scholarly journals Stability of retained austenite in martensitic high carbon steels. Part I: Thermal stability

2018 ◽  
Vol 711 ◽  
pp. 683-695 ◽  
Author(s):  
Wen Cui ◽  
David San-Martín ◽  
Pedro E.J. Rivera-Díaz-del-Castillo
Keyword(s):  
Thermal Stability ◽  
Retained Austenite ◽  
Carbon Steels ◽  
High Carbon

Investigation of Lath and Plate Martensite in a Carbon Steel

2011 ◽  
Vol 172-174 ◽  
pp. 61-66 ◽  
Author(s):  
Albin Stormvinter ◽  
Annika Borgenstam ◽  
Peter Hedström
Keyword(s):  
Carbon Steel ◽  
Carbon Content ◽  
Morphological Change ◽  
Retained Austenite ◽  
Alloy Composition ◽  
Lath Martensite ◽  
Carbon Steels ◽  
Plate Martensite ◽  
High Carbon ◽  
Martensite Microstructure

Martensite in carbon steels forms in different morphologies, often referred to as lath andplate martensite. The alloy composition has a strong effect on the morphology, for instance in car-bon steels there is a morphological change of the martensite microstructure from lath martensite atlow carbon contents to plate martensite at high carbon contents. In the present work a decarburizedhigh-carbon steel, enabling the isolation of carbons' influence alone, has been studied in order to in-vestigate the changes in morphology and hardness. From the results it is concluded that there is acontinuous change of hardness with increased carbon content. The increasing hardness slows down atabout 0.6 wt%C before decreasing at higher carbon contents. This is in accordance with the change inmorphology since it was found that lath martensite dominates below 0.6 wt%C and the first units ofgrain boundary martensite and plate martensite appear above 0.6 wt%C. At high carbon contents thedominating morphology is plate martensite, but retained austenite is also present.

Effect of Partitioning of Quenching-Partitioning-Tempering Process on Microstructures and Hardness in High Carbon Steels

2012 ◽  
Vol 538-541 ◽  
pp. 1053-1056
Author(s):  
Yang Zheng Zeng ◽  
Kai Ming Wu ◽  
Feng Hu ◽  
Hua Zheng
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Retained Austenite ◽  
Carbon Steels ◽  
High Carbon ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Scanning Electron

The effect of partitioning process of quenching-partitioning-tempering (Q-P-T) process on hardness and microstructure were investigated. The 1-step Q-P-T and 2-step Q-P-T heat treatment were designed and carried out. The microstructure and carbides were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) patterns. Results showed that compared with 1-step Q-P-T heat treatment, more amount of retained austenite was obtained by 2-step Q-P-T heat treatment, however, the carbides were bigger in size and the hardness was lower.

Laser Surface Treatment of Aerospace Steels

1981 ◽  
Vol 8 ◽  
Author(s):  
G. Christodoulou ◽  
P. Henry ◽  
W.M. Steen ◽  
D.R.F. West
Keyword(s):  
Heat Transfer ◽  
Laser Power ◽  
Retained Austenite ◽  
Three Dimensional ◽  
Carbon Steels ◽  
Laser Surface ◽  
Transfer Model ◽  
High Carbon ◽  
Laser Surface Treatment ◽  
Alloy Steels

ABSTRACTAn investigation is reported of the laser surface melting of four alloy steels with carbon contents ranging up to 1 wt%. Studies were made of the profiles, microstructures and hardnesses of zones produced using a laser power of 1.7 kW and a range of traverse speeds and beam diameters. The observed zone profiles were correlated with calculations from a three-dimensional, moving source, heat transfer model. In the high carbon steels, the shallow laser melted zones contained substantial amounts of retained austenite.

Effect of Fast Prototyping Means on the Fatigue Strength of High Carbon Steels

2013 ◽  
Vol 302 ◽  
pp. 241-247
Author(s):  
Rinaldo Puff ◽  
Renato Barbieri
Keyword(s):  
Fatigue Strength ◽  
Shot Peening ◽  
Retained Austenite ◽  
Fatigue Tests ◽  
Carbon Steels ◽  
Work Piece ◽  
High Carbon ◽  
Fast Prototyping ◽  
Cutting Processes ◽  
Finishing Processes

