scholarly journals Precipitation Versus Partitioning Kinetics during the Quenching of Low-Carbon Martensitic Steels

Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 850
Author(s):  
Shashank Ramesh Babu ◽  
Matias Jaskari ◽  
Antti Jarvenpää ◽  
Thomas Paul Davis ◽  
Jukka Kömi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Satisfactory Agreement ◽  
Ferrite Matrix ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Martensitic Steels ◽  
Cooling Rates ◽  
Theoretical Predictions ◽  
Alloy Steels ◽  
Carbide Precipitate

Low-carbon, low-alloy steels undergo auto-tempering and carbon partitioning to austenite during quenching to martensite. The microstructures of two such steels quenched at two cooling rates have been evaluated using electron microscopy to characterise lath and carbide precipitate morphologies, and the results have been compared with theoretical predictions based on the Thermo-Calc modules DICTRA and TC-Prisma. The modelling tools predicted the carbon depletion rates due to diffusion from the bcc martensite laths into austenite and the precipitation of cementite in the ferrite matrix. The predictions showed a satisfactory agreement with the metallographic results, indicating that the Thermo-Calc based software can aid in the design of new low-carbon martensitic steels.

scholarly journals Comparative Study of the Tempering Behavior of Different Martensitic Steels by Means of In-Situ Diffractometry and Dilatometry

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5058
Author(s):  
Martin Hunkel ◽  
Juan Dong ◽  
Jeremy Epp ◽  
Daniel Kaiser ◽  
Stefan Dietrich ◽  
...  
Keyword(s):  
Comparative Study ◽  
Length Change ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Martensitic Steels ◽  
High Alloy ◽  
Microstructural Effects ◽  
Alloy Steels ◽  
The Individual

Martensitic steels are tempered to increase the toughness of the metastable martensite, which is brittle in the as-quenched state, and to achieve a more stable microstructure. During the tempering of steels, several particular overlapping effects can arise. Classical dilatometric investigations can only detect effects by monitoring the integral length change of the sample. Additional in-situ diffractometry allowed a differentiation of the individual effects such as transformation of retained austenite and formation of cementite during tempering. Additionally, the lattice parameters of martensite and therefrom the tetragonality was analyzed. Two low-alloy steels with carbon contents of 0.4 and 1.0 wt.% and a high-alloy 5Cr-1Mo-steel with 0.4 wt.% carbon were investigated by dilatometry and in-situ diffractometry. In this paper, microstructural effects during tempering of the investigated steels are discussed by a comparative study of dilatometric and diffractometric experiments. The influence of the chemical composition on the tempering behavior is illustrated by comparing the determined effects of the three steels. The kinetics of tempering is similar for the low-alloy steels and shifted to much higher temperatures for the high-alloy steel. During tempering, the tetragonality of martensite in the steel with 1.0 wt% carbon shifts towards a low carbon behavior, as in the steels with 0.4 wt.% carbon.

Recent Aspects on the Effect of Inclusion Characteristics on the Intragranular Ferrite Formation in Low Alloy Steels: A Review

2017 ◽  
Vol 36 (4) ◽  
pp. 309-325 ◽  
Author(s):  
Wangzhong Mu ◽  
Pär Göran Jönsson ◽  
Keiji Nakajima
Keyword(s):  
Heat Affected Zone ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Intragranular Ferrite ◽  
Metallic Inclusions ◽  
Theoretical Investigations ◽  
Alloy Steels ◽  
Institute Of Technology ◽  
Future Work

AbstractIntragranular ferrite (IGF), which nucleates from specific inclusion surfaces in low alloy steels, is the desired microstructure to improve mechanical properties of steel such as the toughness. This microstructure is especially important in the coarse grain heat affected zone (CGHAZ) of weldments. The latest review paper focusing on the role of non-metallic inclusions in the IGF formation in steels has been reported by Sarma et al. in 2009 (ISIJ int., 49(2009), 1063–1074). In recent years, large amount of papers have been presented to investigate different issues of this topic. This paper mainly highlights the frontiers of experimental and theoretical investigations on the effects of inclusion characteristics, such as the composition, size distribution and number density, on the IGF formation in low carbon low-alloyed steels, undertaken by the group of Applied Process Metallurgy, KTH Royal Institute of Technology. Related results reported in previous studies are also introduced. Also, plausible future work regarding various items of IGF formation is mentioned in each section. This work aims to give a better control of improving the steel quality during casting and in the heat affected zone (HAZ) of weldment, according to the concept of oxide metallurgy.

Mechanism of corrosion cracking in low-carbon and low-alloy steels in an alkaline medium

1976 ◽  
Vol 11 (1) ◽  
pp. 15-17
Author(s):  
O. N. Chaplya ◽  
N. I. Isaev ◽  
P. S. Osadtsiv
Keyword(s):  
Alkaline Medium ◽  
Corrosion Cracking ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Alloy Steels

Behavior of Titanium Nitride Nanosized Particles in Molten Pool upon Welding of Low-Carbon Low-Alloy Steels

2017 ◽  
Vol 12 (9-10) ◽  
pp. 534-538
Author(s):  
M. V. Grigor’ev ◽  
A. A. Linnik ◽  
N. V. Kobernik ◽  
R. S. Mikheev ◽  
A. S. Pankratov ◽  
...  
Keyword(s):  
Titanium Nitride ◽  
Molten Pool ◽  
Low Alloy Steels ◽  
Nanosized Particles ◽  
Low Carbon ◽  
Alloy Steels

Technologies of Nanomodification of Low-Carbon Low Alloyed Steels

2010 ◽  
Vol 638-642 ◽  
pp. 3123-3127
Author(s):  
V.A. Malyshevsky ◽  
E.I. Khlusova ◽  
V.V. Orlov
Keyword(s):  
Large Scale ◽  
Physical And Mechanical Properties ◽  
Metallurgical Industry ◽  
Low Alloy Steels ◽  
Scale Production ◽  
Low Carbon ◽  
Fine Grained ◽  
Interphase Boundaries ◽  
Alloy Steels ◽  
High Level

Metallurgical industry can be considered as a field most accommodated for perception of nano-technologies, which in the near future will be able to provide large scale production and high level of investments return. Specially noted should physical and mechanical properties of nano-structured steels and alloys (strength, plasticity, toughness and so on) which will cardinally excel characteristics of respective materials developed using conventional technologies. Investigations have shown that basic principles of selection of a structure up to nano-level for low-carbon low-alloy steels can be put forward, that is: 1) morphological similarity of structural components, pre-domination of globular type structures due to reduction in carbon components and rational alloying; 2) formation of fine-dispersed carbide phase of globular morphology; 3) exclusion of lengthy interphase boundaries; 4) formation of fragmented structure with boundaries close to wide-angle ones, which inherited structure of fine-grained deformed austenite.

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