Enhanced Surface Hardness by Boron Diffusion in Martensitic Stainless Steel via Cathodic Reduction and Thermal Diffusion Based Boriding (CRTD-Bor)

2015 ◽  
Vol 719-720 ◽  
pp. 25-28 ◽  
Author(s):  
G. Kartal Sireli ◽  
C. Yelkarasi ◽  
P. Ozkalafat ◽  
S. Timur ◽  
M. Urgen
Keyword(s):  
Thermal Diffusion ◽  
Single Phase ◽  
Surface Hardness ◽  
Boride Layer ◽  
Cathodic Reduction ◽  
Boron Diffusion ◽  
Cross Sectional ◽  
The Matrix ◽  
Enhanced Surface ◽  
Borided Steel

In this study, a developed new boriding method called as “Cathodic Reduction and Thermal Diffusion based Boriding” (CRTD-Bor) was applied to increase the surface hardness of 400 series steels. The cross-sectional examination of borided steel revealed that the boride layers consisted of single phase Fe2B. A dense and continuously 25μm thick Fe2B layer could be formed after 20 minutes of CRTD-Bor. The grown boride layer exhibited 1500±200 HV on top, and gradually decreased to the matrix (325 ± 25 HV).

Compression Method for Superplastic Boronizing of DSS

2006 ◽  
Vol 326-328 ◽  
pp. 1745-1748
Author(s):  
Rafidah Hasan ◽  
Iswadi Jauhari ◽  
Hiroyuki Ogiyama ◽  
Raden Dadan Ramdan
Keyword(s):  
Single Phase ◽  
Compressive Load ◽  
Surface Hardness ◽  
Boride Layer ◽  
Metal Substrate ◽  
High Plasticity ◽  
Superplastic Material ◽  
Compression Method ◽  
Superplastic Behavior ◽  
Fine Grain

Superplastic boronizing (SPB) is a new surface hardening technique utilizing the ultra high plasticity phenomenon in metals in carrying out boronizing process. In boronizing, boron atoms are diffused into the metal substrate to form a hard boride layer. In this research, a new compression method for the SPB process was introduced. A clamp with an initial compressive load of about 1960 N was used. Thermo-mechanical treated duplex stainless steel (DSS) with fine grain microstructure which can show superplastic behavior at high temperatures was used as the superplastic material. SPB experiments were conducted at temperatures between 1123 and 1223 K for durations of 1 - 6 hours. The boronized specimens demonstrated thin, smooth and compact morphology of boride layer. The boride layer thickness was within ±10 0m - ±46.2 0m. On the boride layer, only the favorable single phase of Fe2B was detected. High value of surface hardness was observed in the range of ±847 HV - ±2914 HV. The overall results from the study show that the SPB process can significantly improve the surface properties of DSS.

scholarly journals Boron Diffusion in Steel 20

2020 ◽  
pp. 58-62
Author(s):  
E.P. Shevchuk ◽  
V.A. Plotnikov ◽  
G.S. Bektasova
Keyword(s):  
Liquid Glass ◽  
High Hardness ◽  
Ammonium Hydroxide ◽  
Boride Layer ◽  
Boron Diffusion ◽  
Volumetric Heating ◽  
High Refractoriness ◽  
The Matrix ◽  
Steel 20 ◽  
Diffusion Mass

As is known, boriding is carried out to increase the wear resistance and corrosion resistance of iron-carbon alloys. Along with high hardness, borides, unfortunately, have very high fragility and high refractoriness. An effective way to counter the fragility of boride layers is to form a composite structure consisting of inclusions of solid borides in a more plastic matrix. Such coatings can be obtained by volumetric heating in a muffle furnace using a boron paste that besides a mixture of iron and boron powders contained ammonium hydroxide and activated carbon with or without liquid glass. Boriding of a surface is carried out at high temperatures =1000 °С for 5 minutes. It is experimentally found that the microhardness of the surface layer increased by about 30% compared with the microhardness of the substrate, and that the thickness of the boride layer depends on the presence of liquid glass in the coating. It has been established that specially calculated proportions of ammonia, liquid glass, and charcoal contribute to the formation of an extensive diffusion zone of iron borides, the formation of which is due to the anomalously high diffusion mass transfer of boron into the matrix.

