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

Cast and forged flanges

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

Forged flanges generally contain less carbon than cast flanges and are not easy to rust. Forged flanges have good streamline, dense structure and better mechanical properties than cast flanges;

Improper forging technology can also lead to large or uneven grains, hardening cracks, and higher forging costs than cast flanges.

Forgings can withstand higher shear and tensile forces than castings.

The advantage of castings is that they can produce more complex shapes and have lower costs;

The advantage of forgings is that their 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 lies in the production process, such as centrifugal flanges, which belong to the category of cast flanges.

Centrifugal flanges belong to the precision casting method for producing flanges. This type of casting has a much finer structure and improved quality compared to ordinary sand casting, and is less prone to problems such as loose structure, air holes, and sand holes.

Firstly, we need to understand how centrifugal flanges are produced and produced, as well as the process and product of centrifugal casting to make flat welded flanges. Its characteristic is that the product is processed through the following process steps:

① Place the selected raw material steel into an intermediate frequency electric furnace for melting, so that the temperature of the molten steel reaches 1600-1700 ℃;

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

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

④ Free cooling of casting to 800-900 ℃ for 1-10 minutes;

⑤ Cool with water to near room temperature, demould and remove the casting.

Let's learn more about the production process of forged flanges:

The forging process generally consists of the following processes: selecting high-quality steel billets for cutting, 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 based on the size of forging quality and the number of production batches.

Free forging has low productivity and large machining allowance, but the tools are simple and versatile, making it widely used for forging single piece and small batch 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 is easy to achieve mechanization and automation. Die forgings have high dimensional accuracy, small machining allowance, and more reasonable fiber structure distribution, which can further improve the service life of the parts.

1. Basic process of free forging: During free forging, the shape of the forging is gradually formed by forging the blank through some basic deformation processes. The basic processes of free forging include upsetting, elongation, punching, bending, and cutting.

(1). Upsetting is the process of forging the original billet along the axial direction to reduce its height and increase its cross-sectional area. This process is commonly used for forging gear blanks and other disc shaped forgings. Upsetting is divided into two types: full upsetting and partial upsetting.

(2). Elongation is a forging process that increases the length of the billet and reduces the cross-sectional area. It is usually used to produce shaft type blanks, such as lathe spindles, connecting rods, etc.

(3). The forging process of punching through or through holes on the blank using a punch.

(4). Bending is a forging process that bends the billet to a certain angle or shape.

(5). Twisting is a forging process in which one part of the billet rotates at a certain angle relative to the other.

(6). The forging process of cutting and dividing billets or cutting material heads.

2. Die forging

The full name of die forging is model forging, which is formed by placing the heated billet in a forging die fixed to the die forging equipment.

(1). The basic process of die forging: cutting, heating, pre forging, final forging, punching, edge cutting, tempering, and shot peening. Common processes include upsetting, elongation, bending, punching, and forming.

(2). Commonly used die forging equipment includes die forging hammers, hot die forging presses, flat forging machines, and friction presses.

Simply put, forged flanges have better quality, usually produced through die forging, with fine crystal structure and high strength. Of course, the price is also higher.

Both cast and forged flanges are commonly used manufacturing methods for flanges. Depending on the strength requirements of the components to be used, if the requirements are not high, turning flanges can also be chosen.

3、 Cutting flange

Directly cut the inner and outer diameter and thickness of the flange on the middle plate with machining allowance, and then proceed with the processing of bolt holes and water lines. The flange produced in this way is called a cut flange, and the maximum diameter of this type of flange is limited to the width of the middle plate.

4、 Rolled flange

The process of using a medium plate to cut strips and then roll them into a circle is called rolling, and is often used in the production of some large flanges. After successful rolling, welding is carried out, and then flattening is carried out, followed by the processing of water lines and bolt holes.