The production process of flange is mainly divided into: forging, casting, cutting and rolling, among which the forging process includes free forging, die forging and tire die forging.
1. Casting flange and forging flange
(1) advantages and disadvantages:
Casting flange: accurate shape and size of blank, small amount of processing, low cost, but casting defects (air holes, cracks, inclusions);Poor streamlining of the internal structure of the casting (if it is cutting parts, the streamlining is worse);
Forging flange: generally, the forging flange contains less carbon than the casting flange, is not easy to rust, and the forging is streamlined, compact, and has better mechanical properties than the forging flange;Improper forging process will also appear large or uneven grain, hardening crack phenomenon, the forging cost is higher than the casting flange.
(2) comparison between forgings and castings
Forgings can withstand higher shear and tensile forces than castings.
The advantage of castings is that they can produce complex shapes with low cost.
Forgings have the advantage of uniform internal structure and no harmful defects such as porosity and inclusion.
2. Cut the flange
The disc with machined inner and outer diameter and thickness is cut directly from the flange on the middle plate, and then the bolt hole and waterline are processed.The flange produced in this way is called cut flange. The maximum diameter of this kind of flange is limited to the width of the plate.
3. Roll the flange
The process of cutting sliver from the middle plate and then rolling it into a circle is called rolling, which is often used in the production of some large flanges.