scholarly journals Effect of Crystal Structure of Surface Compound Layer on Fatigue Strength of Nitrided SCM 435 Steel

2018 ◽  
Vol 104 (10) ◽  
pp. 594-601 ◽  
Author(s):  
Shinichi Takagi ◽  
Yasuyuki Tonozuka ◽  
Norio Nakamura ◽  
Tsunenori Itou
Keyword(s):  
Crystal Structure ◽  
Fatigue Strength ◽  
Compound Layer ◽  
Surface Compound

scholarly journals Influence of Crystal Structure of Nitride Compound Layer on Torsion Fatigue Strength of Alloy Steel

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1352 ◽  
Author(s):  
Yoshitomi Yamada ◽  
Eto Hirohito ◽  
Koji Takahashi
Keyword(s):  
Crystal Structure ◽  
Fatigue Strength ◽  
Crystal Structures ◽  
Alloy Steel ◽  
High Strength ◽  
Compound Layer ◽  
Fatigue Tests ◽  
Commercial Vehicles ◽  
Torsional Fatigue ◽  
Number Of Cycles

The demand for high-strength components for commercial vehicles has recently increased. Conventional gas nitrocarburizing has been used to increase strength and productivity of the crankshaft. A potential-controlled nitriding process was recently developed to control the crystal structure of the nitride compound layer. It has been found that this treatment improves the bending fatigue strength compared with conventional treatment, and has the potential to cope with the increase in crankshaft strength. However, the effect of torsional fatigue strength has not been studied. Therefore, in this study, the influence of the crystal structure of the nitride compound layer on torsional fatigue strength was investigated. Two kinds of test specimens with different crystal structures of the compound layer were prepared using gas nitriding treatment with controlled nitriding potential for an alloy steel bar (JIS-SCM435). Torsional fatigue tests were carried out using these test specimens. Although the compound layer of these test specimens had different crystal structures, the hardness distribution and residual stress distribution on the diffusion layer were almost the same. The relationship between stress amplitude and number of cycles to failure (S-N curve) showed that the torsional fatigue limits of the specimens were almost the same. This indicates that the crystal structure of the nitride compound layer did not affect the torsional fatigue limits, because the origin of the torsional fatigue failure is inside the specimen.

SEGREGATION IN MULTICOMPONENT ALLOYS: ORDERED CrN AND CrC SURFACE PHASES ON A Fe-15%Cr-C, N(100) SINGLE CRYSTAL

1996 ◽  
Vol 03 (05n06) ◽  
pp. 1721-1731 ◽  
Author(s):  
C. UEBING ◽  
V. SCHEUCH ◽  
M. KISKINOVA ◽  
H. P. BONZEL
Keyword(s):  
Single Crystal ◽  
Bulk Composition ◽  
Polar Angle ◽  
Compound Layer ◽  
Single Scattering ◽  
Forward Scattering ◽  
Surface Compound ◽  
Bcc Lattice ◽  
Rocksalt Structure ◽  
Surface Phases

In general the chemical composition of multicomponent alloy surfaces exhibits significant deviations from the bulk composition due to thermally activated segregation processes. Upon cosegregation epitaxially stabilized two-dimensional surface compounds are formed on substrate surfaces of suitable orientation, e.g. CrN on Fe-15%Cr-N(100) and CrC on Fe-15%Cr-C(100) . The important role of the epitaxial stabilization manifests itself by the fact that on Fe-15%Cr-C(100) crystals the formation of cubic CrC surface precipitates is possible upon nonequilibrium cosegregation of the constituent components. Such a chromium carbide with rocksalt structure is not stable in the bulk of bcc Fe-Cr-C alloys . Angle-resolved photoemission of Cr 2 p 3/2, N 1s and C 1s core level photoelectrons is used to determine the structure of the CrN surface compound and of the CrC surface precipitate on a Fe-15%Cr-C,N(100) single crystal. Both surface phases exhibit a sharp 1×1 LEED pattern. Polar angle intensity distributions of photoelectrons (x-ray photoelectron diffraction) are recorded in the [001] and [011] azimuths, respectively. For CrN the angular intensity distributions exhibit forward scattering peaks for Cr 2 p 3/2 but not for N 1s. Most likely, the CrN phase consists of a CrN compound layer with significant N outward relaxation of about 0.6 Å and a second completed Cr layer. Single scattering cluster (SSC) calculations indicate that the Cr-Cr interlayer distance is expanded by about 26% with respect to the bcc lattice. For CrC , on the other hand, Cr 2 p 3/2 and C 1s show both strong forward scattering features in all distributions. The CrC phase consists of at least three complete compound layers with NaCl structure.

The Effect of Relative Thickness on Microstructures of TiB2/TiC Particles Reinforced Carbon Steel Matrix Surface Composite

2014 ◽  
Vol 940 ◽  
pp. 3-6
Author(s):  
Chang Qing Guo
Keyword(s):  
Carbon Steel ◽  
Low Cost ◽  
Compound Layer ◽  
Steel Matrix ◽  
Surface Compound ◽  
Relative Thickness ◽  
Surface Composite ◽  
High Temperature Synthesis ◽  
Matrix Surface ◽  
The Matrix

This paper introduces a process that combines a vacuum expandable pattern casting V-EPC with self-propagation high–temperature synthesis SHS of TiB2/TiC particles for fabricating the TiB2/TiC duplex particulates reinforced carbon steel matrix surface composite, and the effect of relative thickness δ on metallurgical quality and microstructures. FeTi-FeB-FeCr system with low cost is adopted as the SHS reactant. Experimental results show that with increasing δ, the surface composite is gradually formed and the metallurgical quality improved. The typical microstructures of the composite from surface to core are consisted of three different layers, i.e., the surface compound layer, the interim transitional layer and the carbon steel base. A certain amount of fineTiB2/TiC particles is distributed in the matrix of the surface compound layer.

