Aluminizing Mechanism and Corrosion Resistance of Pipeline Steel X80 by Combined Pack Cementation Process under Low Temperature

2011 ◽  
Vol 194-196 ◽  
pp. 232-236
Author(s):  
Min Huang ◽  
Yu Wang ◽  
Xiang Hong Lv
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Pipeline Steel ◽  
Element Distribution ◽  
Surface Mechanical Attrition Treatment ◽  
Gradual Change ◽  
Mechanical Attrition ◽  
Pack Aluminizing ◽  
Aluminide Layer ◽  
Pack Cementation Process

In order to improve the corrosion resistance of pipeline steel X80 and maintain its good mechanical properties simultaneously, a low-temperature pack aluminizing process was carried out at 723 K on pipeline steel X80 after a surface mechanical attrition treatment (SMAT). The phase composition, microstructure and element distribution of the as-aluminized pipeline steel X80 were characterized by XRD, SEM and EDS, respectively.The results show that the as-received aluminide layer consists of Fe2Al5, which exhibits a good cohesion with SMATed pipeline steel X80 substrate with the thickness of around 90 μm. The element concentrations of Al and Fe atoms show a gradual change in the range of aluminide layer. After corrosion test processed in 3.5% NaCl solution, there is no obvious corrosion crack or uphills piled up by corrosion products on the surface of as-aluminized SMATed pipeline steel, which can conclude that pack aluminizing assisting by SMAT at low-temperature is an effective way for protecting pipeline steel X80 against corrosion.

EFFECT OF MAGNETRON-SPUTTERED Al FILM ON LOW-TEMPERATURE PACK-ALUMINIZING COATING FOR OIL CASING STEEL N80

2014 ◽  
Vol 21 (04) ◽  
pp. 1450053 ◽  
Author(s):  
MIN HUANG ◽  
YU WANG ◽  
MENG-XIAN ZHANG ◽  
YAN-QIU HUO ◽  
PENG-JIN GAO
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Aluminide Coating ◽  
Iron Aluminide ◽  
Concentration Change ◽  
Corrosion Condition ◽  
Pack Aluminizing ◽  
Aluminide Layer ◽  
Positive Effect

Low-temperature aluminizing coating was prepared onto the surface of oil casing steel N 80 with a magnetron-sputtered Al film to improve its corrosion resistance. Results show that magnetron-sputtered Al film is able to form gradient aluminide coating, composed of iron aluminide FeAl 3, Fe 2 Al 5 and Fe 3 Al with different contents of aluminum. Both the density and continuity of iron aluminide layer for oil casing steel N 80 with magnetron-sputtered Al film can be improved. Under the same corrosion condition, aluminized oil casing steel N 80 with a magnetron-sputtered Al film shows an outstanding corrosion resistance than those of original and aluminized ones without magnetron-sputtered Al film. The positive effect of Al film is considered as the concentration change of active Al atom for diffusion to form the aluminizing coating during the pack processing.

Aluminizing Coating Prepared on Oil Casing Steel N80 by Low-Temperature Pack Cementation

2011 ◽  
Vol 368-373 ◽  
pp. 2180-2184
Author(s):  
Yu Wang ◽  
Min Huang
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Aluminide Coating ◽  
Electrochemical Corrosion ◽  
Hardness Test ◽  
Element Distribution ◽  
Pack Cementation ◽  
Mechanical Attrition ◽  
Pre Treatment ◽  
Steel Substrates

Aluminizing has been verified to be an effective way to improve the corrosion resistance of steel due to the formation of continuous Al2O3layer, but traditional aluminizing processing carried out at high temperature can not be used to prepare aluminide layer on the surface of oil casing steel. In this paper, an aluminide coating was prepared on oil casing steel N80 by a low-temperature pack cementation only at 803 K for 2 hours by adding zinc in the pack powder and pre-treatment of N80 substrate by surface mechanical attrition. The phase compostion, microstructure, element distribution and properties of as-aluminized oil casing steel N80 were characterized by means of XRD, SEM, EDS, micro-hardness test and electrochemical corrosion measurements. The results indicate that aluminide coating mainly consists of FeAl3, Fe2Al5 and FeAl. The continuous aluminide coating with an average thickness around 50 μm could be successfully formed on the surface of oil casing steel N80 which shows a good coherence with as-packed substrate. After preparation of aluminide coating, oil casing steel N80 shows a higher microhardness in the range of aluminizing coating than that of the virgin material because of the formation of iron aluminide. The exception noted is that the proposed low-temperature aluminizing processing does not have any damaging impact on the mechanical properties of steel substrates. Moreover, it is concluded that oil casing steel N80 with aluminizing coating shows a better corrosion resistance than that of original N80 by analyzing of electrochemical test results.

