Flange production process

The production process of flange is mainly divided into four types: forging, casting, cutting and rolling.

Cast flange and forged flange

Flange cast, the shape and size of the blank are accurate, the processing volume is small, and the cost is low, but there are casting defects (pores, cracks, inclusions); the internal streamline of the casting is poor (if it is a cutting part, the streamline is worse);

Forged flanges are generally lower in carbon content than cast flanges and are not easy to rust. The forged parts are streamlined, the organization is dense, and the mechanical properties are better than cast flanges;

Improper forging process can also cause large or uneven grains, hardening cracks, forging cost is higher than casting flange.

Forged parts can withstand higher shear and tensile forces than castings.

The advantage of castings is that they can produce more complex shapes with lower cost;

The advantage of forgings is that the internal structure is uniform, and there are no harmful defects such as pores and inclusions in the castings;

The difference between cast flanges and forged flanges is distinguished from the production process. For example, centrifugal flanges are a type of cast flanges.

Centrifugal flanges are produced by precision casting methods. This type of casting is much finer than ordinary sand casting. The quality is much improved, and it is not easy to have problems such as loose structure, porosity and trachoma.

First of all, we need to understand how centrifugal flanges are produced and manufactured. The process and products of centrifugal casting to make flat welded flanges are characterized by the following process steps:

①Put the selected raw materials into the intermediate frequency electric furnace to make the molten steel temperature reach 1600-1700 ℃;

② Preheat the metal mold to 800-900 ℃ to maintain constant temperature;

③ Start the centrifuge and inject the molten steel in step ① into the metal mold after preheating in step ②;

④The casting is naturally cooled to 800-900 ℃ for 1-10 minutes;

⑤ Cool to near normal temperature with water, remove the castings from the mold.

Let's take a look at the production process of forged flanges:

Forging process is generally composed of the following procedures, namely, selecting high-quality steel billet blanking, heating, forming, cooling after forging. The forging process methods include free forging, die forging and tire forging. During production, different forging methods are selected according to the quality of forgings and the number of production batches.

Free forging has low productivity and large machining allowance, but the tool is simple and versatile, so it is widely used for forging single-piece and small batch forgings with relatively simple shapes. Free forging equipment includes air hammer, steam-air hammer and hydraulic press, etc., which are suitable for the production of small, medium and large forgings respectively. The productivity of die forging is high, the operation is simple, and it is easy to realize mechanization and automation. The die forgings have high dimensional accuracy, small machining allowance, and the fiber structure distribution of the forgings is more reasonable, which can further improve the service life of the parts.

1. The basic process of free forging: during free forging, the shape of the forging is gradually forged by some basic deformation processes. The basic processes of free forging include upsetting, lengthening, punching, bending and cutting.

1. Upsetting Upsetting is the operation process of forging the original blank in 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 full upsetting and partial forging.

2. Drawing length Drawing length is a forging process that increases the length of the billet and reduces the cross section. It is usually used to produce blanks for shafts, such as lathe spindles and connecting rods.

3. Punching Forging process of punching through holes or non-through holes in the blank with a punch.

4. Bending Forging process to bend the blank into a certain angle or shape.

5. Twist the forging process that rotates a part of the blank relative to another part by a certain angle.

6. Forging process of cutting and dividing blanks or cutting off the material head.

2. Die forging

Die forging is called model forging, and the heated billet is placed in a forging die fixed on the die forging equipment and forged.

1. The basic process of die forging Die forging process: blanking, heating, pre-forging, final forging, punching and skinning, trimming, tempering, shot peening. Common processes include upsetting, lengthening, bending, punching and forming.

2. Common die forging equipment Common die forging equipment includes die forging hammer, hot die forging press, flat forging machine and friction press.

Popularly speaking, the quality of forged flanges is better, generally produced by die forging, the crystal structure is fine, the strength is high, and of course the price is more expensive.

Both cast flanges and forged flanges are common flange manufacturing methods. Depending on the strength requirements of the parts to be used, if the requirements are not high, turning flanges can also be used.

Third, cut flange

Cut the disc with the inner and outer diameters and thickness of the flange directly on the middle plate, and then process the bolt hole and water line. The flange produced in this way is called a cut flange. The maximum diameter of such flanges is limited to the width of the middle plate.

Four, rolled flange

The process of cutting the sliver with the middle plate and rolling it into a circle is called rolling, which is mostly used in the production of some large flanges. After the coiling is successful, welding is carried out, then flattened, and then the water line and bolt hole process are processed.