Corrosion behaviour and corrosion mechanism of corundum block and mullite block in hearth of blast furnace

2021 ◽  
Vol 118 (5) ◽  
pp. 511
Author(s):  
Shun Yao ◽  
Heng Zhou ◽  
Shengli Wu ◽  
Bo Song ◽  
Mingyin Kou
Keyword(s):  
Corrosion Resistance ◽  
Blast Furnace ◽  
High Temperature ◽  
Corrosion Rate ◽  
Molten Slag ◽  
Molten Iron ◽  
Transport Rate ◽  
Diffusive Transport ◽  
The Matrix ◽  
Corrosion Mechanisms

A ceramic cup is often used to prolong the hearth life of a blast furnace (BF). Corundum blocks and mullite blocks are two kinds of refractories widely used for building ceramic cups in China. Therefore, research on the corrosion resistance of these two kinds of refractories is beneficial to realize the BF longevity. In this study, the corrosion behaviours and corrosion mechanisms of molten slag and molten iron on corundum block and mullite block samples were investigated by corrosion tests. The results show that the slag corrosion resistance of corundum block was better than that of mullite block, and the corrosion mechanisms of molten slag on corundum block and mullite block were different. The aggregates fell from the matrix of the corundum sample when the matrix was corroded to a certain degree by slag, and the corrosion rate of slag on the corundum sample was controlled by the diffusive transport rate of a substance and the chemical reaction rate between slag and matrix. However, the aggregate and matrix of the mullite sample was corroded by slag at the same time, and the corrosion rate of slag on the mullite sample was controlled by the diffusive transport rate of Ca through the newly formed reaction layer. Moreover, the corundum block and mullite block had excellent iron corrosion resistance. The high temperature of molten iron led to an in situ reaction to generate a mullite phase in the corundum sample, and the high temperature affected the microstructure of the corundum block and mullite block.

scholarly journals High Temperature and Corrosion Properties of A Newly Developed Fe-Al-O Based OPH Alloy

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 167 ◽  
Author(s):  
Omid Khalaj ◽  
Ehsan Saebnoori ◽  
Hana Jirková ◽  
Ondřej Chocholatý ◽  
Jiří Svoboda
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Thermomechanical Properties ◽  
Production Costs ◽  
Nacl Solution ◽  
Corrosion Properties ◽  
Ambient Temperatures ◽  
The Matrix ◽  
Specific Amount

Fe–Al–O-based materials are currently undergoing a great deal of development because of their many special properties. However, lack of strength at high temperatures, limited ductility at ambient temperatures and corrosion resistance have hindered a wider application of these materials. Recently, a new Fe–Al-based oxide precipitation hardened (OPH) steel was developed by the authors to improve the mechanical properties and oxidation resistance. The new OPH alloys are produced by dissolving a specific amount of oxygen in the matrix during mechanical alloying followed by precipitation of fine dispersion of aluminum or yttrium oxides during hot consolidation. A series of tests was performed to evaluate the thermomechanical properties and corrosion resistance in a 3.5% NaCl solution. The results show improved corrosion resistance, as well as mechanical properties, while the production costs of this material are lower than for traditional materials.

Effect of Dense Layer Formation on Dissolution Rate of MgO-C Refractory in Molten Slag

2006 ◽  
Vol 45 ◽  
pp. 162-166 ◽  
Author(s):  
Hiroyuki Sunayama ◽  
Masayasu Kawahara
Keyword(s):  
Chemical Composition ◽  
Corrosion Rate ◽  
Corrosion Test ◽  
Molten Slag ◽  
Cylindrical Specimen ◽  
Rotating Cylinder ◽  
Dense Layer ◽  
Layer Formation ◽  
The Matrix ◽  
Cylinder Method

The corrosion test for magnesia-carbon refractory, MgO-C, with dense layer has been carried out by a rotating cylinder method at 1673 K. The specimen, which was a cylinder of 25 mm diameter and 25mm height, was rotated in molten slag at 50 rpm. The chemical composition of slag was CaO-SiO2-FeO-MgO-CaF2. The corrosion rate was determined by the variation of radius of the cylindrical specimen against corrosion time. The decrease of radius was obtained by a calculation of dissolved MgO into the slag. In addition, the diameter of the specimen was measured with a slide calipers after the corrosion test. The cylindrical specimen was heated to form a dense layer before the corrosion test. The corrosion rate of the MgO-C refractory with dense layer was slower than that of the MgO-C refractory without dense layer. The oxidized layer, where the dense layer formed, dissolved at much the same rate as the MgO brick. The dense layer probably obstructed contact between slag and carbon in the matrix, and then oxidation of C by slag did not take place. Formation of the dense layer was effective to inhibit corrosion of MgO-C refractory by molten slag.

scholarly journals Corrosion Resistance of Al/SiC Laser Cladding Coatings on AA6082

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 673
Author(s):  
Ainhoa Riquelme ◽  
Pilar Rodrigo ◽  
María Dolores Escalera-Rodríguez ◽  
Joaquín Rams
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Laser Cladding ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
The Matrix ◽  
Corrosion Mechanisms ◽  
Silicon Carbide Particles ◽  
Carbide Particles

