Hard Protective Layers on Forging Dies—Development and Applications

Smolik, J.

doi:10.3390/coatings11040376

Cited by 6 publications

(5 citation statements)

References 90 publications

(103 reference statements)

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“…the coating is applied on nitrided surfaces. Nitriding counteracts early coating cracking, which is associated with softer surface layers below the coating (also known as "egg shall" effect) [5].…”

Section: Introductionmentioning

confidence: 99%

Hot die forging with nitrided and thermally stabilized DLC coated tools

Siegmund

2023

Materials Research Proceedings

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Abstract. Hot forging dies are subjected to high loads, which can lead to early tool failures. Abrasive wear, plastic deformation and thermal softening of the surface layer can be counteracted in particular by a high surface hardness. Thermochemical diffusion treatments and coatings are established as wear protection measures. DLC coatings, which feature excellent frictional properties and high hardness, are commonly applied on cold forging tools. However, the low coating adhesion to steel and the thermal stability of the diamond bond limit the current range of application. In this study, DLC coatings are applied in metallic treatment atmospheres with the aim of increasing the diamond bond’s temperature resistance. Furthermore, the influence of weak and intense nitriding to coating adhesion is investigated to reduce coating delamination. A pre-selection of modified DLC coatings for hot forging dies was carried out on the basis of hardness and scratch tests. The most promising tungsten DLC coating was tested in serial forging tests. Based on tool contour comparisons before and after forging, the potential as a wear protection measure for hot forging dies was determined. Tool wear was reduced by up to 29 % after 100 forging cycles with the tungsten DLC coating compared to the nitrided reference.

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Section: Introductionmentioning

confidence: 99%

Hot die forging with nitrided and thermally stabilized DLC coated tools

Siegmund

2023

Materials Research Proceedings

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“…Increasing the service life of forging tools, and thus reducing the number of sets of tools used for a given batch of products, is a solution to meet rising costs. Today's manufacturing techniques and methods offer a whole spectrum of possibilities for affecting the service life of forging tools [14][15][16][17][18][19], however, a common requirement as to the effectiveness of these procedures is the repeatability and stability of the forging process itself, which is in principle achievable only through the use of automation and robotisation.…”

Section: Introductionmentioning

confidence: 99%

Studies on a Robotised Process for Forging Steel Synchronizer Rings in the Context of Forging Tool Life

Meller¹,

Suszyński²,

Legutko³

et al. 2023

Manufacturing Technology

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This paper proposes a solution not previously used in the forging industry, which aims to reduce the proportion of arduous human labour. The concept of a prototype robotic station for hot forging includes a system that allows the selection of batch material with its heating, the execution of the process of lubrication of forging tools and the forging itself, synchronised with the feeding and removal of material using full automation, in accordance with the idea of Industry 4.0. At the same time, by increasing the repeatability of the entire forging process and changing some of its key parameters, it will be possible to influence the durability of the tools used during its implementation. In order to verify the impact of such a modified technological process on forging tool life, computer simulations of forging were performed, where the currently applied technology using hand forging was compared with a conceptual automated process.

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“…Given the external forces in the forging process that typically fall within the range of 500 to 1000 MPa, it is evident that the die material is likely to undergo deformation when exposed to temperatures exceeding ~427 • C (800 • F) [10,11]. These die materials are also susceptible to thermal and mechanical fatigue due to transformational stresses and the nature of the forging process, respectively [12]. During the hot-forging process, dies are preheated to mitigate the chilling effect on the workpiece, which reduces the need for repeated reheating of the workpiece and enhances the thermomechanical processing of the forged products, thus improving their quality at the expense of softening the die during its service [13,14].…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the performance of these materials hinges on the localized temperature at the interface between the die and the forging stock. This issue is exacerbated in press operations with prolonged dwell times and higher contact pressures, potentially impacting die longevity [3,[10][11][12][13][14]. In scenarios involving the forging of steel, superalloys, and titanium alloy products that require hot forming temperatures of up to ~1205 • C (2200 • F), surface temperatures on the die exceeding ~650 • C (1200 • F) can be reached.…”

Section: Introductionmentioning

confidence: 99%

Strategic Selection of Refractory High-Entropy Alloy Coatings for Hot-Forging Dies by Applying Decision Science

Jayaraman,

Canumalla

2023

Coatings

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We compiled, assessed, and ranked refractory high-entropy alloys (RHEAs) from the existing literature to identify promising coating materials for hot-forging dies. The selection methodology was rigorously guided by decision science principles, seamlessly integrating multiple attribute decision making (MADM), principal component analysis (PCA), and hierarchical clustering (HC). By employing a combination of twelve diverse MADM methods, we successfully ranked a total of 22 RHEAs. This analytical technique unveiled the top five RHEAs: Ti20-Zr20-Hf20-Nb20-Cr20, Al20.4-Mo10.5-Nb22.4-Ta10.1-Ti17.8-Zr18.8, Ti20-Zr20-Hf20-Nb20-V20, Al11.3-Nb22.3-Ta13.1-Ti27.9-V4.5-Zr20.9, and Al7.9-Hf12.8-Nb23-Ta16.8-Ti18.9-Zr20.6 pertinent for generating data on other significant properties, including wear resistance, fatigue (both thermal and mechanical), bonding compatibility with the substrate die material, oxidation resistance, potential reactions with the workpiece, cost-effectiveness, fabricability, and more. The three highest-ranked RHEAs share key characteristics, including a body-centered cubic (BCC) crystal structure, thermal conductivity below ~70 W/mK, and impressive yield strength at ambient and elevated temperatures, surpassing 1100 MPa. Moreover, they exhibit a remarkable ~73% similarity among themselves. The decision science-driven analyses yield sound metallurgical insights and provide valuable guidelines for developing RHEA coatings tailored for hot-forging dies. The strategy for designing RHEA-based coating materials for hot-forging dies should focus on compositions featuring a substantial presence of refractory metals while maintaining a BCC crystal structure. This combination is likely to deliver the desired blend of thermal and mechanical properties, rendering these coatings exceptionally well-suited for the demanding requirements of hot-forging operations.

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Hard Protective Layers on Forging Dies—Development and Applications

Cited by 6 publications

References 90 publications

Hot die forging with nitrided and thermally stabilized DLC coated tools

Hot die forging with nitrided and thermally stabilized DLC coated tools

Studies on a Robotised Process for Forging Steel Synchronizer Rings in the Context of Forging Tool Life

Strategic Selection of Refractory High-Entropy Alloy Coatings for Hot-Forging Dies by Applying Decision Science

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