Simpler Estimation of Fracture Toughness during Material Development, Process Optimization and Quality Control of Structural Materials

Abstract:

Existing standard International methods to estimate fracture toughness of structural materials as documented in ASTM standard E-1820 are neither appropriate for material development due to the requirement of considerable volume nor suitable for process optimizations like deciding suitable heat treatment or for quality control of tonnage materials at the stage of production due to techno-economic reasons owing to their time-consuming nature. This report overviews several investigations often in their feasibility stage and aims to suggest a common solution to all these problems considering measurement of fracture toughness (K_IVM) using chevron notched bend bar specimens with either rectangular cross-section (RC) or circular cross-section (CC). At the outset the theoretical background for obtaining K_IVMRC and K_IVMCC and the corresponding normalized stress intensity factors are discussed in order to illustrate the relatively simpler principle of estimation of fracture toughness. The usefulness of this technique is next illustrated using a number of examples related to: (a) design of small specimens for fracture toughness determination using this principle (b) optimization of the volume fraction of the constituent phases in dual phase steels, (c) design of heat treatment for cast rolls, (d) optimization of cryotreatment for tool steels and (e) study of the effect of inclusions on toughness characteristics of microalloyed steels. The examples related to (a) is for demonstrating the capability of this technique for material development, that related to (b), (c) and (d) are to illustrate its potential for process optimization and the one related to (e) is to illustrate its potential for quality control of tonnage materials.

• Periodical: Materials Science Forum (Volume 736)
• Pages: 192-206
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.736.192
• Online since: December 2012
• Authors: Kalyan Kumar Ray
• Keywords: Chevron Notched Specimen, Cryotreatment, Dual Phase Steel, Fracture Toughness, Microalloyed Steel, Quality Control, Small Specimen, Tool Steel

References

[1] Annual Book of ASTM Standards, Standard test method for measurement of fracture toughness, E 1820-01, ASTM International, Philadelphia, USA, (2001).

[2] Annual Book of ASTM Standards, Standard test method for measurement of fracture toughness, E 399-03, ASTM International, Philadelphia, USA, (2001).

[3] Jr. J. C. Newman, A review of chevron notched fracture specimens,. In: Chevron Notched Specimens: Testing and Stress Analysis, ASTM STP 855 (Edited by J. H. Underwood, S.W. Friemann & F. I. Baratta), ASTM, Philadelphia, (1984), 5–31.

DOI: 10.1520/stp32719s

[4] L. M. Barker, A simplified method for measuring plane strain fracture toughness, Eng. Fract. Mech., 9, (1977), 361–369.

DOI: 10.1016/0013-7944(77)90028-5

[5] L. M. Barker, Theory for determining KIC from small, non-LEFM specimens, supported by experiments on aluminum, International Journal of Fracture, 15(06), (1979), 515-536.

DOI: 10.1007/bf00019921

[6] Annual Book of ASTM Standards, Standard test method for plane-strain (chevron-notch) fracture toughness of metallic materials, E1304-89, ASTM, Philadelphia, USA, 03. 01, (1993), 962–972.

DOI: 10.1520/e1304-97

[7] K. K. Ray, D. Chakraborty, and S. Ray, Toughness characterization of niobium-bearing HSLA steels, J. Mater. Sci., 29, (1994). 921–928.

DOI: 10.1007/bf00351410

[8] K. K. Ray and S. Ray, Accelerated fracture toughness testing for quality control of microalloyed steels, In: Fatigue and Fracture in Steel and Concrete Structure, Oxford and IBH, New Delhi, (1991), 317–332.

[9] Wu, S. -X., Fracture toughness determination of bearing steel using chevron-notch three point bend specimen, Eng . Fract. Mech., 19, (1984), 221–232.

DOI: 10.1016/0013-7944(84)90017-1

[10] L. M. Barker, F. I. Baratta, Comparison of fracture toughness measurements by short-rod and ASTM standard method of test for plane-strain fracture toughness of metallic materials,. J Test Eval JTEVA, 8(03), (1980), 97–102.

DOI: 10.1520/jte10604j

[11] K.K. Ray, and G.P. Poddar, Estimation of fracture toughness of steel using chevron notched round bar specimens, Fatigue Fract Engg Mater Struct, 27, (2003), 253–261.

DOI: 10.1111/j.1460-2695.2004.00753.x

[12] Wang, Qizhi, and Xian, Xuefu, A method for calculating stress intensity factors of chevron-notched three-point bend round bars, Int. J. Fract., 45(03), (1990), R37-R41.

