scholarly journals Investigation of Heat Treatment Strategies for Additively-Manufactured Tools of X37CrMoV5-1

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 854 ◽  
Author(s):  
Daniel Junker ◽  
Oliver Hentschel ◽  
Michael Schmidt ◽  
Marion Merklein
Keyword(s):  
Heat Treatment ◽  
Additive Manufacturing ◽  
Treatment Strategies ◽  
Life Cycles ◽  
Thermal Processes ◽  
High Flexibility ◽  
Forming Tools ◽  
Flexible Processes ◽  
Microstructure Of The Material ◽  
Tool Cost

For cost-intensive products like automobiles, clients often wish to personalize their product, what forces the industry to create a large diversity of combinable parts. Additionally, the life cycles of many components become shorter. For highly-stressable parts, which are commonly manufactured by forging, the short changeover cycles result in expensive products, as the costs of tools must be offset by the sale of only a few parts. To reduce the tool cost, new, flexible processes have to be established in tool manufacturing. Laser-based additive manufacturing is noted for its high flexibility; notably, Laser Metal Deposition (LMD) is gaining increasing relevance in research, as it is already used for coating and repairing forming tools, this technology makes it possible to add material onto free-formed surfaces. Therefore, investigations are being conducted to qualify this process to produce forging tools. Due to the thermal processes which are required during additive manufacturing, the microstructure of the material differs from that of wrought material. This, in turn, affects the strategy of post heat treatment in order that the required mechanical properties for tools be attained. Within this manuscript, the influence of additive manufacturing on performance characteristics of hot work tool steel X37CrMoV5-1 (1.2343) is analyzed. To investigate the behavior of additively manufactured material during the process chain of tool manufacturing, properties for different states of a heat treatment are characterized by hardness and strength. It was shown that the strength of the additively manufactured material could be increased compared to wrought material by using a tailored heat treatment. The effects that cause this behavior are investigated by comparing the microstructure at different states of heat treatment.

Connection Strength of Additive Manufactured Tool Elements to the Substrate

2016 ◽  
Vol 716 ◽  
pp. 389-394 ◽  
Author(s):  
Daniel Junker ◽  
Aleksandr Fedorov ◽  
Oliver Hentschel ◽  
Michael Schmidt ◽  
Marion Merklein
Keyword(s):  
Tensile Tests ◽  
Life Cycles ◽  
Connection Strength ◽  
Laser Metal Deposition ◽  
High Carbon ◽  
Heat Treated ◽  
High Flexibility ◽  
Forming Tools ◽  
Flexible Processes ◽  
Very High

In industry the increasing variety of products leads to shorter product life cycles. For parts made by forging processes this trend results in very high prizes, as the tool costs have to be assimilated with only few parts. To reduce the tool costs new, flexible processes have to be investigated and established in tool manufacturing. Laser based additive manufacturing is noted for its high flexibility and especially laser metal deposition (LMD) gets in the focus of the research as it allows adding material on free formed surfaces. Therefore it is already used for coating and repairing of forming tools. New investigations are made to qualify this process for the production of forging tools. The aim is to generate active elements onto a geometrical simple base unit. Within first investigations the manufacturing of high carbon hot work tool steel 1.2343 was analysed. The measured mechanical properties were similar to those of conventional manufactured material.The focus of this paper is the connection strength of the additively built structures to the substrate. Therefore cylindrical specimens for tensile tests are manufactured with the linkage zone in the parallel area, in which the highest tension will be achieved. To assess the strength of the connection a comparison with conventional manufactured steel will be made. Furthermore specimens produced with various settings will be tested to analyse the influence of the LMD process. Additionally post heat treated samples will be analysed to recognize the effect of the hardening on the strength of the specimens.

scholarly journals Studies of Post-Fabrication Heat Treatment of L-PBF-Inconel 718: Effects of Hold Time on Microstructure, Annealing Twins, and Hardness

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 266
Author(s):  
Wakshum M. Tucho ◽  
Vidar Hansen
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Additive Manufacturing ◽  
Inconel 718 ◽  
Solution Heat Treatment ◽  
Hold Time ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Annealing Twins ◽  
Complete Recrystallization

The widely adopted temperature for solid solution heat treatment (ST) for the conventionally fabricated Inconel 718 is 1100 °C for a hold time of 1 h or less. This ST scheme is, however, not enough to dissolve Laves and annihilate dislocations completely in samples fabricated with Laser metal powder bed fusion (L-PBF) additive manufacturing (AM)-Inconel 718. Despite this, the highest hardness obtained after aging for ST temperatures (970–1250 °C) is at 1100 °C/1 as we have ascertained in our previous studies. The unreleased residual stresses in the retained lattice defects potentially affect other properties of the material. Hence, this work aims to investigate if a longer hold time of ST at 1100 °C will lead to complete recrystallization while maintaining the hardness after aging or not. For this study, L-PBF-Inconel 718 samples were ST at 1100 °C at various hold times (1, 3, 6, 9, 16, or 24 h) and aged to study the effects on microstructure and hardness. In addition, a sample was directly aged to study the effects of bypassing ST. The samples (ST and aged) gain hardness by 43–49%. The high density of annealing twins evolved during 3 h of ST and only slightly varies for longer ST.

scholarly journals Additive Manufacturing of Ti-Based Intermetallic Alloys: A Review and Conceptualization of a Next-Generation Machine

