Casting flange, with advantage of the accurate dimension of billet, small amount of finishing and low cost, also has disadvantage of casting defects such as pores, cracks and inclusion. Besides, the internal structure of casting is less streamlined, especially worse if it is a cutting part. Compared with casting flange, forging flange is generally lower in carbon content, less likely to be rusted, better fairshaped of compacted internal structure which results in superior mechanical properties. Large or uneven grains, hardening cracks will also appear in the improper forging process, Forging cost is higher than the casting.
Forgings can bear higher shear and tensile forces than castings. The advantage of casting is that it can produce a more complex shape with the low cost. And the internal structure is uniform without casting pores, inclusions and other harmful defects. The casting flange and forging flange can be distinguished by the manufacturing process, which centrifugal flange is a kind of casting flange.
Centrifugal flange is applied to the precision casting method, which has much finer structure and much better quality. than ordinary sand mold casting, the later one has problems such as loose pores and trachoma
The manufacturing process flow of forging flange
To select the high quality steel billet to cut to produce, heating, forming and cooling after forging. There are various methods of forging process, such as open die forging, die forging and loose tooling forging. It depends on quality and size of billet, and quantity of batch.
The process flow of hammer forging is that forging shape is through some basic deformation process into billet forging step by step. The basic procedures of hammer forging include upsetting, stretching and punching bending and cutting, etc
Upsetting is the operation process of forging the raw material along the axis to reduce its height and increase the cross section
Stretching means the process to increase the length of the billet and reduce the section of forging, which is usually used to produce shaft parts blank, such as lathe spindle connecting rod
Punching means the process of forging is to drill through or through a billet with a punch.
Bending refers to bend a billet into an angle or shape.
Tensional process means the process of turning one part of a billet from a relative angle to another.
Cutting means the forging process of cutting and dividing billet or cutting off the head.
Die forging refers to the process flow that place the billet which is after heating on a fixed in die forging equipment. The basic process is as followings: cutting the billet, heating, pre-forging, finish forging, trimming, cutting the edge, and shot blasting. There are several basic process flow, such as upsetting, stretching, bending, punching and forming. The common die forging equipment include forging hammer, hot die forging press, horizontal forging and friction press. Generally, forged flanges have a better quality and much higher price by the means of fie forging, which with compacted crystal structure.
The cutting flange refers to that directly cutting out of middle plate into with margin of the inner and outer diameter and thickness, and then machines on the processing of bolt hole and waterline so as to produce the cutting flange, the maximum diameter of this flange is defined to the width of the middle plate
Rolling process, which is used to cut strip with middle plate and then roll into a circle and commonly used for the process of large flange. The welding process after the successful rolling and flattening, and then the processing of waterline and bolt holes