Enhancement of Fatigue Endurance Limit through Ultrasonic Surface Rolling Processing in EA4T Axle Steel

Fatigue property is a key evaluation index for the service reliability of railway axle. In this work, the effect of ultrasonic surface rolling processing (USRP) on the surface characteristic and fatigue property was investigated in an EA4T axle steel used on high speed trains by several characterization techniques and the staircase method fatigue testing. The surface characteristics were initially studied in EA4T axle steel under different static loads of 1.0 kN, 1.5 kN and 2.0 kN, and served as the important USRP parameter. It was found that the larger static load greatly improved the surface microstructure, microhardness and compressive residual stress, but also increased the surface roughness. Furthermore, the rotating bending fatigue endurance limit of the USRP specimen with a static load of 1.5 kN was obviously enhanced by ~14% (from ~352 MPa to ~401 MPa) relative to the untreated specimen. The enhanced fatigue limit induced by USRP was attributed to the synergistic effect of the grain refinement, as evidenced by transmission electron microscope (TEM) observation, work-hardening, the increased compressive residual stress and the reduced surface roughness. Moreover, the fatigue limit of the USRP specimen was ~4% higher than that of the rolling specimen with turning off the ultrasonic system, ~386 MPa, which showed that the role of the ultrasonic impact could enhance the fatigue property. These findings demonstrate the validity of this technique in modifying the surface characteristics and thus improving the fatigue resistance of axle material, further ensuring its service safety and reliability.

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Effect of the Type of Grinding Wheel on the Surface Characteristics of a Titanium Alloy with Internal Coolant Supply

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.825.92 ◽

2019 ◽

Vol 825 ◽

pp. 92-98

Author(s):

Nakatsuka Nagatoshi ◽

Sumito Toyokawa ◽

Atsushi Kusakabe ◽

Shinya Nakatsukasa ◽

Hiroyuki Sasahara

Keyword(s):

Residual Stress ◽

Surface Roughness ◽

Silicon Carbide ◽

Titanium Alloy ◽

Aluminum Oxide ◽

Compressive Residual Stress ◽

Surface Characteristics ◽

Grinding Wheel

The objective of this paper is to clarify the effect of grinding surface characteristics in the grinding of a titanium alloy with a coolant supply from the inner side of the grinding wheel. In this paper, we selected a white aluminum oxide (WA) vitrified bonded grinding wheel and a green silicon carbide (GC) vitrified bonded grinding wheel, and compared their grinding characteristics. As a result, in the case of the GC vitrified bonded grinding wheel, the surface roughness decreased by about 54% and the compressive residual stress increased by about 128%.

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Effect of Pre-Strain and Roller Working on Torsional Fatigue Properties of a Structural Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.295-297.2227 ◽

2011 ◽

Vol 295-297 ◽

pp. 2227-2230

Author(s):

Cong Ling Zhou

Keyword(s):

Residual Stress ◽

Fatigue Limit ◽

Work Hardening ◽

Compressive Residual Stress ◽

Strain Ratio ◽

Fatigue Tests ◽

The Other ◽

Fatigue Properties ◽

Torsional Fatigue ◽

Stress Work

In this study, fatigue tests have been performed using two kinds of specimens made of 25 steel. One is pre-strained specimen with pre-strain ratio changing from 2% to 8% by tension, the other is roller worked with deformation of 0.5 mm and 1.0 mm in diameter direction. In the case of pre-strained specimen, the fatigue limit increases according to increase of tensile pre-strain, the fatigue limit of 8% pre-strained specimen is 25% higher than that of non-pre-strained one; in the case of roller worked specimen, the fatigue limit of R05 and R10 is 126% and 143% to that of non-roller worked specimen, respectively. These remarkable improvements of fatigue limit would be caused by the existence of compressive residual stress, work-hardening and the elongated microscopic structures.

