TEMPERATURE EFFECT ON MICROSTRUCTURAL ANALYSIS OF STEEL DURING HEAT TREATMENT

Author(s):  
SAMUEL BRITO ◽  
RODOLFO SOBRAL ◽  
Luiz Carlos Sacramento ◽  
Marcos Paulo de Souza Junior
2020 ◽  
Vol 70 (12) ◽  
pp. 4519-4524

The efficiency of time-temperature treatment (T-TT) on metal melts can be microstructurally analysed through their degree of purity in non-metallic inclusions. In the case of the Ni-based super alloy under discussion (MSRR 7045) the heat treatment was the undercooling consequences both on the durability of the casting environment (ingots-refractories) and on the internal structure of the metal (porosity, microstructural isotropy). Keywords: time-temperature treatment, undercooled melt, non-metallic inclusions, purity, microstructural isotropy


1983 ◽  
Vol 48 (2) ◽  
pp. 421-438 ◽  
Author(s):  
Milan Pospíšil ◽  
Jiří Spěváček ◽  
Jindřich Kryška

Hydrated iron(III) oxides were obtained by discontinuous precipitation of an iron(II) sulfate solution with aqueous ammonium - saturated with carbon dioxide to different CO2/NH3 ratios. An additional thermal treatment of these oxides, under different conditions, provided genetic sequences of intermediates and their final products - catalysts on a Fe2O3/K2O basis, with different promoters. The catalysts were studied by means of the microstructural; analysis, thermogravimetry, DTA, IR spectroscopy and further tested by the dehydrogenation of ethylbenzene to styrene. It was observed that by changing the CO2/NH3 ratio in the precipitation of the initial solutions one can influence some of the properties, as well as, the morphology and thermal stability of the initial intermediates of the preparation of the catalysts. The above mentioned properties become practically unified with the increasing number of the heat treatment operations, with all the investigated catalysts - with the exception of the catalysts' behaviour during their reduction with hydrogen. The presence of iron oxides in various valency states and the different phase composition of the catalysts during their reduction affect the final activity and selectivity of the catalyst in the reaction under the study.


Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 185
Author(s):  
Felix Clemens Ewald ◽  
Florian Brenne ◽  
Tobias Gustmann ◽  
Malte Vollmer ◽  
Philipp Krooß ◽  
...  

In order to overcome constraints related to crack formation during additive processing (laser powder bed fusion, L-BPF) of Fe-Mn-Al-Ni, the potential of high-temperature L-PBF processing was investigated in the present study. The effect of the process parameters on crack formation, grain structure, and phase distribution in the as-built condition, as well as in the course of cyclic heat treatment was examined by microstructural analysis. Optimized processing parameters were applied to fabricate cylindrical samples featuring a crack-free and columnar grained microstructure. In the course of cyclic heat treatment, abnormal grain growth (AGG) sets in, eventually promoting the evolution of a bamboo like microstructure. Testing under tensile load revealed a well-defined stress plateau and reversible strains of up to 4%.


2008 ◽  
Vol 591-593 ◽  
pp. 611-615
Author(s):  
Adriana Scoton Antonio Chinelatto ◽  
Milena K. Manosso ◽  
Elíria Maria Jesus Agnolon Pallone ◽  
Adilson Luiz Chinelatto

The control of the heating curve to manipulate microstructure during sintering is a way that has being studied and it presents advantages such as simplicity and economy. In this work, it was studied the sintering in two-steps of a commercial ultrafine alumina. For this, the alumina power was deagglomerated in milling ball and the specimens for sintering were pressed. Sintering was performed in a dilatometer, with constant heating rate of 15°C/min up to 1500°C. By these results, heat treatment temperatures for two-step sintering were defined. The sintering specimens were characterized through the apparent density measures using Archimedes method, the grain size measures using image analysis program and microstructural analysis using a scanning electron microscope. The results showed that the two-step sintering influence in the development of the final microstructure and permit the control of the grain size and density.


2013 ◽  
Vol 28 (5) ◽  
pp. 862-867
Author(s):  
Wenyan Zhang ◽  
Chunhua Lu ◽  
Yaru Ni ◽  
Jianbin Song ◽  
Wenjuan Huang ◽  
...  

