Cast flange and forged flange are common flanges, but the two kinds of flanges are different in price.
The cast flange has accurate shape and size, small processing volume and low cost, but has casting defects (such as pores, cracks and inclusions); The internal structure of casting is poor in streamline; The advantage is that it can make a more complex shape, and the cost is relatively low;
Forged flanges generally have lower carbon content than cast flanges and are not easy to rust. Forgings have good streamline, compact structure and better mechanical properties than cast flanges; Improper forging process will also lead to large or uneven grains and hardening cracks, and the forging cost is higher than that of the cast flange. Forgings can withstand higher shear and tensile forces than castings. The advantages are that the internal structure is uniform and there are no harmful defects such as pores and inclusions in the casting;
The difference between cast flange and forged flange is based on the production process. For example, centrifugal flange is a kind of cast flange. Centrifugal flange belongs to the precision casting method to produce flange. Compared with ordinary sand casting, this kind of casting has much finer structure and better quality, and is not easy to have problems such as loose structure, air hole and trachoma.
Let's understand the production process of forged flange again: the forging process generally consists of the following processes, namely, selecting high-quality billet blanking, heating, forming, and cooling after forging.
The forging process includes free forging, die forging and die film forging. During production, different forging methods shall be selected according to the size of forging quality and production batch. 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 simple shape. Free forging equipment includes air hammer, steam-air hammer and hydraulic press, which are respectively suitable for the production of small, medium and large forgings. Die forging has high productivity, simple operation, and is easy to realize mechanization and automation. Die forgings have high dimensional accuracy, small machining allowance, and more reasonable fiber structure distribution of forgings, which can further improve the service life of parts.
1、 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, drawing, punching, bending and cutting.
1. Upsetting is the operation process of forging the original blank along the axial direction to reduce its height and increase its cross section. This process is often used for forging gear blanks and other disc-shaped forgings. Upsetting is divided into full upsetting and partial upsetting.
2. Drawing is a forging process that increases the length of the blank and reduces the cross section. It is usually used to produce shaft parts, such as lathe spindle, connecting rod, etc.
3. Punching The forging process of punching through or through holes on the blank with a punch.
4. The forging process of bending the blank to a certain angle or shape.
5. Forging process in which one part of the blank rotates at a certain angle relative to the other.
6. Forging process of cutting and dividing blank or cutting material head.
2、 Die forging; The full name of die forging is model forging, which is formed by placing the heated blank in the forging die fixed on the die forging equipment.
1. Basic process of die forging: blanking, heating, pre-forging, final forging, punching, trimming, tempering, shot peening. Common processes include upsetting, drawing, bending, punching and forming.
2. Common die forging equipment Common die forging equipment includes die forging hammer, hot die forging press, flat forging machine, friction press, etc.
3、 Cutting flange; Directly cut the inner and outer diameter and thickness of the flange with machining allowance on the middle plate, and then process the bolt hole and water line. The flange thus produced is called cutting flange. The maximum diameter of such flange is limited to the width of the middle plate.
4、 Rolled flange; The process of using medium plate to cut strips and then roll them into a circle is called coiling, which is mostly used for the production of some large flanges. After successful rolling, welding shall be carried out, and then flattening shall be carried out, and then the processing of waterline and bolt hole shall be carried out.
Common flange executive standards: American standard flange ASME B16.5, ASME B16.47
Post time: Mar-02-2023
