Development of micro-plasma transferred arc (μ-PTA) wire deposition process for additive layer manufacturing applications

Prediction of residual stresses induced by any additive layer manufacturing process greatly helps in preventing thermal cracking and distortion formed in the substrate and deposition material. This paper presents the development of a model for the prediction of residual stresses using three-dimensional finite element simulation (3D-FES) and their experimental validation in a single-track and double-track deposition of Ti-6Al-4V powder on AISI 4130 substrate by the microplasma transferred arc (µ-PTA) powder deposition process. It involved 3D-FES of the temperature distribution and thermal cycles that were validated experimentally using three K-type thermocouples mounted along the deposition direction. Temperature distribution, thermal cycles, and residual stresses are predicted in terms of the µ-PTA process parameters and temperature-dependent properties of substrate and deposition materials. Influence of a number of deposition tracks on the residual stresses is also studied. Results reveal that (i) tensile residual stress is higher at the bonding between the deposition and substrate and attains a minimum value at the midpoint of a deposition track; (ii) maximum tensile residual stress occurs in the substrate material at its interface with deposition track. This primarily causes distortion and thermal cracks; (iii) maximum compressive residual stress occurs approximately at mid-height of the substrate material; and (iv) deposition of a subsequent track relieves tensile residual stress induced by the previously deposited track.

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Characteristics of Single-Track and Multi-track Depositions of Stellite by Micro-plasma Transferred Arc Powder Deposition Process

Journal of Materials Engineering and Performance ◽

10.1007/s11665-017-2828-y ◽

2017 ◽

Vol 26 (8) ◽

pp. 4029-4039 ◽

Cited By ~ 3

Author(s):

Mayur S. Sawant ◽

N. K. Jain

Keyword(s):

Deposition Process ◽

Single Track ◽

Plasma Transferred Arc ◽

Powder Deposition ◽

Transferred Arc

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A DEM study of powder spreading in additive layer manufacturing

Granular Matter ◽

10.1007/s10035-019-0971-x ◽

2019 ◽

Vol 22 (1) ◽

Cited By ~ 5

Author(s):

Yahia M. Fouda ◽

Andrew E. Bayly

Keyword(s):

Shear Layer ◽

Powder Coating ◽

Packing Fraction ◽

Powder Layer ◽

Process Conditions ◽

Additive Layer Manufacturing ◽

Layer Manufacturing ◽

The Mean ◽

Manufacturing Applications ◽

Layer Packing

AbstractIn this paper, discrete element method simulations were used to study the spreading of an idealised, blade based, powder coating system representative of the spreading of spherical, mono-sized, non-cohesive titanium alloy (Ti6AlV4) particles in additive layer manufacturing applications. A vertical spreader blade was used to accelerate a powder heap across a horizontal surface, with a thin gap between the blade and the surface, resulting in the deposition of a thin powder layer. The results showed that it is inevitable to deposit a powder layer with a lower packing fraction than the initial powder heap due to three mechanisms: shear-induced dilation during the initiation of powder motion by the spreader; dilation and rearrangement due to powder motion through the gap; and the inertia of the particles in the deposited powder layer. It was shown that the process conditions control the contribution of these three mechanisms, and that the velocity profile in the shear layer in front of the gap is critical to the final deposited layer packing fraction. The higher the mean normalised velocity in the shear layer the lower the deposited layer packing fraction. The gap thickness and the spreader blade velocity affect the properties of the deposited layer; with the former increasing its packing fraction and the latter decreasing it. The analysis presented in this study could be adapted to powders of different materials, morphologies and surface properties.

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Plasma Transferred Arc (PTA) Cladding and TOPTIG Cladding of Tubes Made of Steel 13CrMo4-5

Biuletyn Instytutu Spawalnictwa ◽

10.17729/ebis.2021.5/4 ◽

2021 ◽

pp. 37-45

Author(s):

Janusz Rykała ◽

Maciej Różański

Keyword(s):

Chemical Composition ◽

Cross Section ◽

Deposition Process ◽

Inconel 625 ◽

Test Results ◽

Geometrical Properties ◽

Plasma Transferred Arc ◽

Transferred Arc ◽

The Stability ◽

Maximum Content

The article presents test results concerning the effect of a cladding method and technological process parameters on geometrical properties and dilution of overlay welds. Test overlay welds were deposited on tubes made of steel 13CrMo4-5. The chemical composition of the filler material used in the deposition process corresponded to that of alloy Inconel 625. The study involved the performance of macro and microscopic metallographic tests of the overlay welds as well as the identification of related dilution. The study also included hardness measurements involving the cross-section of the overlay welds as well as tests of the chemical composition of the overlay weld surface (paying attention to the maximum content of iron in the overlay weld, which should not exceed 5%). Adopted PTA and TOPTIG cladding parameters enabled the satisfaction of the maximum criterion related to the acceptable content of iron in the overlay weld, ensuring the stability of the cladding process and the invariable geometry of the overlay welds around the entire tube circumference.

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