Tempering Influence on Residual Stresses and Mechanical Properties of AISI 4340 Steel

Abstract The present work evaluated the tempering temperature influence on microstructure, mechanical properties and residual stresses of AISI 4340 steel. The residual stresses were measured by X‑ray diffraction (XRD) by the sin²ψ method and compared to magnetic Barkhausen noise (MBN). The residual stresses exhibited high tensile values after quenching, but a small relief was observed in tempering treatments at 300°C and 400°C, which also presented a hardness decrease compared to the as‑quenched condition. XRD and MBN analyses indicated that residual stresses became compressive in tempering performed between 500°C and 650°C. Therefore, compressive residual stresses combined with appropriate hardness and toughness values (35 HRC and 33 J) obtained from 500°C tempering temperature can be used to improve the mechanical properties of AISI 4340 steel components. Additionally, a mathematical model was established to estimate the tempered martensite hardness for different tempering temperature conditions. This model showed high accuracy (R2=0.99) for a holding time of 90 minutes.

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X-Ray Fractography On Fatigue Fracture Surfaces of Aisi 4340 Steel*

Advances in X-ray Analysis ◽

10.1154/s0376030800010132 ◽

1985 ◽

Vol 29 ◽

pp. 63-70 ◽

Cited By ~ 1

Author(s):

Yukio Hirose ◽

Zenjlro Yajima ◽

Toshio Mura

Keyword(s):

Simple Model ◽

Residual Stresses ◽

Fatigue Fracture ◽

Plastic Strains ◽

X Ray Diffraction ◽

Aisi 4340 Steel ◽

X Ray ◽

Fracture Surfaces ◽

4340 Steel ◽

Aisi 4340

The X-ray fractographic technique was applied to fatigue fracture surfaces of tempered AISI 4340 steel. Residual stresses and half-value breadths were measured by the X-ray diffraction.In the present paper, the residual stresses and plastic strains on fatigue fracture surfaces and some parameters in the fracture mechanics were investigated. A simple model of mechanics was proposed to explain these experimental results.

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Residual Stresses Near SCC Fracture Surfaces of AISI 4340 Steel

Advances in X-ray Analysis ◽

10.1154/s0376030800020772 ◽

1988 ◽

Vol 32 ◽

pp. 451-458 ◽

Cited By ~ 2

Author(s):

Zenjiro Yajima ◽

Masaaki Tsuda ◽

Yukio Hirose ◽

Keisuke Tanaka

Keyword(s):

Fracture Surface ◽

Stress Corrosion ◽

Crack Nucleation ◽

Notch Root ◽

Compact Tension ◽

X Ray Diffraction ◽

Aisi 4340 Steel ◽

X Ray ◽

4340 Steel ◽

Aisi 4340

X-ray diffraction observation of the material beneath the fracture surface provides failure analysists with useful information to judge the mechanical condition of fracture.In the present paper, stress corrosion cracking (SCC) tests were conducted by using the bluntly notched compact tension (CT) specimens of 200°C tempered AISI 4340 steel in a 3.5 NaCl solution etwixonmeat. The distribution of the residual stress beneath the fracture surface near the root of the notch was measured with the X-ray diffraction technique. The effect of the notch root radius on crack nucleation with stress corrosion was discussed on the bases of the results of X-ray observation.

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X-ray Determination of Compressive Residual Stresses in Spring Steel Generated by High-Speed Water Quenching

Materials ◽

10.3390/ma12071154 ◽

2019 ◽

Vol 12 (7) ◽

pp. 1154

Author(s):

Diego E. Lozano ◽

George E. Totten ◽

Yaneth Bedolla-Gil ◽

Martha Guerrero-Mata ◽

Marcel Carpio ◽

...

