:
The chemical composition of ASTM A105 lap joint flanges directly determines its mechanical properties, welding performance, corrosion resistance and stability. Strict control and testing of chemical composition is the basis for ensuring its reliable operation in harsh working conditions such as oil, gas and chemical industry.
| CHEMICAL | LIMITS | C | Mn | P | S | Si | Cu | Ni | Cr | Mo | V |
| ASTM A105 | MIN | 0.60 | 0.10 | ||||||||
| MAX | 0.35 | 1.05 | 0.035 | 0.040 | 0.35 | 0.40 | 0.40 | 0.30 | 0.12 | 0.08 |
Mechanical Properties:
The mechanical properties of ASTM A105 lap joint flanges are critical to their safe use under high pressure, high temperature, and continuous stress conditions. These properties are the core indicators that determine whether the flange can operate reliably and stably in demanding environments.
| MATERIAL | T.S (MPA) | Y.S (MPA) | EL % | R/A % | HARDNESS |
| ASTM A105 | 485 min | 250 min | 22 min | 30 min | 197 max |
Dimension of Lap Joint Flange:
ZIZI specializes in the production and supply of various types of lap joint flanges, which cover pressure values including 150#, 300#, 600#, 900#, 1500#, 2500#.
300# lap joint flange:
| Nominal Pipe Size | A | B | C | D | F | G | H | I | J | Weight | |
| inch | mm | mm | mm | mm | mm | mm | mm | Holes | mm | mm | kg / piece |
| 1/2 | 21.3 | 95.2 | 22.4 | 14.2 | 22.4 | 38.1 | 35.1 | 4 | 15.7 | 66.55 | 0.64 |
| 3/4 | 26.7 | 27.7 | 15.7 | 25.4 | 47.7 | 42.9 | 4 | 19.1 | 82.5 | 1. 12 | |
| 1 | 33.4 | 123.9 | 34.5 | 17.5 | 26.9 | 53.8 | 50.8 | 4 | 19.1 | 88.9 | 1.36 |
| 11/4 | 42.2 | 133.3 | 43.2 | 19 | 26.9 | 63.5 | 63.5 | 4 | 19.1 | 98.6 | 1.68 |
| 11/2 | 48.3 | 155.4 | 49.5 | 20.6 | 30.2 | 69.85 | 73.15 | 4 | 22.4 | 4.500 114.3 | 2.49 |
| 2 | 60.3 | 165.1 | 62 | 22.3 | 33.2 | 84 | 91.9 | 8 | 19.1 | 127 | 2.87 |
| 21/2 | 73 | 190.5 | 74.7 | 25.4 | 38.1 | 100 | 104.6 | 8 | 22.4 | 149.4 | 4.32 |
| 3 | 88.9 | 209.5 | 90.7 | 28.4 | 42.9 | 117.3 | 127 | 8 | 22.4 | 168.1 | 5.85 |
| 31/2 | 101.6 | 228.6 | 103.4 | 30.2 | 44.4 | 133.3 | 139.7 | 8 | 22.4 | 184.2 | 7.34 |
| 4 | 114.3 | 254 | 116.1 | 31.7 | 47.7 | 146 | 157.2 | 8 | 22.4 | 200.1 | 9.61 |
| 5 | 141.3 | 279.4 | 143.8 | 35 | 50.8 | 177.8 | 185.7 | 8 | 22.4 | 234.9 | 12.3 |
| 6 | 168.3 | 317.5 | 170.7 | 36.5 | 52.3 | 206.2 | 215.9 | 12 | 22.4 | 269.7 | 15.6 |
| 8 | 219. 1 | 381 | 221.5 | 41.1 | 61.9 | 260.3 | 269.7 | 12 | 25.4 | 330.2 | 24.2 |
| 10 | 273 | 444.5 | 276.3 | 47.7 | 66.55 | 320.5 | 323.9 | 16 | 28.4 | 387.3 | 34.1 |
| 12 | 323.8 | 520.7 | 327.1 | 50.8 | 73.15 | 374.6 | 381 | 16 | 31.7 | 450.8 | 49.8 |
| 14 | 355.6 | 584.2 | 359.1 | 53.8 | 76.2 | 425.4 | 412.8 | 20 | 31.7 | 514.4 | 69.9 |
| 16 | 406.4 | 647.7 | 410.5 | 57.15 | 82.5 | 482.6 | 469.9 | 20 | 35 | 571.5 | 88.1 |
| 18 | 457.2 | 711.2 | 461.8 | 60.45 | 88.9 | 533.4 | 533.4 | 24 | 35 | 628.7 | 109 |
| 20 | 508 | 774.7 | 513.1 | 63.5 | 95.2 | 587.2 | 584.2 | 24 | 35 | 685.8 | 134 |
| 24 | 609.6 | 914.4 | 616 | 69.85 | 106.4 | 701.5 | 692.2 | 24 | 41 | 812.8 | 201 |
Advantages of ASTM A105 Lap Joint Flange:
Convenient installation and flexible bolt hole alignment: the flange ring of the lap joint flange can be rotated freely without the need for precise adjustment of the bolt hole position, which greatly simplifies the installation process, and is especially suitable for piping systems with space constraints or the need for frequent disassembly.
Convenient maintenance, reducing long-term costs: when servicing, just loosen the bolts to replace the gasket or inspect the inside of the pipe, no need to cut and weld the joints, reducing downtime.
Good adaptability to vibration and thermal expansion: the lap joint structure absorbs pipe vibration and reduces stress concentration, suitable for vibration environments such as ships and compressors.
High degree of standardization and global application: Comply with international standards such as ASME B16.5 and ASTM A105 to ensure interchangeability, applicable to global engineering projects.
Areas of Application：
Oil & Gas Industry: Widely used in oil and gas transmission pipeline systems, especially in high pressure, high temperature environments, such as wellhead units, compressor stations and long distance oil/gas pipelines.
Chemical Industry：In chemical production, lap joint flanges are commonly used in reaction kettles, storage tanks and corrosive media (e.g. acid, alkali) transportation pipelines.
Power and Energy Industry：ASTM A105 LAPJ flanges are suitable for boiler feedwater systems, steam piping and heat pipe networks, and can withstand high temperature and pressure.
Shipbuilding and Marine Engineering：Ship piping systems often face vibration and seawater corrosion problems, the flexible connection of lap joint flanges can effectively absorb vibration and reduce stress concentration.
Water treatment and municipal engineering：In sewage treatment, water supply and drainage and pumping station systems, lap joint flanges are widely used for their convenient installation and low maintenance cost.
ZIZI specializes in the production of various flanges of different types and materials, and the products are widely used in many industries, such as petroleum, chemical, electric power, shipbuilding, pharmaceutical, food, construction and so on. The company has advanced production equipment and perfect testing means, including multiple cold drawing machines, cold rolling machines, automatic welding equipment, hydraulic testing machines, spectral analyzers, non-destructive testing equipment, etc., to ensure that each flange meets the relevant standards at home and abroad.
We are professional in manufacturing and exporting flanges in various materials.
