Forgings stand out due to their optimised grain flow, which enhances fibre alignment and significantly improves structural integrity. This makes them ideal for critical applications such as bolts, pinions, gear wheels, and pressurised components. In die forging, materials like steel and superalloys are reshaped between two die halves, or sometimes additional die segments, strengthening the component further by aligning its internal grain structure. Unlike casting, forging refines the internal material, minimising defects such as porosity and significantly improving overall mechanical properties.
Forged components are characterised by a grain structure that follows their geometry, much like the grain in wood, providing exceptional stability. This structural integrity is a key reason why forging is preferred for demanding applications like bolts, supports, gears, and pressure-bearing components, including valve bodies and boiler components. The optimised grain structure of forged parts results in superior mechanical strength and reliability, which is crucial for components operating under extreme conditions.
Die Forging Process
Die forging is a hot forging process that plastically deforms an alloy, such as steel, between two halves of a tool, forcing the material to adopt the desired shape. Components produced through this process exhibit exceptional mechanical strength due to the fibre orientation of the material, which is further optimised during the forging process. The raw material, typically supplied in the form of metal bars, already has a longitudinal fibre orientation from its production, and this orientation is enhanced through forging.
Forging challenging materials like titanium alloys or duplex stainless steel requires expert handling due to their high strength and low forgeability. Titanium and duplex steels, for instance, are difficult to work with because of their abrasive nature and low fluidity, which can quickly lead to defects and tool damage. Extensive experience is therefore essential for ensuring optimal results when forging these materials.
Forging vs. Casting: A Comparative Analysis
The primary advantage of forging over casting lies in the modification of the material’s internal structure, particularly its grain orientation. In casting, raw materials are poured into moulds, resulting in a structure with no specific grain alignment. This often leads to defects such as porosity, inclusions, and shrinkage, compromising the structural integrity of the finished product. Casting also risks introducing bubbles and impurities into the material, which can further weaken its mechanical properties.
In contrast, forged components inherently avoid these issues by refining the internal grain structure. The optimised grain alignment in forged parts results in significantly better strength, fatigue resistance, and overall mechanical performance. Although casting allows for the creation of complex shapes and hollow structures, the mechanical properties of cast components are often inferior to those of forged components due to inherent defects and a less-than-optimal microstructure.
As Thomas Henneke, managing partner of KB Schmiedetechnik GmbH, states:
“For 20 years, we have been assisting our clients in optimising forged components through material flow simulation and advising on the transition from assemblies such as welded structures or cast parts to forged components with optimised grain flow.”
In summary, forged components consistently demonstrate greater reliability and superior mechanical properties, making them the preferred choice in demanding environments where strength and structural integrity are paramount.
Examples of forged products include holders, hoists, hooks, eyelets, chain links, lifting gear, special nuts, bolts, and screws, as well as forged gear blanks, pinions, pipe connections, and pressure-bearing components. Additionally, forged parts are commonly used in nuclear, hydrogen, and cryogenic valves, parts for boiler systems and power plants, and seawater-compatible components for naval vessels, shipyard supplies, and military and defence applications.
The interested reader can find an image gallery of KB and additional information here: https://waisch.ch/firma/la-forge-kb-schmiedetechnik-gmbh-hagen-nrw/posts/cv-and-publications-by-thomas-henneke
KB Schmiedetechnik GmbH is a highly certified German drop forge, located in Hagen (Westphalia) – between the historic “blade & metal” region Solingen and the “soccer city” Dortmund – specializing in small series production of safety-relevant closed die forgings from 200g to 130Kg unit weight of all steel grades including duplex stainless steels, nickel based and titanium alloys according to following standards, norms and certifications – these can be downloaded from the company´s website under “quality“:
ISO 9001+14001 and
- ☢️ nuclear power – atomic energy: KTA (Germany), RCC-M (France)
- ⚗️ boiler systems and piping: Alstom, ASME, Babcock, CNIM, MHPS
- ✴️ pressure equipment like valves: PED 2014/68/EU, AD 2000-W0
Shipbuilding:
- ⚓️ American Bureau of Shipping (ABS)
- ⚓️ Bureau Veritas Marine & Offshore (BV)
- ⚓️ Nippon Kaiji Kyōkai (ClassNK)
- ⚓️ Det Norske Veritas (DNV)
- ⚓️ Lloyd´s Register (LR)
Forgings – Made in Germany of European quality steel!
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