Adapted diffusion processes for effective forging dies

Paschke, H.; Nienhaus, A.; Brunotte, Kai; Petersen, T. B.; Siegmund, Martin; Lippold, Lennard; Weber, Martin; Mejauschek, M.; Landgraf, Pierre; Braeuer, G.; Behrens, Bernd Arno; Lampke, Thomas

doi:10.1063/1.5034870

Cited by 4 publications

(4 citation statements)

References 15 publications

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“…Within the last decade, the authors worked cooperatively on this topic in order to enhance service life times and profitability of forging dies through a number of different concepts such as diffusion or coating treatments [6]. The results have shown that wear reduction strategies must be adapted to the specific wear mechanisms in each forging process.…”

Section: Investigation Conceptmentioning

confidence: 99%

“…While high hardness and a steep gradient negatively influence the crack sensitivity of the tools, starting with low surface hardness (ductile zone of up to 30 µm) with a following hardness increase and then a shallow gradient to the unaffected base material is positive in the context of thermal shock loading [6]. A combination of plasmanitrocarburizing (PNC) with following plasmanitriding (PN) can reduce tool wear since the formation of carbonitrides may provide different mechanical properties in the surface layer.…”

Section: Development Of Adapted Plasma Diffusion and Dlc Coating Trea...mentioning

confidence: 99%

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Load-Adapted Surface Modifications to Increase Lifetime of Forging Dies

Paschke

Weber

Brunotte

et al. 2022

KEM

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Diffusion treatments offer possibilities to enhance the performance and the service lifetime of hot forging tools. In combination with coating after nitriding, the surface layer hardness can be further increased. Within the scope of this study, a surface layer hardness above 2,000 HV0.005 was determined for borided or DLC (diamond-like carbon) coated surface layers. An increased surface layer hardness improves the abrasive wear resistance of forging dies. Furthermore, the plastic deformation of thermally softened forging die areas can be reduced. Beside these desirable effects, the ductility of diffusion treated or coated near surface layers is reduced and thermomechanical cracks are promoted. Therefore, additional approaches were developed to improve the thermomechanical crack behaviour of forging dies. Patterned plasmanitriding by the use of coverages to prevent areas from nitrogen diffusion, new combination processes of plasmanitrocarburizing (PNC) followed by plasmanitriding (PN) and the innovative boriding were investigated on different abstraction levels. A system of several testing rigs was set up to enable the abstraction of the thermal shock conditions in different stages. The patterned nitriding, boriding and combination plasma process (PN + PNC) were evaluated in a series of industrial field tests to derive recommendations for suitable tool treatments.

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Section: Investigation Conceptmentioning

confidence: 99%

Section: Development Of Adapted Plasma Diffusion and Dlc Coating Trea...mentioning

confidence: 99%

Load-Adapted Surface Modifications to Increase Lifetime of Forging Dies

Paschke

Weber

Brunotte

et al. 2022

KEM

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“…In addition, these superimposed loads can cause plastic deformation and cracking [2]. The surface layer of the forging dies softens in contact with the hot blanks, which promotes abrasive wear and plastic deformation [3]. The use of cooling lubricants reduces the thermal tool load.…”

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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“…The application of cooling lubricants reduces thermal loads, but leads to cyclic heating and cooling of the tool surface, resulting in thermomechanical cracking [6]. Further loads can provoke material breakouts [7].…”

Section: Introductionmentioning

confidence: 99%

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

Behrens,

Bräuer,

Brunotte

et al. 2023

MSF

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In cold forging processes, diamond-like carbon (DLC) coatings have become established as a wear protection for forging dies, featuring high hardness and advantageous friction properties. This counteracts the particular critical abrasive tool wear and increases tool life. A major disadvantage of DLC coatings is their low thermal stability. In this study, the influence of metallic elements (niobium, tungsten and chromium) in the treatment atmosphere of the coating process is investigated with the aim of increasing the temperature resistance of the DLC coating and enabling its application as a wear-protection measure for hot forging dies. Preliminary studies were carried out to investigate the influence of different treatment atmospheres on wear-reducing properties such as high hardness and coating adhesion depending on prior nitriding processes. The most promising metal-doped DLC coating, with 30 % tungsten in the treatment atmosphere, was used in serial forging tests. At a blank temperature of 1,200 °C and a moderate count of 100 forging cycles, wear was reduced by up to 60 % compared to the nitrided reference tool.

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Adapted diffusion processes for effective forging dies

Cited by 4 publications

References 15 publications

Load-Adapted Surface Modifications to Increase Lifetime of Forging Dies

Load-Adapted Surface Modifications to Increase Lifetime of Forging Dies

Hot die forging with nitrided and thermally stabilized DLC coated tools

Metal-Containing Diamond-Like Carbon Coatings with Increased Temperature Stability for Wear Protection of Nitrided Hot Forging Dies

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