scholarly journals Surface engineering of titanium by multi-interstitial diffusion using plasma processing

2020 ◽  
Vol 321 ◽  
pp. 11010
Author(s):  
M. Drouet ◽  
L. Pichon ◽  
J.B. Dubois ◽  
E. Le Bourhis ◽  
T. L. Christiansen
Keyword(s):  
Surface Engineering ◽  
Plasma Nitriding ◽  
Compound Layer ◽  
Case Depth ◽  
Surface Compound ◽  
Specific Strength ◽  
High Specific Strength ◽  
Excellent Corrosion Resistance ◽  
Composition Profiles ◽  
Hardness Depth

Titanium and its alloys possess a range of highly interesting properties such as excellent corrosion resistance, high specific strength and biocompatibility, but suffers from poor wear resistance. The present work addresses plasma assisted surface treatment of CP 2 titanium using various combinations of oxygen and nitrogen, i.e. mixed interstitials. The sequence of controlled plasma nitriding and oxidizing treatments plays a significant role for the evolution of the hardness depth profiles and the development of the surface compound layer and the underlying diffusion/transition zone. Composition profiles of oxygen and nitrogen are obtained by GDOES; Mixed interstitial solubility of nitrogen and oxygen is found in both h.c.p. α titanium and in the compound layer. The combination of interstitials leads to larger case depth, in particular for the diffusion zone (expanded h.c.p. α titanium). Therefore, it highlights the advantages of combined nitriding and oxidizing compared to single nitriding treatments on the mechanical properties.

scholarly journals Influence of Compound Layer on Fatigue Strength of Radical Nitrided SNCM439 Steel

2003 ◽  
Vol 69 (686) ◽  
pp. 1490-1496 ◽  
Author(s):  
Kazuhiro MORINO ◽  
Norio KAWAGOISHI ◽  
Kazunori FUKADA ◽  
Qingyuan WANG ◽  
Eiji KONDO
Keyword(s):  
Fatigue Strength ◽  
Compound Layer

Fabrication & Microstructure of TiB2+TiC Duplex Particulates Reinforced Carbon Steel Matrix Surface Composite

2013 ◽  
Vol 575-576 ◽  
pp. 198-202
Author(s):  
Chang Qing Guo
Keyword(s):  
Carbon Steel ◽  
Uniform Distribution ◽  
Compound Layer ◽  
Steel Matrix ◽  
Surface Compound ◽  
Transitional Layer ◽  
Composite Matrix ◽  
Microstructural Investigation ◽  
Surface Composite ◽  
Matrix Surface

This paper presents a novel fabrication process that combines SHS with V-EPC (vacuum expandable pattern casting) and microstructural features of TiB2+TiC duplex particulates reinforced surface composite with carbon steel matrix. Macro structural observation shows that the surface composite is dense and there are no obvious defects. Microstructural investigation demonstrates that the composite from surface to core is consisted of three different layers, i.e., the top surface compound layer, the interim transitional layer and the bottom carbon steel matrix. A large amount of fine TiB2 and TiC duplex particles are evenly distributed in the composite matrix, while the concentration are significantly decreased and non-uniform distribution increased for these particles in the interim layer.

scholarly journals Influence of Indentation on the Fatigue Strength of Carbonitrided Plain Steel

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Jiewei Gao ◽  
Guangze Dai ◽  
Junwen Zhao ◽  
Hengkui Li ◽  
Lei Xu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fatigue Strength ◽  
Fatigue Limit ◽  
Compound Layer ◽  
Indentation Size ◽  
Fracture Surfaces ◽  
Significant Difference ◽  
Scanning Electron

To study the influence of indentation on the fatigue strength of untreated and carbonitrided specimens of S38C steel, the fatigue limit of specimens with and without indentations was tested. Fracture surfaces were observed using scanning electron microscopy (SEM). The results show that the fatigue strength of the untreated specimen decreases with increasing dimension of indentation, without significant difference compared to the predicted results. Compared to the fatigue limit of the untreated specimen, those of the carbonitrided specimen and the carbonitrided specimen whose compound layer was polished were improved by 12% and 40%, respectively. The fatigue strength of the carbonitrided specimen decreased sharply with increasing indentation size because of the presence of microcracks in the compound layer. When the compound layer was removed, the fatigue limit was observed to be less sensitive to indentation than that of the carbonitrided specimen.

Effect of Radical Nitriding on Fatigue Strength of Ni-Base Superalloy

2009 ◽  
Vol 417-418 ◽  
pp. 205-208 ◽  
Author(s):  
Kazuhiro Morino ◽  
Norio Kawagoishi ◽  
K. Yamane ◽  
K. Fukada
Keyword(s):  
Fatigue Strength ◽  
Base Alloy ◽  
Compound Layer ◽  
Fatigue Tests ◽  
Bending Fatigue ◽  
Propagation Behavior ◽  
Initiation And Propagation ◽  
Rotating Bending Fatigue ◽  
Rotating Bending ◽  
Base Superalloy

In order to investigate the effect of nitriding on the crack initiation and propagation behavior of Ni-base super alloy, Alloy 718, rotating bending fatigue tests were carried out until 108 cycles at room temperature. By nitriding at 500°C for 12h, compound layer of about 5μm in thickness was formed and the initiation of a fatigue crack was strongly suppressed causing the increase in fatigue strength. A crack initiated in brittle manner at the compound layer in all of fractures. However the crack propagated in ductile manner controlled by the property of the base alloy. That is, there is no or little influence of nitriding on the crack growth rate of the alloy.

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