Aluminum matrix composites reinforced with silicon carbide particles (SiCp) were deposited by laser cladding on AA6082 aluminum alloy. Different compositions of the matrix of the composites coating were used and different amounts of Si and Ti were added to a base of Al-12Si in order to control the reactivity between molten aluminum and SiCp during laser cladding. The corrosion behavior of the coatings deposited was evaluated in 3.5 wt.% NaCl solution using gravimetric analyses and electrochemical polarization tests. The corrosion products observed were Al(OH)3 and Al2O3, and they formed a layer that limited the evolution of corrosion. However, the presence of discontinuities in it reduced the corrosion resistance of the coating. The corrosion mechanisms were different depending on the coating composition. The addiction of Ti to the alloy allowed for better corrosion behavior for the composite coating than that of the aluminum substrate.

An environmental procedure to extract titanium components and metallic iron from Ti-bearing blast furnace slag

2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Wu Zhang ◽  
Li Zhang ◽  
Yuhai Li ◽  
Xin Li
Keyword(s):  
Blast Furnace ◽  
High Temperature ◽  
Metallic Iron ◽  
Blast Furnace Slag ◽  
Gravity Separation ◽  
Modification Process ◽  
Temperature Modification ◽  
The Matrix ◽  
Furnace Slag ◽  
High Temperature Modification

AbstractAn environmental procedure to extract titanium components and metallic iron from Ti-bearing blast furnace slag is accomplished via three steps, which are high-temperature modification, gravity separation and hydrometallurgy method. The behaviors of metallic iron during the high-temperature modification process are studied. The feasibility of separating rutile from the matrix phase are investigated; based on the feasibility analysis results, the gravity separation experiment is carried out in order to improve the TiO

scholarly journals High-temperature corrosion behavior of TP91, C22 alloy and C22 based on laser coatings in simulated reducing corrosion environment

2021 ◽  
Author(s):  
CongCong Liu ◽  
Zongde Liu ◽  
Yuan Gao ◽  
Xinyu Wang ◽  
Chao Zheng
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Corrosion Behavior ◽  
Corrosive Medium ◽  
High Temperature Corrosion ◽  
Dense Layer ◽  
Corrosion Tests ◽  
The Matrix ◽  
Reducing Environment ◽  
Low Nitrogen

Abstract To explore corrosion characteristics of TP91, C22 alloy and C22 laser coatings in reducing environment caused by low-nitrogen combustion at 500°C-600°C, a synthetic corrosive medium containing 0.2 vol. % H2S-0.1 vol. % O2-N2 were selected. Results showed that the order of corrosion resistance is: C22 laser coatings>C22 alloy>TP91. 550°C was the limit corrosion temperature for C22 alloy and C22 laser coatings. The reason for the strong corrosion resistance of C22 alloy and C22 laser coatings is that a dense layer of Cr-rich corrosion products due to the is produced in the inner layer, thus protecting the matrix from direct corrosion by corrosive gas. Finer grains before corrosion tests and the formation of dense Cr2O3 inner layers in much speedier process were the main reasons for the best corrosion resistance of C22 laser coatings.

Corrosion of Nickel-Based Alloys in Ultra-High Temperature Heat Transfer Fluid

2017 ◽  
Vol 36 (3) ◽  
pp. 267-277 ◽  
Author(s):  
Tao Wang ◽  
Ramana G. Reddy
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Corrosion Rate ◽  
Energy Dispersive Spectrometer ◽  
Heat Transfer Fluid ◽  
Excellent Thermal Stability ◽  
Rate Analysis ◽  
Operation Temperature ◽  
Corrosion Mechanisms ◽  
Molten Salt System

AbstractMgCl2-KCl binary system has been proposed to be used as high temperature reactor coolant. Due to its relatively low melting point, good heat capacity and excellent thermal stability, this system can also be used in high operation temperature concentrating solar power generation system as heat transfer fluid (HTF). The corrosion behaviors of nickel based alloys in MgCl2-KCl molten salt system at 1,000 °C were determined based on long-term isothermal dipping test. After 500 h exposure tests under strictly maintained high purity argon gas atmosphere, the weight loss and corrosion rate analysis were conducted. Among all the tested samples, Ni-201 demonstrated the lowest corrosion rate due to the excellent resistance of Ni to high temperature element dissolution. Detailed surface topography and corrosion mechanisms were also determined by using scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS).

