scholarly journals Failure Analysis and the Evaluation of Forced-In Joint Reliability for Selected Operation Conditions

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1305
Author(s):  
Sławomir Kowalski ◽  
Martin Pexa ◽  
Zdeněk Aleš ◽  
Jakub Čedík
Keyword(s):  
Fatigue Strength ◽  
Adhesive Wear ◽  
Additional Treatment ◽  
Fretting Wear ◽  
Fatigue Wear ◽  
Reliability Indicators ◽  
Operation Conditions ◽  
Joint Reliability ◽  
Wear Products ◽  
Sample Damage

In this article, sample damage and wear of forced-in joints is presented, and their reliability evaluated. Compared were shafts without additional finish treatment, rolled shafts and those with a TiSiN coating. Tribological samples under investigation operated in rotational bending conditions. Recorded was the number of fatigue cycles at which damage might occur. Reliability indicators were plotted, which demonstrated that coated shafts are distinguished by the highest reliability and low damage intensity. Macroscopic observations of shaft surfaces demonstrated the traces of adhesive wear and, in the case of shafts without additional treatment and in the case of rolled shafts, fretting wear traces in the form of a ring comprising the entire shaft circumference. Microscopic observations showed numerous build-ups on the surface, microcracks, and the occurrence of wear products in the gap between the shaft and sleeve. The highest fatigue strength was demonstrated by shafts with a TiSiN coating. The shaft section change area was the place where fatigue wear occurred.

scholarly journals Effects of Microstructure Evolution on Fretting Wear Behaviors of 25CrNi2MoVE Steel under Different Tempering States

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 351
Author(s):  
Xiongfeng Hu ◽  
Fuqiang Lai ◽  
Shengguan Qu ◽  
Yalong Zhang ◽  
Haipeng Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Wear Resistance ◽  
Wear Rate ◽  
Wear Mechanisms ◽  
Adhesive Wear ◽  
Operating Conditions ◽  
Fretting Wear ◽  
Fatigue Wear ◽  
Tempering Temperature ◽  
Worn Surface

Increasing load requirements and harsh operating conditions have worsened the wear of drive shafts in special field vehicles. In this paper, the evolution of the microstructure and fretting wear behaviors of 25CrNi2MoVE torsion shaft steel and their influence on the wear mechanisms were investigated as a function of tempering temperature. The results showed that the coarse grain size, low matrix hardness and non-metallic inclusions in the as-received state lead to a high wear rate and serious adhesive wear. The grain refinement after normalizing and the formed M5C2 carbide and bainite helped to improve the wear resistance and worn surface quality. Low temperature tempering is conducive to further improve the wear resistance of normalized samples, and the wear rate and worn surface roughness are increased gradually after tempering temperature increases. For quenching, although martensite structure can achieve a lower wear rate, the coefficient of friction is much higher; the wear mechanisms are primarily fatigue wear and adhesive wear. Although the adhesive wear degree and worn surface roughness were increased, the optimal anti-wear performances are obtained under tempering at 350 °C with good continuity of the surface oxide film. Excessive tempering temperature will make the softened matrix unable to form a beneficial “third-body wear”.

scholarly journals Taking into account multi-axiality of loads on marine structures in their fatigue strength calculations

2019 ◽  
pp. 153-161
Author(s):  
Gennadiy Kryzhevich ◽  
Anatoliy Filatov
Keyword(s):  
Mathematical Model ◽  
Fatigue Strength ◽  
Axial Loading ◽  
Failure Criteria ◽  
Design Parameters ◽  
Optimal Assignment ◽  
Marine Structures ◽  
Fatigue Wear ◽  
Mathematical Simulations ◽  
Complex Mathematical Model

This paper studies marine structures made of steels and light alloys and exposed to cyclic operational loads. Stress-strain parameters of their joints were taken from mathematical simulations of loads and strains or from actual strain gauging data. The aim of this study is to develop recommendations on fatigue strength calculations: specifically, how to quite the complex mathematical model of multi-axial loading at critical structural points with fast fatigue wear in favour of a simplified stressstrain state description based on optimal assignment of design parameters (stresses) in fatigue failure criteria. Preferability of this approach depends on case-specific requirements to calculation accuracy and timeframes. Uniaxial description of stressed state instead of the three-axial one enables much faster calculation with acceptable drop in accuracy.

