Performance of 75Cr3C2-25NiCr Coating Produced by HVOF Process in a Coal-Fired Thermal Power Plant

2016 ◽  
Vol 1137 ◽  
pp. 88-100 ◽  
Author(s):  
Sukhpal Singh Chatha ◽  
Hazoor S. Sidhu ◽  
Buta Singh Sidhu
Keyword(s):  
High Temperature ◽  
Internal Oxidation ◽  
Steel Substrate ◽  
Thermal Power ◽  
Tube Steel ◽  
Boiler Steel ◽  
Internal Corrosion ◽  
Thickness Loss ◽  
Hvof Process ◽  
Boiler Tube Steel

In the present investigation, 75Cr3C2-25NiCr coating was deposited on T91 boiler tube steel substrate by high velocity oxy-fuel (HVOF) process to enhance high-temperature corrosion resistance. High-temperature performance of bare, as well as HVOF-coated steel specimens was evaluated for 1500 h under cyclic conditions in the platen superheater zone coal-fired boiler, where the temperature was around 900 °C. Experiments were carried out for 15 cycles each of 100 h duration followed by 1 h cooling at ambient temperature. The performance of the bare and coated specimens was assessed via metal thickness loss corresponding to the corrosion scale formation and the depth of internal corrosion attack. The uncoated boiler steel suffered from a catastrophic degradation in the form of internal oxidation attack and thickness loss. The 75Cr3C2-25NiCr coating showed good adherence to the boiler steel during the exposures with no tendency for internal oxidation.

Experimental Analysis of Hot Corrosion Behaviour of some Composite Coatings on Boiler Steel at Elevated Temperature

2021 ◽  
Vol 41 ◽  
pp. 43-54
Author(s):  
Prince Puri ◽  
Khushdeep Goyal ◽  
Rakesh Goyal ◽  
Bal Krishan
Keyword(s):  
Hot Corrosion ◽  
Power Plants ◽  
Corrosion Behaviour ◽  
Composite Coatings ◽  
Thermal Power ◽  
Tube Steel ◽  
X Ray Diffraction ◽  
Boiler Steel ◽  
Boiler Tube Steel ◽  
Silicon Tube

Hot corrosion is the main reason of failure of boiler tubes used at high temperature in thermal power plants. This paper is an attempt to investigate the effect of different composite coatings on boiler tube steel in corrosive environment of Na2SO4 – 60%V2O5 at 900°C for 50 cycles. The coatings have been deposited with high velocity oxy fuel process. The samples were exposed to hot corrosion in a Silicon tube furnace at 900°C for 50 cycles. The kinetics of corrosion behaviour were analysed by the weight gain measurements after each cycle. Corrosion products were analysed with weight change statistics, X-ray diffraction, and scanning electron microscopy. It is found that 100Cr3C2 composite coatings provided the higher resistance to corrosion as compared to other types of coatings. Cr carbide layer was formed on the surface and these layers provided the protection from hot corrosion.

scholarly journals PERFORMANCE OF NI3AL AND TIO2 COATINGS ON T22 BOILER TUBE STEEL IN SIMULATED BOILER ENVIRONMENT IN LABORATORY

2017 ◽  
Vol 46 (1) ◽  
pp. 54-61 ◽  
Author(s):  
Simranjeet Singh ◽  
Khushdeep Goyal ◽  
Rakesh Goyal
Keyword(s):  
Thermal Power ◽  
Steel Tube ◽  
Tube Steel ◽  
Operating Life ◽  
Boiler Steel ◽  
Thermo Gravimetric ◽  
Corrosion Studies ◽  
Boiler Tube Steel ◽  
Boiler Environment ◽  
Kinetics Of

The corrosion of boiler steel tube in coal fired boiler is main matter during design and operation of thermal power plant and it leads to both direct and indirect cost and energy lost, including losses due to plant shut down time and inefficiency of operation. One of the feasible solution to solve the problem is providing surface coating on boiler steel tube, which on one hand protect the tube from highly corrosive flue gaseous and on other hand increase their operating life. Ni3Al and TiO2 and coatings were sprayed on ASTM SA213-T22 steel by using the HVOF process. Hot corrosion studies were conducted on the uncoated as well as coated sprayed specimens in molten salt environment of Na2SO4-60%V2O5 at 900ºC for 50 cycles. In the experiment each cycle consist of 1 hr of heating in tube furnace followed by 20 minute of cooling in air. The thermo-gravimetric technique was used in order to establish the kinetics of corrosion. XRD, SEM/EDS testing were used to examine the corrosion specimens. Theresult shows that both the coated samples are beneficial to corrosion resistance over uncoated samples. TiO2 coating was found to be most protective followed by the Ni3Al coating.