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Law of Fatigue Limit : Part I. Condition of Fatigue Endurance Limit, and Relations between Various Endurance Limits

Transactions of the Japan Society of Mechanical Engineers ◽

10.1299/kikai1938.18.104 ◽

1952 ◽

Vol 18 (65) ◽

pp. 104-109 ◽

Cited By ~ 1

Author(s):

Fujio NAKANISHI

Keyword(s):

Fatigue Limit ◽

Endurance Limit ◽

Endurance Limits ◽

Fatigue Endurance

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Experimental Study on the Effect of Surface Integrity on Fatigue Performance of Aero-Engine Blades

Volume 2: Manufacturing Processes; Manufacturing Systems; Nano/Micro/Meso Manufacturing; Quality and Reliability ◽

10.1115/msec2021-63712 ◽

2021 ◽

Author(s):

Yun Huang ◽

Shaochuan Li ◽

Guijian Xiao ◽

Benqiang Chen ◽

Yi He ◽

...

Keyword(s):

Residual Stress ◽

Surface Roughness ◽

Fatigue Life ◽

Fatigue Strength ◽

Fatigue Test ◽

Surface Texture ◽

Surface Characteristics ◽

Service Performance ◽

Aero Engine ◽

Vibration Fatigue

Abstract As the core component of aero-engine, the service performance of aero-engine blade has an important influence on the engine’s reliability and safety performance. Existing studies have shown that machined surface characteristics affect the fatigue strength of components. However, current studies are all based on regular fatigue samples. The structure of blades different from fatigue samples, and the influence mechanism of structural differences on the service performance of blades is still unclear. In addition, the conventional fatigue test conditions are not representative for the blades’ actual service conditions, so it is difficult to realize the processing process for the service performance optimization. In this study, the aero-engine blades processed by abrasive belt grinding and the vibration fatigue test bench were used to explore the influence of surface roughness, surface texture, and surface residual stress on the fatigue performance of aero-engine blades under actual working conditions. The aero-engine blades were ground with different process parameters to obtain different single-factor surface characteristics. By comparing the vibration fatigue life of blades with different surface features, the influence degree of each surface feature on the fatigue life was explored. Results showed that surface roughness has the greatest influence on fatigue strength, followed by residual stress, and surface texture has the least influence on fatigue strength.

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Effect of Microshot Peening on Surface Characteristics of Spring Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.654-656.374 ◽

2010 ◽

Vol 654-656 ◽

pp. 374-377

Author(s):

Yasunori Harada ◽

Koji Yoshida

Keyword(s):

Residual Stress ◽

Shot Peening ◽

Compressive Residual Stress ◽

Cast Steel ◽

High Hardness ◽

Surface Characteristics ◽

Spring Steel ◽

Cemented Carbide ◽

High Carbon ◽

New Type

Shot peening is a surface treatment that improves the performance of engineering components. In conventional shot peening, the medium consists of small spheres, which are usually made of high-carbon cast steel; the diameter of the spheres is in the range from 0.3 to 1.2mm. More recently, however, a new type of microshot has been developed to enhance the peening effect. The diameter of the spheres in the new medium is in the range from 0.02 to 0.15mm. In the present study, the effect of microshot peening on the surface characteristics of spring steel was investigated. The injection method of the microshot was of the compressed air type. The microshots of 0.1mm diameter were high-carbon cast steel and cemented carbide, and the workpiece used was the commercially spring steel JIS-SUP10. The surface roughness, hardness and compressive residual stress of the peened workpieces were measured. The surface layer of the workpieces was sufficiently deformed by microshot peening. A high hardness or residual stress was observed near the surface. The use of hard microshots such as cemented carbide was found to cause a significantly enhanced peening effect for spring steel.

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A Study on the Fatigue Characteristics of Al6061-T651 by Shot Peening Velocity

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.326-328.1093 ◽

2006 ◽

Vol 326-328 ◽

pp. 1093-1096 ◽

Cited By ~ 1

Author(s):

Won Jo Park ◽

Sun Chul Huh ◽

Sung Ho Park

Keyword(s):

Residual Stress ◽

Surface Roughness ◽

Fatigue Life ◽

Shot Peening ◽

High Speed ◽

Compressive Residual Stress ◽

Velocity Increase ◽

Fatigue Characteristics ◽

Height Increase ◽

Small Steel

Small steel ball is utilized in Shot peening process. Called “shot ball” are shot in high speed on the surface of metal. When the shot ball hit the surface, it makes plastic deformation and bounce off, that increase the fatigue life by compressive residual stress on surface. In this study, the results of observation on the tensile strength, hardness, surface roughness, compressive residual stress and fatigue life of a shot peened Al6061-T651 were obtained. Experimental results show that arc height increase tremendously by shot velocity. Also, it shows that surface roughness, hardness, compressive residual stress and fatigue life increase as shot velocity increase.

