Effect of heat treatment and cleanness of ultra low carbon bainitic (ULCB) steel on its impact toughness.

• Autorzy: Lis A. K.
• Konferencja: XV Physical Metallurgy and Materials Science Conference on Advanced Materials & Technologies, AMT'98, Kraków-Krynica 17-21May 1998, Poland
• Języki publikacji: EN

Abstrakty

EN

The small variations in sulphur and carbon concentrations can have a major influence on the impact transition temperature (ITT) of ultra low carbon HSLA100 steel which has been quenched in water and tempered (WQ&T). Since the average carbon concentration is very low thus sensitivity of ITT to heat treatment parameters depends also on the yield strength increase due to precipitation effect of epsilon_Cu phase. The regression analysis has been used to establish equations taking into account those parameters. The properties of a mixed microstructure formed from partially austenitic regions have been also considered. The fine austenite grains transform into more desirable fine bainitic ferrite phases with lower hardness values and higher toughness. On the other hand, if cooling rate is sufficiently large, then the carbon enriched austenite transforms partially into hard martensite and some of the remaining untransformed austenite being retained to ambient temperature. Because hard martensite islands are located in much softer surroundings consisting of tempered ferrite, they do not cause a general reduction in impact toughness tests. Due to further grain refinement of microstructure the measured toughness on Charpy V specimens can be very high at low temperatures. The very detrimental effect of sulphur in ULCB steel has been confirmed by presented results.

Słowa kluczowe

EN

heat treatment; bainitic steel; low carbon steel; toughness; microstructure

PL

obróbka cieplna; stal bainityczna; stal niskowęglowa; wiązkość; mikrostruktura

• Wydawca: Wydawnictwo SIGMA-NOT
• Czasopismo: Inżynieria Materiałowa
• Rocznik: 1998
• Tom: R. XIX, nr 3
• Strony: 191--195
• Opis fizyczny: Bibliogr. 8 poz., rys.

Twórcy

autor

Lis A. K.

• Institute of Materials Engineering, Technical University of Częstochowa, Poland

• Technical University of Częstochowa, Institute of Materials Engineering

Bibliografia

• [1] MIL-S-24371B & (SH), Military Specification, Steel Plate, Structural, High Yield Strength (HY-130), August 2, (1989).
• [2] MIL-S-24645A(SH), Military Specification, Steel Plate, Sheet, or Coil, Age-Hardening Alloy, Structural, High Yield Strength (HSLA-80 and HSLA-100) Steels, January (1990).
• [3] R. P. Foley, M. E. Fine, Microstructure and property investigation of quenched and tempered HSLA-100 steel, Proc. Int. Conf. on Processing, Microstructure and Properties of Microalloyed and Other Modern High Strength Low Alloy Steels, Pittsburgh, 1991, (ed.)
• [4] M. Blicharski, Wpływ węgla i siarki na własności mechaniczne wysokowytrzymałej stali o dużej udarności utwardzanej miedzią [in] (ed.) A. Dobrzański, Proc. 14th Int. Scient. Conf. „Advanced Materials & Technologies”, „Polish Presentations” volume, Gliwice-Zakopane, (1995) 5-8.
• [5] A. G. Wilson, E. G. Hamburg, D. J. Colvin, W. S. Thompson, G. Krauss, Properties and Microstructures of Copper Precipitation Aged Plate Steels, Conf. Proc. „Microalloyed HSLA Steels”, World Materials Congress, ASM International, (1988) 259-275.
• [6] C.I.Garcia, A. K. Lis, A. J. DeArdo, Ultra Low Carbon Bainitic Plate Steels: Processing, Microstructure and Properties, Proc. 31st Conf.,,Mechanical Working and Steel Processing”, Chicago, 1989, Vol.XXVII, Publ. The Iron & Steel Society of AIME, Warrendale, US. (1990) 505-516.
• [7] A.K. Lis, J. Lis, L. Jeziorski, Journal of Materials Processing Technology, ELSEVIER, vol.64, No. 1-3, (1997) 255-266.
• [8] A.K. Lis, Mechanical properties and microstructure of ULCB steels affected by thermomechanical rolling, quenching and tempering, Proc. Int. Conf. „Challenges to Civil and Mechanical Engineering in 2000 and Beyond”, Wrocław, vol. III, (1997) 185-194