The Effect of Plastic Strain Followed by Aging on the Elastic Limit of Quenched and Tempered and Austempered 4340 Steel

The torsion fatigue limit of 4340 steel in the quenched and tempered condition is compared with the quenched, tempered and strain-aged condition. Previous experimental work by the authors indicated that strain-aging of tempered martensite of 4340 improved the tensile strength, yield strength and tensile elastic limit. Other workers have shown that the tensile elastic limit and rotating beam fatigue limit of 4340 steel were related at high hardness. The results of this work show that strainaging tempered martensite of 4340 at a hardness of 54-55 Rockwell C does not improve the high cycle torsion fatigue limit.

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A statistical approach to micro-plastic strain in metals

Journal of Strain Analysis ◽

10.1243/03093247v015415 ◽

1966 ◽

Vol 1 (5) ◽

pp. 415-421 ◽

Cited By ~ 19

Author(s):

A Esin ◽

W J D Jones

Keyword(s):

Plastic Strain ◽

Elastic Limit ◽

Statistical Approach ◽

Physical Reality ◽

General Concept ◽

Distribution Functions ◽

Point Of View ◽

Plastic Strains ◽

Statistical Point ◽

Suggested Approach

The paper presents an outline of a theory of micro-inhomogeneity of stresses and strains resulting from the micro-structural properties of engineering materials. The problem is approached from a statistical point of view and it is experimentally shown that the degree of micro-inhomogeneity can be defined by normal distribution functions. Using the experimental results a general concept is postulated which takes into account the physical reality as completely as is practicable. It is shown that the suggested approach can be used to take into account the micro-plastic strains which exist while the material is nominally within the elastic limit.

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THE INFLUENCE OF DEFORMATION OF SELECTED THERMOPLASTICS ON THE FRICTION WITH STEEL

Tribologia ◽

10.5604/01.3001.0010.6989 ◽

2016 ◽

Vol 268 (4) ◽

pp. 137-144 ◽

Cited By ~ 1

Author(s):

Maciej KUJAWA ◽

Aneta NIEMIEC ◽

Wojciech WIELEBA

Keyword(s):

Friction Coefficient ◽

Plastic Strain ◽

Tensile Stress ◽

Friction And Wear ◽

Elastic Limit ◽

Kinetic Friction ◽

Scientific Publications ◽

Friction Coefficients ◽

Wear And Friction ◽

Friction Analysis

Friction and wear of materials with additional deformation or stress is not a broadly described case. However, scientific publications considering this issue point out that additional deformation and stress ought to be taken into account during wear and friction analysis. In this article, the influence of strain in thermoplastics (POM, PTFE, PE-HD, PMMA) over the friction coefficient is described. Materials were deformed under tensile stress and examined after 24 hours. For specimens in which plastic strain was maintained, the decline of hardness (PE-HD: approximately 70% decrease, PTFE: approximately 40% decrease) and the reduction of the coefficient of kinetic friction (both PTFE and PE-HD: about 20% decrease) were observed. POM returned to its pre-deformed shape and PMMA was deformed without reaching its elastic limit. In these cases, only small changes in hardness (POM: approximately 10% decrease, PMMA: approximately 6% increase) and friction coefficients (maximum 4% change) occurred.

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Plastic Deformation in Microtomed Sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066346 ◽

1971 ◽

Vol 29 ◽

pp. 458-459

Author(s):

J. Temple Black

Keyword(s):

Plastic Deformation ◽

Plastic Strain ◽

Applied Stress ◽

Elastic Strain ◽

High Strain ◽

Tool Material ◽

Cutting Edge ◽

Material Structure ◽

Geometrical Constraints

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.

