Influence of the Abrasive on Fatigue in Precision Grinding

1987 ◽  
Vol 109 (3) ◽  
pp. 203-205 ◽  
Author(s):  
H. K. To¨nshoff ◽  
F. Hetz
Keyword(s):  
Fatigue Strength ◽  
Residual Stresses ◽  
Strong Influence ◽  
Cubic Boron Nitride ◽  
Fatigue Tests ◽  
Machining Parameters ◽  
Precision Grinding ◽  
Surface Residual Stresses ◽  
Alternating Bending ◽  
Compressive Residual Stresses

The surface residual stresses produced by grinding may have a strong influence on the life of highly stressed components. Different abrasives such as aluminum oxide (Al2O3) and cubic boron nitride (CBN) may lead to very different results. While CBN produces compressive residual stresses in nearly all combinations of machining parameters, the use of Al2O3 normally leads to tensile residual stresses. Fatigue tests carried out in alternating bending showed a remarkable increase in fatigue strength for CBN ground specimens compared with Al2O3 ground ones.

Influence of Milling Parameters on Surface Residual Stresses of 7050-T7451 Aluminum Alloy

2012 ◽  
Vol 723 ◽  
pp. 208-213 ◽  
Author(s):  
Yi Wan ◽  
Chen Li ◽  
Zhan Qiang Liu ◽  
Shu Feng Sun
Keyword(s):  
Aluminum Alloy ◽  
Residual Stresses ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Milling Process ◽  
X Ray Diffraction ◽  
Orthogonal Direction ◽  
Mechanical Coupling ◽  
Surface Residual Stresses ◽  
Compressive Residual Stresses

Residual stresses generated in milling process affect the performance of machined components. Milling residual stresses correlate closely with the cutting parameters. In this paper, the generation and distribution of surface residual stresses in milling of aluminum alloy 7050-T7451 was investigated. The cutting speed changes from 300m/min to 3000m/min. In the experiments, the residual stresses on the surface of specimen are detected by X-ray diffraction technique. The result shows that compressive residual stresses are generated when cutting speed is under 500 m/min. In feed and its orthogonal direction, the effect of cutting speed and feed rate on residual stresses is similar. The formation of the residual stresses can be explained by thermo-mechanical coupling effects.

Effect of Cutting-Edge Geometry and Workpiece Hardness on Surface Residual Stresses in Finish Hard Turning of AISI 52100 Steel

1999 ◽  
Vol 122 (4) ◽  
pp. 642-649 ◽  
Author(s):  
Jeffrey D. Thiele ◽  
Shreyes N. Melkote ◽  
Roberta A. Peascoe ◽  
Thomas R. Watkins
Keyword(s):  
Residual Stresses ◽  
Hard Turning ◽  
Cutting Edge ◽  
Edge Geometry ◽  
Surface Residual Stresses ◽  
Aisi 52100 ◽  
Aisi 52100 Steel ◽  
Finish Hard Turning ◽  
Hardness Values ◽  
Compressive Residual Stresses

An experimental investigation was conducted to determine the effects of tool cutting-edge geometry (edge preparation) and workpiece hardness on surface residual stresses for finish hard turning of through-hardened AISI 52100 steel. Polycrystalline cubic boron nitride (PCBN) inserts with representative types of edge geometry including “up-sharp” edges, edge hones, and chamfers were used as the cutting tools in this study. This study shows that tool edge geometry is highly influential with respect to surface residual stresses, which were measured using x-ray diffraction. In general, compressive surface residual stresses in the axial and circumferential directions were generated by large edge hone tools in longitudinal turning operations. Residual stresses in the axial and circumferential directions generated by large edge hone tools are typically more compressive than stresses produced by small edge hone tools. Microstructural analysis shows that thermally-induced phase transformation effects are present at all feeds and workpiece hardness values with the large edge hone tools, and only at high feeds and hardness values with the small edge hone tools. In general, continuous white layers on the workpiece surface correlate with compressive residual stresses, while over-tempered regions correlate with tensile or compressive residual stresses depending on the workpiece hardness. [S1087-1357(00)00304-X]

