The Production Techniques of Flanges
The production techniques of flanges fall into four major types: forging, casting, cutting, rolling.
Cast Flange
Pros: Precise, sophisticated shape and size
light workload
low cost
Cons: Defects such as pores, crack, containing impurities
Poor internal streamline (worse in cutting parts)
Compared to cast flange, forged flange is generally with lower carbon content and better in rust prevention, streamline, compact structure, mechanical capacity.
Improper forging process will cause bigger or uneven grain, hardening, seaminess and higher cost.
Forged flange can withstand stronger shearing force and tensile strength. And due to its well-distributed inner, it won't have defects such as pores, impurities containing like cast flange.
The production processes of these two kinds of flanges are quite different. For example, centrifugal flange, made in a sophisticated casting method, belongs to cast flange.
The structure of this higher-quality cast flange is way finer than that of common, sand molded type.
First we need to understand the production process of centrifugal flange. Centrifugal casting is a process of making welded flange, which is processed by the following typical process steps:
Cast Flange
Pros: Precise, sophisticated shape and size
light workload
low cost
Cons: Defects such as pores, crack, containing impurities
Poor internal streamline (worse in cutting parts)
Compared to cast flange, forged flange is generally with lower carbon content and better in rust prevention, streamline, compact structure, mechanical capacity.
Improper forging process will cause bigger or uneven grain, hardening, seaminess and higher cost.
Forged flange can withstand stronger shearing force and tensile strength. And due to its well-distributed inner, it won't have defects such as pores, impurities containing like cast flange.
The production processes of these two kinds of flanges are quite different. For example, centrifugal flange, made in a sophisticated casting method, belongs to cast flange.
The structure of this higher-quality cast flange is way finer than that of common, sand molded type.
First we need to understand the production process of centrifugal flange. Centrifugal casting is a process of making welded flange, which is processed by the following typical process steps:
- Step 1: Put the picked raw steel materials into a medium-frequency furnace for melting, and raise the temperature of liquid steel to 1600℃~1700℃.
- Step 2: Preheat the metal mold between 800℃ and 900℃, and maintain the temperature.
- Step 3: Turn on the centrifuge machine, pour the liquid steel (step 1) into the metal mold (step 2).
- Step 4: Wait until the temperature of the casting drops between 800-900℃, and maintain the temperature for 1-10 minutes.
- Step 5: Water-cool the casting until its temperature is close to 25℃, and take it out from the mold.
Forged Flange
The production process includes selecting high-quality steel billet, heating, molding, cooling after forging, and methods like open die forging, closed die forging (impression die forging), swage forging.
Open die forging is a low-efficiency and heavy-workload method, but its versatility and easy-to-use tools are pretty suitable for simple-shaped pieces and small-lot production. For forged pieces from different sizes, there are air hammer, steam-air hammer, hydraulic press, etc.
Closed die forging is high-efficiency, easy-operation, and painless for mechanization and automation. The lifespan of parts can further prolong if the size of the part is more precise, structure more reasonable, machining allowance smaller.
The production process includes selecting high-quality steel billet, heating, molding, cooling after forging, and methods like open die forging, closed die forging (impression die forging), swage forging.
Open die forging is a low-efficiency and heavy-workload method, but its versatility and easy-to-use tools are pretty suitable for simple-shaped pieces and small-lot production. For forged pieces from different sizes, there are air hammer, steam-air hammer, hydraulic press, etc.
Closed die forging is high-efficiency, easy-operation, and painless for mechanization and automation. The lifespan of parts can further prolong if the size of the part is more precise, structure more reasonable, machining allowance smaller.
- Upsetting - Axially forge the blank so as to increase its cross-section by compressing its length. This is often used in forging wheel gears or other disc-shaped pieces.
- Drawing out - To increase the length of the blank by decreasing its cross-section. It usually works for axial blank, like lathe spindles, connecting rods.
- Piercing - To pierce a hole or hollow on the blank by a center punch.
- Bending - To bend the blank into a certain angle, or shape.
- Twisting - To turn a part of the blank around.
- Cutting - To cut the blank or remove the remnant.
Closed die forging
After heating, the blank is placed and shaped in a die resembling a mold.
The basic procedures includes: blanking, heating, pre-forging, finish forging, stamping, trimming, tempering, shot blasting.
Methods: upsetting, drawing out, bending, piercing, molding.
Equipments: forging hammer, hot forging press, upsetting machine, friction press, etc.
Generally, workpieces producing through closed die forging have finer crystal structure, higher intensity, better quality and apparently more expensive price tags.
Both casting and forging are common used flange manufacturing methods. If the intensity of the needed part is undemanding, then lathing is another feasible option.
Cut Flange
A disc that directly cut on the middle plate, with bolt holes, waterlines, reserved internal and external diameters, thickness. Its max diameter is within the limit of the breadth of the middle plate.
Rolled Flange
It is a rolled strip cut by the middle plate, mostly in large size. The producing procedures of rolled flange, in sequence, are: rolling, welding, planishing, making waterlines and blot holes.
After heating, the blank is placed and shaped in a die resembling a mold.
The basic procedures includes: blanking, heating, pre-forging, finish forging, stamping, trimming, tempering, shot blasting.
Methods: upsetting, drawing out, bending, piercing, molding.
Equipments: forging hammer, hot forging press, upsetting machine, friction press, etc.
Generally, workpieces producing through closed die forging have finer crystal structure, higher intensity, better quality and apparently more expensive price tags.
Both casting and forging are common used flange manufacturing methods. If the intensity of the needed part is undemanding, then lathing is another feasible option.
Cut Flange
A disc that directly cut on the middle plate, with bolt holes, waterlines, reserved internal and external diameters, thickness. Its max diameter is within the limit of the breadth of the middle plate.
Rolled Flange
It is a rolled strip cut by the middle plate, mostly in large size. The producing procedures of rolled flange, in sequence, are: rolling, welding, planishing, making waterlines and blot holes.
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