In the present work hot corrosion studies were carried out on electron beam welded AISI 304 and AISI 4140 dissimilar weldment in molten salt (K2SO4-60% NaCl) environment at 800 °C for 50 cycles. The weight gain follows parabolic law in all the cases. It is observed that the scale formation was maximum on 4140 side as compared on 304 side. Moreover higher content of Fe2O3 and Cr2O3 on scale over weld zone may be due to enrichment of this zone with Fe and Cr. This could be attributed to diffusion of chromium towards AISI 4140 from the AISI 304 and diffusion of iron from AISI 4140 side towards AISI 304. Furthermore weld interface suffered accelerated corrosion behavior in the chloride and sulfate mixed molten salt environment in the form of intense spalling and sputtering of its scale. The cracking of oxide scale on the weldment might be attributed to different composition of base metals, weld metal and oxide formed.

Arivazhagan N

Department of Manufacturing Engineering

School of Mechanical Engineering

Vellore Campus

Narayanan S

Singh S

Prakash S

Reddy G.M.

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

&nbsp;

&nbsp;

VIT University

Advanced Materials Research

Alloy C-276 is widely used in the power plant environment due to high strength and corrosion in highly aggressive environment. The investigation on high- temperature corrosion resistance of the alloy C-276 PCGTA weldment is necessary for prolonged service lifetime of the components used in corrosive environments. Investigation has been carried out on Pulsed Current Gas Tungsten Arc Welding by autogenous and different filler wires (ERNiCrMo-3 and ERNiCrMo-4) under molten state of K2SO4-60% NaCl environment at 675oC under cyclic condition. Thermogravimetric technique was used to establish the kinetics of corrosion. Weight gained in the molten salt reveals a steady-state parabolic rate law while the kinetics with salt deposits displays multi-stage growth rates. PCGTA ERNiCrMo-3 shows the higher parabolic constant compared to others. The scale formed on the weldment samples upon hot corrosion was characterized by using X-ray diffraction, SEM and EDAX analysis to understand the degradation mechanisms. From the results of the experiment the major phases are identified as Cr2O3, Fe2O3, and NiCr2O4. The result showed that weld fabricated by ERNiCrMo-3 found to be more prone to degradation than base metal and ERNiCrMo-4 filler wire due to higher segregation of alloying element of Mo and W in the weldment. © Published under licence by IOP Publishing Ltd.

Fulltext

IOP Conference Series: Materials Science and Engineering

High Temperature Corrosion studies on Pulsed Current Gas Tungsten Arc Welded Alloy C-276 in Molten Salt Environment

This paper presents the investigations carried out to study the microstructure and mechanical properties of AISI 304 stainless steel and AISI 4140 low alloy steel joints by Gas Tungsten Arc Welding (GTAW), Electron Beam Welding (EBW) and Friction Welding (FRW). For each of the weldments, detailed analysis was conducted on the phase composition, microstructure characteristics and mechanical properties. The results of the analysis shows that the joint made by EBW has the highest tensile strength (681. MPa) than the joint made by GTAW (635. Mpa) and FRW (494. Mpa). From the fractographs, it could be observed that the ductility of the EBW and GTA weldment were higher with an elongation of 32% and 25% respectively when compared with friction weldment (19%). Moreover, the impact strength of weldment made by GTAW is higher compared to EBW and FRW. © 2011 Elsevier Ltd.

Materials & Design

Investigation on AISI 304 austenitic stainless steel to AISI 4140 low alloy steel dissimilar joints by gas tungsten arc, electron beam and friction welding

High temperature corrosion tests were performed on dissimilar friction weldment of low alloy steel and austenitic stainless steel. Test conditions simulated the environment of a biofuel fired boiler. The samples were exposed to synthetic salt containing 40 wt-%K2SO4, 40 wt-%Na 2SO4, 10 wt-%KCl and 10 wt-%NaCl. In the present paper, hot corrosion behaviour of friction welded AISI 4140 and AISI 304 dissimilar materials in molten salt environments at 500, 550 and 600°C was studied. Corrosion was extremely severe on the interface of the dissimilar weldment in molten salt environment. Comparative evaluation was based on the effect of burn-off length and temperature of exposure on hot corrosion behaviour of the dissimilar weldment. Even the interface was attacked through chromium rich phases in hot corrosion environment. The metals formed on the weldment were non-protective. © 2009 Institute of Materials, Minerals and Mining.

Corrosion Engineering, Science and Technology

Hot corrosion studies on dissimilar friction welded low alloy steel and austenitic stainless steel under chlorine containing salt deposits under cyclic conditions

Materials Science and Engineering: B

High temperature corrosion studies on friction-welded dissimilar metals

Surface and Coatings Technology

Evaluation of the corrosion behaviour of plasma-sprayed Ni3Al coatings on steel in oxidation and molten salt environments at 900 °C

Corrosion Science

The environment assisted cracking of diffusion bonded stainless to carbon steel joints in an aqueous chloride solution

Corrosion Behaviour of Electron Beam Welded AISI 304 and AISI 4140

Journal	Advanced Materials Research
Publisher	Trans Tech Publications, Ltd.
ISSN	10226680
Open Access	No