(FORGED FLANGES)
In this method, the flange is produced from round sections of forged metal by turning, or the raw material of the metal is placed inside the forging mold and the forging operation is performed on it until the overall shape of the flange is obtained, and then it is turned. Forging operation means beating a metal piece at high temperature in order to improve its mechanical properties. Forged flanges with ASTM A105 standard for material and mechanical properties are the most resistant type of flanges and are the best choice for industrial uses and high temperature and pressure conditions.
Cast flange or cast flange
These flanges, which are also known as cast iron flanges, are often used for water and sewage lines, urban uses, and generally low temperatures and pressures. In order to make these flanges, first the desired metal melt is cast in the flange mold and in the next step, the final shape of the flange is produced by turning. Due to the possibility of cracks, internal cracks, porosity and inhomogeneity of the internal metal structures in the cast piece and their complete destruction by methods such as heat treatment, it is not possible to use cast flanges for industrial purposes and temperature and pressure. used above and the industrial use of these flanges carries the risk of explosion and life risks, and since it cannot be determined after turning that the flange is cast, metallographic testing is recommended for sensitive uses.
Flange produced from sheet metal
In this method, the flange is produced directly by turning the metal sheet, and most of the PN flanges in the market are produced by this method. Since in the production process of sheet metal, rolling is done on it, the possibility of porosity and cracks in these flanges is less than that of cast flanges, and hence they have higher resistance than cast flanges, but compared to forged flanges. They have less resistance and are suitable for low to medium temperature and pressure applications. Usually, rocket and spectacle flanges, blind flanges and flat PN flanges or slipon flanges are made in this way, which are supplied in PN10 and PN16 pressures and with ST37 material. It is not economical to make a throat flange from sheet metal, and if you encounter it, you should suspect that the flange is defective.
Standard material for making forged flanges
- ASTM A105: Forged carbon steel
- ASTM A182: Forged stainless steel
- ASTM A350: Forged alloy steel suitable for low temperatures and with high toughness
- ASTM A694: Forged alloy steel with special mechanical properties
