304 stainless steel flange standard system and production process

There are two main international pipe 304 stainless steel flange standards, namely the European pipe 304 stainless steel flange system represented by German DIN (including the former Soviet Union) and the American pipe 304 stainless steel method represented by the American ANSI pipe 304 stainless steel flange. blue system. In addition, there are Japanese JIS pipe 304 stainless steel flanges, but they are generally only used in public projects in petrochemical plants and have little impact internationally. Here is a brief introduction to 304 stainless steel flanges in various countries:
 1, European system pipe 304 stainless steel flange represented by Germany and the former Soviet Union.
  2, American system pipe 304 stainless steel flange standard, represented by ANSI B16.5 and ANSI B 16.47.
 3, British and French pipe 304 stainless steel flange standards, each country has two casing 304 stainless steel flange standards.
To sum up, the internationally accepted 304 stainless steel pipe flange standards can be summarized into two different and non-interchangeable pipe 304 stainless steel flange systems: one is the European pipe 304 stainless steel flange system represented by Germany; the other is the European pipe 304 stainless steel flange system represented by Germany; One is the American Pipe 304 stainless steel flange system represented by the United States.
IOS7005-1 is a standard promulgated by the International Organization for Standardization in 1992. This standard is actually a pipe 304 stainless steel flange standard that merges two series of pipe 304 stainless steel flanges from the United States and Germany.
 The production process is mainly divided into four types: forging, casting, cutting and rolling.
 Cast 304 stainless steel flange and forged 304 stainless steel flange
The cast 304 stainless steel flange has accurate blank shape and size, small processing volume, and low cost, but it has casting defects (pores, cracks, inclusions); the internal structure of the casting has poor streamlines (if it is a cutting part, the streamlines are even worse);
Forged 304 stainless steel flanges generally have lower carbon content than cast 304 stainless steel flanges and are less likely to rust. Forgings have better streamlines, denser structures, and better mechanical properties than cast 304 stainless steel flanges;
 Inappropriate forging process will also cause large or uneven grains and hardening cracks. The forging cost is higher than that of cast 304 stainless steel flange.
 Forgings can withstand higher shear and tensile forces than castings.
 The advantage of castings is that they can produce more complex shapes and the cost is relatively low;
The advantage of forgings is that the internal structure is uniform and there are no harmful defects such as pores and inclusions in castings;
 Hence the difference between cast 304 stainless steel flange and forged 304 stainless steel flange in terms of production process. For example, centrifugal 304 stainless steel flange is a type of cast 304 stainless steel flange.
Centrifugal 304 stainless steel flange is a precision casting method that produces 304 stainless steel flange. This type of casting has a much finer structure than ordinary sand casting, and the quality is much improved. It is less prone to problems such as loose tissue, pores, and trachoma.
 First of all, we need to understand how centrifugal 304 stainless steel flanges are produced. The process and products of centrifugal casting to make flat welded 304 stainless steel flanges are characterized by the fact that the product is processed through the following process steps:
① Put the selected raw material steel into the medium frequency electric furnace for melting, so that the temperature of the molten steel reaches 1600-1700℃;
②Preheat the metal mold to 800-900℃ to maintain a constant temperature;
③Start the centrifuge and pour the molten steel in step ① into the metal mold preheated in step ②;
④Cool the casting naturally to 800-900℃ for 1-10 minutes;
⑤Cool with water to close to normal temperature, demould and take out the casting.
Let's take a closer look at the production process of forged 304 stainless steel flanges:
 The forging process generally consists of the following processes, namely, selecting high-quality steel billets for blanking, heating, forming, and cooling after forging. The forging process methods include free forging, die forging and membrane forging. During production, different forging methods are selected according to the quality of the forgings and the size of the production batch.
 Free forging has low productivity and large machining allowance, but the tools are simple and versatile, so it is widely used for forging single pieces and small batch production forgings with relatively simple shapes. Free forging equipment includes air hammers, steam-air hammers and hydraulic presses, which are suitable for the production of small, medium and large forgings respectively. Die forging has high productivity, simple operation, and easy mechanization and automation. Die forgings have high dimensional accuracy, small machining allowances, and more reasonable fiber tissue distribution, which can further increase the service life of the parts.
 Basic processes of free forging: During free forging, the shape of the forging is gradually forged from the blank through some basic deformation processes. The basic processes of free forging include upsetting, drawing, punching, bending and cutting.
  1. Upsetting Upsetting is an operation process of forging the original blank along the axial direction to reduce its height and increase its cross-section. This process is commonly used for forging gear blanks and other disc-shaped forgings. Upsetting is divided into two types: total upsetting and partial forging.
2. Drawing Drawing is a forging process that increases the length of the blank and reduces its cross-section. It is usually used to produce blanks for shafts, such as lathe spindles, connecting rods, etc.
3. Punching is a forging process in which a punch is used to punch out through-holes or non-through-holes in the blank.
  4. Bending is a forging process that bends the blank into a certain angle or shape.
5. Torsion is a forging process in which one part of the blank is rotated at a certain angle relative to another part.
6. Cutting is the forging process of dividing the blank or cutting off the head.
  Die forged 304 stainless steel flange
Die forging is the full name of die forging. The heated blank is placed in a forging die fixed on the die forging equipment and is forged into shape.
  Basic processes of die forging Die forging process: blanking, heating, pre-forging, final forging, skin punching, trimming, tempering, shot blasting. Commonly used processes include upsetting, lengthening, bending, punching, and forming.
 Commonly used die forging equipment Commonly used die forging equipment include die forging hammers, hot die forging presses, flat forging machines and friction presses.
 In layman terms, forged 304 stainless steel flanges have better quality and are generally produced through die forging. They have fine crystal structure and high strength, but of course they are more expensive.
 Whether it is cast 304 stainless steel flange or forged 304 stainless steel flange, they are all common manufacturing methods of 304 stainless steel flange. Depending on the strength requirements of the parts to be used, if the requirements are not high, you can also choose to use turning 304 stainless steel flange.
  Cut 304 stainless steel flange
 Directly cut out the inner and outer diameter and thickness disks of the 304 stainless steel flange on the middle plate, and then process the bolt holes and water lines. The 304 stainless steel flange produced in this way is called a cut 304 stainless steel flange. The maximum diameter of this type of 304 stainless steel flange is limited to the width of the middle plate.
  Rolled 304 stainless steel flange
 The process of cutting strips from a medium plate and then rolling them into circles is called rolling, and is mostly used in the production of some large 304 stainless steel flanges. After successful rolling, welding is carried out, then flattened, and then the waterline and bolt holes are processed.