Flanges and their connection materials
Flanged connections - most common way of connecting steel industrial pipelines to each other. Used in pipes of water supply systems, main heating, gas supply, oil and gas pipelines. Also, flange connections are used to connect pipelines to devices and process vessels, most often heat exchangers. In this case, the flange is welded to the ends of the pipes, with fedded fitting. An insulated flange is a coupling used in metal pipes to interrupt the path of electrical currents in them and prevent galvanic corrosion in pipelines. Insulated flange kits contain an electrically insulating flange gasket, insulating bolt sleeves and insulating bolt washers to prevent current passing through the bolts, as well as backup washers from zinc coated carbon steel.
Flanged joints are a quick-disconnect alternative to welded and couplable conections. The tightness of the connection is achieved through the use of seals made of rubber or fluoroplastic. Also can be used obturators - steel plugs, installed between two flanges.
Depending on the functional purpose, the following types of flange connections are distinguished: for joining pipes and installing shut-off valves (withstanding pressure from 0.1 to 20 MPa), and for connecting to pipelines of vessels and equipment.
Bolts for flange connections, as well as most bolts with a hexagon head, are manufactured in two ways: First - groove, when the hexagon is taken and the excess metal is removed from the lathe with it. As a result of such a groove, a blank is obtained in the form of a circular leg with a hexagonal head. The second is the stamping of such a billet from the circle. Bolts can be manufactured with different strength classes: 5.8, 8.8, 10.8, 12.9. The higher the bolt strength class, the harder the bolts. Bolts can be manufactured with different coatings. The most popular coating of bolts for flanges is galvanizing. Hexagon bolts for flanged galvanized joints are less susceptible to corrosion and remain in good condition longer. If the environment in which bolts for flange connections are used is aggressive, such as oil, gas or various acids, such bolts are made of stainless steel grades.
Our company can supply bolts for flange joints from different steel grades, such as: steel 20, 35, 40x and 09g2s (bolts for flange connections steel, bolts for flanged galvanized connections), steel 12x18n10t, 14x17n2, 20x13 and 10x17n13m2t (bolts for flanged stainless compounds) and others.
Sealing the flange connections directly affect the working pressure that the pipeline can withstand during operation, as well as the reliability and safety of the system as a whole. When selecting the gasket material, it is necessary to take into account the characteristics of the working environment of the pipeline - its pressure, temperature, corrosive and chemical aggressiveness, as well as the configuration of the joining flange plates.
Depending on the material of manufacture, all flange gaskets are classified into the following types:
- Non-metallic (made of rubber, fluoroplastic, paronite and asbestos cardboard);
- Steel (divided into subgroups in the form of section - oval and octagonal);
- Combined type (from thermally stabilized graphite or graphite fluoroplastic).
The most common are non-metallic gaskets made of paronite and rubber.
For more information and offer, please contact us.