Influence of Residual Stresses and of Mean Stress on the Fatigue Strength of Specimens with Longitudinal Non-Load-Carrying Fillet Welds

1970 ◽  
Vol 12 (6) ◽  
pp. 381-390
Author(s):  
T. R. Gurney
Keyword(s):  
Fatigue Strength ◽  
Residual Stresses ◽  
Stress Ratio ◽  
Fillet Welds ◽  
Direct Result ◽  
Mean Stress ◽  
Test Results ◽  
Load Carrying ◽  
Quantitative Explanation ◽  
Compressive Residual Stresses

Using results obtained in work on fatigue crack propagation in unwelded sheet specimens, an analysis has been made of fatigue test results for specimens with longitudinal non-load-carrying fillet welds tested in the as-welded and stress relieved conditions and also after treatment by local compression and by spot heating. It is shown that, by this means, it is possible to provide a quantitative explanation of the effect of residual stresses and applied stress ratio on fatigue strength, since all the results can be normalized on the basis of an effective stress range. In the course of the work it has been shown that the gross stress concentration factor for this type of joint is approximately 2·57. It has also again been demonstrated that the beneficial effect of spot heating on fatigue strength is a direct result of induced compressive residual stresses.

Prediction and Measurement of Residual Stresses Arising From Quenching of Stainless Steels

2004 ◽  
Author(s):  
S. Hossain ◽  
C. E. Truman ◽  
D. J. Smith ◽  
M. R. Daymond
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Stainless Steels ◽  
Numerical Study ◽  
Hole Drilling ◽  
The Core ◽  
Residual Stress State ◽  
Surface Residual Stresses ◽  
Compressive Residual Stresses ◽  
Good Agreement

This paper presents results from an experimental and numerical study examining the creation of highly triaxial residual stresses in stainless steel. This was motivated by a need to model and understand creep in aged power plant. The residual stresses were introduced by rapid spray water quenching of heated solid stainless steel spheres and cylinders. Finite element (FE) simulations predicted high compressive residual stresses around the surface of the specimens and tensile residual stresses near the centre. Surface residual stresses were measured using the incremental centre-hole drilling (ICHD) technique. Neutron diffraction (ND) was used to measure the interior residual stresses. The measurements were in good agreement with FE predictions. The ND measurements confirmed that a highly triaxial residual stress state existed in the core of the specimens.

Characteristics of High Frequency Peening Methods and their Effects on the Fatigue Strength of Welded Details

2007 ◽  
Vol 348-349 ◽  
pp. 429-432
Author(s):  
Imke Weich ◽  
Thomas Ummenhofer
Keyword(s):  
Fatigue Strength ◽  
Residual Stresses ◽  
High Frequency ◽  
Crack Detection ◽  
Surface Hardness ◽  
Detection Methods ◽  
Laser Measurements ◽  
Mechanical Effects ◽  
Weld Toe ◽  
Compressive Residual Stresses

Research has been initiated on the effects of high frequency peening methods on the fatigue strength. These methods combine an improvement of weld toe profile with an initiation of compressive residual stresses and surface hardening. The effects of two techniques, High Frequency Impact Treatment (HiFIT) and Ultrasonic Impact Treatemnt (UIT) are compared. Laser measurements of the weld seam prove that both methods increase the overall weld toe radii. Further, residual stress measurements verify the introduction of compressive residual stresses at least up to a depth of 1 mm. The values meet the yield strength combined with an increase of the surface hardness. These material mechanical effects cause an increased crack resistance. Crack detection methods prove that the material mechanical effects yield to a retarded crack initiation. Experimental results show that these effects lead to a significant increase of the fatigue strength and reduced slopes of the SN-curves.