The objective of this article is to present the effect of fast prototyping means on the fatigue strength of SAE 1075 steel used for planar springs, which are commonly used in different type of machines. Two cutting processes are used for rapid prototyping those components. The first one, with CO2 laser cutting machines and the second, using Electrical Discharge Machines – EDM. It was also evaluated the effect of applying three levels of finishing processes on the work pieces: tumbling, polishing and shot peening. Fatigue tests were performed using a machine specially developed for this purpose, applying fluctuating loads. An analytic formulation and also the use of Finite Element Method – FEM – were applied in order to obtain the stresses present in the work piece during the load application. The characteristics of the work pieces´ surface, mainly at the cutting edge were analyzed, and so was the microstructure of them near the cutting region. It was found that, mainly in the pieces cut by laser, there is a Thermally Affected Zone – TAZ – composed by bainite with retained austenite, which affects the fatigue strength of the material. It was also found that finishing processes improve the fatigue strength of the material by removing defects introduced by the cutting means, and the application of shot peening introduces the better final characteristics.

scholarly journals Stability of retained austenite in martensitic high carbon steels. Part II: Mechanical stability

2018 ◽  
Vol 711 ◽  
pp. 696-703 ◽  
Author(s):  
Wen Cui ◽  
Marius Gintalas ◽  
Pedro E.J. Rivera-Diaz-del-Castillo
Keyword(s):  
Retained Austenite ◽  
Mechanical Stability ◽  
Carbon Steels ◽  
High Carbon

Precipitation at the transformation interface of pearlite in steel

1990 ◽  
Vol 48 (4) ◽  
pp. 912-913
Author(s):  
F. A. Khalid ◽  
D. V. Edmonds
Keyword(s):  
Thin Foil ◽  
Carbon Steels ◽  
Model Alloy ◽  
Low Carbon ◽  
High Carbon ◽  
Growth Interface ◽  
Medium Carbon ◽  
Interphase Precipitation ◽  
Solution Treated ◽  
Wide Range

The austenite/pearlite growth interface in a model alloy steel (Fe-1lMn-0.8C-0.5V nominal wt%) is being studied in an attempt to characterise the morphology and mechanism of VC precipitation at the growth interface. In this alloy pearlite nodules can be grown isothermally in austenite that remains stable at room temperature thus facilitating examination of the transformation interfaces. This study presents preliminary results of thin foil TEM of the precipitation of VC at the austenite/ferrite interface, which reaction, termed interphase precipitation, occurs in a number of low- carbon HSLA and microalloyed medium- and high- carbon steels. Some observations of interphase precipitation in microalloyed low- and medium- carbon commercial steels are also reported for comparison as this reaction can be responsible for a significant increase in strength in a wide range of commercial steels.The experimental alloy was made as 50 g argon arc melts using high purity materials and homogenised. Samples were solution treated at 1300 °C for 1 hr and WQ. Specimens were then solutionised at 1300 °C for 15 min. and isothermally transformed at 620 °C for 10-18hrs. and WQ. Specimens of microalloyed commercial steels were studied in either as-rolled or as- forged conditions. Detailed procedures of thin foil preparation for TEM are given elsewhere.

scholarly journals Mechanical and thermal stability of retained austenite in plastically deformed bainite-based TRIP-aided medium-Mn steels

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Aleksandra Kozłowska ◽  
Adam Grajcar ◽  
Aleksandra Janik ◽  
Krzysztof Radwański ◽  
Ulrich Krupp ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Stability ◽  
Retained Austenite ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Stability ◽  
Electron Backscatter Diffraction ◽  
Cost Effective ◽  
Tensile Tests ◽  
Thermal Stability Of

AbstractAdvanced medium-Mn sheet steels show an opportunity for the development of cost-effective and light-weight automotive parts with improved safety and optimized environmental performance. These steels utilize the strain-induced martensitic transformation of metastable retained austenite to improve the strength–ductility balance. The improvement of mechanical performance is related to the tailored thermal and mechanical stabilities of retained austenite. The mechanical stability of retained austenite was estimated in static tensile tests over a wide temperature range from 20 °C to 200 °C. The thermal stability of retained austenite during heating at elevated temperatures was assessed by means of dilatometry. The phase composition and microstructure evolution were investigated by means of scanning electron microscopy, electron backscatter diffraction, X-ray diffraction and transmission electron microscopy techniques. It was shown that the retained austenite stability shows a pronounced temperature dependence and is also stimulated by the manganese addition in a 3–5% range.

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