Corrosive-wear behavior of LSP/MAO treated magnesium alloys in physiological environment with three pH values

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Yongshui Shen ◽  
Tongjin Sun ◽  
Tao Zhu ◽  
Ying Xiong
Keyword(s):  
Abrasive Wear ◽  
Wear Mechanisms ◽  
Adhesive Wear ◽  
Laser Shock ◽  
Corrosion Wear ◽  
Fatigue Wear ◽  
Wear Rates ◽  
Ph Values ◽  
Wear And Corrosion ◽  
Micro Arc Oxidation

Abstract A laser shock peening (LSP) layer, a micro-arc oxidation (MAO) coating, and an LSP/MAO composite coating were fabricated on the surface of AZ80 magnesium alloy by laser shock and micro-arc oxidation process. The ball-disc grinding method was used to perform wear test on the three treated specimens in simulated body fluids (SBF) with pH values of 4, 7.4 and 9. The morphology and element content of worn surface were investigated by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). The results indicated that the wear rates of the three treated specimens in three pH environment in numerical order were pH 4 > pH 7.4 > pH 9, respectively. The wear rates of the three treated specimens in the same pH environment were arranged in the order of MAO > LSP > LSP/MAO, respectively. The main wear mechanisms of the LSP specimen in pH 4 environment were fatigue wear and corrosion wear, while it were corrosion wear and adhesive wear in pH 7.4 and pH 9 environments. Abrasive wear, fatigue wear and corrosion wear were the main wear mechanisms of the MAO specimen in pH 4 environment, while abrasive wear, adhesive wear and corrosion wear were the main wear mechanisms of that in pH 7.4 and pH 9 environments. The corrosion wear resistance of the LSP/MAO specimen in SBF solution with three pH values was improved due to the synergism of LSP fine crystal layer and MAO coating.

scholarly journals Preparation and Tribological Behaviors of Lubrication-Enhanced PEEK Composites

2020 ◽  
Vol 10 (21) ◽  
pp. 7536
Author(s):  
Yutao Yan ◽  
Cheng Jiang ◽  
Yuqiu Huo ◽  
Chaofeng Li
Keyword(s):  
Tensile Strength ◽  
Graphene Oxide ◽  
Adhesive Wear ◽  
Hot Isostatic Pressing ◽  
Fatigue Wear ◽  
Pressing Method ◽  
Tribological Behaviors ◽  
Ether Ether Ketone ◽  
Poly Ether Ether Ketone ◽  
Ether Ketone

Poly-ether-ether ketone (PEEK) is a great potential thermoplastic in industry and medical treatment and health. In this work, PEEK/graphene oxide (GO) and PEEK/MoS2 composites were prepared by a novel hot isostatic pressing method. The addition of GO alters the tribological behaviors mechanism; fatigue wear mechanism is predominant to PEEK/GO composites. However, the combination of abrasive and adhesive wear mechanisms is observed for PEEK/MoS2 composites and PEEK. The reason for this is that the hardness and tensile strength of composites are increased with the appropriate addition of GO. The response time to stable friction state of PEEK/GO and PEEK/MoS2 composites is reduced in comparison with PEEK, which is conducive to shorten running-in time, reduce the energy consumption, and improve the tribological performances of composites. The addition of GO and MoS2 can effectively decrease the friction coefficient and wear rate, and the optimal content of GO and MoS2 was 0.7 wt.% and 15 wt.%, respectively. The results indicate that PEEK/GO and PEEK/MoS2 are impressive composites that possess super tribological properties.

Progressive Tool Failure in High Speed End Milling of Inconel 718 with Coated Carbide Inserts

2011 ◽  
Vol 188 ◽  
pp. 32-37 ◽  
Author(s):  
An Hai Li ◽  
Jun Zhao ◽  
Z.Q. Pei ◽  
S.G. Guo
Keyword(s):  
Abrasive Wear ◽  
Inconel 718 ◽  
Adhesive Wear ◽  
End Milling ◽  
Failure Mechanisms ◽  
Cutting Speed ◽  
Fatigue Wear ◽  
Edge Chipping ◽  
Tool Failure ◽  
Coated Carbide

The failure progression of coated carbide tools in end milling of Inconel 718 superalloy was investigated. Tool wear was measured and failure mechanisms were discussed in the experimental process periodically. The experimental results indicated that the tool failure mechanisms were synergistic interaction among abrasive wear, adhesive wear, and fatigue wear. However, abrasive wear and adhesive wear were the main failure mechanisms at the beginning, fatigue wear prevailed the upper hand around the time when edge chipping appeared, and after edge chipping abrasive wear and adhesive wear dominated until the failure time. In addition, the macroscopic failure of the cutting tools is closely correlated to the nucleation and propagation of the crack under cyclic mechanical and thermal impact forces. Mechanical fatigue wear was the key form of fatigue wear at lower cutting speed, while at higher cutting speed thermal fatigue wear was the dominant fatigue wear.

