Casting flange, blank shape and size accurate, processing quantity small, low cost, but there are casting defects (holes, cracks, inclusions); The internal organization of casting is poor (if it is a cutting part, the streamline is worse); Forging flanges generally contain less carbon than casting flanges and are not easy to rust, the forging pieces are streamlined and compact, and the mechanical properties are better than casting flanges. Improper forging process will also appear large or uneven grains, 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 complicated shape and low cost. And the internal organization is uniform, there is no casting porosity, inclusion and other harmful defects; From the production process to distinguish the casting flange and forging flange, such as centrifugal flange is a kind of casting flange.
Centrifugal flange belongs to the precision casting method, this kind of casting is much finer in structure than ordinary sand casting, and the quality is much improved.
Forging flange production process flow
Select high quality billets for blanking, heating, forming and cooling after forging. There are free forging, die forging and tire die forging. During production, choose different forging methods according to the quality of forgings and the number of production batches.
Basic process of free forging: during free forging, the shape of the forging piece is gradually forged into the blank through some basic deformation processes. The basic processes of free forging include upsetting, drawing, punching, bending and cutting.
Upsetting is the process of forging the blank along the axis, reducing its height and increasing its cross section. This process is often used to forge gear billets and other disc-shaped forgings. Upsetting can be divided into full upsetting and partial upsetting.
Drawing length: it is a forging process to increase the length of the blank and reduce the section. It is usually used to produce the blank of shaft parts, such as lathe spindle and connecting rod.
Punching: the forging process of punching through or through holes in the blank.
Bending: forging process in which the blank is bent to an Angle or shape.
Torsion: forging process in which one part of the blank is rotated at an Angle to the other.
Cutting: the forging process of dividing blank or cutting head.
Die forging: it is called model forging in which the heated billet is placed in a forging die fixed on the die forging equipment. Basic procedures: blanking, heating, pre-forging, final forging, blanking, trimming, toning and tempering, shot peening. Commonly used processes are upsetting, drawing, bending, punching, molding. Commonly used die forging equipment is die forging hammer, hot die forging press, flat forging press and friction press. Generally speaking, forged flange quality is better, generally through die forging production, fine crystal structure, high strength, of course, the price is higher.
Cutting system of the flange
The disc with inner and outer diameter and thickness of flange with machining quantity is cut directly on the middle plate, and then the bolt hole and waterline are processed. The flange produced in this way is called cutting flange, and the maximum diameter of such flange is limited by the width of the plate.
The process of cutting sliver from medium plate and then rolling it into a circle is called rolling and is often used in the production of large flanges. After successful rolling, welding, then flattening, then waterline and bolt hole processing.