The production process is mainly divided into forging, casting, cutting and rolling. (1) Casting flange and forged flange casting flange, blank shape and size accurate, small processing amount, low cost, but there are casting defects (porosity. Cracks. Inclusions); The internal organization of the casting is poor in streamlining (if it is a cutting part, the streamlining is worse); The forged flange is generally lower in carbon than the cast flange and is not easy to rust, the forging is streamlined, the organization is relatively dense, and the mechanical properties are better than the cast flange; Improper forging process will also appear large or uneven grain, hardening crack phenomenon, forging cost is higher than casting flange.
Forgings can withstand higher shear and tensile forces than castings. The advantage of casting is that it can produce a more complex shape and the cost is relatively low; The advantage of forging is that the internal organization is uniform, and there is no harmful defects such as pores and inclusions in castings. From the production process to distinguish the difference between casting flange and forged flange, such as centrifugal flange is a kind of casting flange. Centrifugal flange is a precision casting method to produce flange, the casting is much finer than the ordinary sand casting, the quality is improved a lot, and it is not easy to have problems such as loose tissue, porosity, trachoma and so on. First of all, we need to understand how the centrifugal flange is produced, the process method and product of the centrifugal casting flat-welded flange, which is characterized by the product processed through the following process steps: ① The selected raw material steel into the medium frequency electric furnace melting, so that the temperature of molten steel reached 1600-1700℃; ② The metal mold is pre-heated to 800-900℃ to maintain a constant temperature; ③ Start the centrifuge and inject the molten steel in step 1 into step 2 to preheat the metal mold; ④ The casting is naturally cooled to 800-900℃ for 1-10 minutes; ⑤ Cool with water to close to room temperature, remove the casting.
Let's understand the production process of forged flange: the forging process is generally composed of the following processes, that is, selecting high-quality billet blanking, heating, forming, and cooling after forging. The forging process includes free forging, die forging and membrane forging. When producing, choose different forging methods according to the size of forging quality and the number of production batches. Free forging has low productivity and large processing allowance, but the tool is simple and the versatility is large, so it is widely used for forging single and small batch forgings with simple shape. Free forging equipment has air hammer, steam-air hammer and hydraulic press, respectively, suitable for small, medium and large forging production. Die forging productivity is high, the operation is simple, easy to realize mechanization and automation. The dimensional accuracy of die forging parts is high, the machining allowance is small, and the fiber structure distribution of forging parts is more reasonable, which can further improve the service life of parts.
The basic process of free forging: In free forging, the shape of the forging is gradually forged into the blank through some basic deformation procedures. The basic processes of free forging include upsetting, drawing, punching, bending and cutting. 1. Upsetting upsetting is the operation process of forging the raw billet along the axis to reduce its height and increase its cross section. This process is often used for forging gear billets and other disc-shaped forgings. There are two kinds of upsetting: full upsetting and partial upsetting. 2. Drawing length is the forging process that increases the length of the billet and reduces the section, which is usually used to produce shaft parts blank, such as lathe spindle and connecting rod. 3. The forging process of punching out through holes or through holes on the blank with punches. 4. Bending Forging process that bends the billet into a certain Angle or shape. 5. Twist the forging process that rotates one part of the blank at an Angle relative to another. 6. Forging process of cutting and dividing billet or cutting out head.
(2) Die forging die forging is called model forging, and the heated blank is placed in the forging die fixed on the die forging equipment. 1. The basic process of die forging Die forging process: blanking, heating, pre-forging, final forging, punching skin, cutting edge, conditioning, shot peening. Common processes include upsetting, drawing, bending, punching and forming. 2. Common die forging equipment Common die forging equipment include die forging hammer, hot die forging press, flat forging machine and friction press. Generally speaking, the quality of the forged flange is better, generally produced by die forging, the crystal structure is fine, the strength is high, and of course the price is more expensive. Whether cast flange or forged flange belong to the common manufacturing method of flange, depending on the strength requirements of the parts that need to be used, if the requirements are not high, you can also choose turning flange.
(3) Cutting flange directly cut out the disc with the inner and outer diameter and thickness of the flange with processing amount on the middle plate, and then process the bolt hole and water line. The flange produced in this way is called cut flange, and the maximum diameter of such flange is limited by the width of the middle plate. (4) Winding flange The process of cutting slivers with the middle plate and then rolling into a circle is called winding, which is mostly used in the production of some large flanges. After successful rolling, welding is performed, and then flattening is performed, and the process of waterline and bolt hole is processed.
