Abstract
Usually bainitic microstructures exhibit good toughness and austempering is typically the preferred heat treatment when toughness is the primary requirement of the component. Several reports have shown such characteristics when compared to tempered martensite. High-carbon steel may exhibit brittle characteristics but it is a good steel with respect to mechanical properties and wear resistance. The objective of this study was to compare the impact properties of AISI O1, a high-carbon tool steel, designated VND in Brazil. This was done by comparing Charpy impact strength under different heat-treatment cycles. Steel test specimens were quenched from 820°C and tempered at 450°C to obtain tempered martensite, then austenitized, cooled, and held at 350°C to obtain bainite by holding at temperature for 20, 40, and 60 min. Because hardness influences impact behavior, comparative studies were performed at the same surface hardness level. The austempered samples with bainite microstructures obtained at a constant temperature and, by varying holding times, exhibited lower impact properties as compared to the quenched and tempered condition.
Issue Section:
Research Papers
References
1.
Barreiro
, J. A.
, Steels Heat Treatment
, 8th ed., Editorial Dossat S. A.
, Madrid, Spain
, 1985
(in Spanish).2.
Canale
, L. C. F.
, Nucci
, J. E.
, Albano
, L. M.
, Vatavuk
, J.
, and Totten
, G.
, “Comparative Behavior of O1 A Steel Under Quenching and Tempering and Austempering
,” Paper No. 141, European Conference on Heat Treatment 2015 and 22nd IFHTSE Congress
, Venice, Italy, May 20–22, Associazione Italiana Metallurgia, Milano, Italy, 2015
.3.
Brooks
, C. R.
, Principles of the Heat Treatment of Plain Carbon and Low Alloy Steel
, ASM International
, Materials Park, OH
, 1996
.4.
Kong
, D.
, Liu
, Q.
, and Yuan
, L.
, “Effect of Austenitizing Temperature on Formation of Hard Bainite
,” Metal Sci. Heat Treat.
, Vol. 56
, Nos. 7–8
, 2014, pp. 445
–448
(in Russian).5.
Reddy
, A. C.
, “Effects of Holding Temperature and Time for Austempering on Impact Toughness of Medium Carbon and High Carbon Alloy Steel
,” Int. J. Comput. Netw. Secur.
, Vol. 3
, No. 1
, 2010
, pp. 8
–11
.6.
Kaleicheva
, J. A.
, “Structure and Properties of High-Speed Steels After Austempering
,” Int. J. Microstruct. Mater. Prop.
, Vol. 2
, No. 1
, 2007
, pp. 16
–23
.7.
Chen
, C.
, Hung
, F.
, Lui
, T.
, and Chen
, L.
, “Microstructures and Mechanical Properties of Austempering Cr-Mo (SCM 435) Alloy Steel
,” Mater. Trans.
, Vol. 54
, No. 1
, 2013
, pp. 56
–60
. https://doi.org/10.2320/matertrans.M20123178.
Kilicli
, V.
and Kaplan
, M.
, “Effect of Austempering Temperatures on Microstructure and Mechanical Properties of a Bearing Steel
,” Scripta Mater.
, Vol. 59
, No. 2
, 2008
, pp. 131
–264
.9.
Chakraborty
, J.
, Bhattacharjee
, D.
, and Manna
, I.
, “Austempering of Bearing Steel Improved Mechanical Properties
,” Scripta Mater.
, Vol. 59
, No. 2
, 2008
, pp. 247
–250
. https://doi.org/10.1016/j.scriptamat.2008.03.02310.
Krishna
, P. V.
, Srikant
, R. R.
, Iqbal
, M.
, and Sriram
, N.
, “Effect of Austempering and Martempering on the Properties of AISI 52100 Steel
,” ISRN Tribol.
, Vol. 2013
, 2013
https://doi.org/10.5402/2013/515484.11.
Vatavuk
, J.
, Borrô
, A.
, Campos
, C. S.
, Monteiro
, W. A.
, and Pala
, P.
, “Austenitizing Temperature Effect on the AISI 5160 Tempered Embrittlement Phenomena
,” Revista Mackenzie de Engenharia e Computação
, Vol. 1
, No. 1
, 2000
, pp. 127
–138
(in Portuguese).12.
Santos
, D. F.
, Goldenstein
, H.
, and Vatavuk
, J.
, “The Modified Martempering and Its Effect on the Impact Toughness of a Cold Work Tool Steel
,” Paper No. 2011–36-0325, SAE Congress
, São Paulo, Brasil, October 4–6, 2011
.13.
Aksu
, E.
, “The Effect of Austenitizing Parameters on Impact and Fracture Toughness of DIN 35NiCrMoV12.5 Gun Barrel Steel
,” M.S. thesis, Middle East Technical University
, Ankara, Turkey, 2005
, 84 pp.14.
Bowen
, P.
, Druce
, S. G.
, and Knott
, J. F.
, “Effects of Microstructure on Cleavage Fracture in Pressure Vessel Steel
,” Acta Metall.
, Vol 34
, No. 6
, 1986
, pp. 1121
–1131
.15.
Tu
, M.-Y.
, Hsu
, C.-A.
, Wang
, W.-H.
, and Hsu
, Y.-F.
, “Comparison of Microstructure and Mechanical Behavior of Lower Bainite and Tempered Martensite in JIS SK5 Steel
,” Mater. Chem. Phys.
, Vol. 107
, Nos. 2–3
, 2008
, pp. 418
–425
.16.
Liu
, C. D.
and Kao
, P. W.
, “Tensile Properties of a 0.34C-3Ni-Cr-Mo-V Steel With Mixed Lower-Bainite-Martensite Structures
,” Mater. Sci. Eng.: A
, Vol. 510
, No. 2
, 1992
, pp. 171
–177
.17.
Sanvik
, B. P. J.
and Nevalainen
, H. P.
, “Structure–Property Relationships in Commercial Low-Alloy Bainitic-Austenitic Steel With High Strength, Ductility, and Toughness
,” Metals Technol.
, Vol. 8
, No. 1
, 1981
, pp. 213
–220
. https://doi.org/10.1179/03071698180327599218.
ASTM E23-12c,
Standard Test Methods for Notched Bar Impact Testing of Metallic Materials
, ASTM International
, West Conshohocken, PA
, 2012
, www.astm.org19.
“
Isothermal Transformation Diagram for O1 Tool Steel, Austenization Temperature 1490°F (810°C)
,” http://www.navaching.com/forge/forge.gifs/O1.jpg (Last accessed Nov 2015
).20.
http://www.metalravne.com/steelselector/steels_cct/ow4.html (Last accessed on Jan
2016
).21.
ASTM E18-15,
Standard Methods for Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials
, ASTM International
, West Conshohocken, PA
, 2015
, www.astm.org22.
Zepter
, P. G.
, “Microstructure Effect on the ABNT 5160 Steel Response in Monotonic and Cyclic Loading
,” M.Sc. dissertation, IPEN - USP
, São Paulo, Brazil, 2007
(in Portuguese).
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