Wear Behaviour of Stellite 6 Coatings Produced on an Austenitic Stainless Steel Substrate by Laser Cladding Using Two Different Heat Inputs

Kusmoko, Alain; Dunne, D. P.; Li, Hui Jun

doi:10.4028/www.scientific.net/amm.619.13

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…Although the compositions of the two coatings are similar, there are significantly lower Fe and Mn contents for the coating deposited at 1 kW, consistent with a lower level of dilution, hence promoting the formation of Cr 7 C 3 particles and hardening of the deposit [12]. The deposit on P91-1 was about 50 HV points higher than for the coating on P91-1.8 (Fig.…”

Section: Discussionmentioning

confidence: 71%

Surface Morphology and Wear Analysis of Stellite 6 Deposited on 9Cr-1Mo Steel Substrate by Laser Cladding

Kusmoko

2015

AMR

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Stellite 6 was deposited by laser cladding on a 9Cr-1Mo (P91) substrate with energy inputs of 1 kW (P91-1) and 1.8 kW (P91-1.8). The chemical compositions, microstructures and surface roughnesses of these coatings were characterized by atomic absorption spectroscopy, optical microscopy, scanning electron microscopy and atomic force microscopy. The microhardness of the coatings was measured and the wear mechanism of the coatings was evaluated using a pin-on-plate (reciprocating) wear testing machine. The results showed less cracking and pore development for Stellite 6 coatings applied to the 9Cr-1Mo (P91) steel substrate with the lower heat input (P91-1). Further, the Stellite coating for P91-1 was significantly harder than that obtained for P91-1.8. The wear test results indicated that the weight loss for P91-1 was much lower than for P91-1.8. The surface topography data indicated that the surface roughness for P91-1 was much lower than for P91-1.8. It is concluded that the lower hardness of the coating for P91-1.8, together with the softer underlying substrate structure, markedly reduced the wear resistance of the Stellite 6 coating.

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Section: Discussionmentioning

confidence: 71%

Surface Morphology and Wear Analysis of Stellite 6 Deposited on 9Cr-1Mo Steel Substrate by Laser Cladding

Kusmoko

2015

AMR

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“…Recently, many publications have referred to studies in which cobalt and its alloys were used as a matrix; however, such materials are seldom described as matrix materials in composite layers [12,13], and more often as homogeneous layers [14][15][16]. Cobalt-chromium alloys, called Stellites, which are characterized by high hardness, resistance to corrosive environments and, above all, high wear resistance (including metal-metal, metal-mineral and metal-liquid resistance) constitute a particularly important group of hardfacing materials used for the production of laser-clad surfaces on elements designed to work in conditions of high abrasive wear and extreme temperatures (up to 1050 • C), often combined with an aggressive working environment.…”

Section: Introductionmentioning

confidence: 99%

Influence of Preheating Temperature on Structural and Mechanical Properties of a Laser-Welded MMC Cobalt Based Coating Reinforced by TiC and PCD Particles

Czupryński

Pawlyta

2022

Materials

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This article presents research on the structural and mechanical properties of an innovative metal matrix composite (MMC) coating designed for use in conditions of intense metal-mineral abrasive wear. The layer, which is intended to protect the working surface of drilling tools used in the oil and natural gas extraction sector, was padded using the multi-run technique on a sheet made of AISI 4715 low-alloy structural steel by Laser Direct Metal Deposition (LDMD) using a high-power fiber laser (FL). An innovative cobalt alloy matrix powder with a ceramic reinforcement of crushed titanium carbide (TiC) and tungsten-coated synthetic polycrystalline diamond (PCD) was used as the surfacing material. The influence of the preheating temperature of the base material on the susceptibility to cracking and abrasive wear of the composite coating was assessed. The structural properties of the coating were characterized by using methods such as optical microscopy, scanning electron microscopy (SEM), energy dispersion spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD). The mechanical properties of the hardfaced coating were assessed on the basis of the results of a metal-mineral abrasive wear resistance test, hardness measurement, and the observation of the abrasion area with a scanning laser microscope. The results of laboratory tests showed a slight dissolution of the tungsten coating protecting the synthetic PCD particles and the transfer of its components into the metallic matrix of the composite. Moreover, it was proved that an increase in the preheating temperature of the base material prior to welding has a positive effect on reducing the susceptibility of the coating to cracking, reducing the porosity of the metal deposit and increasing the resistance to abrasive wear.

