Krom içeriğinin Fe(18-x)CrxB2 (X=3,4,5) sert dolgu elektrotunda mikroyapı, aşınma ve korozyon davranışı üzerindeki etkisi

Abstract

 Coatings of Fe(18-x)CrxB2 (x=3,4,5) based hardfacing electrodes on steel substrate.  Microstructural development of coatings formed on steel surface.  Hardness, wear and corrosion behavior of coatings depending on chromium ratio. Figure A. Schematic illustration of coating process Purpose: The aim of this study is to investigate the effect of chromium content on coating carried out with Fe(18-x)CrxB2 (x=3,4,5) hardfacing electrode. Theory and Methods:Electrode cover composition was prepared with ferro-chromium, ferro-bor and various flux components as starting material. Then the mixed powders were compressed in a mold to form electrode and dried a certain period. The coating on to an AISI 1010 steel surface was carried out by using these electrodes. The coating samples were prepared according to standard metallographic operations and The microstructure, hardness, wear and corrosion behavior of coating was investigated. Results:For each sample, the average coating layer thickness ranged from 4 to 6 mm and has a smooth surface and porosity free topography. It has been determined that a-(Fe-Cr) phase and eutectic phases in coatings which were carried out according to changing chrome ratio. In the coating containing 15% chromium, primary eutectic (a-Fe,Cr)+orthorhombic (Cr,Fe)2B structure surrounded by secondary eutectic (a-(Fe,Cr)+tetragonal (Fe,Cr)2B phase and ın the coating containing 20% and 25% chromium, primary eutectic (a-Fe,Cr) surrounded by chromium-rich boride (α-(Fe,Cr)+ortorombik (Cr,Fe)2B) were observed. X-ray diffraction analysis shows that the system includes -(Fe,Cr)+orthorhombic (Cr,Fe)2B phases as well as tetragonal (Cr,Fe)2B and (Fe,Cr)3(C,B) phases. Hardness values were measured as 65 (+/-0.4) HRC, 65.3 HRC (+/-0.3) and 67.5 HRC (+/-0.5), respectively, according to the increasing chromium ratio. The lowest wear rate was found 2.32x10 -5 (mm 3 /m) in 3N load for the electrode with the Fe13Cr5B2 composition and the highest value was found to be 8.16x10 -5 (mm 3 /m) for electrode with Fe15Cr3B2 composition at 9N load. In addition, the Icor value decreased according to the increasing amount of chromium and was measured as 2.166 µA/cm 2 and 1.615 µA/cm 2 and 1.242 µA/cm 2 , respectively. It was determined that the Ecor value increased with increasing chrome ratio and reached -473.991 mV, -450.056 mV and -347.157 mV respectively. Conclusion:Due to the increase in the chromium ratio in the coating layers, the amount of boride in the eutectic structure, which causes better mechanical and metallurgical properties, has increased. Accordingly, with the increase of Cr ratio in the coating layer, hardness values increased and wear rate values decreased. In addition, the corrosion resistance of the coatings increased with the increase of Cr ratio.

Effect of the Molybdenum Content on Wear and Corrosion Behavior of Fe-B-Based Surface-Alloyed Layer

“…Atomic calculation of the electrode compositions and details of the production process can be found in previous studies carried by Kocaman et al. [32,33]. The coating process was carried out using an electric arc welding machine at a 125 A (amperes) and 25 V (volts) constant potential on the AISI 1020 steel substrate, of which its chemical composition is given in Table 1.…”

“…Although the solubility of molybdenum in α-Fe is quite low under normal conditions, its solubility has been reported to be ~24% at ~1450 • C [40,41]. In a process where solidification is dynamic, such as welding, rapid regional or structural cooling might have occurred [33]. For this reason, it was normal for the molybdenum solubility to increase regionally in α-Fe, and the dark gray regions are called α-(Fe,Mo).…”

Effect of titanium content on the microstructure and wear behavior of Fe(13-x)TixB7 (x=0-5) hardfacing alloy

“…It is also seen that there are partial fluctuations in the microhardness results. The reason for these fluctuations is due to the small hard phases such as TiB2 in the microstructure [27]. On the other hand, according to the graph, it is seen that the microhardness values increase from the substrate to the coating layer.…”

Effect of Exothermic Addition (CuO - Al) on the Structure, Mechanical Properties and Abrasive Wear Resistance of the Deposited Metal During Self-Shielded Flux-Cored Arc Welding

“…Fe-B-С system flux-cored wire electrode hardfacing technology is used in different industry branches for equipment worn parts reinforcement [32][33][34][35][36]. However, are becoming more widespread by Fe-Cr-B-C and Fe-Ti-Cr-B-C system alloys, which have the best mechanical properties and wear resistance [8, [37][38][39][40][41].…”