Convenient connection method of welded flange connection

Flange is a component used to connect valves and pipelines. There are various types of flanges and various connection methods of flanges. Welding flange is only a kind of flange connection, and the connection mode of welding flange is a little troublesome, so it is used for some flanges with more difficult welding. The installation process of welding flange is complicated, and there are many manual and auxiliary materials used, and the connection mode of welding flange is also complicated. Rabbit will introduce it to you in detail.

First of all, we need to know how the centrifugal flange is produced, the process method and products of centrifugal casting to make flat welded flange, which are characterized in that the products are processed according to the following process steps:

(1) Put the selected raw steel into an intermediate frequency electric furnace for smelting, so that the temperature of molten steel reaches1600-1700℃;

(2) preheating the metal mold to 800-900 DEG C and keeping the temperature constant;

(3) star that centrifuge to inject the molten steel in step (1) into the preheated metal mold in step (2);

(4) naturally cooling the casting to 800-900 DEG C for 1- 10 minute;

(5) cooling to near normal temperature with water, demoulding and taking out the casting.

1. The grade and technical requirements of welded flanges shall meet the corresponding requirements of JB4726-4728.

Class I forgings are allowed for carbon steel and austenitic stainless steel forgings with 1 and nominal pressure PN of 0.25mp-1.0mpa..

2. Forgings with nominal pressure PN of 1.6MPa-6.3MPa shall meet the requirements of Grade II or above in addition to the following provisions.

3. When one of the following conditions is met, the requirements of Class III and forgings shall be met:

Flange forgings with nominal pressure pn ≥ 10.0mpa (1);

(2) Cr-Mo steel forgings with nominal pressure of PN & gt4.0 MPa;

(3) the nominal pressure PN > 0.00 1. 1.6MPa ferritic steel forgings with working temperature ≤-20 degrees Celsius.

2. Welded flanges are generally made of forgings or forging and rolling processes. When made of steel plate or section steel, the following requirements must be met:

1, the welded flange shall be subject to ultrasonic flaw detection, and there is no delamination defect;

2, should be cut into strips along the direction of steel bar rolling, bending and butt welding into a ring, and make the surface of the steel ring cylindrical. Steel plates shall not be directly processed into welded flanges with necks;

3. The butt weld of the circular ring should adopt full penetration weld;

4. The butt weld of circular ring shall be subjected to post-weld heat treatment and 100% X-ray or ultrasonic flaw detection, with X-ray flaw detection meeting the requirements of Class II of JB4730 and ultrasonic flaw detection meeting the requirements of? Class I requirements of JB4730.

Third, the transverse slope of the neck of the welding flange should not be greater than 7 O. The technical parameters of the welding flange should be strictly controlled in production and welding to ensure its full role and value in production and use.

manufacturing technique

Forging, Casting and Plate Turning System

slip-on weld flange

Connection form? Single-sided welding, double-sided nut connection.

Product features? Beautiful appearance, smooth surface, acid and alkali resistance, corrosion resistance and strong texture performance.

Production technology? Cutting in an oxygen furnace, integrally forging or forging, cutting and forming the finished product.

How to deal with it? High precision CNC lathe turning, CNC rocker arm drilling.

Product parameters:

(1) Diameter of central circle of bolt hole: 50mm-2 130mm.

(2) Bolt hole diameter: 1 1mm-30mm.

(3) Flange thickness:12mm-58mm.

(4) Outside diameter of pipeline? :? A( 17。 ? 2-2032MM)？ B( 14-2020MM？ )

(5) Inner diameter of flange: A( 18-2036MM? )? B( 15-2024 mm)

(6) Theoretical weight of flange: 0.36kg-234.6kg (DN 1800).

technical requirement

1. The grade and technical requirements of welded flanges shall meet the corresponding requirements of JB4726-4728.

Class I forgings are allowed for carbon steel and austenitic stainless steel forgings with 1 and nominal pressure PN of 0.25mp-1.0mpa..

2. Forgings with nominal pressure PN of 1.6MPa-6.3MPa shall meet the requirements of Grade II or above in addition to the following provisions.

3. When one of the following conditions is met, the requirements of Class III and forgings shall be met:

Flange forgings with nominal pressure pn ≥ 10.0mpa (1);

(2) Cr-Mo steel forgings with nominal pressure of PN & gt4.0 MPa;

(3) the nominal pressure PN > 0.00 1. 1.6MPa ferritic steel forgings with working temperature ≤-20 degrees Celsius.

2. Welded flanges are generally manufactured by forging or forging-rolling process. When made of steel plate or section steel, the following requirements must be met:

1, the welded flange shall be subject to ultrasonic flaw detection, and there is no delamination defect;

2, should be cut into strips along the direction of steel bar rolling, bending and butt welding into a ring, and make the surface of the steel ring cylindrical. Steel plates shall not be directly processed into welded flanges with necks;

3. The butt weld of the circular ring should adopt full penetration weld;

4. The butt weld of circular ring shall be subjected to post-weld heat treatment and 100% X-ray or ultrasonic flaw detection, with X-ray flaw detection meeting the requirements of Class II of JB4730 and ultrasonic flaw detection meeting the requirements of? Class I requirements of JB4730.

Third, the transverse slope of the neck of the welding flange should not be greater than 7 O. The technical parameters of the welding flange should be strictly controlled in production and welding to ensure its full role and value in production and use.

Flange is widely used, and this welding method bears great pressure, so it is widely installed in the boiler rooms of schools, large industrial workshops and some high-end hotels. Flange adopts mechanical principle, bears great pressure, is convenient for cutting and secondary welding, and is of great significance to the whole machinery industry. With the wide application of flange, flange technology is also improving. The above tutu introduces the latest connection method.

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