What Are The Effects Of Forging Process On Forging Quality?
Jan 03, 2025
fracturing
Fracturing is the appearance of shallow turtle cracks on the forging surface. This defect is most likely to occur on surfaces under tensile stress in forging forming (for example, unfilled protrusions or bent parts).
The internal causes of cracking may be many:
① too many fusible elements of raw materials. When heated at high temperature for a long time, there is copper precipitation on the surface of the steel, the surface grain is coarse, decarburized, or the surface has been heated several times.
② The sulfur content of the fuel is too high, and sulfur permeates the surface of the steel material.
Flash crack
Flash crack is the crack produced at the parting surface during die forging and cutting.
The causes of flash cracks may be as follows:
① In the die forging operation, the metal flows strongly due to heavy percussion.
② The cutting temperature of magnesium alloy die forging is too low; The cutting temperature of copper alloy die forging is too high.
Parting surface crack
Parting surface crack refers to the crack along the parting surface of the forging. There are many non-metallic inclusions in raw materials, and the flow to the parting die surface and the concentrated or contracted pipe residue often form cracks in the parting die surface when the edge is squeezed during die forging.
fold
Folding is formed when the oxidized surface metal joins together in the process of metal deformation. It can be formed by the confluence of two (or more) metal currents, or it can be formed by a rapid mass flow of metal that carries the flow of the adjacent surface metal with it. It can also be formed by bending and backflow of deformed metal; It can also be a partial deformation of a part of the metal, which is formed by being pressed into another part of the metal. Folding is related to the shape of raw materials and billets, the design of molds, the arrangement of forming processes, lubrication conditions, and the actual operation of forging, etc. Folding not only reduces the bearing area of parts, but also often becomes a fatigue source because of the stress concentration here.
free-draining
Flow through is a form of improper distribution of flow lines. In the flow zone, the flow lines originally distributed at a certain Angle converge to form the flow zone, which may cause the grain size difference between the flow zone and outside the flow zone. The reason for the perforation is similar to the folding, which is formed by the confluence of two metals or one metal with another metal, but the metal in the perforation part is still a whole perforation, which reduces the mechanical properties of the forging, especially when the grain difference on both sides of the perforation zone is very large, the performance is more obvious.
The forging flow line is not well distributed
The flow line distribution of forging is not smooth, which means the flow line disordered phenomenon, such as flow line cut off, backflow, and eddy current, occurs at low times of forging.
The forging process is very important; there is no room for a little mistake in this process. Remember that there are defects, so we must pay more attention when forging.