scholarly journals DEVELOPMENT OF INNOVATIVE METHOD OF STEEL SURFACE HARDENING BY A COMBINED CHEMICAL-THERMAL TREATMENT

2016 ◽  
Vol 6 ◽  
pp. 46-52
Author(s):  
Kateryna Kostyk
Keyword(s):  
Thermal Treatment ◽  
Transition Zone ◽  
Diffusion Layer ◽  
Treatment Time ◽  
Combined Treatment ◽  
Surface Hardness ◽  
Boride Layer ◽  
Complex Chemical ◽  
The Matrix ◽  
Different Temperatures

The aim of the article is a hardening of the surface steel layers due to the combination treatment. Samples of steel 38Cr2MoAl were hardened by complex chemical and thermal treatment such as carburizing and subsequent boriding. It was established that surface double-layer hardening for steel 38Cr2MoAl with sequential saturation with atomic carbon (during carburizing) and atomic boron (during furnace boriding) at different temperatures allowed to form a boride layer with transition zone. The obtaining transition zone can improve operational properties of machine parts and tools by micro-friability reduction of diffusion layer. An optimal mode of complex chemical-thermal treatment (CTT) was obtained for the regime, which includes carburizing at 950 °C for 2 hours, boriding at 950 °C for 2 hours, which allows to get the best value for the surface hardness of 22 GPa with a maximum overall diffusion layer 1.4 mm. Due to the technology of combined treatment we can significantly reduce treatment time compared to traditional hardening means and significantly improve product performance properties due to the transition zone between the borides and the matrix of machine elements. The technology can be used in enterprises where there is any hardening furnace without additional installation or conversion of equipment.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

A Novel Approach for Metal Surface Modification

2007 ◽  
Vol 280-283 ◽  
pp. 1805-1806
Author(s):  
Zhi Jun Cao ◽  
Jia Chen Liu ◽  
Li Bin Liu ◽  
Hao Ye ◽  
Yan Qiu Wei
Keyword(s):  
Surface Modification ◽  
Wear Rate ◽  
Charge State ◽  
Metal Surface ◽  
Surface Hardness ◽  
Metallic Surface ◽  
New Approach ◽  
Novel Approach ◽  
Complex Shapes ◽  
Enhanced Surface

A new approach was developed for surface modification of metallic surface. By treating nano-zirconia particles and metal surface in different charge state, nano-zirconia particles can be dispersedly inlaid in metal surface owing to electrostatic and nanometer effects. By using this method, metal components of complex shapes, especially those having inside surfaces, might be easily improved, i.e., enhanced surface hardness and wear rate.

Fabrication and Mechanical Properties of Dense/Porous β-Tricalcium Phosphate Bioceramics

2007 ◽  
Vol 330-332 ◽  
pp. 907-910
Author(s):  
Fa Ming Zhang ◽  
Jiang Chang ◽  
Jian Xi Lu ◽  
Kai Li Lin
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Exponential Growth ◽  
Weight Bearing ◽  
Area Ratio ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Matrix ◽  
Porous Bioceramics

Attempt to increase the mechanical properties of porous bioceramics, a dense/porous structured β-TCP bioceramics that mimic the characteristics of nature bone were fabricated. Experimental results show that the dense/porous structured β-TCP bioceramics demonstrated excellent mechanical properties with compressive strength up to 74 MPa and elastic modulus up to 960 MPa, which could be tailored by the dense/porous cross-sectional area ratio obeying the rule of exponential growth. The interface between the dense and porous bioceramics is connected compactly and tightly with some micropores distributed in the matrix of both porous and dense counterparts. The dense/porous structure of β-TCP bioceramics may provide an effective way to increase the mechanical properties of porous bioceramics for bone regeneration at weight bearing sites.

scholarly journals Method for the Microstructural Characterisation of Unidirectional Composite Tapes

2021 ◽  
Vol 5 (10) ◽  
pp. 275
Author(s):  
Nico Katuin ◽  
Daniël M. J. Peeters ◽  
Clemens A. Dransfeld
Keyword(s):  
Voronoi Tessellation ◽  
Unidirectional Composite ◽  
Fibre Volume ◽  
Cross Sectional ◽  
Reinforced Polymer ◽  
Novel Approach ◽  
The Matrix ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Microstructural Characterisation

The outstanding properties of carbon fibre-reinforced polymer composites are affected by the development of its microstructure during processing. This work presents a novel approach to identify microstructural features both along the tape thickness and through the thickness. Voronoi tessellation-based evaluation of the fibre volume content on cross-sectional micrographs, with consideration of the matrix boundary, is performed. The method is shown to be robust and is suitable to be automated. It has the potential to discriminate specific microstructural features and to relate them to processing behaviour removing the need for manufacturing trials.