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4317
Author(s):  
Thywill Cephas Dzogbewu ◽  
Willie Bouwer du Preez
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Additive Manufacturing ◽  
Complex Geometries ◽  
Intermetallic Alloys ◽  
Tial Alloys ◽  
Conventional Methods ◽  
Manufacturing Technologies ◽  
In Situ Heat Treatment

TiAl-based intermetallic alloys have come to the fore as the preferred alloys for high-temperature applications. Conventional methods (casting, forging, sheet forming, extrusion, etc.) have been applied to produce TiAl intermetallic alloys. However, the inherent limitations of conventional methods do not permit the production of the TiAl alloys with intricate geometries. Additive manufacturing technologies such as electron beam melting (EBM) and laser powder bed fusion (LPBF), were used to produce TiAl alloys with complex geometries. EBM technology can produce crack-free TiAl components but lacks geometrical accuracy. LPBF technology has great geometrical precision that could be used to produce TiAl alloys with tailored complex geometries, but cannot produce crack-free TiAl components. To satisfy the current industrial requirement of producing crack-free TiAl alloys with tailored geometries, the paper proposes a new heating model for the LPBF manufacturing process. The model could maintain even temperature between the solidified and subsequent layers, reducing temperature gradients (residual stress), which could eliminate crack formation. The new conceptualized model also opens a window for in situ heat treatment of the built samples to obtain the desired TiAl (γ-phase) and Ti3Al (α2-phase) intermetallic phases for high-temperature operations. In situ heat treatment would also improve the homogeneity of the microstructure of LPBF manufactured samples.

The effect of phase transformations in the process of electrom-beam 3D-printing and post-built heat treatment on the peculiarities of plastic deformation and fracture of high nitrogen Cr-Mn steel

2021 ◽  
pp. 10-17
Author(s):  
E.G. Astafurova ◽  
◽  
K.A. Reunova ◽  
S.V. Astafurov ◽  
M.Yu. Panchenko ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Plastic Deformation ◽  
Electron Beam ◽  
Phase Composition ◽  
Additive Manufacturing ◽  
3D Printing ◽  
Raw Material ◽  
High Nitrogen ◽  
Two Phase ◽  
Deformation And Fracture

We investigated the phase composition, plastic deformation and fracture micromechanisms of Fe-(25-26)Cr-(5-12)Mn-0.15C-0.55N (wt. %) high-nitrogen chromium-manganese steel. Obtained by the method of electron-beam 3D-printing (additive manufacturing) and subjected to a heat treatment (at a temperature of 1150°C following by quenching). To establish the effect of the electron-beam 3D-printing process on the phase composition, microstructure and mechanical properties of high-nitrogen steel, a comparison was made with the data for Fe-21Cr-22Mn-0.15C-0.53N austenitic steel (wt. %) obtained by traditional methods (casting and heat treatment) and used as a raw material for additive manufacturing. It was experimentally established that in the specimens obtained by additive manufacturing method, depletion of the steel composition by manganese in the electron-beam 3D-printing and post-built heat treatment contributes to the formation of a macroscopically and microscopically inhomogeneous two-phase structure. In the steel specimens, macroscopic regions of irregular shape with large ferrite grains or a two-phase austenite-ferrite structure (microscopic inhomogeneity) were observed. Despite the change in the concentration of the basic elements (chromium and manganese) in additive manufacturing, a high concentration of interstitial atoms (nitrogen and carbon) remains in steel. This contributes to the macroscopically heterogeneous distribution of interstitial atoms in the specimens - the formation of a supersaturated interstitial solid solution in the austenitic regions due to the low solubility of nitrogen and carbon in the ferrite regions. This inhomogeneous heterophase (ferrite-austenite) structure has high strength properties, good ductility and work hardening, which are close to those of the specimens of the initial high-nitrogen austenitic steel used as the raw material for additive manufacturing.

scholarly journals Investigation of microstructure and hardness of a rib geometry produced by metal forming and wire-arc additive manufacturing

2018 ◽  
Vol 190 ◽  
pp. 02005 ◽  
Author(s):  
Markus Hirtler ◽  
Angelika Jedynak ◽  
Benjamin Sydow ◽  
Alexander Sviridov ◽  
Markus Bambach
Keyword(s):  
Additive Manufacturing ◽  
Metal Forming ◽  
Batch Size ◽  
Unit Costs ◽  
Batch Sizes ◽  
Traditional Manufacturing ◽  
Manufacturing Technologies ◽  
Forming Tools ◽  
Wire Arc Additive Manufacturing ◽  
Am Processes

Within the scope of consumer-oriented production, individuality and cost-effectiveness are two essential aspects, which can barely be met by traditional manufacturing technologies. Conventional metal forming techniques are suitable for large batch sizes. If variants or individualized components have to be formed, the unit costs rise due to the inevitable tooling costs. For such applications, additive manufacturing (AM) processes, which do not require tooling, are more suitable. Due to the low production rates and limited build space of AM machines, the manufacturing costs are highly dependent on part size and batch size. Hence, a combination of both manufacturing technologies i.e. conventional metal forming and additive manufacturing seems expedient for a number of applications. The current study develops a process chain combining forming and additive manufacturing. First, a semi-finished product is formed with forming tools of reduced complexity and then finished by additive manufacturing. This research investigates the addition of features using AlSi12 created by Wire Arc Additive Manufacturing (WAAM) on formed EN-AW 6082 preforms. By forming, the strength of the material was increased, while this effect was partly reduced by the heat input of the WAAM process.

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