Experimental Validation of Fretting Fatigue Strength and Fretting Wear Rate at Contact Surface of Turbine-Blade-Shroud Cover

2012 ◽  
Author(s):  
Kunio Asai ◽  
Takeshi Kudo ◽  
Hideo Yoda
Keyword(s):  
Fatigue Strength ◽  
Wear Rate ◽  
Contact Pressure ◽  
Contact Force ◽  
Contact Surface ◽  
Fretting Fatigue ◽  
Fretting Wear ◽  
Dissipated Energy ◽  
Normal Contact ◽  
Vibratory Load

In continuously coupled blade structures, fretting fatigue and wear have to be considered as supposed failure modes at the contact surface of the shroud cover, which is subject to steady contact pressure from centrifugal force and the vibratory load of the blade. We did unique fretting tests that modeled the structure of the shroud cover, where the vibratory load is only carried by the contact friction force, i.e., a type of friction. What was investigated in this study are fretting fatigue strength, wear rate, and friction characteristics, such as friction coefficient and slip-range of 12%-Cr steel blade material. The friction-type tests showed that fretting fatigue strength decreases with the contact pressure and a critical normal contact force exists under which fretting fatigue failure does not occur at any vibratory load. This differs from knowledge obtained through pad-type load carry tests that fretting fatigue strength decreases with the increase of contact pressure and that it almost saturates under a certain contact pressure. Our detailed observation in the friction-type tests clarified that this mechanism was the low contact pressure narrowing the contact area and a resulting high stress concentration at a local area. The fretting wear rate was explained by the dissipated energy rate per cycle obtained from the measured hysteresis loop between the relative slip range and the tangential contact force. This fretting wear rate per cycle is almost the same as the general adhesion wear rate when energy dissipation per cycle is high, and the former is smaller than the latter as the dissipated energy decreases. Finally, to prevent fretting fatigue and wear, we propose an evaluation design chart of the contact surface of the shroud cover based on our friction-type fretting tests.

Adhesive Wear of Polymers

1977 ◽  
Vol 99 (4) ◽  
pp. 396-400 ◽  
Author(s):  
V. A. Belyi ◽  
A. I. Sviridyonok ◽  
V. A. Smurugov ◽  
V. V. Nevzorov
Keyword(s):  
Adhesive Wear ◽  
Contact Region ◽  
The Other ◽  
Polymer Materials ◽  
Cohesive Failure ◽  
Adhesive Interaction ◽  
Antifrictional Materials ◽  
Friction Polymers ◽  
Wear Products ◽  
The One

Adhesive wear is a characteristic but inadequately studied type of wear of polymer materials. In local regions of real contact an intensive molecular (adhesive) interaction is observed under rubbing conditions, which is stronger than the bonds between individual elements in the supermolecular formations or in polymer molecules, leading to cohesive failure of the material. Wear products can escape from the contact region as gases or as solid substances, or they can form a “third body”, i.e., a transferred layer of one material is deposited on the surface of the other. The direction, mechanism, and character of the occurring processes are determined, first of all, by the structures of the interacting materials. To know the mechanism of adhesive wear enables one to predict dangerous failures of the surfaces under rubbing due to seizure, on the one hand, and to find ways of governing the frictional interaction and create efficient self-lubricated polymer-based materials on the other hand. One of the efficient ways of providing minimum wear in metal-polymer friction pairs is to govern the process of developing “friction polymers” and to use mixtures of polymers having different thermophysical properties as antifrictional materials.

scholarly journals High Temperature Tribological Behavior of Borocarburized Layer on Q235 Steel

2021 ◽  
Vol 27 (1) ◽  
pp. 42-49
Author(s):  
Zhengang YANG ◽  
Wenping LIANG ◽  
Yanlin JIA ◽  
Qiang MIAO ◽  
Zheng DING ◽  
...  
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Carbon Steel ◽  
Wear Mechanism ◽  
Adhesive Wear ◽  
Low Carbon Steel ◽  
Boride Layer ◽  
Low Carbon ◽  
Fatigue Wear ◽  
Carburized Layer

A borocarburized layer was successfully fabricated on the surface of Q235 low-carbon steel via double glow treatment to improve the wear resistance at elevated temperature. The phase composition and microstructure of borocarburized layer were investigated by XRD and SEM. The microhardness of borocarburized layer from the surface to the substrate were detected. And the tribological behaviors of borocarburized layer and substrate were investigated under the dry-sliding against ZrO2 ball at three temperatures. The results indicate that the borocarburized layer consists of an outermost boride layer and a transition layer of carburized layer. The boride layer with main phase of Fe2B has a high hardness around 1700 HV, and the hardness of transition layer with main phase of Fe5C3 is around 600 HV. The novel gradient structure of an outermost boride layer and inner carburized layer is design in this research decreases the hardness mismatch of coating to prevent the boride layer peeling off. The friction coefficient and specific wear rate of borocarburized layer are much lower than that of substrate at the same temperature. In addition, the wear mechanism of substrate is mainly fatigue wear and slightly adhesive wear at 20℃. When the wear test performs at 200℃, the substrate wear mechanism is adhesive wear and fatigue wear. The wear mechanism of borocarburized layer is main abrasive wear at 20℃ and 200℃. And the wear mechanism of both substrate and borocarburized layer are main oxidation wear and adhesive wear at 500℃. The borocarburized layer effectively improves the wear resistance of low carbon steel due to the higher hardness and great thermal stability at high temperature.

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