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“…Both of these factors can result in increased wear resistance of coatings. A study by Kusmoko et al (26) 2014 compared the reciprocating wear performance of HVOF, plasma sprayed and laser clad coatings of Stellite 6 and found the laser clad coating to exhibit the lowest wear rates, linking the results to high density, high hardness and reasonable ductility.…”

Section: High Temperature Wear and Corrosion Applicationsmentioning

confidence: 99%

Investigation of induction-assisted laser metal deposition of crack susceptible coatings

Barras

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Protecting components against severe wear and corrosion in high temperature environments is an ongoing challenge that is often resolved by applying an advanced functional coating. Environments like steam turbines present ever-evolving demands with industrial push to utilise higher operating temperatures that in turn increase power generation efficiencies. Tribaloy T800 is a superior coating composition that presents challenges in processability due to its low toughness and crack susceptible nature. Weld overlay/ cladding processes based on fusion technology such as Laser Metal Deposition (LMD) (AKA Laser Cladding) offer significant benefits for the application of coating materials including a high strength metallurgical bond and a dense, defect free coating. LMD generates more rapid melting and solidification of the alloy compared to arc cladding, which produces a fine microstructure, but can lead to solidification cracking due to induced thermal stresses during the process and a lack of toughness in the coating material. A small number of papers and published research projects have looked into LMD coatings of Tribaloy T800 with the ultimate aim to prove the feasibility of protecting components in high-temperature (600-1000°C) gas turbines, jet engines, shafts and pumps. Many of these studies conclude the findings of process optimisation, material characteristics and integrity, based on small-scale deposits. Small area deposits can present a lack of representation compared to full-scale coatings, including thermal control/accuracy, residual stresses, and even effects on dilution. In all circumstances, preheating was found to reduce or eliminate cracking by minimising the thermal shock and cooling rate of the alloy upon solidification. In this study, part of the objectives was to review and ensure the relevance of the experiments and findings for transferability to full-scale components. Using Design of Experiments (DoE), experiments were constructed that evaluated the relationship between dilution, hardness and cracking response of the LMD deposited T800 against critical process variables including particularly induction heating temperature. One substrate alloy was investigated, 316L stainless steel, (although there was an intention to transfer developments to In718 nickel superalloy at a later stage). Through this process, it was determined that cracks form during solidification of the meltpool. Another objective was to evaluate two methods of improving coatings speeds for the application of T800, 1) by implementing equipment adaptions to increase melt pool size and material feed rate and 2) to make initial assessment of a novel LMD technique known as Extreme High-speed Laser Application (EHLA). Cracking was only eliminated in the large-scale undiluted coatings of T800 when using high levels of substrate heating (800-950°C) prior and during the coating operation by induction-assisted LMD. The resultant material behaviour of the deposited T800 showed promising results in terms of material integrity, and tribological and protective properties. Improvements in coating speeds were made when using laser defocus methods and increased deposition rate from 300 grams/hour to 600- 1000grams/hour, though increased cracking was observed. Trials using EHLA demonstrated unique process characteristics of high-speed thin coatings with promising cracking behaviour at lower preheat temperatures than required for LMD (200-500°C), ultra-low dilution and good material properties.

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Wear Behaviour of Stellite 6 Coatings Produced on an Austenitic Stainless Steel Substrate by Laser Cladding Using Two Different Heat Inputs

Cited by 5 publications

References 10 publications

Surface Morphology and Wear Analysis of Stellite 6 Deposited on 9Cr-1Mo Steel Substrate by Laser Cladding

Surface Morphology and Wear Analysis of Stellite 6 Deposited on 9Cr-1Mo Steel Substrate by Laser Cladding

Influence of Preheating Temperature on Structural and Mechanical Properties of a Laser-Welded MMC Cobalt Based Coating Reinforced by TiC and PCD Particles

Investigation of induction-assisted laser metal deposition of crack susceptible coatings

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