Effect of isothermal transformation temperature on the fine structure of steel 12Kh1MF

1976 ◽  
Vol 18 (1) ◽  
pp. 6-9
Author(s):  
I. I. Mints ◽  
T. G. Berezina ◽  
Z. I. Nenasheva ◽  
K. A. Lanskaya
Keyword(s):  
Fine Structure ◽  
Transformation Temperature ◽  
Isothermal Transformation ◽  
Steel 12Kh1mf

Effect of retained aluminum on the fine structure of steel 12Kh1MF

1979 ◽  
Vol 21 (12) ◽  
pp. 893-896
Author(s):  
K. A. Lanskaya ◽  
A. V. Smirnova ◽  
L. V. Kulikova ◽  
V. V. Yarovoi
Keyword(s):  
Fine Structure ◽  
Steel 12Kh1mf

scholarly journals Novel Approach of Nanostructured Bainitic Steels’ Production with Improved Toughness and Strength

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1220
Author(s):  
Peter Kirbiš ◽  
Ivan Anžel ◽  
Rebeka Rudolf ◽  
Mihael Brunčko
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fine Structure ◽  
Retained Austenite ◽  
Bainitic Ferrite ◽  
High Hardness ◽  
Tensile Tests ◽  
Isothermal Transformation ◽  
Impact Testing ◽  
Bainitic Steels

The tendencies of development within the field of engineering materials show a persistent trend towards the increase of strength and toughness. This pressure is particularly pronounced in the field of steels, since they compete with light alloys and composite materials in many applications. The improvement of steels’ mechanical properties is sought to be achieved with the formation of exceptionally fine microstructures ranging well into the nanoscale, which enable a substantial increase in strength without being detrimental to toughness. The preferred route by which such a structure can be produced is not by applying the external plastic deformation, but by controlling the phase transformation from austenite into ferrite at low temperatures. The formation of bainite in steels at temperatures lower than about 200 °C enables the obtainment of the bulk nanostructured materials purely by heat treatment. This offers the advantages of high productivity, as well as few constraints in regard to the shape and size of the workpiece when compared with other methods for the production of nanostructured metals. The development of novel bainitic steels was based on high Si or high Al alloys. These groups of steels distinguish a very fine microstructure, comprised predominantly of bainitic ferrite plates, and a small fraction of retained austenite, as well as carbides. The very fine structure, within which the thickness of individual bainitic ferrite plates can be as thin as 5 nm, is obtained purely by quenching and natural ageing, without the use of isothermal transformation, which is characteristic for most bainitic steels. By virtue of their fine structure and low retained austenite content, this group of steels can develop a very high hardness of up to 65 HRC, while retaining a considerable level of impact toughness. The mechanical properties were evaluated by hardness measurements, impact testing of notched and unnotched specimens, as well as compression and tensile tests. Additionally, the steels’ microstructures were characterised using light microscopy, field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM). The obtained results confirmed that the strong refinement of the microstructural elements in the steels results in a combination of extremely high strength and very good toughness.

β → β + α Isothermal Phase Transformation in Ti17 Titanium Alloy: Chemical Composition and Crystallographic Aspect

2011 ◽  
Vol 172-174 ◽  
pp. 396-401 ◽  
Author(s):  
Moukrane Dehmas ◽  
Julien Kovac ◽  
Benoît Appolaire ◽  
Elisabeth Aeby-Gautier ◽  
Benoit Denand ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Phase Transformation ◽  
Chemical Composition ◽  
Transformation Temperature ◽  
Isothermal Transformation ◽  
Alloying Elements ◽  
Crystallographic Aspect ◽  
Thermocalc Software

The partitioning of alloying elements between a and b phases was measured at different steps of the isothermal transformation at 710 and 610°C in Ti 17 alloy using EDX analyzer in the TEM. In addition, the transformation crystallography was determined. No differences in substitution elements were observed for a same transformation temperature in the a phase, however the composition varied with the transformation temperature. For the partial transformed specimens, gradient in composition were obtained. Results are compared to calculated compositions using ThermoCalc software and Saunders database.

