The production process is mainly divided into forging, casting, cutting and rolling.
Cast flanges and forged flanges
The flanges cast are accurate in shape and size, small in volume and low in cost, but have casting defects (porosity, cracks, inclusions); the internal organization of the casting is less streamlined (if it is a cutting part, the streamlined shape is worse);
Forged flanges generally have lower carbon content than cast flanges and are less prone to rust. The forgings are more streamlined, the structure is denser, and the mechanical properties are better than the cast flanges.
不 Improper forging process will also cause large or uneven grains, hardening cracks, and the cost of forging is higher than that of cast flanges.
Upsets can withstand higher shear and tensile forces than castings.
The advantage of castings is that they can produce more complex shapes and lower costs;
The advantage of upset forging is that the internal structure is uniform, and there are no harmful defects such as pores and inclusions in the casting;
区别 The difference between the cast flange and the forged flange is distinguished from the production process. For example, the centrifugal flange is a type of cast flange.
The centrifugal flange belongs to the production flange of the precision casting method. This type of casting is much thinner than ordinary sand molds, and the quality is improved.
First of all, we need to understand how centrifugal flanges are produced. The process and products of centrifugal casting to make flat welding flanges are characterized by the following process steps:
①The selected raw material steel is smelted in an intermediate frequency electric furnace, so that the temperature of molten steel reaches 1600-1700 ° C;
② Preheat the metal mold to 800-900 ℃ to keep constant temperature;
③ Start the centrifuge and inject the molten steel in step ① into the metal mold after preheating in step ②;
④ The casting is naturally cooled to 800-900 ° C and held for 1-10 minutes;
⑤Cool with water to near normal temperature and remove the casting from the mold.
Let's understand the production process of forged flange again:
The forging process generally consists of the following processes, that is, selecting high-quality steel blanks, heating, forming, and cooling after forging. The methods of forging include free forging, die forging and membrane forging. During production, different forging methods are selected according to the quality of the forgings and the number of production batches.
Free forging has low productivity, large machining allowance, but simple tools and great versatility, so it is widely used to forge single-piece and small-batch forgings with simpler shapes. Free forging equipment includes air hammer, steam-air hammer and hydraulic press, which are suitable for the production of small, medium and large forgings. 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 organization for forgings, which can further increase the service life of parts.
The basic process of free forging: During free forging, the shape of the forging is gradually forged into the blank through some basic deformation processes. The basic processes of free forging include upsetting, drawing, punching, bending and cutting.
1. Upsetting Upsetting 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 blanks and other disc-shaped forgings. Upsetting is divided into two types: upsetting and local forging.
2. Drawing length Drawing length is a forging process that increases the length of the blank and reduces the cross section. It is usually used to produce shaft blanks, such as lathe spindles and connecting rods.
3. Punching The forging process of punching through holes or non-through holes on the billet with a punch.
4. Bending A forging process that bends the billet into a certain angle or shape.
5. Twisting A forging process in which one part of the billet is rotated at a certain angle with respect to the other part.
6. Cutting Forging process that divides the blank or cuts the blank.
Die forging
Upset die forging is called model forging, and the heated blank is placed in a forging die fixed on a die forging device and forged.
工序 The basic process of die forging Die forging process: blanking, heating, pre-forging, final forging, punching skin, trimming, quenching and tempering, shot peening. Common processes are upsetting, drawing, bending, punching and forming.
Common die forging equipment Common die forging equipment includes die forging hammer, hot die forging press, flat forging press and friction press.
In general, forged flanges have better quality. They are generally produced by die forging. The crystal structure is dense and the strength is high. Of course, the price is also more expensive.
Whether it is a cast flange or a forged flange, it is a common method of manufacturing flanges. Depending on the strength requirements of the components that need to be used, if the requirements are not high, you can also choose a turned flange.
III. Cutting flange
直接 Cut directly on the middle plate the disc with the machining volume of the inside and outside diameter and thickness, and then perform bolt hole and waterline processing. The flange produced in this way is called a cut flange, and the maximum diameter of such flanges is limited to the width of the middle plate.
Four, rolled flange
The process of cutting the sliver from the middle plate and rolling it into a circle is called rolling, and it is mostly used for the production of some large flanges. After the rolling is successful, welding is performed, then flattened, and then the waterline and bolt holes are processed.