What is a forged flange?
Forged flange is a product with the best mechanical properties among flange products. Its raw material is generally a pipe blank, which is then cut and then continuously beaten to eliminate defects such as segregation and looseness in the steel ingot. The price and mechanical properties are one level higher than ordinary cast flanges. Flange is a part that connects pipes to pipes and valves, and is connected to the pipe end; it is also used as a flange on the inlet and outlet of equipment, and is used to connect two devices. It is a part that connects pipes to pipes. It is a part that connects pipes to each other. at the pipe end. It is an accessory product for pipelines. The main materials of forged flanges are carbon steel, alloy steel, and stainless steel. The main standards include national standards, electric standards, American standards, German standards, Japanese standards, etc. The main anti-corrosion treatments are oiling and galvanizing. Forged flanges have better pressure resistance and temperature resistance, and are generally suitable for working environments with high pressure and high temperature.
Production Process
The production process is mainly divided into two types: forging and casting.
Cast flange and forged flange
The cast flange has accurate rough shape and size, small processing volume, and low cost, but it has casting defects (pores, cracks, inclusions); the internal structure of the casting has poor streamlines (if it is a cutting part, the streamlines are even worse);
Forged flanges generally have lower carbon content than cast flanges and are less likely to rust. Forgings have better streamlines, denser structures, and better mechanical properties than cast flanges;
Improper forging process will also cause large or uneven grains, hardening cracks, and the forging cost is higher than that of 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 the cost is relatively low;
The advantage of forgings is that the internal structure is uniform and there are no harmful defects such as pores and inclusions in castings;
The difference between cast flanges and forged flanges is distinguished from the production process. For example, centrifugal flanges are a type of cast flanges.
Centrifugal flanges are produced by precision casting. This type of casting has a much finer structure than ordinary sand casting, and its quality is much improved. It is less prone to problems such as loose tissue, pores, and trachoma.
The main steps
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 fact that the product is processed through the following process steps:
① Put the selected raw material steel into the intermediate frequency electric furnace for melting, so that the temperature of the molten steel reaches 1600-1700°C;
② Preheat the metal mold to 800-900℃ to maintain a constant temperature;
③Start the centrifuge and inject the molten steel in step ① into the preheated metal mold in step ②;
④Cool the casting naturally to 800-900℃ for 1-10 minutes;
⑤ Cool with water to close to normal temperature, demould and take out the casting.
Let’s learn about the production process of forged flanges:
The forging process generally consists of the following steps, namely, selecting high-quality steel billets for blanking, 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 according to the quality of the forgings and the size of the production batch.
Free forging has low productivity and large machining allowance, but the tools are simple and versatile, so it is widely used for forging single pieces and small batch production 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 easy mechanization and automation. Die forgings have high dimensional accuracy, small machining allowances, and more reasonable fiber tissue distribution, which can further increase the service life of the parts.
1. Free forging
Basic process: During free forging, the shape of the forging is gradually forged from the blank through some basic deformation processes. The basic processes of free forging include upsetting, drawing, punching, bending and cutting.
1. Upsetting Upsetting is an operation process of forging the original blank along the axial direction to reduce its height and increase its cross-section. This process is commonly used for forging gear blanks and other disc-shaped forgings. Upsetting is divided into two types: total upsetting and partial forging.
2. Drawing Drawing is a forging process that increases the length of the blank and reduces its cross-section. It is usually used to produce blanks for shafts, such as lathe spindles, connecting rods, etc.
3. Punching is a forging process in which a punch is used to punch out through-holes or non-through-holes in the blank.
4. Bending is a forging process that bends the blank into a certain angle or shape.
5. Torsion is a forging process that rotates one part of the blank at a certain angle relative to another part.
6. Cutting is the forging process of dividing the blank or cutting off the head.
2. Die forging
The full name of die forging is die forging. The heated blank is placed in a forging die fixed on the die forging equipment and is forged into shape.
1. Basic processes of die forging: die forging process: blanking, heating, pre-forging, final forging, skin punching, trimming, tempering, and shot blasting. Commonly used processes include upsetting, lengthening, bending, punching, and forming.
2. Commonly used die forging equipment Commonly used die forging equipment include die forging hammers, hot die forging presses, flat forging machines and friction presses, etc.
In layman's terms, forged flanges have better quality and are generally produced through die forging. They have fine crystal structure and high strength, but of course they are more expensive.
Whether it is cast flange or forged flange, they are common flange manufacturing methods. Depending on the strength requirements of the components to be used, if the requirements are not high, you can also choose to use turning flange.
