There are mainly two systems of international pipe flange standards, namely the European pipe flange system represented by Germany DIN (including the former Soviet Union) and the American pipe flange system represented by the U.S. ANSI pipe flange. In addition, there are Japanese JIS pipe flanges, but in petrochemical installations are generally used only for public works, and have less impact in the international arena. Now the pipe flanges of various countries are introduced in the following.
1, Germany and the former Soviet Union as the representative of the European system pipe flange
2, the American system pipe flange standards, represented by ANSI B16.5 and ANSI B 16.47
3, the British and French pipe flange standards, two sets of pipe flange standards in each country.
In summary, the international common pipe flange standards can be summarized as two different, and not interchangeable pipe flange system: a European pipe flange system represented by Germany; the other is the American pipe flange system represented by the United States.
IOS7005-1 is a standard promulgated by the International Organization for Standardization in 1992, which is actually a pipe flange standard that combines two series of pipe flanges from the United States and Germany
Production Process of flange
The production process is mainly divided into four kinds: forging, casting, cutting and rolling.
(1) casting flange and forging flange
Casting out of the flange, the shape and size of the blank is accurate, small processing volume, low cost, but there are casting defects (porosity. Crack. Inclusions); casting internal organization of poor streamlined (if the cutting parts, streamline worse).
Forged flange generally contains less carbon than the casting flange is not easy to rust, forging good streamline, the organization is more dense, mechanical properties better than the casting flange.
Improper forging process will also appear large or uneven grain size, hardening cracking phenomenon, forging costs are higher than casting flange.
Forgings can withstand higher shear and tensile forces than castings.
the advantage of castings is that more complex shapes can be manufactured, the cost is relatively low.
the advantage of forgings is that the internal organization is uniform, there is no casting in the porosity, inclusions and other harmful defects.
Difference between casting flange and forging flange from the production process, such as centrifugal flange is a kind of casting flange.
Centrifugal flange belongs to the production of precision casting method flange, the casting than ordinary sand casting organization is much finer, the quality is improved a lot, not easy to appear tissue loosening, porosity, trachoma and other problems.
First of all, we need to understand how the centrifugal flange is produced, centrifugal casting to make flat welding flange process methods and products, which is characterized by the product after the following process steps are processed.
① the selected raw material steel into the medium frequency electric furnace melting, so that the temperature of the steel to 1600-1700 ℃.
② Pre-heating the metal mold to 800-900°C to maintain a constant temperature.
③ Start the centrifuge and inject the steel in step ① into the preheated metal mold in step ②.
④ Naturally cooling the casting to 800-900°C keeping 1-10 minutes.
⑤ Cool down with water to near room temperature, take off the mold and take out the casting.
Let's understand the production process of forged flanges again.
The forging process generally consists of the following procedures, namely, selecting high-quality billets for undercutting, heating, forming, and cooling after forging. The forging process methods are free forging, die forging and tire film forging. Production, according to the size of the forging quality, the number of production batch to choose different forging methods.
Free forging productivity is low, processing allowance is large, but the tool is simple, versatility, so it is widely used to forge the shape of a simple single piece, small batch production of forgings. Free forging equipment includes air hammer, steam-air hammer and hydraulic press, which are suitable for the production of small, medium and large forgings respectively. Die forging productivity is high, simple operation, easy to achieve mechanization and automation. Die forging parts have high dimensional accuracy, small machining allowance and more reasonable fiber tissue distribution of forgings, which can further improve the service life of the parts.
The basic process of free forging: In free forging, the shape of forgings is gradually forged into the billet through some basic deformation processes. The basic processes of free forging are upsetting, drawing, punching, bending and cutting, etc. 1.
Heading is the process of forging the original billet in the axial direction to reduce its height and increase its cross section. This process is often used to forge gear billets and other disc-shaped forgings. There are two types of upsetting: full upsetting and partial upsetting. 2.
2. Drawing is a forging process that increases the length and decreases the cross-section of a billet, and is usually used to produce shaft blanks such as lathe spindles and connecting rods.
3. punching A forging process in which a punch is used to punch through holes or not through holes in a billet.
4. bending The forging process of bending a billet into a certain angle or shape.
5. twist A forging process in which one part of a billet is rotated at an angle with respect to another part.
6. cutting The forging process of dividing the billet or removing the head.
(2) Die forging
Die forging is called model forging, in which the heated billet is placed in a forging die fixed on the die forging equipment.
1. The basic process of die forging Die forging process: the material, heating, pre-forging, final forging, punching even skin, cutting edge, tempering, shot peening. Commonly used processes are upsetting, drawing, bending, punching, forming. 2.
2. Commonly used die forging equipment Commonly used die forging equipment are die forging hammer, hot die forging press, flat forging machine and friction press.
Generally speaking, the quality of forged flanges is better, which are generally produced by die forging, with fine crystal organization and high strength, but of course, the price is also expensive.
Whether casting flange or forging flange are flange common manufacturing methods, depending on the strength requirements of the parts to be used, if the requirements are not high, you can also choose to turn the system flange.
(3) Cutting flange
In the plate directly cut out the flange of the inner and outer diameter and thickness of the disk with the amount of processing, and then the bolt hole and water line processing. The flange produced in this way is called cut flange, the maximum diameter of such flange is limited to the width of the plate.
(4) Rolled flange
Cut strips with the plate and then rolled into a round process is called rolling, mostly used in the production of some large flange. After the successful rolled welding, and then flattened, and then the waterline and bolt hole processing technology
