Cleavage fracture of microalloyed forging steels

Linaza, M. A.; Romero, J. L.; Rodríguez-Ibabe, J.M.; Urcola, J. J.

doi:10.1016/s0956-716x(99)80071-5

Cited by 66 publications

(40 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It has been reported that, such particles can act as cleavage crack initiation points with a deleterious effect on impact energy. 9,35) As illustrated in Fig. 5, the engineering stress-strain curve, for specimen with 1 200°C reheating temperature and 0.3°C/s cooling rate, shows a sharp peak followed by a stress drop during necking accompanied with high postuniform strain.…”

Section: Mechanical Properties 421 Influence Of Reheating Temperatmentioning

confidence: 95%

Impact Toughness and Tensile Properties Improvement through Microstructure Control in Hot Forged Nb-V Microalloyed Steel

et al. 2005

View full text Add to dashboard Cite

The influence of thermomechanical processing parameters such as reheating temperature, deformation temperature, deformation percent and cooling rate on achieving high impact toughness properties was studied in a Nb-V microalloyed steel to be used as forged parts in automotive applications. 15 mm long and 65 mm diameter billets were forged using a 20 MN mechanical press. Tensile and Charpy impact tests specimens were machined out of the central part of the forged billets. The microstructure of the specimens was examined for each experimental condition using optical microscopy. Phase identification and distribution was studied using X-ray diffraction and orientation image microscopy techniques. The results indicate that, increasing the reheating temperature above the dissolution temperature of (Nb)(C, N) improved the impact energy values. By increasing the cooling rate from 0.3 to 3°C/s both tensile strength and impact toughness were improved. High elongation percent was also observed on samples reheated at higher temperature and/or cooled with the higher cooling rates. The obtained mechanical properties were related to the characteristics of microstructural components including acicular ferrite, retained austenite, pearlite and ferrite.The interrelationship between thermomechanical processing parameters, microstructure development, and final mechanical properties were identified and optimized forging conditions to obtain high impact energy (Ͼ30 J) microalloyed forge steels were determined.KEY WORDS: microalloy steel; mechanical properties; acicular ferrite; forging.The growth of ferrite plates results in carbon enrichment of the remaining austenite, which may remain untransformed or transform to martensite, bainite or interlath carbides. Upon the application of strain, the untransformed austenite is converted to martensite, which would increase strain hardening and residual compressive stresses bringing higher resistance to necking and crack arrest properties, respectively. 24) In the acicular ferrite microstructure, refining the ferrite lath size, eliminating pearlite, minimizing the development of interlath carbides, and control of the amount and distribution of retained austenite are critical for the achievement of optimum strength and toughness properties. 7,9,25) In the present article the influence of thermomechanical process parameters on the above mentioned microstructural characteristics particularly with regard to the formation of acicular ferrite and the resultant mechanical properties of a Nb-V microalloyed steel is investigated. The overall objective of the study was the development of a forging process to produce high strength-high toughness (tensile strength Ͼ850 Mpa, impact energy at room temperature Ͼ30 J) microalloyed forged automotive safety parts such as axles, hubs and steering parts. Material and Experimental ProceduresThe material used in this investigation was a Nb-V microalloyed steel produced in an electric arc furnace equipped with semi-automatic charging system and oxy-gas burners. Sec...

show abstract

Section: Mechanical Properties 421 Influence Of Reheating Temperatmentioning

confidence: 95%

Impact Toughness and Tensile Properties Improvement through Microstructure Control in Hot Forged Nb-V Microalloyed Steel

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Recently, this phenomenon has received great attention seeking for the improvement of the toughness in the steel, specially when conventional austenite grain refinement techniques are not enough. [7][8][9][10][11][12] Therefore, a thorough study dealing with the simultaneous transformation of austenite in allotriomorphic and/or idiomorphic ferrite is vital.…”

Section: Introductionmentioning

confidence: 99%

Relevant aspects of allotriomorphic and idiomorphic ferrite transformation kinetics

Capdevila¹,

Caballero²,

Andrés³

2003

Materials Science and Technology

View full text Add to dashboard Cite

Recently, the grain boundary−intragranular nucleation of ferrite has received great attention seeking for the improvement of the toughness in the steel, specially when conventional austenite grain refinement techniques are not enough. This paper deals with some relevant aspects about the competitive process of allotriomorphic and idiomorphic ferrite transformations in a medium carbon vanadium-titanium microalloyed steel for two different isothermal temperatures and different values of prior austenite grain sizes. It is concluded that the consideration of proeutectoid ferrite (allotriomorphic + idiomorphic) as a single transformation might lead to wrong conclusions in an analysis of the isothermal decomposition of austenite.

show abstract

“…Its main interest lies in the good combination of mechanical properties that presents as compared with bainite and above all with ferritic-perlitic microstructures. The major improvement is obtained in toughness, thanks to the fine interlocking microstructure characteristic of acicular ferrite which makes crack propagation difficult due to the presence of a great number of ferrite grain boundaries per unit length (7)(8)(9)(10)(11)(12).…”

Section: Introductionmentioning

confidence: 99%

Acicular ferrite formation in a medium carbon steel with a two stage continuous cooling

Madariaga¹,

Gutiérrez²,

Andrés

et al. 1999

Scripta Materialia

View full text Add to dashboard Cite

Cleavage fracture of microalloyed forging steels

Cited by 66 publications

References 9 publications

Impact Toughness and Tensile Properties Improvement through Microstructure Control in Hot Forged Nb-V Microalloyed Steel

Impact Toughness and Tensile Properties Improvement through Microstructure Control in Hot Forged Nb-V Microalloyed Steel

Relevant aspects of allotriomorphic and idiomorphic ferrite transformation kinetics

Acicular ferrite formation in a medium carbon steel with a two stage continuous cooling

Contact Info

Product

Resources

About