The production process is mainly divided into forging, casting, cutting
Cast and forged flanges
Cast flange, blank shape and size is accurate, small processing volume, low cost, but there are casting defects (air holes. Cracks. Inclusions); The internal organization of the casting is poorly streamlined (even worse if it is a cutting part);
Forged flanges generally have lower carbon content than cast flanges and are not easy to rust. The forging has good streamline, compact structure and better mechanical properties than cast flanges.
Improper forging process will also appear grain size or uneven, 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, the cost is relatively low;
The advantages of forging are that the internal organization is uniform, there is no pores in the casting, inclusions and other harmful defects;
The difference between cast flange and forged flange is distinguished from the production process. For example, centrifugal flange belongs to a kind of cast flange.
Centrifugal flanges are produced by precision casting method. Compared with ordinary sand casting, the structure of centrifugal flanges is much finer and the quality is improved. It is not easy to have problems such as loose tissue, pores and trachoma.
First of all, we need to understand how the centrifugal flange is produced, the process method and product of centrifugal casting to make flat welding flange, which is characterized by the product processed by the following process steps:
①Put the selected raw material steel into the intermediate frequency furnace melting, so that the temperature of molten steel reaches 1600-1700℃;
② preheat the metal mold to 800-900℃ to maintain constant temperature;
③Start the centrifuge and inject the molten steel into the metal mold after preheating;
④Naturally cool the casting to 800-900℃ for 1-10 minutes;
⑤ Cool with water to near room temperature, and remove the casting.
Let's understand the production process of forged flange:
The forging process generally consists of the following steps: selecting the high quality billet for blanking, heating, forming and cooling after forging. The forging processes include free forging, die forging and membrane forging. Production, according to the size of forging quality, the number of production batch choose different forging methods.
Free forging productivity is low, processing allowance is large, but the tool is simple, versatility is large, so it is widely used in forging simple shape of single, small batch production forgings. The 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, easy to realize mechanization and automation. The die forging has high dimensional accuracy, small machining allowance and more reasonable fiber distribution, which can further improve the service life of the parts.
Die forging, also known as model forging, is formed by placing a heated blank in a forging die fixed on the die forging equipment.
Generally speaking, forging flange quality is better, generally through die forging production, crystal structure fine, high strength, of course, the price is a little more expensive.
Whether casting flange or forging flange is a common flange manufacturing method, see the need to use the strength of the components, if the requirements are not high, can also choose turning flange.
In the middle plate directly cut out the flange with the processing amount of inner and outer diameter and thickness of the disk, and then the bolt hole and waterline processing. The flange produced in this way is called cut flange, the maximum diameter of such flange is limited to the width of the middle plate.
The process of cutting sliver with middle plate and rolling into a circle is called rolling, which is used in the production of some large flanges. After successful rolling, welding, then flattening, and then the waterline and bolt hole processing process.
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