What are the common defects in forging?
Common Defects of Steel Forgings
- 1) Unfilled Section: As the name implies in this type of defect some of the forging section remain unfilled.
- 2) Cold Shut: Cold shut includes small cracks at corners.
- 3) Scale Pits:
- 4) Die Shift:
- 5) Flakes:
- 6) Improper Grain Growth:
- 7) Incomplete Forging Penetration:
- 8) Surface Cracking:
What is the advantage of open die and closed die forging?
Advantages & Disadvantages
| Open Die Forging | Closed Die Forging |
|---|---|
| Continuous grain flow and finer grain size | Economic for large production runs. |
| Increased strength and longer part life | No material limitation |
| Less material waste | Better surface finish |
| Reduced chance of voids | Less or no machining required for its close tolerances |
What are the advantages of open die forging?
There are many advantages to forging a part in the open die process. The open die method tends to be more cost effective for low volume parts. Additionally, parts forged in this method can result in finer grain sizes and continuous grain flow, resulting in an overall stronger part.
What is the difference between Fullering edging and blocking?
Explain the difference between fullering, edging, and blocking. Fullering: Material is distributed away from an area. Edging: Material is gathered into a localized area. Blocking: The part is formed into the rough shape.
What is the difference between closed and open die forging?
While impression or closed die forging confines the metal in dies, open die forging is distinguished by the fact that the metal is never completely confined or restrained in the dies. Most open die forgings are produced on flat dies.
How can forging defects be prevented?
To avoid this forging defect, care should be taken during the operation and the smith must have experience in forging. Types of forging defects include unfilled section, cold shut, scale pits, die shaft, flakes, improper grain growth, incomplete forging penetration, surface cleaning, and residual stresses in forging.
What is Fullering and edging?
Fullering acts to cause metal to flow out of one area and to both sides. Edging acts to cause metal to flow into an area from both sides. It increase the thickness of unused area. It decrease the thickness of unused area.
What is cogging in forging?
Cogging, or open die forging, is a process used to convert a cast ingot into a forged billet. The material is locally compressed between two dies which “bite” their way along the length of the ingot. As a result, the cross section is reduced and the length increases.
What kind of dies are used in open die forging?
Open die forging is a hot forming process that uses standard flat, “V”, concave or convex dies in presses. The process is used to form a virtually limitless range of component sizes from a few pounds to over 300 tons.
Are there any defects in the forging process?
If the material has been dis- tributed improperly during the blocking stage, defects may appear in the finishing stage. In a good-quality forging, all sections of the die cav- ity must be filled, and the part must not contain flow defects, such as laps, cold shuts, or folds.
How are forging dies tested before being used in production?
Before being used in production, forging dies are tested to verify proper filling of the die cavi- ties. The most commonly used method of process verification is die tryout, in which full- scale dies are manufactured and prototype parts are forged to determine metal flow patterns and the possible occurrence of defects.
What makes a good impression die forging?
In a good-quality forging, all sections of the die cav- ity must be filled, and the part must not contain flow defects, such as laps, cold shuts, or folds. Before being used in production, forging dies are tested to verify proper filling of the die cavi- ties.
