Effect of Stress Ratio on Fatigue Life of Warm/Cold Forging Die Steel  under Constant Amplitude Loading

High cycle fatigue behavior of the representative cold forging die steel, YXR3 with Rockwell C scale hardness number of 60.0 is investigated. Axial fatigue strength of plane and notched bar specimens with stress concentration factor, Kt of 1.5, 2.0 and 2.5 is presented. The emphasis is placed upon the subsurface crack initiation observed on notched specimens failed at number of cycles over than 106 cycles. Crack initiation and propagation mode of cold forging die steel is discussed with respect to fracture surface morphology.

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Effect of stress ratio on fatigue life of die steel for cold-pressing

The Proceedings of Conference of Kyushu Branch ◽

10.1299/jsmekyushu.2019.72.f32 ◽

2019 ◽

Vol 2019.72 (0) ◽

pp. F32

Author(s):

Keisuke KOJIMOTO ◽

Toshihiko MURAOKA ◽

Atsuhiro KOYAMA ◽

Toru TAKASE

Keyword(s):

Fatigue Life ◽

Stress Ratio ◽

Die Steel ◽

Cold Pressing

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Thermo-mechanical fatigue life assessment of hot forging die steel

Fatigue & Fracture of Engineering Materials & Structures ◽

10.1111/j.1460-2695.2005.00940.x ◽

2005 ◽

Vol 28 (11) ◽

pp. 1025-1034 ◽

Cited By ~ 17

Author(s):

G. A. BERTI ◽

M. MONTI

Keyword(s):

Fatigue Life ◽

Hot Forging ◽

Life Assessment ◽

Die Steel ◽

Mechanical Fatigue ◽

Fatigue Life Assessment ◽

Hot Forging Die ◽

Forging Die

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Uniaxial Ratcheting and Low-Cycle Fatigue Failure of U75V Rail Steel

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.853.246 ◽

2016 ◽

Vol 853 ◽

pp. 246-250 ◽

Cited By ~ 2

Author(s):

Tao Fang ◽

Qian Hua Kan ◽

Guo Zheng Kang ◽

Wen Yi Yan

Keyword(s):

Fatigue Life ◽

Strain Amplitude ◽

Stress Ratio ◽

Stress Amplitude ◽

Rail Steel ◽

Low Cycle Fatigue ◽

Mean Stress ◽

Cycle Fatigue ◽

Ratcheting Strain ◽

Cyclic Straining

Experiments on U75V rail steel were carried out to investigate the cyclic feature, ratcheting behavior and low-cycle fatigue under both strain- and stress-controlled loadings at room temperature. It was found that U75V rail steel shows strain amplitude dependent cyclic softening feature, i.e., the responded stress amplitude under strain-controlled decreases with the increasing number of cycles and reaches a stable value after about 20th cycle. Ratcheting strain increases with an increasing stress amplitude and mean stress, except for stress ratio, and the ratcheting strain in failure also increases with an increasing stress amplitude, mean stress and stress ratio. The low-cycle fatigue lives under cyclic straining decrease linearly with an increasing strain amplitude, the fatigue lives under cyclic stressing decrease with an increasing mean stress except for zero mean stress, and decrease with an increasing stress amplitude. Ratcheting behavior with a high mean stress reduces fatigue life of rail steel by comparing fatigue lives under stress cycling with those under strain cycling. Research findings are helpful to evaluate fatigue life of U75V rail steel in the railways with passenger and freight traffic.

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A Multi-Level Low Cycle Fatigue Damage Model for Forging Die Material

Materials Science Forum ◽

10.4028/www.scientific.net/msf.514-516.804 ◽

2006 ◽

Vol 514-516 ◽

pp. 804-809

Author(s):

S. Gao ◽

Ewald Werner

Keyword(s):

Fatigue Life ◽

Fatigue Damage ◽

Low Cycle Fatigue ◽

Damage Model ◽

Fatigue Loading ◽

Cycle Fatigue ◽

Die Material ◽

Multi Level ◽

Loading Sequence ◽

Forging Die

The forging die material, a high strength steel designated W513 is considered in this paper. A fatigue damage model, based on thermodynamics and continuum damage mechanics, is constructed in which both the previous damage and the loading sequence are considered. The unknown material parameters in the model are identified from low cycle fatigue tests. Damage evolution under multi-level fatigue loading is investigated. The results show that the fatigue life is closely related to the loading sequence. The fatigue life of the materials with low fatigue loading first followed by high fatigue loading is longer than that for the reversed loading sequence.

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