CORROSION RESISTANT CERAMIC COATING FOR X80 PIPELINE STEEL BY LOW-TEMPERATURE PACK ALUMINIZING AND OXIDATION TREATMENT

2013 ◽  
Vol 20 (06) ◽  
pp. 1350063
Author(s):  
HUANG MIN ◽  
FU QIAN-GANG ◽  
WANG YU ◽  
ZHONG WEN-WU
Keyword(s):  
Corrosion Resistance ◽  
Low Temperature ◽  
Ceramic Coating ◽  
Pipeline Steel ◽  
Ceramic Coatings ◽  
X80 Pipeline Steel ◽  
Oxidation Treatment ◽  
Pack Aluminizing ◽  
Steel Substrates ◽  
Al Coating

In this paper, we discuss the formation of ceramic coatings by a combined processing of low-temperature pack aluminizing and oxidation treatment on the surface of X80 pipeline steel substrates in order to improve the corrosion resistance ability of X80 pipeline steel. First, Fe - Al coating consisting of FeAl 3 and Fe 2 Al 5 was prepared by a low-temperature pack aluminizing at 803 K which was fulfilled by adding zinc in the pack powder. Pre-treatment of X80 pipeline steel was carried out through surface mechanical attrition treatment (SMAT). Further oxidation treatment of as-aluminized sample was carried out in the CVD reactor at 833 K under oxygen containing atmosphere. After 1 h duration in these conditions, ceramic coating consisting of α- Al 2 O 3 was formed by in situ oxidation reaction of Fe - Al coating. Those coatings have been characterized by different techniques including X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscope (EDS), respectively. Ceramic coating shows a dense and uniform microstructure, and exhibits good coherences with X80 pipeline steel substrates. By electrochemical corrosion test, the self-corrosion current density of X80 pipeline steel with as-obtained ceramics coating in 3.5% NaCl solution shows an obvious decrease. The formation of α- Al 2 O 3 ceramic coating is considered as the main reason for the corrosion resistance improvement of X80 pipeline steel.

Low-Temperature Pack Aluminizing of X80 Pipeline Steel through Addition of Zinc and Surface Self-Nanocrystallization

2011 ◽  
Vol 233-235 ◽  
pp. 2516-2521
Author(s):  
Yu Wang ◽  
Min Huang ◽  
Xiang Xu Xie
Keyword(s):  
Low Temperature ◽  
Solid Phase ◽  
Pipeline Steel ◽  
Bulk Diffusion ◽  
Surface Mechanical Attrition Treatment ◽  
Unstable State ◽  
X80 Pipeline Steel ◽  
Active Aluminum ◽  
Pack Aluminizing ◽  
Lower Melting Point

Rapid low-temperature pack aluminizing was achieved on pipeline steel X80 through combined effect of surface refinement treatment and modification of pack powder. Self-nanocrystallization surface of pipeline steel X80 was obtained by surface mechanical attrition treatment (SMAT). In addition, zinc (Zn), which has lower melting point than that of Al, was added in the pack powder, to enhance the concentration of active aluminum (Al) atom. The mechanism of the low- temperature pack aluminizing was analyzed by examining the distribution of atoms and coating thickness using EDS and SEM. The study shows that aluminizing rate of as-SMATed pipeline steel with self-nanocrystallization surface is higher than that of non-SMATed pipeline steel under the same pack condition. The addition of Zn can increase the activity of diffusion atoms and accelerate the aluminizing by changing the state of pack powder from a single solid phase to a mixture of solid phase and liquid phase. The diffusion of atoms in this low-temperature pack aluminizing is considered as bulk diffusion which is driven by the activity of diffusion atoms in an unstable state following Fick law.

scholarly journals Gradient Microstructure Design in Stainless Steel: A Strategy for Uniting Strength-Ductility Synergy and Corrosion Resistance