Investigation of Surface Integrity in Path Controlled Grinding of Crankshaft Pin

2013 ◽  
Vol 404 ◽  
pp. 100-105
Author(s):  
Man Chao Zhang ◽  
Zhen Qiang Yao
Keyword(s):  
Residual Stresses ◽  
Small Difference ◽  
Cubic Boron Nitride ◽  
Wheel Speed ◽  
Depth Of Cut ◽  
Surface Residual Stress ◽  
Test Conditions ◽  
Surface Residual Stresses ◽  
Wide Range ◽  
Grinding Conditions

This paper investigates the effects of path controlled grinding on the grinding performance of 40Cr using vitrified-bonded cubic boron nitride (CBN) abrasive at low revolution. The evaluation of surface roughness and surface residual stress are presented. Experiments were carried out for path controlled cylindrical grinder in a wide range of grinding conditions. It can be obtained that the variation is slight in agreement with the small difference about roughness. The wheel speed and depth of cut are two key parameters to the surface residual stresses, and work speed does not seem to influence the residual stresses in the test conditions. The high residual grinding stresses of pin bearing resulting from path controlled grinding are compressive type at the surface for all conditions.

Generating Compressive Surface Residual Stresses Using Hydraulic Autofrettage Process With Heat Treatment

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Rajkumar Shufen ◽  
Uday S. Dixit
Keyword(s):  
Heat Treatment ◽  
Critical Temperature ◽  
Residual Stresses ◽  
Outer Wall ◽  
Temperature Dependent ◽  
Surface Residual Stresses ◽  
Lower Critical Temperature ◽  
Lower Temperature ◽  
Compressive Residual Stresses ◽  
Treatment Design

Abstract Recently, a method of inducing compressive residual stresses in the vicinity of the walls of a thermally autofrettaged cylinder was proposed. In the proposed method, the thermally autofrettaged cylinder was heated in such a manner that its outer wall attained a temperature more than the lower critical temperature and the inner wall was at a sufficiently lower temperature. When the cylinder was quenched, compressive residual stresses were induced in the vicinity of the cylinder walls. This article investigates the feasibility of the same procedure for a hydraulic-autofrettaged cylinder made of AISI 1080 steel. A finite element method (FEM)-based analysis is carried out using commercial package abaqus by incorporating microstructure and temperature-dependent material properties. The results indicate that the heat treatment design proposed for the thermally autofrettaged cylinder to induce compressive residual stresses at the outer wall can also be adapted for a hydraulic-autofrettaged cylinder. However, for cylinders subjected to high percentage of autofrettage, heating of the outer wall needs to be carried out well below the lower critical temperature. In fact, this is an advantage in terms of energy saving and can be implemented even for cylinders subjected to a low percentage of autofrettage.

Fatigue Life Improvement Using Mechanical Post Treatment for Weldment

2008 ◽  
Vol 580-582 ◽  
pp. 97-100
Author(s):  
Seung Ho Han ◽  
Jeong Woo Han ◽  
Yong Yun Nam
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Residual Stresses ◽  
Quantitative Measure ◽  
Fatigue Strength Improvement ◽  
Weld Profile ◽  
Weld Toe ◽  
Life Improvement ◽  
Hammer Peening ◽  
Compressive Residual Stresses

Mechanical post treatments for welded structures have been applied in various industrial fields and, in most cases, have been found to cause substantial increase in their fatigue strength. These methods, generally, consist of the modification of weld toe geometry and the introduction of compressive residual stresses. In hammer peening, the weld profile is modified due to removal or reduction of minute crack-like flaws; compressive residual stresses are also induced by repeated hammering of the weld toe region with blunt-nosed chisel. In this study, a hammer peening procedure, using commercial pneumatic chipping hammer, was developed; a quantitative measure of fatigue strength improvement was performed. The fatigue life of hammer-peened specimen was prolonged by approximately 10 times in S=240MPa, and was doubled for the as-welded specimen.

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