Flange: types, dimensions and marking of flanges and their drawings

Use the welds on the pipeline elements is not always convenient. In some places need to install additional products - valves, pumps. Then come to the aid of a flange - special parts for the connection of pipes where welding is not suitable. They are classified according to size, construction materials, surface type, and other criteria.

Flange - definition

According to the handbook of terminology, the flange - a flat piece with holes, protruding pipe connecting portion. The opening parts are mounted studs, bolts and other fasteners to help secure it on the pipe. Flange dimensions correspond to a particular pipe diameter, so often equips a tube manufacturer in advance such element.

The main requirement for the connection of pipes - sealing: this criterion is just provide the flange. It reliably tightens parts confers connection reliability, durability, the ability to use a wide temperature range. If you carry out timely maintenance, flange connection will last for many years. This type of parts manufactured according to GOST, however thereto have special requirements.

Design features flanges

At present, flanged pipe is one of the most popular and simple connections enable fast and reliable dock detail. This is due to design features:

• round (rarely square) shape;
• the presence of small holes around the perimeter;
• flat design;
• having a central core opening.

Detail demand in assembling a pipeline from the simplicity and speed. The user needs to insert the flange on the desired pipe diameter, and then fastened to the same device to another tube, if the docking of the two parts is carried out. Often pipe manufacturers already equip with a flange on the end product, which simplifies the operation. Repair flange required when present on the surface defects or broken seal the joint.

Where flanges are used?

This type of pipe is used for assembly, assembly of any flange occurs only in the presence of suitable diameter pipe. several areas of application components can be identified:

• Civil assembly central conduits;
• assembly of gas pipelines;
• installation of domestic water supply systems;
• installation of heating;
• assembly of industrial systems and communications.

These parts may be elements of the pipe shaft fitting or housing part. This is a universal product which when combined with the other components will provide a seal. Element withstand high temperature and pressure, however this type of fastening can be used in gas and water pipelines. Parameters, which are selected - the size, the shape of the sealing surface, and the method of fixing.

The main types of flanges

The first classification, on which you can share all kinds - constructive. According to her, there are basic types:

1. The flat weld - it looks like a metal ring with holes diameter. Fastened to the pipe due to the two circumferential welds.
2. Collar - apart holes diameter also equipped with a skirt weld. Simple to install, as the fixed one weld.
3. Free on the welded ring - consists of two elements: the flange and the ring with the same diameter and pressure. The ring is fixed to the pipe by welding, and the flange remains free to allow for easy installation.

These types of flanges used for docking valves and equipment. Specifically define the area where the item is used, the material help of its manufacturing.

What produce item?

The industry uses steel flanges, however steel, which is manufactured item, also be different. Marking steel flanges will determine under what conditions better use of this detail:

1. Steel 20 - the most used raw. This carbon steel, the details of it are used for the assembly of fittings on highways where the external temperature is lower than -40 degrees, and the internal data are not above 475 degrees.
2. 09G2S steel - steel alloys of nickel, chromium and molybdenum are designed for welding. Products made of this material can be used at an external temperature of -70 degrees.
3. 12X18H10T - cryogenic steel. Details of this material can be used in a corrosive environment, for example with alkalis and acids. Permissible temperature from - 196 degrees to 350 degrees.
4. 10X17H13M2T - corrosion-resistant carbon steel. Mounting of it operated in a particularly extreme conditions, because it maintains the resistance to stress corrosion. The operating temperatures from -196 to +600 degrees.
5. 15X5M - low-alloy heat-resistant steel. Such products have a high resistance to oxidation at + indicators 600-650 degrees.

These brands are the most used, but besides these manufacturers use other raw materials. There are polypropylene models - they are intended for joining polypropylene pipes with metal valves. The operating temperature for such a material is much lower than - 80 degrees. These included may sell shoulder flange - a special detail to create a flange made of polypropylene compounds.

Furthermore propylene steel and cast iron are used two kinds - gray and ductile. Details of ductile iron are used at operating temperatures of from -30 to +400 degrees, and gray cast iron - at a temperature of from -15 to +300 degrees.

pressure classes Flange

Parts manufactured according Asme standards (Asni) always characterized by a number of parameters. One such parameter is the nominal pressure. The diameter of the product must be consistent with its pressure according to established designs. Nominal diameter is denoted by a combination of letters "control" or "the DN", and then the numeral characterizing himself diameter. Nominal pressure measured in the "administration" or "to PN".

