A robust design in hardfacing using a plasma transfer arc

Abstract

This paper presents the use of the Taguchi-regression method in developing the optimal plasma transferred arc welding (PTAW) process for obtaining high hardfacing quality characteristics. An "optimal" process means that the best performance characteristic would be produced while the least number of process parameters are involved. In the experimental tests, the surface hardening process is conducted using Cobalt-based and Nickel-based powdery metal materials together with L 18 orthogonal arrays. The dependent variable, wear, obeys the-smallerthe-better quality characteristic, and the performance statistics, the signal-to-noise ratios (SNRs), are obtainable.The experimental results show that the most efficient process parameters based on analysis of variance are set as follows: hardfacing material, the accelerating voltage, the powder feed rate , and the pre-heat treatment temperature. They account for almost 90% of the total variance of wear. Under the optimal setting, the average error rates for using Taguchi and Taguchi-regression methods are 7.05 and 5.50%, respectively. The outcome of the experiment indicates that predicted values of the optimal setting fit well with the actual data. The reproducibility of the optimal plasma transfer arc hardfacing is obtained from the experimental data of the confirmation run. A reliable analysis based on the results from plasma transfer arc hardfacing conditions can be achieved through the Taguchi-regression method.

Modeling and Optimization in Investigating Thermally Sprayed Ni-Based Self-Fluxing Alloy Coatings: A Review

“…Tu et al [ 70 ] aimed at finding optimal parameters of PTA welding for two types of coatings (Stellite cobalt alloy and Ni-based self-fluxing alloy) on 0.48% carbon steel. Two methods were applied and compared, the Taguchi method and the Taguchi regression method for obtaining optimal values of accelerating voltage, powder feed rate, and preheat temperature (these factors were identified as significant), as well as of current, waving oscillation, plasma gas rate, and rotation, which will give minimal sliding (pin on disc) wear mass loss.…”

Minimização de defeitos em revestimentos de superligas de níquel depositada pelo processo TIG com alimentação de arame frio

“…Recentemente, alguns trabalhos têm sido encontrados na literatura apresentando estudos sobre a aplicação de revestimentos por diversos processos, no entanto, tais trabalhos avaliam somente as características geométricas e diluição através da deposição de apenas um cordão de solda [7][8][9][10].…”

“…A qualidade de um revestimento obtida através da deposição de camadas de solda sobre um substrato está, em geral, relacionada com a correta escolha dos parâmetros de soldagem, de forma a produzir revestimentos com espessura adequada e com reduzido grau de diluição, especialmente em soldagens dissimilares de ligas que devem apresentar alta resistência à corrosão [5,6]. Recentemente, alguns trabalhos têm apresentado estudos sobre a aplicação de revestimentos por diversos processos, no entanto, nas avaliações são considerados somente os resultados de diluição e características geométricas para apenas um cordão de solda [7][8][9][10]. É obvio que o estudo das condições operacionais com simples cordão é capaz de fornecer informações relevantes sobre a diluição, penetração, reforço, etc., além de reduzir o tempo e a quantidade de experimentos.…”

Inspection of nickel-based boron carbide PTA coatings on AISI 4140 steel

“…Nickel, with its corrosion resistance (Davis and ASM International, 2000), is an important base material for PTA coating in corrosive and high-temperature applications such as nuclear reactors (Gurumoorthy et al , 2007). Nickel-based PTA coating research was conducted using Nickel-based alloys (Gatto et al , 2004) or powder mixtures (Tu et al , 2006). Although the NiCrBSi matrix phase has been used in PTA coating (Flores et al , 2009; Ramachandran et al , 2009), the research on Ni-B 4 C coating still lacks investigation.…”