Isothermal Bainite Transformation in Aluminium Bearing TRIP Steel

2013 ◽  
Vol 749 ◽  
pp. 237-242
Author(s):  
Peng Chen ◽  
Yun Bo Xu ◽  
Xiao Long Yang ◽  
Hong Liang Yi ◽  
Guo Dong Wang
Keyword(s):  
Radio Frequency ◽  
Induction Heating ◽  
Trip Steel ◽  
Transformation Temperature ◽  
Electron Probe ◽  
Annealing Temperature ◽  
Intercritical Annealing ◽  
Isothermal Transformation ◽  
Bainite Transformation ◽  
Intercritical Annealing Temperature

In this work, the bainite transformation during isothermality of aluminium bearing TRIP steel was studied by dilatometric experiment on a pushrod Formastor-F highspeed dilatometer with radio frequency induction heating. The aluminium bearing TRIP steel consisted of the microstructure of austenite, ferrite and bainite in the form of laths which produced by intercritical annealing and isothermal transformation followed by rapid cooling. The effect of intercritical annealing temperature and isothermal transformation temperature were studied by dilatometric experiment and JEOL JXA-8530F Electron Probe Microscopic Analyzer (EPMA).

scholarly journals The Impact of Retained Austenite on the Mechanical Properties of Bainitic and Dual Phase Steels

2022 ◽  
Author(s):  
Bogusława Adamczyk-Cieślak ◽  
Milena Koralnik ◽  
Roman Kuziak ◽  
Kamil Majchrowicz ◽  
Tomasz Zygmunt ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Transformation Temperature ◽  
Retained Austenite ◽  
Tensile Tests ◽  
Total Elongation ◽  
Isothermal Transformation ◽  
Bainitic Transformation ◽  
Bainitic Steel ◽  
Continuous Cooling

AbstractThis paper presents the microstructural changes and mechanical properties of carbide-free bainitic steel subjected to various heat treatment processes and compares these results with similarly treated ferritic–pearlitic steel. A key feature of the investigated steel, which is common among others described in the literature, is that the Si content in the developed steel was >1 wt.% to avoid carbide precipitation in the retained austenite during the bainitic transformation. The phase identification before and after various heat treatment conditions was carried out based on microstructural observations and x-ray diffraction. Hardness measurements and tensile tests were conducted to determine the mechanical properties of the investigated materials. In addition, following the tensile tests, the fracture surfaces of both types of steels were analyzed. Changing the bainitic transformation temperature generated distinct volume fractions of retained austenite and different values of mechanical strength properties. The mechanical properties of the examined steels were strongly influenced by the volume fractions and morphological features of the microstructural constituents. It is worth noting that the bainitic steel was characterized by a high ultimate tensile strength (1250 MPa) combined with a total elongation of 18% after austenitizing and continuous cooling. The chemical composition of the bainitic steel was designed to obtain the optimal microstructure and mechanical properties after hot deformation followed by natural cooling in still air. Extensive tests using isothermal transformation to bainite were conducted to understand the relationships between transformation temperature and the resulting microstructures, mechanical properties, and fracture characteristics. The isothermal transformation tests indicated that the optimal relationship between the sample strength and total elongation was obtained after bainitic treatment at 400 °C. However, it should be noted that the mechanical properties and total elongation of the bainitic steel after continuous cooling differed little from the condition after isothermal transformation at 400 °C.

The Optimization of the Isothermal Transformation Dwell of the ADI Obtained at Transformation Temperature of 380 °C

2007 ◽  
Vol 567-568 ◽  
pp. 337-340
Author(s):  
Klára Hanzlíková ◽  
Stanislav Vĕchet ◽  
Jan Kohout ◽  
Josef Zapletal
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Ductile Iron ◽  
Transformation Temperature ◽  
Isothermal Transformation ◽  
Mixture Composition ◽  
Austempered Ductile Iron ◽  
Treatment Conditions ◽  
Static Mechanical ◽  
Static Mechanical Properties

The structure of austempered ductile iron (ADI) matrix and consequently its mechanical properties are influenced by the heat treatment conditions, above all by the temperature and dwell length of isothermal transformation. The paper is focused on deeper understanding the interrelation between matrix mixture composition and static mechanical properties of ADI in dependence on the isothermal transformation dwell. Practical aim of the paper is to find the optimal isothermal transformation dwell range for ADI isothermally transformed at the temperature of 380 °C with emphasis on the level of static mechanical properties in tension. Microstructure and mechanical properties changes that proceed during isothermal transformation are observed and evaluated for the transformation dwells of 2, 5, 10, 25, 60, 120, 270, and 540 minutes.

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