American system pressure classes correspond to translation in MPa:

• 150 psi - 1,03 MPa;
• 300 psi - 2,07 MPa;
• 400 psi - 2,76 MPa;
• 600 psi - 4,14 MPa;
• 900 psi - 6,21 MPa;
• 1500 psi - 10,34 MPa;
• 2000 psi - 13,79 MPa;
• 3000 psi - 20,68 MPa.

Translated MPa with each class will indicate the pressure flange kgf / cm². Pressure class depends where the selected item is used.

types of surfaces

This type of coupling fasteners may also be divided according to the type sealing surface. They are:

• A - the plane;
• B - the coupling protrusion;
• F - depression;
• E - protrusion;
• D, M - groove;
• C, L - stud;
• K - for lens gaskets;
• J - for the construction of an oval cross-section.

These types GOST recently been adopted, it is noted that the type of surface C, L, and E are issued only on demand and are stamped.

The height of the protrusion

If one looks at the drawing of the steel flange, it has several parameters, including the height of the protrusion. It is designated by the letters H and B, it can be measured in all types of products, except for the one having a lap joint. Keep in mind the following:

• model pressure class 150 and 300 will have a protrusion height of 1.6 mm;
• model pressure class 400, 600,900,1500, and 2000 have a height of 6.4 mm ledge.

In the first case, parts suppliers and manufacturers accounted surface of the projection, in the second case, the projection surface is not included in said parameter. The brochures to detail these parameters may be specified in inches, where 1.6 mm is 1/16 inch, and 6.4 mm - ¼ inch.

Geometry and proportion of products

An important parameter defining the geometry is conventional products pass. As already noted, it is denoted by the letters "control" and has rates from 10 to 200. This applies to the choice of the necessary details when the user knows Du, all the other dimensions are attributed to the flange automatically. For example, the model DN 50 will be equal to the height of the indentation 57-59; DN 80, the figure is 89-91 and DN 100 - 108-110, where the first number indicates the inside diameter of a tube or pipe, and the second - on the outer diameter.

Another important indicator - the weight of the flange. It depends not only on the volume, size and height, but also on its geometry, the manufacturing material. It is necessary to give an example: GOST 12820-80 flange DN 100 flat type has a weight of 2.85 kg, whereas the flange of the same diameter, but a collar type in accordance with GOST 12821-80 has a weight of 4.4 kg. From this it follows that the Collar flanges have a greater weight than the flat parts.

How is the flange connection?

When it is necessary to connect two parts of the steel pipeline is used to weld the flange to the pipe. This fixation is called a flange connection in the future makes it possible to disassemble the pipe to be repaired. To understand how the assembly, it is necessary to consider in detail the process:

1. For joining of the two elements are applied flat parts having a central hole, where a pipe end is inserted.
2. Along the perimeter of the ring has holes - are inserted in fastening elements: bolts, or studs with nuts.
3. Place the connection is detachable, so that it was sealed using gaskets. Flange connection is intended to join two pipes or pipe attaching to a container equipped with a flange-introducing pipe.

The flange can be done by hand - this detail is perfect on the grindstone for sharpening machine items.

Tools for the production of compound

To manually carry out the connection of two tube parts, it is necessary to prepare tools. Basically this equipment designed for the twisting by bolting flanges circumferentially:

• manual key;
• spanner;
• Pneumatic wrench Impact wrenches;
• hydraulic torque wrench;
• bolt tensioner hydraulic type.

Additionally need special lubricant, which is applied to both surfaces to avoid friction components and provide ease of torque. The sequence of operation is simple: at first the first spin the bolt, and then proceeds to a twist of which is diagonally at 180 degrees from the first. Next go to the bolt, disposed at an angle of 90 degrees from the second, and from there - to the contrary.

Tips from the Masters

There are a number of useful recommendations from professional artists to help the first time to cope with flange connection:

1. If the items have 4 holes, then tighten the bolts must be wise.
2. The surface of the structure must always be degreased and check for corrosion and rust.
3. It is recommended to only use the new gaskets, and the need to set them exactly in the center.
4. Tightening force should be uniform - the only way to provide a reliable and tight flange connection.

In the future to remove a flange using special machines that help to chisel it and loosen the bolts. Extract parts by hand is difficult, so use a pneumatic tools.

Compound pipes by means of flanges is convenient and reliable type of joining of the two parts. It helps in the future to repair the pipeline by removing connecting elements, while the welding is not allow to carry out this procedure. It is chosen in exact accordance with the operating conditions, temperature and diameter of the pipe.