scholarly journals Wear Behavior of Borided Cold-Rolled High Manganese Steel

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1207
Author(s):  
Fatih Hayat ◽  
Cihangir Tevfik Sezgin
Keyword(s):  
Wear Behavior ◽  
Xrd Analysis ◽  
Boride Layer ◽  
Manganese Steel ◽  
Dry Sliding Wear ◽  
Low Alloy Steels ◽  
Boron Diffusion ◽  
High Manganese ◽  
High Manganese Steel ◽  
Boriding Process

In this study, a novel high-manganese steel (HMS) was borided at 850, 900 and 950 °C for 2, 4, and 6 h by the pack boriding process. Contrary to previous literature, borided HMS uncommonly exhibited saw-tooth morphology like low alloy steels, and manganese enhanced the boron diffusion. Another striking analysis is that the “egg-shell effect” did not occur. The present study demonstrated the silicon-rich zone for the first time in the literature by EDX mapping. Moreover, the formation mechanism of silicon-rich zones was explained and termed as “compact transfer of silicones (CTS)”. XRD analysis showed the existence of FeB, Fe2B, MnB and SiC phases. The boriding time and temperature increased the thickness of the boride layer from 31.41 μm to 117.65 µm. The hardness of the borided layer ranged from 1120 to 1915 HV0.05. The activation energy of borided HMS was found to be a very low result compared to high alloy steel investigated in the literature. The Daimler-Benz Rockwell-C adhesion test showed that adhesions of borided HMS surfaces are sufficient. The dry sliding wear tests showed that boriding treatment increased the wear resistance of untreated HMS by 5 times. The present study revealed that the boriding process extended the service life of HMS components.

SYNTHESIS OF ALLOY METAL NANOCLUSTERS IN SILICA GLASS BY SEQUENTIAL ION IMPLANTATION

2007 ◽  
Vol 06 (06) ◽  
pp. 423-430 ◽  
Author(s):  
B. JOSEPH ◽  
H. P. LENKA ◽  
P. K. KUIRI ◽  
D. P. MAHAPATRA ◽  
R. KESAVAMOORTHY
Keyword(s):  
Ion Implantation ◽  
Silica Glass ◽  
Metallic Nanoparticles ◽  
Rutherford Backscattering Spectrometry ◽  
Low Frequency ◽  
Peak Position ◽  
Negative Ion ◽  
Metal Nanoclusters ◽  
Cross Sectional ◽  
The Matrix

High fluence low energy negative ion implantation has been used to synthesize embedded metal nanoclusters of Au , Ag and Sb in silica glass. The Au - and Ag -implanted samples showed peaks, corresponding to surface plasmon resonance (SPR) in the optical absorption (OA) spectra, confirming the formation of metallic nanoparticles in the matrix. No SPR peak was observed in case of Sb -implanted samples which is attributed to the absence of pure metallic precipitates which could be detected in the OA spectrum. Low frequency Raman scattering (LFRS) measurements also confirm this. Cross-sectional transmission electron microscopy has been used to infer about the size distribution of the nanoparticles. Sequential implantations of Au and Ag or Au and Sb have been found to result in SPR peaks at locations in between those for nanoparticles of the constituent atoms, indicating the formation of alloy nanoparticles in the system. In case of the Au + Ag system, Rutherford backscattering spectrometry has been used to infer about the composition of the nanoparticles in terms of the concentrations of the metallic constituents. A direct, one-to-one correspondence between the SPR peak position and composition has been observed.

Study of Quenching Organization Property under Wind Cooling Condition

2014 ◽  
Vol 487 ◽  
pp. 682-686
Author(s):  
Fu Quan Tu ◽  
Yang Mao ◽  
Ren Bo Xu
Keyword(s):  
Surface Hardness ◽  
Hardened Layer ◽  
Spray Cooling ◽  
Cooling Time ◽  
Cooling Condition ◽  
Micro Structure ◽  
Cross Sectional ◽  
Quenching Process ◽  
Quenching Time ◽  
Heavy Rail

In this paper, the steel of U71Mn specifications for 60kg/m heavy rail is seen as a research object. Experimental method is employed to study the heavy rail hardened layer, including surface hardness, micro-structure and cross-sectional hardness under different cooling time during quenching. Experimental results showed that obtained heavy rail after wind cooling quenching finally met the Tb/T2344-2003 43-75 kg/m standard. Best quenching treatment condition is found and the defect is reduced to large extent when quenching time is 40 seconds, cooling time is 40 to 45 seconds, superior to the traditional spray cooling condition. These results provide an important reference for the quenching process of heavy rail.

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