scholarly journals Structure, phase composition, mechanical properties and wear resistance of steel after microarc boriding and vanadation

2019 ◽  
Vol 62 (6) ◽  
pp. 446-451 ◽  
Author(s):  
M. S. Stepanov ◽  
Yu. M. Dombrovskii ◽  
L. V. Davidyan

Boriding is a common method of thermo-chemical treatment of steel products. It increases their hardness and wear resistance, but also increases the surface fragility, has a long duration and high labor intensity. The combined coating with boron and vanadium is used to improve the properties, and it is possible to apply microarc surface alloying to reduce the duration of the diffusion saturation process. This makes it possible to intensify the diffusion of alloying elements by forming a gas discharge zone at the surface of the steel product. The aim of this work was to study the structure, phase composition, mechanical properties and wear resistance of steel after boriding and vanadation. During the experiments, a lubricant containing boron carbide powders B4C and ferrovanadium FeV80 were used, which was applied to the surface of the steel sample. During boriding and vanadation of steel a surface layer with a thickness of 150 – 190 μm is formed. It has a base with microhardness of 7.8 – 8.3 GPa and light grey granular inclusions and eutectic areas with microhardness of 13.5 – 14.0 GPa. Further there is a carbonized layer of eutectoid concentration, passing into the original ferrite-perlite structure. The content of alloying elements in the characteristic points of the surface layer was determined, which confirmed the increased content of carbon, vanadium and boron in the base layer, areas of eutectic and carbide phase. X-ray phase analysis revealed the presence of iron borides FeB and Fe2B, vanadium borides VB2 and V2B3 and vanadium carbide VC0.88 in the surface layer. Mechanical properties of coatings were studied by microindentation of its cross-section with registration and analysis of deformation diagram under loading and subsequent unloading of the indenter. Hardness at indentation in the base layer increased to 7.95 GPa, in dispersed inclusions – to 13.90 GPa. The modulus of elasticity for indentation in the base and inclusions is 238 MPa and 340 MPa, respectively. Creep and proportion of the plastic component in microindentation is naturally reduced with increase in hardness. Fine inclusions of iron borides, vanadium borides and carbides significantly increase the steel wear resistance. It has increased in 4 times during friction against the fixed abrasive particles in comparison with the initial state. 

2020 ◽  
Vol 2020 (12) ◽  
pp. 1439-1445
Author(s):  
I. O. Bannykh ◽  
O. A. Bannykh ◽  
L. G. Rigina ◽  
E. N. Blinova ◽  
K. Yu. Demin ◽  
...  

2020 ◽  
Vol 59 (1) ◽  
pp. 340-351
Author(s):  
Lin Yinghua ◽  
Ping Xuelong ◽  
Kuang Jiacai ◽  
Deng Yingjun

AbstractNi-based alloy coatings prepared by laser cladding has high bonding strength, excellent wear resistance and corrosion resistance. The mechanical properties of coatings can be further improved by changing the composition of alloy powders. This paper reviewed the improved microstructure and mechanical properties of Ni-based composite coatings by hard particles, single element and rare earth elements. The problems that need to be solved for the particle-reinforced nickel-based alloy coatings are pointed out. The prospects of the research are also discussed.


1993 ◽  
Vol 29 (1) ◽  
pp. 56-60 ◽  
Author(s):  
O. I. Eliseeva ◽  
V. I. Kalyandruk ◽  
A. A. Denisova ◽  
V. V. Shirokov

Author(s):  
T.A. Krylova ◽  
◽  
Y.A. Chumakov ◽  

The effect of heat treatment on the structure and properties of composite coatings based on chromium carbide with titanium carbide fabricated by non-vacuum electron beam cladding without has been studied. It was shown that tempering leads to a decrease in microhardness and wear resistance, which is associated with the decomposition of the austenitic structure with the formation of a soft ferrite-carbide structure. The post heat treatment tempering was showed to decrease of microhardness and wear resistance, which leads to the decomposition of the austenitic structure with the formation of a soft ferrite-carbide structure. The bulk quenching of coatings after tempering leads to an increase in microhardness comparable to the values of microhardness in the initial state after electron beam cladding, due to the formation of high hard martensite. The wear resistance of composite coatings after tempering is lower than after cladding due to brittle martensite, which is not able to hold solid carbide particles. The composite coatings obtained at the optimal processing conditions have a combination of improved properties and do not require additional heat treatment, resulting in structural changes, causing a decrease in mechanical properties.


2021 ◽  
pp. 557-564
Author(s):  
N.S. Ulakhanov ◽  
U.L. Mishigdorzhiyn ◽  
A.G. Tikhonov ◽  
A.I. Shustov ◽  
A.S. Pyatykh

The effect of diffusion high-temperature boroaluminizing (HBA) on the mechanical properties and quality parameters of the surface layer of stamp steels 5KhNM and 3Kh2V8F is shown. An analysis of the microstructure and composition of diffusion composite layers obtained as a result of thermal-chemical treatment (TCT) is presented and the distribution of microhardness in these layers is studied depending on the formed borides and carbides. The influence of processing temperature modes of on the parameters of roughness was experimentally established and the wear resistance characteristics of the processed surfaces of the investigated materials were determined.


2020 ◽  
Vol 121 (4) ◽  
pp. 367-373 ◽  
Author(s):  
A. G. Illarionov ◽  
A. G. Nezhdanov ◽  
S. I. Stepanov ◽  
G. Muller-Kamskii ◽  
A. A. Popov

2004 ◽  
Vol 842 ◽  
Author(s):  
Han-Sol Kim ◽  
In-Dong Yeo ◽  
Tae-Yeub Ra ◽  
Won-Yong Kim

ABSTRACTWe report on microstructure, mechanical properties and wear resistance of Fe-Al based alloys with various alloying elements. The microstructures were examined using optical and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscope (EDS). Two types of alloys were prepared using vacuum arc melting; one is Fe-28Al based alloys (D03 structured) with and without alloying elements such as Mo and Zr. The other one is Fe-35Al based alloys (B2 structured) produced with same manner. For both types of alloys, equiaxed microstructures were observed by the addition of Mo, while dendritic structures were observed by the Zr addition. These microstructural features were more evinced with increasing the content of alloying elements. Concerning the mechanical properties and wear resistance, Fe-35Al based alloys with or without Mo addition superior to Fe-28Al based alloys especially in the high temperature region.


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