Keyword(s):

Heat Treatment ◽

Residual Stresses ◽

High Speed ◽

Spring Steel ◽

X Ray Diffraction ◽

Laboratory Equipment ◽

X Ray ◽

Water Chamber ◽

Hardened Case ◽

Compressive Residual Stresses

Automotive components manufacturers use the 5160 steel in leaf and coil springs. The industrial heat treatment process consists in austenitizing followed by the oil quenching and tempering process. Typically, compressive residual stresses are induced by shot peening on the surface of automotive springs to bestow compressive residual stresses that improve the fatigue resistance and increase the service life of the parts after heat treatment. In this work, a high-speed quenching was used to achieve compressive residual stresses on the surface of AISI/SAE 5160 steel samples by producing high thermal gradients and interrupting the cooling in order to generate a case-core microstructure. A special laboratory equipment was designed and built, which uses water as the quenching media in a high-speed water chamber. The severity of the cooling was characterized with embedded thermocouples to obtain the cooling curves at different depths from the surface. Samples were cooled for various times to produce different hardened case depths. The microstructure of specimens was observed with a scanning electron microscope (SEM). X-ray diffraction (XRD) was used to estimate the magnitude of residual stresses on the surface of the specimens. Compressive residual stresses at the surface and sub-surface of about −700 MPa were obtained.

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Residual Stresses Near SCC Fracture Surfaces of AISI 4340 Steel

Advances in X-Ray Analysis ◽

10.1007/978-1-4757-9110-5_55 ◽

1989 ◽

pp. 451-458 ◽

Cited By ~ 3

Author(s):

Zenjiro Yajima ◽

Masaaki Tsuda ◽

Yukio Hirose ◽

Keisuke Tanaka

Keyword(s):

Residual Stresses ◽

Aisi 4340 Steel ◽

Fracture Surfaces ◽

4340 Steel ◽

Aisi 4340

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The effect of grain size on fracture behaviour in tempered martensite embrittlement for AISI 4340 steel

Materials Science and Engineering ◽

10.1016/0025-5416(88)90247-9 ◽

1988 ◽

Vol 100 ◽

pp. 121-128 ◽

Cited By ~ 13

Author(s):

Hoon Kwon ◽

Jin C. Cha ◽

Chong H. Kim

Keyword(s):

Grain Size ◽

Fracture Behaviour ◽

Tempered Martensite ◽

Aisi 4340 Steel ◽

4340 Steel ◽

Aisi 4340

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Comparison of the mechanical properties of ESR and directionally solidified AISI 4340 steel

Metals Technology ◽

10.1179/030716974803287780 ◽

1974 ◽

Vol 1 (1) ◽

pp. 348-349

Author(s):

A. Mitchell ◽

R. K. Buhr ◽

F. Weinberg

Keyword(s):

Mechanical Properties ◽

Directionally Solidified ◽

Aisi 4340 Steel ◽

4340 Steel ◽

Aisi 4340

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Investigation of Residual Stresses in a Sleeve Coldworked Lug Specimen by Neutron and X-ray Diffraction

Advances in X-ray Analysis ◽

10.1154/s0376030800018103 ◽

1994 ◽

Vol 38 ◽

pp. 455-461

Author(s):

R. Lin ◽

B. Jaensson ◽

T. M. Holden ◽

R. B. Rogge ◽

J. H. Root

Keyword(s):

Fatigue Life ◽

Residual Stresses ◽

Fatigue Cracks ◽

Fatigue Properties ◽

Aircraft Industry ◽

X Ray Diffraction ◽

X Ray ◽

Initiation And Propagation ◽

Structural Parts ◽

Compressive Residual Stresses

Sleeve coldworking (SCW) is a mechanical process used in the aircraft industry to strengthen fastener holes of structural parts. By cold-expanding the holes, compressive residual stresses and a high dislocation density are introduced around the holes, the effect of which is to counteract the initiation and propagation of fatigue cracks and thus increase the fatigue life of the parts. The knowledge of residual stress due to SCW is therefore crucial for assessing the fatigue properties of a treated part. In this study, residual stresses were investigated, by employing neutron and X-ray diffraction methods, in a lug specimen that was sleeve coldworked and fatigued. The specimen had been used for testing the influence of the SCW process on fatigue life and crack propagation behaviour under constant amplitude or variable amplitude cyclic loading.

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