Mechanical and microstructural properties of carbon nanotubes reinforced chromium oxide coated boiler steel

2018 ◽  
Vol 15 (4) ◽  
pp. 429-439 ◽  
Author(s):  
Khushdeep Goyal ◽  
Hazoor Singh ◽  
Rakesh Bhatia
Keyword(s):  
Carbon Nanotubes ◽  
Composite Coatings ◽  
Tube Steel ◽  
Microstructural Properties ◽  
Boiler Tube ◽  
Boiler Steel ◽  
Content Type ◽  
X Ray ◽  
Boiler Tube Steel ◽  
Mechanical And Microstructural Properties

Purpose The purpose of this study was to fabricate carbon nanotubes (CNT)-reinforced chromium oxide coatings and investigate mechanical and microstructural properties of these newly developed coatings on the boiler tube steel. Design/methodology/approach 1 and 4 Wt.% CNT-reinforced Cr2O3 composite coatings were prepared and successfully deposited on ASTM-SA213-T22 (T22) boiler tube steel substrates using high-velocity oxy fuel (HVOF) thermal spraying method. Microhardness, porosity, metallography, X-ray diffraction (XRD), scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy, cross-sectional elemental analysis and X-ray mapping analysis have been used to examine the coated specimens. Findings The porosity of the CNT-Cr2O3 composite coatings was found to be decreasing with the increases in CNT content, and hardness has been found to be increasing with increase in percentage of CNT in the composite coatings. The CNT were able to increase hardness by approximately 17 per cent. It was found that the CNT were uniformly distributed throughout Cr2O3 matrix. The CNT were found to be chemically inert during the spraying process. Originality/value It must be mentioned here that studies related to fabrication of HVOF sprayed CNT reinforced Cr2O3 composite coatings on T22 boiler tube steel are not available in the literature. Hence, present investigation can provide valuable information related to fabrication and properties of CNT reinforced coatings on boiler steel.

scholarly journals Sulphur and vanadium-induced high-temperature corrosion behaviour of different regions of SMAW weldment in ASTM SA 210 GrA1 boiler tube steel

2020 ◽  
Vol 39 (1) ◽  
pp. 256-260
Author(s):  
Ravindra Kumar ◽  
Vinay Kumar Tewari ◽  
Satya Prakash
Keyword(s):  
High Temperature ◽  
Weld Metal ◽  
Power Plants ◽  
Corrosion Behaviour ◽  
Thermal Power ◽  
High Temperature Corrosion ◽  
Tube Steel ◽  
Low Grade ◽  
Shielded Metal Arc Welding ◽  
X Ray

AbstractCorrosion at elevated temperature is a serious problem in running thermal power plants because of the use of low-grade fuels that contain substantial amounts of sulphur, vanadium, sodium etc. This article reports the high-temperature corrosion of weld metal and heat-affected zone (HAZ) of shielded metal arc-welding (SMAW) weldment in GrA1 steel in a molten salt (Na2SO4–60% V2O5) environment at 900°C under cyclic conditions. The thermogravimetric technique was used to observe the kinetics of corrosion. The corrosion products formed on weld metal and HAZ of SMAW welded steel were characterized by scanning electron microscopy with energy dispersive X-ray analysis (EDX) and X-ray diffraction pattern. Weld metal was found to oxidize at a higher rate than those of HAZ due to the presence of sodium and sulphur in the inner oxide scale as confirmed by EDX, and this leads to high corrosion rate (in terms of weight gain).

Improving the high-temperature oxidation resistance of ASME-SA213-T11 boiler tube steel by plasma spraying with CNT-reinforced alumina coatings

2018 ◽  
Vol 65 (2) ◽  
pp. 217-223 ◽  
Author(s):  
Rakesh Goyal ◽  
Buta Singh Sidhu ◽  
Vikas Chawla
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Composite Coatings ◽  
Tube Steel ◽  
Boiler Tube ◽  
Alumina Coatings ◽  
Temperature Oxidation ◽  
Content Type ◽  
Boiler Tube Steel

Purpose This paper aims to discuss that a conventional Al2O3, 1.5 Wt.% carbon nanotubes (CNTs)-Al2O3, 2 Wt.% CNTs-Al2O3 and 4 Wt.% CNTs-Al2O3 composite coatings were deposited with the help of Plasma spray process. Design/methodology/approach To better understand the effect of CNT reinforcement on oxidation resistance, high-temperature oxidation behaviour of conventional Al2O3, 1.5 Wt.% CNTs-Al2O3, 2 Wt.% CNTs-Al2O3 and 4 Wt.% CNTs-Al2O3 composite coatings at 900°C was compared with the performance of the uncoated ASME-SA213-T11 boiler tube steel substrate. Findings The results showed that the CNT-reinforced alumina coatings exhibited better oxidation resistance and thermal stability than uncoated ASME-SA213-T11 boiler tube steel. The coated steel substrates had a lower mass gain rate than the substrate after different oxidation times. Originality/value Limited literature is available where the CNT have been reinforced into the composite alloy powders and has been thermally spray-deposited for various surface engineering applications. This research showed that with the increase in the percentage of CNTs into the alloy powder mixture, there is a significant reduction in weight gain and hence higher resistance to oxidation.

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