Jon Iñaki Arrizubieta

Combination of Laser Material Deposition and Laser Surface Processes for the Holistic Manufacture of Inconel 718 Components

The present work proposes a novel manufacturing technique based on the combination of Laser Metal Deposition, Laser Beam Machining, and laser polishing processes for the complete manufacturing of complex parts. Therefore, the complete process is based on the application of a laser heat source both for the building of the preform shape of the part by additive manufacturing and for the finishing operations. Their combination enables the manufacture of near-net-shape parts and afterwards removes the excess material via laser machining, which has proved to be capable of eliminating the waviness resulting from the additive process. Besides, surface quality is improved via laser polishing so that the roughness of the final part is reduced. Therefore, conventional machining operations are eliminated, which results in a much cleaner process. To validate the capability of this new approach, the dimensional accuracy and surface quality as well as the microstructure of the resulting parts are evaluated. The process has been validated on an Inconel 718 test part, where a previously additively built-up part has been finished by means of laser machining and laser polishing.

Evaluation of efficiency and mechanical properties of Inconel 718 components built by wire and powder laser material deposition

Purpose The purpose of this paper is to evaluate and compare powder and wire laser material deposition (LMD) processes. Design/methodology/approach In the present paper, Inconel 718 tensile test probes were built layer by layer using a longitudinal strategy, and the quality of the deposited material was characterized for both wire and powder LMD processes. The measured data during the deposition tests have been used for comparing the efficiency of both powder and wire LMD processes. Afterwards, to evaluate the mechanical properties of the parts generated by means of both processes, standard tensile tests were carried out. Furthermore, other factors have been evaluated, such as process reliability or presence of residual material, after the deposition process. Findings Results show a higher efficiency of the wire LMD process, and even similar ultimate tensile stress values were reached for both processes; powder LMD parts resulted in a more brittle nature. Originality/value In the present paper, a thorough analysis that compared both processes has been carried out. The results obtained will help in the future when choosing between wire and powder LMD. The main points of the wealth of knowledge generated with these research efforts are highlighted herein.

Overlap Ratio in Wire- and Powder-Based Laser Metal Deposition of H11 + Nb for Hot Forging Dies

AISI H11 tool steel is a complex tool steel alloy used to manufacture hot forging dies. These dies however have a limited life, which depends upon the working conditions, the tool design, the heat treatment, and the quality of tool steels. In this paper, a novel wire-and powder-based laser metal deposition (WP-LMD) process was investigated to deposit H11 wire and niobium (Nb) powder simultaneously and develop a coating on existing forging dies for enhancing their life. The main aim was the development of a novel WP-LMD process, and consequently a new H11 tool steel with improved toughness and hardness. The developed WP-LMD process was later implemented to build a multilayer block made of the modified H11 tool steel. The overlap ratio was optimized in both, horizontal and vertical, directions, and were found to be 30% and 20% respectively in order to achieve a fully dense coating and avoid pores and unmelted Nb particles. The potential of the WP-LMD can be used to fabricate an outer layer of the modified H11 tool steel with improved toughness and hardness, which ultimately enhances the life of hot forging.

Study of the Influence of Shielding Gases on Laser Metal Deposition of Inconel 718 Superalloy

The use of the Laser Metal Deposition (LMD) technology as a manufacturing and repairing technique in industrial sectors like the die and mold and aerospace is increasing within the last decades. Research carried out in the field of LMD process situates argon as the most usual inert gas, followed by nitrogen. Some leading companies have started to use helium and argon as carrier and shielding gas, respectively. There is therefore a pressing need to know how the use of different gases may affect the LMD process due there being a lack of knowledge with regard to gas mixtures. The aim of the present work is to evaluate the influence of a mixture of argon and helium on the LMD process by analyzing single tracks of deposited material. For this purpose, special attention is paid to the melt pool temperature, as well as to the characterization of the deposited clads. The increment of helium concentration in the gases of the LMD processes based on argon will have three effects. The first one is a slight reduction of the height of the clads. Second, an increase of the temperature of the melt pool. Last, smaller wet angles are obtained for higher helium concentrations.