Effect of a Cold Wire on the Metallurgical Characteristics of Nickel-Based Welds Deposited by GMAW-CW

2020 ◽  
Vol 73 (10) ◽  
pp. 2425-2434
Author(s):  
Adriane Lopes Mougo ◽  
Francisco Machado de Assis Bentes Neto ◽  
Douglas Neves Garcia ◽  
Carlos Alberto Mendes da Mota
Keyword(s):  
Author(s):  
Shuang Liu ◽  
Wei Liu ◽  
Radovan Kovacevic

Laser cladding by cold-wire feeding is known as an efficient cladding method due to its advantages, such as near 100% material utilization, high deposition rate, and flexible adaptation to the cladding position. However, it has very stringent requirements on the operative conditions, such as a small range of wire feeding rate and precise wire feeding position. The aim of this work was to investigate the laser hot-wire cladding technique, which improved the productivity and stability of the process significantly with respect to laser cold-wire cladding. The external preheating of the filler wire resulted in reduction in required laser power, a low dilution, and a higher deposition rate. A comparison was made between laser cold-wire cladding and laser hot-wire cladding of Inconel 625 on mild steel, with respect to the clad characteristics, microstructure, and hardness. An optimization of the main processing parameters in laser hot-wire cladding, such as the laser power, laser spot size, laser scanning speed, wire feeding orientation and position, wire preheating voltage, and wire feeding rate, was performed. The optimal parameters were used to create a multi-track deposit.


2019 ◽  
Vol 64 (1) ◽  
pp. 123-140 ◽  
Author(s):  
R. A. Ribeiro ◽  
P. D. C. Assunção ◽  
E. B. F. Dos Santos ◽  
E. M. Braga ◽  
A. P. Gerlich

Author(s):  
Kristofer M. Womack ◽  
Ralph J. Volino ◽  
Michael P. Schultz

Pulsed film cooling jets subject to periodic wakes were studied experimentally. The wakes were generated with a spoked wheel upstream of a flat plate. Cases with a single row of cylindrical film cooling holes inclined at 35 degrees to the surface were considered at blowing ratios, B, of 0.50, and 1.0 with jet pulsing and wake Strouhal numbers of 0.15, 0.30, and 0.60. Wake timing was varied with respect to the pulsing. Temperature measurements were made using an infrared camera, thermocouples, and constant current (cold wire) anemometry. The local film cooling effectiveness and heat transfer coefficient were determined from the measured temperatures. Phase locked flow temperature fields were determined from cold wire surveys. With B = 0.5, wakes and pulsing both lead to a reduction in film cooling effectiveness, and the reduction is larger when wakes and pulsing are combined. With B = 1.0, pulsing again causes a reduction in effectiveness, but wakes tend to counteract this effect somewhat by reducing jet liftoff. At low Strouhal numbers, wake timing had a significant effect on the instantaneous film cooling effectiveness, but wakes in general had very little effect on the time averaged effectiveness. At high Strouhal numbers, the wake effect was stronger, but the wake timing was less important. Wakes increased the heat transfer coefficient strongly and similarly in cases with and without film cooling, regardless of wake timing. Heat transfer coefficient ratios, like the time averaged film cooling effectiveness, did not depend strongly on wake timing for the cases considered.


2017 ◽  
Vol 31 (6) ◽  
pp. 415-424
Author(s):  
Victor Vergara Díaz ◽  
John Michea Cortes ◽  
Abdón Espinosa Alvarez
Keyword(s):  

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