Effect of Sn Addition on the Corrosion Performance of Cast X-52 in H2S-Containing Environment at 60°C

2013 ◽  
Vol 743-744 ◽  
pp. 607-612 ◽  
Author(s):  
Hong Liang Lin ◽  
Jian Qiu Wang ◽  
En Hou Han
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Corrosion Performance ◽  
Positive Role ◽  
Surface Corrosion ◽  
The Matrix ◽  
The Relationship ◽  
Small Content

The electrochemical behavior of cast X-52 with different Sn content ranging from 0 to 1 wt. % was investigated using the methods of potentiodynamic test, electrochemical impedance spectroscopy (EIS). The immersion tests involved to examine the relationship between Sn addition and corrosion performance of cast X-52. In addition, the morphology and the compositions of surface corrosion products were analyzed using scanning electron microscope (SEM)/ energy dispersive spectroscopy (EDS). Potentiodynamic polarization curves showed that the presence of Sn decreased the corrosion current density. EIS indicated that Sn-containing steels had higher polarization resistances. These results confirmed that Sn played a positive role in reducing corrosion rate in H2S-containing environment. However, the corrosion resistance decreased with increasing Sn addition. It was proved that Sn improved the corrosion resistance with only a small content and large amount of Sn might lead to an advance of the pit due to occurrence of more acidification. Moreover, a continuous inner O-rich layer adherent to the matrix was found for Sn-addition samples, which lead to a decrease of corrosion rate due to its compact characteristic, compared with porous sulfide formed on the outer surface.

Effect of Aging on Yield Stress and Corrosion Resistance of Die Cast Magnesium Alloy

2005 ◽  
Vol 488-489 ◽  
pp. 709-712 ◽  
Author(s):  
Guang Ling Song ◽  
Amanda L. Bowles ◽  
David H. StJohn
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Yield Strength ◽  
Corrosion Rate ◽  
Ageing Time ◽  
Aluminium Content ◽  
Β Phase ◽  
Die Cast ◽  
The Matrix ◽  
Cast Magnesium

Corrosion resistance is an important property that could be affected by the ageing process. In order to investigate whether aging affects the corrosion resistance, corrosion rate and yield strength of diecast magnesium alloy AZ91D were measured and analysed after ageing. It was found that the dependence of the corrosion rate on ageing time can be ascribed to the changes in microstructure of the alloy and chemical composition of its matrix. Precipitation of the β phase (Mg17Al12) occurred along the grain boundaries during the initial ageing stages, resulting in a decreasing corrosion rate and an inceasing yield strength. In the later stages, the decreasing aluminium content in the a matrix made it more active, causing an increase in the corrosion rate. The decrease in aluminium content in the matrix also leads to a decrease in yield strength.

Corrosion Behavior of P110S Oil Pipe in Simulated Working Condition

2019 ◽  
Vol 944 ◽  
pp. 815-820
Author(s):  
Xiao Jun Fang ◽  
Li Liu ◽  
Zhi Gang Yang ◽  
Yong Qiang Zhang
Keyword(s):  
High Pressure ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Corrosion Rate ◽  
Tensile Stress ◽  
Partial Pressure ◽  
Stress Corrosion Cracking ◽  
Working Condition ◽  
Xrd Analysis ◽  
Corrosive Environment

The corrosion resistance of P110S steel in CO2 and H2S coexistence corrosion environment under different temperature and PCO2/PH2S was investigated by high temperature and high pressure (HTHP) reaction kettle combined with SEM, EDS and XRD analysis methods. The stress corrosion cracking (SCC) resistance of P110S steel was studied under loading pressure of 682.2MPa (758MPa×90%) in simulated conditions after 720 hours test. The results show that the P110S steel has serious corrosion in the range of simulative temperature and H2S partial pressure. With the increase of temperature, the corrosion rate decreases first and then increases. With the increase of H2S partial pressure, the corrosion rate increases first and then decreases. The P110S steel has the highest corrosion rate when the temperature is 50 °C and H2S partial pressure is 0.1%. After the anti-SCC test, the specimens did not fracture, and cracks perpendicular to the tensile stress were not found on the surface. That is, P110S has good SCC resistance in the corrosive environment.

Research on the Alkali Corrosion Resistance Mechanism of Ni-Cr-Cu Alloy Cast Iron

2011 ◽  
Vol 230-232 ◽  
pp. 1298-1302
Author(s):  
Jun Ping Yao ◽  
Sun Zhong
Keyword(s):  
Corrosion Resistance ◽  
Cast Iron ◽  
High Temperature ◽  
Caustic Soda ◽  
Resistance Mechanism ◽  
Uniform Corrosion ◽  
Cast Irons ◽  
Cu Alloy ◽  
The Matrix ◽  
Alloy Cast

In allusion to facility corrosion problem in caustic soda industry five types of ni-Cr-cu alloy cast irons were developed. The corrosion rates of ni-Cr-cu alloy cast irons in hot concentrated alkali solution were measured by using self-made dynamic corrosion experiment equipment; the microstructures and surface corrosion morphology of alloy cast irons were observed by means of the optical microscope and SEM; the composition was analyzed using XES. Corrosion resistance mechanism were discussed detailedly. the experimental results showed that ni-Cr-cu cast iron was uniform corrosion macroscopically in the dense caustic soda at high temperature and there was ni, cu enrichment microcosmically. The Ni and Cu enriched in the matrix , which increase in local electrode voltage of the matrix,are advantageous to the improvement of caustic corrosion resistances of that zone. The higher Ni content,the better alkali corrosion resistance performance with high temperature.

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