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The Influence of Surface Residual Stress on Fatigue Limit of Titanium

Journal of Engineering for Industry ◽

10.1115/1.3663004 ◽

1960 ◽

Vol 82 (1) ◽

pp. 76-78 ◽

Cited By ~ 16

Author(s):

E. C. Reed ◽

J. A. Viens

Keyword(s):

Residual Stress ◽

Titanium Alloy ◽

Fatigue Limit ◽

Experimental Error ◽

Endurance Limit ◽

Simple Equation ◽

Surface Residual Stress ◽

A Value ◽

Effect Of Surface

Investigation of the effect of surface residual stress on the endurance limit of 6Al 4V titanium alloy shows that this effect is equal within experimental error to the residual stress divided by a constant. Results can be expressed by a simple equation. A value for the constant has been derived.

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Enhancement of Fatigue Strength on SAE 1541 Steel Link Plate with Slip Ball Burnishing Technique

Defence Science Journal ◽

10.14429/dsj.70.14704 ◽

2020 ◽

Vol 70 (4) ◽

pp. 454-460

Author(s):

K. Krishnakumar ◽

A. Arockia Selvakumar

Keyword(s):

Residual Stress ◽

Surface Roughness ◽

Fatigue Strength ◽

Compressive Residual Stress ◽

Repeated Loading ◽

Ball Burnishing ◽

Novel Technique ◽

Conventional Process ◽

Chain Link ◽

Local Plastic Deformation

This research paper describes a technique for the enhancement of the fatigue strength of the chain link plate in the drive system of a military armoured vehicle. SAE 1541 steel link plates of chains were subjected to cyclical tensile stress due to repeated loading and un-loading conditions. The crack was getting originated from the pitch hole and growth perpendicular to the chain pulling load, due to fatigue mechanism. In general plate holes are manufactured using the conventional process. An additional novel technique called the slip ball burnishing (SBB) method is applied for improving the hole properties. The improvement is made by producing local plastic deformation, improving surface finish and compressive residual stress throughout in the pierced hole. Both the conventional process (CP) and the SBB technique have been evaluated by optical, profile, surface roughness and micro harness tests. Experimental fatigue test validations were done in both chain samples using the Johnson-Goodman method. SBB chains passed 3x106 cycles at the load of 17.61 kN and CP chains passed 3x106 cycles at the load of 13.92 kN. The conclusion was that SBB made a significant improvement of 26.51 per cent of fatigue strength compared to CP.

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Surface Integrity and Fatigue Property of a High Speed Milled Titanium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.53-54.305 ◽

2008 ◽

Vol 53-54 ◽

pp. 305-310 ◽

Cited By ~ 9

Author(s):

Guo Sheng Geng ◽

Jiu Hua Xu

Keyword(s):

Residual Stress ◽

Surface Roughness ◽

Titanium Alloy ◽

Surface Integrity ◽

Work Hardening ◽

High Speed ◽

Cutting Speed ◽

Fatigue Property ◽

Machined Surface ◽

Metallurgical Structure

Surface integrity has a great effect on the fatigue property of titanium alloy. The surface integrity and fatigue property of a high speed milled Ti-6.5Al-2Zr-1Mo-1V (TA15) titanium alloy were investigated in this research. The main objective of this paper is to study the influence of milling speed on the surface integraty and fatigue property of the machined part. The surface roughness, work hardening, metallurgical structure and residual stress of the machined surface were studied in a cutting speed range of from 50m/min to 300m/min. To verify the relationship between cutting speed and the surface integrity of machined surface, the fatigue property of titanium alloy specimens milled at four different cutting speeds ranging from 50 to 200m/min were compared at two stress levels. This research shows that the cutting speed has little effect on the work hardening, metallurgical structure and residual stress, but the surface roughness decreases with the increasing cutting speed. Therefore, increasing milling speed has a positive effect on the surface integrity and fatigue property of the machined surface.

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