scholarly journals Effect of Initial Microstructures on Austenite Formation Behavior during Intercritical Annealing in Low-Carbon Steel

2019 ◽  
Vol 68 (9) ◽  
pp. 718-722
Author(s):  
Hiroyuki DANNOSHITA ◽  
Toshio OGAWA ◽  
Kuniaki MARUOKA ◽  
Kohsaku USHIODA
Keyword(s):  
Carbon Steel ◽  
Intercritical Annealing ◽  
Low Carbon Steel ◽  
Austenite Formation ◽  
Low Carbon ◽  
Formation Behavior

Effect of Intercritical Annealing Temperature and Holding Time on Microstructure and Mechanical Properties of Dual Phase Low Carbon Steel

2014 ◽  
Vol 493 ◽  
pp. 721-726 ◽  
Author(s):  
Alfirano ◽  
Wibawa Samdan ◽  
Hidayat Maulud
Keyword(s):  
Carbon Steel ◽  
Annealing Temperature ◽  
Volume Fraction ◽  
Intercritical Annealing ◽  
Low Carbon Steel ◽  
Growth Rate Constant ◽  
Dual Phase ◽  
Initial Condition ◽  
Low Carbon ◽  
Intercritical Annealing Temperature

Dual phase steels are an important advanced high strength steel, which have been widely used in the automotive industry for vehicle components requiring light weight and safety. In this study, the formation of dual phase structure with various volume fraction of martensite in a low carbon steel SS400 during intercritical annealing were investigated. It was found that intercritical annealing temperature and holding time affected the microstructure and mechanical properties of dual phase low carbon steel. The specimens were heated at intercritical annealing temperature of 750°C, 775°C, 800°C and 825°C, for holding periods of 6-18 minutes, followed by water quenching in order to get a dual phase ferrite and martensite. After quenching, it was obtained the optimal annealing conditions at 800°C with a holding periods of 10 minutes. In this condition, the tensile strength was increased up to 621 N/mm2or 39.24% higher than the initial condition, while the elongation decreased up to 13.8%. The hardness of specimens increased from 127.7 to 235.83 HVN or up to 84.67% higher than the initial condition. Meanwhile the volume fraction of martensite was 24.08%. The higher the temperature of the heating value of grain growth rate constant (K) increases. In addition, at the optimal poin, the value ofK(grain growth rate constant) andn(Avramis exponent) were 0.263 and 0.318, respectively, with activation energy (Q) of 3.98 J/mol.

scholarly journals A study of isochronal austenitization kinetics in a low carbon steel

2014 ◽  
Vol 67 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Maximiano Maicon Batista Lopes ◽  
André Barros Cota
Keyword(s):  
Carbon Steel ◽  
Heating Rate ◽  
Low Carbon Steel ◽  
Carbon Diffusion ◽  
Austenite Formation ◽  
Low Carbon ◽  
Heating Rates ◽  
Initial Microstructure ◽  
Ferrite Structure ◽  
Kinetics Of

The austenite formation under isochronal conditions in Nb microalloyed low carbon steel was studied by means of dilatometric analysis and the data was adjusted to the Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation, for different heating rates and for three initial microstructures. It was shown that the kinetics of austenitization of a pearlite+ferrite structure is faster than that of martensite (tempered martensite) at a heating rate of 0.1ºC/s. For heating rates higher than 0.1ºC/s, the kinetics of austenitization of a martensite structure is faster than of pearlite+ferrite one. The K parameter of the JMAK equation increases with the heating rate for the three previous microstructures and it is greater for the initial microstructure composed of ferrite+pearlite. At lower heating rates, the formation of austenite in this steel is controlled by carbon diffusion, independently of the initial microstructure. At higher heating rates, the formation of austenite from an initial microstructure composed of pearlite and ferrite is controlled by interface-controlled transformation.

scholarly journals Spheroidization heat treatment and intercritical annealing of low carbon steel

2019 ◽  
Vol 55 (3) ◽  
pp. 405-411 ◽  
Author(s):  
Z. Nasiri ◽  
H. Mirzadeh
Keyword(s):  
Carbon Steel ◽  
Intercritical Annealing ◽  
Low Carbon Steel ◽  
Dual Phase ◽  
Low Carbon ◽  
Dp Steel ◽  
Martensitic Microstructure ◽  
Uniform Dispersion ◽  
Dp Steels ◽  
Carbide Particles

Spheroidization annealing of low carbon steel and its effects on the microstructure and mechanical properties of dual phase (DP) steel were studied. It was revealed that the reduction in strength and hardness of the quenched martensitic microstructure was much more pronounced compared to the fully annealed ferritic-pearlitic banded microstructure with spheroidizing time. This was related to the confinement of spheroidized carbide particles to distinct bands in the latter, and the uniform dispersion of carbides and high-temperature tempering of martensite in the former. During intercritical annealing of the spheroidized microstructures, the tendency to obtain martensite particles as discrete islands was observed. This, in turn, resulted in an inferior strength-ductility balance compared to the DP steel obtained from the intercritical annealing of martensite, which negated the usefulness of the spheroidized microstructures as the initial microstructures for the processing of DP steels.

Influence of intercritical annealing on the texture formation in low-carbon steel strips

1993 ◽  
Vol 64 (5) ◽  
pp. 262-266 ◽  
Author(s):  
Christian Klinkenberg ◽  
Dierk Raabe ◽  
Kurt Lücke
Keyword(s):  
Carbon Steel ◽  
Intercritical Annealing ◽  
Low Carbon Steel ◽  
Texture Formation ◽  
Low Carbon ◽  
Steel Strips
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