Jurnal METTEK ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 23
Author(s):  
I Ketut Suarsana ◽  
IGN Nitya Santhiarsa ◽  
DNK Putra Negara

Perlakuan panas adalah pemanasan yang diikuti dengan penahanan dan pendinginan menggunakan media quenching. Pengerasan adalah pemanasan logam hingga suhu austenit, tahan pada suhu tersebut untuk sementara waktu dan kemudian didinginkan pada media pendinginan seperti air, minyak, udara, air garam. Untuk mengatasi perubahan sifat mekanik, perlu diberikan proses perlakuan panas. Hal ini perlu dilakukan untuk menghilangkan stress internal dan mencegah terjadinya retak atau cacat. Sifat mekanis ketangguhan adalah kemampuan material untuk menyerap energi sesaat sebelum terjadi fraktur pada struktur itu. Penelitian ini membahas tentang prediksi ketangguhan properti mekanik dengan memberikan pemanasan pada temperatur 800, 850 dan 9000C dan masing-masing specimen  diquenching dengan : air tawar, air laut dan minyak. Hasil penelitian menunjukkan bahwa terjadi peningkatan sifat ketangguhan dari efek temperatur dan media pendinginan yang digunakan. Data menunjukan pada 8000C dengan media quenching minyak nilai ketangguhan adalah 33,833 kg/cm2, serta suhu 9000C dengan quenching media air nilai ketangguhan adalah 40,8747 kg/cm2). Jadi semakin meningkat temperature perlakuan,  berpengaruh terhadap sifat ketangguhan impak bahan. Heat treatment is carried out by heating followed by anchoring and using quenching medium as cooling. Hardening is metal heating to austenite temperature, hold it at a temporary temperature and then cooled to cooling media such as water, oil, air, brine. To overcome the change of mechanical properties, need to be given process of heat treatment. This is to remove internal stress and prevent the occurrence of cracks or defects. The mechanical properties of toughness are the ability of the material to absorb energy without fracturing the structure. This study discusses the prediction of toughness of mechanical properties by heating at temperatures of 800, 850 and 9000C and each specimen quenching with: freshwater, seawater and oil. The results showed that there was an increase in the toughness properties of the temperature effect and the cooling medium used. The data show on 8000C with medium quenching oil the toughness value is 33.833 kg/cm2, and the temperature of 9000C with quenching medium water toughness value is 40.8747 kg/cm2). So the increasing of treatment temperature has influence to the material toughness


Author(s):  
Sergey F. Golovashchenko ◽  
Al Krause ◽  
Alan J. Gillard

Insufficient formability can be a major issue in the manufacturing of complex parts, particularly in aluminum alloys that have less formability when compared to steel. The approach which is the subject of this work is to determine the technical feasibility of partial forming, followed by a fast heat treatment and then further deformation. Alloys for consideration would include both 5xxx and 6xxx alloys typically used on interior and exterior automotive panels. The heat treatment regimes used for 6xxx alloys did not affect the material structure, which was confirmed by microstructural analysis and comparison of mechanical properties before and after the heat treatment. Experiments on 5xxx alloys indicated relative improvement of 300% or more. Regimes of material deformation and heat treatment will be presented.


2009 ◽  
Vol 423 ◽  
pp. 105-112 ◽  
Author(s):  
I. Torca ◽  
A. Aginagalde ◽  
J.A. Esnaola ◽  
L. Galdos ◽  
Zigor Azpilgain ◽  
...  

Aluminium alloys are more and more important for the automotive industry due to their high strength to weight ratio and their elevated ductility; they are used for many different parts in automobiles as exterior panels, structural parts, brake housings and others. However, their formability at room temperature is limited. This inconvenient can be improved by increasing the forming temperature of the part. That lack of formability has lead to this research project dealing with the tensile behaviour of aluminium alloys sheets, at different conditions of temperature and strain rate. The analyzed material has been 6082 aluminium alloy, under two different heat treatment conditions (O and T6). Material testing has been carried out in a temperature range between room temperature and 250°C, and a strain rate range between 0.001s-1 and 0.1s-1. Testing samples have been obtained from laminated sheet of 1.5mm thickness. This article shows that the alloy under T6 condition has a reduced formability, even in warm conditions. In order to get higher deformation values an annealed condition is proposed to form the material. The effect of T6 heat treatment and O annealing treatment in the uniaxial warm formability is discussed and a microstructural analysis is also presented in order to understand the differences on the alloy behaviour.


2021 ◽  
Vol 16 (1) ◽  
pp. 19-24
Author(s):  
Michal Krbaťa ◽  
◽  
Róbert Cíger ◽  

The article is a continuation of the article ,DILATOMETRIC ANALYSIS OF COOLING CURVES FOR HIGH STRENGTH STEEL X153CrMoV12”, which deals with the phase transformations of tool steel X153CrMoV12. The experimental data obtained was used to evaluate the resulting CCT diagram, which consists of seven dilation curves. All experimental samples from dilatometric analyses were then subjected to microstructural analysis and hardness measurements to characterize the microstructure and hardness for each heat treatment mode tested. AFM microscopy was also used to study the carbides present in steels and their size and shape for all selected cooling modes.


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