Interior-Induced Fracture Mechanism of High Cleanliness Spring Steel (JIS SWOSC-V) in Very High Cycle Regime

Abstract:

In order to investigate the interior-induced fatigue crack propagation behavior of high cleanliness valve spring steel (JIS SWOSC-V), rotating bending fatigue tests were performed for various kinds of specimens with different hardness or surface finishings. The harder specimen with higher compressive residual stress showed longer fatigue life. The electrochemical polished specimen pre-treated with shot peening showed almost same fatigue life as the shot-peened specimen in spite of the difference in surface roughness. After fatigue tests, fracture surfaces were observed using a scanning electron microscope (SEM) to evaluate the fatigue fracture mechanism. Most specimens failed in surface-induced fracture mode due to high cleanliness; however, some specimens failed in interior-induced fracture mode in the very high cycle regime. Although non-metallic inclusions were not observed at interior fatigue crack initiation sites, 2 types of significant microstructures (with smooth surface or granular surface) were observed. EBSD analysis, profile analysis and computational simulation using a fracture surface topographic analysis (FRASTA) method were performed to investigate the mechanism of the interior-induced fatigue fracture caused by the microstructure at defect without any inclusion.

• Periodical: Key Engineering Materials (Volume 664)
• Pages: 209-218
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.664.209
• Online since: September 2015
• Authors: Taku Miura*, Takayuki Sakakibara, Takanori Kuno, Akira Ueno, Shoichi Kikuchi, Tatsuo Sakai
• Keywords: Fractography, Interior-Induced Fracture, Spring Steel, Very High Cycle Fatigue

References

[1] C. Masuda, S. Nishijima and Y. Tanaka, Relationship between fatigue strength and hardness for high strength steels, Transactions of the Japan Society of Mechanical Engineers (series A), 52(476) (1986) 847–852.

DOI: 10.1299/kikaia.52.847

[2] T. Sakai, M. Takeda, K. Shiozawa, Y. Ochi, M. Nakajima, T. Nakamura and N. Oguma, Experimental recommendation of characteristic S-N property for high carbon chromium bearing steel in wide life region in rotating bending, Journal of the Society of Materials Science, Japan, 49(7), (2000).

DOI: 10.1299/jsmemm.2008._os1510-1_

[3] T. Sakai, M. Takeda, N. Tanaka, M. Kanemitsu, N. Oguma and K. Shiozawa, Characteristic S-N property of high carbon chromium bearing steel in ultra-wide life region under rotating bending, Materials Science Research International, STP1 (2001).

DOI: 10.1109/ecodim.2001.992395

[4] H. Mughrabi, Zur Dauerschwingfestigkeit im Bereich extrem hoher Bruchlastspielzahlen: Mehrstufige Lebensdauerkurven, Harterei-technische Mitteilungen, 56(5), (2001) 300-303.

[5] C. Bathias and P. C. Paris, Gigacycle Fatigue in Mechanical Practice, Marcel Dekker, (2005), New York.

[6] D. G. Harlow, R. P. Wei, T. Sakai and N. Oguma, Crack growth based probability modeling of S-N response for high strength steel, International Journal of Fatigue, 28(11), (2006), 1479-1485.

DOI: 10.1016/j.ijfatigue.2005.05.019

[7] K. Shiozawa, Y. Morii, S. Nishino and L. Lu, Subsurface crack initiation and propagation mechanism in high-strength steel in a very high cycle fatigue regime, International Journal of Fatigue, 28(11), (2006) 1521-1532.

DOI: 10.1016/j.ijfatigue.2005.08.015

[8] T. Sakai, Review and prospects for current studies on very high cycle fatigue of metallic materials for machine structural use, Journal of Solid Mechanics and Materials Engineering, 3(3), (2009) 425-439.

DOI: 10.1299/jmmp.3.425

[9] M. Sugimoto, K. Kanazawa and A. Tange, The influence of slack quenching structures on internal fatigue fracture of a shot peened spring steel, Journal of the Society of Materials Science, Japan, 57(11) (2008) 1146-1152.

DOI: 10.2472/jsms.57.1146

[10] Y. Kuroshima, M. Shimizu and K. Kawasaki, Fracture mode transition in high cycle fatigue of high strength steel, Transactions of the Japan Society of Mechanical Engineers (series A), 59(560) (1993) 1001-1006.

DOI: 10.1299/kikaia.59.1001

[11] T. Toriyama, Y. Murakami, T. Yamashita, K. Tsubota and K. Furumura, Inclusion rating by statistics of extreme for electron beam remelted super clean bearing steel and its application to fatigue strength prediction, TETSU-TO-HAGANE, 81(10) (1995).

DOI: 10.2355/tetsutohagane1955.81.10_1019

[12] G. Chai, The formation of subsurface non-defect fatigue crack origins, International Journal of Fatigue, 28 (2006) 1533-1539.

DOI: 10.1016/j.ijfatigue.2005.06.060

[13] T. Miura, T. Sakakibara, S. Mimura, T. Kuno, S. Kikuchi, A. Ueno and T. Sakai, Fractographical investigation on mechanism of interior-induced fatigue fracture of SUP7 steel for hot formed springs, Journal of the Society of Materials Science, Japan, (2015).

DOI: 10.2472/jsms.64.613

[14] R. E. Peterson, Stress Concentration Design Factors, John Wiley & Sons, Inc., New York, (1962), p.50.

[15] K. Kobayashi and D. A. Shockey, A fractographic investigation of thermal embrittlement in cast duplex stainless steel, Metallurgical and Materials Transactions A, 18A(11) (1987) 1941-(1949).

DOI: 10.1007/bf02647024

[16] A. Ueno, H. Kishimoto, K. Kino and Y. Ishii, Topographical fractography and fracture simulation with scanning laser microscope, Transactions of the Japan Society of Mechanical Engineers (series A), 63(615) (1997) 2393–2399.

DOI: 10.1299/kikaia.63.2393