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Comparison of Substructures Between Uniaxial and Biaxial Deformation in 1100-0 Aluminum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100096989 ◽

1981 ◽

Vol 39 ◽

pp. 52-53

Author(s):

D. L. Rohr ◽

S. S. Hecker

Keyword(s):

Plastic Strain ◽

Cell Walls ◽

Room Temperature ◽

Mechanical Response ◽

Biaxial Tension ◽

Initial Deformation ◽

Uniaxial Deformation ◽

Biaxial Deformation ◽

Stress States ◽

Comprehensive Study

As part of a comprehensive study of microstructural and mechanical response of metals to uniaxial and biaxial deformations, the development of substructure in 1100 A1 has been studied over a range of plastic strain for two stress states.Specimens of 1100 aluminum annealed at 350 C were tested in uniaxial (UT) and balanced biaxial tension (BBT) at room temperature to different strain levels. The biaxial specimens were produced by the in-plane punch stretching technique. Areas of known strain levels were prepared for TEM by lapping followed by jet electropolishing. All specimens were examined in a JEOL 200B run at 150 and 200 kV within 24 to 36 hours after testing.The development of the substructure with deformation is shown in Fig. 1 for both stress states. Initial deformation produces dislocation tangles, which form cell walls by 10% uniaxial deformation, and start to recover to form subgrains by 25%. The results of several hundred measurements of cell/subgrain sizes by a linear intercept technique are presented in Table I.

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Thermomechanical Treatment of a 4340 Ni-Cr-Mo Alloy Steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098083 ◽

1981 ◽

Vol 39 ◽

pp. 314-315 ◽

Cited By ~ 1

Author(s):

M.T. Jahn ◽

J.C. Yang ◽

C.M. Wan

Keyword(s):

Mechanical Property ◽

Chemical Composition ◽

Alloy Steel ◽

Thermomechanical Treatment ◽

Room Temperature ◽

Good Combination ◽

Thermal Treatments ◽

Low Carbon ◽

4340 Steel ◽

Good Improvement

4340 Ni-Cr-Mo alloy steel is widely used due to its good combination of strength and toughness. The mechanical property of 4340 steel can be improved by various thermal treatments. The influence of thermomechanical treatment (TMT) has been studied in a low carbon Ni-Cr-Mo steel having chemical composition closed to 4340 steel. TMT of 4340 steel is rarely examined up to now. In this study we obtain good improvement on the mechanical property of 4340 steel by TMT. The mechanism is explained in terms of TEM microstructures4340 (0.39C-1.81Ni-0.93Cr-0.26Mo) steel was austenitized at 950°C for 30 minutes. The TMTed specimen (T) was obtained by forging the specimen continuously as the temperature of the specimen was decreasing from 950°C to 600°C followed by oil quenching to room temperature. The thickness reduction ratio by forging is 40%. The conventional specimen (C) was obtained by quenching the specimen directly into room temperature oil after austenitized at 950°C for 30 minutes. All quenched specimens (T and C) were then tempered at 450, 500, 550, 600 or 650°C for four hours respectively.

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Lamellar grains distribution and plastic strain heterogeneities in TiAI cast samples. Experiments and modelling

Matériaux & Techniques ◽

10.1051/mattech:2004008 ◽

2004 ◽

Vol 92 (1-2) ◽

pp. 69-76 ◽

Cited By ~ 2

Author(s):

L. Gélébart ◽

M. Bornert ◽

T. Bretheau ◽

D. Caldemaison ◽

J. Crépin ◽

...

Keyword(s):

Plastic Strain

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On the nominal transverse shear strain to characterize the severity of creasing

TAPPI Journal ◽

10.32964/tj17.04.231 ◽

2018 ◽

Vol 17 (04) ◽

pp. 231-240

Author(s):

Douglas Coffin ◽

Joel Panek

Keyword(s):

Shear Strain ◽

Transverse Shear ◽

Elastic Limit ◽

Experimental Results ◽

Transverse Shear Strain ◽

Maximum Strain ◽

Machine Direction ◽

Engineering Approach ◽

Wide Range ◽

Analytic Expression

A transverse shear strain was utilized to characterize the severity of creasing for a wide range of tooling configurations. An analytic expression of transverse shear strain, which accounts for tooling geometry, correlated well with relative crease strength and springback as determined from 90° fold tests. The experimental results show a minimum strain (elastic limit) that needs to be exceeded for the relative crease strength to be reduced. The theory predicts a maximum achievable transverse shear strain, which is further limited if the tooling clearance is negative. The elastic limit and maximum strain thus describe the range of interest for effective creasing. In this range, cross direction (CD)-creased samples were more sensitive to creasing than machine direction (MD)-creased samples, but the differences were reduced as the shear strain approached the maximum. The presented development provides the foundation for a quantitative engineering approach to creasing and folding operations.

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