DOI: 10.1007/bf00693352

[13] K.K. Ray, and D. Chakraborty, A comparative analysis of fracture toughness measurements by chevron notched specimens in three and four point bending, International Journal of Fracture, 57, (1992), R7-R11.

DOI: 10.1007/bf00013012

[14] Wu Shang-Xian, Compliance and Stress-Intensity factory of chevron-notched three-point bend specimens, In chevron-notched specimens: Testing and stress analysis, ASTM STP 855, J H Underwood, S W Freimann , And F I Baratta, Eds. American society for testing and materials, Philadelphia, (1984).

DOI: 10.1520/stp32729s

[15] O.E.K. Daoud, and D.J. Cartwright, Strain energy release rates for a straight-fronted edge crack in a circular bar subject to bending, Engng. Fract. Mech., 19, (1984), 701-707.

DOI: 10.1016/0013-7944(84)90102-4

[16] A. J. Bush, Experimentally determined stress-intensity factor for single-edge-crack round bar loaded in bending, Experimental Mechanics, 16, (1976), 249-257.

DOI: 10.1007/bf02321148

[17] J. l. Bluhm, Stability consideration in the generalized three dimensional 'work of fracture' specimen, Fracture, ICF4, University of Waterloo Press, Canada, 3, (1977), 409-417.

DOI: 10.1016/b978-0-08-022142-7.50064-8

[18] Shang-Xian, Wu, Stability and optimum geometry of chevron notched three point bend specimens, Int. J. Frac., 26, (1984), R43-R47.

DOI: 10.1007/bf01157552

[19] A.M. Calomino, L.J. Ghosn, Optimum notch configurations for the chevron-notched four-point bend specimen, Int. J. Frac., 72, (1995), 331-326.

DOI: 10.1007/bf00040370

[20] K. K. Ray, A. Veerababu, and R. Sarkar, Stability analysis and experimental verification for optimum notch configuration in chevron-notched round bar specimens, Fatigue Fract Engng Mater Struct, 27, (2003), 253–261.

DOI: 10.1111/j.1460-2695.2009.01357.x

[21] R. Sarkar, and K. K. Ray, Estimation of fracture toughness using miniature chevron-notched specimens, Fatigue Fract Engng Mater Struct, 31, (2008) 340–345.

DOI: 10.1111/j.1460-2695.2008.01237.x

[22] J. Toribio, F. J. Ayaso, Anisotropic fracture behaviour of cold drawn steel: a materials science approach, Mater. Sci. Eng., 343A, (2003), 265-272.

DOI: 10.1016/s0921-5093(02)00364-7

[23] H.A. Aglan, Z.Y. Liu, M.F. Hassan, M. Fateh, Mechanical and fracture behavior of bainitic rail steel, J. Mater. Proc. Tech., 151, (2004), 268-274.

DOI: 10.1016/j.jmatprotec.2004.04.073

[24] A. Bag, K.K. Ray, and E.S. Dawarkadasa, Influence of martensite content and morphology on tensile and impact properties of high-martensite dual-phase steels, Metall. And Mater. Trans. A, 30A, (1999), 1193.

DOI: 10.1007/s11661-999-0269-4

[25] American Society for Testing of Materials, Standard test methods for tension testing of metallic materials, E8M-00, ASTM International, Philadelphia, USA, (2003).

[26] A. Bag, K.K. Ray, and E.S. Dawarkadasa, Influence of martensite content and morphology on toughness and fatigue behavior of high-martensite dual-phase steels, Metall. And Mater. Trans. A, 32A, (2001), 2207.

DOI: 10.1007/s11661-001-0196-5

[27] S. Kang, and H. Kwon, Fracture behavior of intercritically treated complex structure in medium-carbon 6Ni steel, Metallurgical and Materials Transaction A, 18A(09), (1987), 1587-1592.

DOI: 10.1007/bf02646142

[28] K. Z. Ghar and W.G. Scholz, Fracture toughness of white cast irons, J. Met, 32, No. 10, (1980), 38-45.

[29] D. Das, R. Sarkar, A.K. Dutta, and K.K. Ray, Influence of sub-zero treatments on fracture toughness of AISI D2 steel, Materials Science and Engineering A, 528, (2010) , 589–603.

DOI: 10.1016/j.msea.2010.09.057

[30] D. Das and K. K. Ray, Structure–property correlation of sub-zero treated AISI D2 steel, Materials Science and Engineering A, 541, (2012), 45–60.

DOI: 10.1016/j.msea.2012.01.130

[31] G.T. Hahn, and A. R. Rosenfeild, Metallurgical factors affecting fracture toughness of aluminum alloys, Metallurgical and Materials Transaction A, 6A(03), (1975), 653.

DOI: 10.1007/bf02672285