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2356
Author(s):  
Qiong He ◽  
Wei Wei ◽  
Ming-Sai Wang ◽  
Feng-Jiao Guo ◽  
Yu Zhai ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Strength ◽  
Back Stress ◽  
High Yield ◽  
Surface Mechanical Attrition Treatment ◽  
Steel Sheets ◽  
Mechanical Attrition ◽  
Gradient Microstructure ◽  
Nano Grains

Martensite transformation and grain refinement can make austenitic stainless steel stronger, but this comes at a dramatic loss of both ductility and corrosion resistance. Here we report a novel gradient structure in 301 stainless steel sheets, which enables an unprecedented combination of high strength, improved ductility and good corrosion resistance. After producing inter-layer microstructure gradient by surface mechanical attrition treatment, the sheet was annealed at high temperature for a short duration, during which partial reverse transformation occurred to form recrystallized austenitic nano-grains in the surface layer, i.e., introducing extra intra-layer heterogeneity. Such 3D microstructure heterogeneity activates inter-layer and inter-phase interactions during deformation, thereby producing back stress for high yield strength and hetero-deformation induced (HDI) hardening for high ductility. Importantly, the recrystallized austenitic nano-grains significantly ameliorates the corrosion resistance. These findings suggest an effective route for evading the strength–ductility and strength–corrosion tradeoffs in stainless steels simultaneously.

Neutral Molten Salt-Bath Carburizing of Ti6Al4V Alloy with Nanocrystalline Surface Layer at Low Temperature Assisted by Surface Mechanical Attrition Treatment

2017 ◽  
Vol 727 ◽  
pp. 1001-1008 ◽  
Author(s):  
Quan Tong Yao ◽  
Wei Ping Tong ◽  
Meng Yao Li ◽  
Guang Lan Zhang
Keyword(s):  
Surface Layer ◽  
Low Temperature ◽  
Molten Salt ◽  
Salt Bath ◽  
Coarse Grained ◽  
Experimental Result ◽  
Surface Mechanical Attrition Treatment ◽  
Neutral Salt ◽  
Mechanical Attrition ◽  
Molten Salt Bath

Nanocrystalline surface layer about 10~15μm thick was fabricated on the surface of Ti6Al4V sheet by means of the surface mechanical attrition treatment (SMAT). The average grain size was about 10nm and the grain characteristic presented equiaxed morphology. The nanocrystalline surface layer could be perfectly maintained below 550°C in the following thermal stability analysis. Neutral salt mixture was about 21% NaCl, 31% BaCl2 and 48% CaCl2 and additionally 5% Na2CO3 of total was utilized. After carburizing process, a continuous charcoal grey carburized layer was composed of TiC and carbon supersaturated solid solution, the hardening layer was about 10~15μm thick. The hardness of the outermost surface reached 1000HV, which was much higher than its coarse-grained counterpart in the same carburizing condition. The experimental result indicated that the carburizing kinetics was obviously enhanced by nanocrystalline surface layer assistance. Furthermore, the neutral molten salt-bath carburizing was verified that it could be performed in a relatively low temperature of 650°C.

Thermal stability and corrosion resistance of nanocrystallized zirconium formed by surface mechanical attrition treatment

2009 ◽  
Vol 24 (10) ◽  
pp. 3136-3145 ◽  
Author(s):  
Yong Han ◽  
Lan Zhang ◽  
Jian Lu ◽  
Wengting Zhang
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Corrosion Resistance ◽  
Grain Growth ◽  
Coarse Grained ◽  
Surface Mechanical Attrition Treatment ◽  
Passive Protection ◽  
Mechanical Attrition ◽  
Nanostructured Layer ◽  
Pure Zirconium

The thermal stability and corrosion behavior of the nanostructured layer on commercially pure zirconium, produced by surface mechanical attrition treatment (SMAT), were investigated. It is indicated that the nanograined Zr is stable at annealing temperatures up to 650 °C, above which significant grain growth occurs and the grain size shows parabolic relationship with annealing time. The activation energy for grain growth of the nanograined Zr is 59 kJ/mol at 750–850 °C, and the grain growth is dominated by grain-boundary diffusion. The as-SMATed nanograined Zr exhibits higher corrosion resistance than the 550–750 °C annealed SMATed Zr and the unSMATed coarse-grained Zr. It is indicated that the corrosion resistance of Zr tends to increase with the reduction of grain size, which is related to the dilution of segregated impurities at grain boundaries due to grain refinement and the formation of passive protection film.

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