Surface Microstructure and Texture Evolution during Interrupted Annealing in Ultra Low Carbon Steels

2010 ◽  
Vol 89-91 ◽  
pp. 202-207
Author(s):  
J. Gautam ◽  
Roumen H. Petrov ◽  
Leo Kestens ◽  
Elke Leunis
Keyword(s):  
Phase Transformation ◽  
Surface Texture ◽  
Texture Evolution ◽  
Low Carbon Steel ◽  
Carbon Steels ◽  
Control Surface ◽  
Surface Microstructure ◽  
Low Carbon ◽  
Metal Vapour ◽  
Low Carbon Steels

The austenite-to-ferrite phase transformation, which is an inherent feature of low-alloyed ultra low carbon steels, has scarcely been investigated to control surface texture and microstructure evolution. This paper investigates the systematic evolution of texture and microstructure at the metal-vapour interface during interrupted annealing in vacuum. Interrupted annealing experiments were carried out on three ultra low carbon steel sheets alloyed with Mn, Al and Si. The texture and microstructures have been investigated by X-ray diffraction and SEM-EBSD techniques. These results reveal a very clear variation in the surface texture components as well as in the surface microstructure after BCC recrystallisation and double  transformation interrupted annealing. The recrystallisation texture consists mainly of a <111>//ND fibre, while the transformation texture at the surface exhibits a <100>// ND fibre in combination with components of the <110> //ND fibre. It has been revealed that the latter specific surface texture was present in a monolayer of outer surface grains which were in direct contact with the vapour atmosphere. This observed phenomenon could be explained by considering the role of surface energy anisotropy occurring during phase transformation annealing.

Surface Microstructure Evolution during Phase Transformation on Mn, Al and Si Alloyed Ultra Low Carbon Steel

2010 ◽  
Vol 297-301 ◽  
pp. 757-763
Author(s):  
Jai Gautam ◽  
Roumen H. Petrov ◽  
Elke Leunis ◽  
Leo Kestens
Keyword(s):  
Phase Transformation ◽  
Carbon Steel ◽  
Surface Texture ◽  
Texture Evolution ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Metal Vapour ◽  
Industrial Composition ◽  
Steel Sheets ◽  
Ultra Low Carbon Steel

This paper investigates the surface texture evolution after a short phase transformation annealing in low vacuum on ultra low carbon steel sheets alloyed with high Mn and Al and the cold rolled steel sheets of industrial composition alloyed with silicon. The ultra low carbon steel sheets with high Mn and Al show surface monolayer which has a characteristic surface texture components <100>//ND texture and microstructure with special grain morphology. Contrastingly, the industrial composition alloyed with silicon does not show specific surface texture components inspired by surface energy anisotropy at the surface. The composition depth profiling investigations performed on the all steel sheet surface shows that oxidation characteristics of alloying elements at the metal vapour interface have played a decisive influence on surface texture evolution. Further, transformation annealing in higher vacuum reveals that surface texture can be obtained in an industrial composition alloyed with silicon.

Nucleation and Growth of Surface Texture during α-γ-α Transformation in Ultra Low Carbon Steel Alloyed with Mn, Al and Si

2010 ◽  
Vol 160 ◽  
pp. 223-228 ◽  
Author(s):  
Jai Gautam ◽  
Roumen H. Petrov ◽  
Elke Leunis ◽  
Leo Kestens
Keyword(s):  
Surface Texture ◽  
Driving Forces ◽  
Texture Evolution ◽  
Low Carbon Steel ◽  
Nucleation And Growth ◽  
Carbon Steels ◽  
Low Carbon ◽  
Metal Vapour ◽  
Orientation Gradient ◽  
Orientation Contrast

. It is well known that surface energy anisotropy is one of the driving forces for the orientation selection at the metal-vapour interface. This affects the microstructure and texture evolution at the surface during phase transformation, which is an inherent feature of low-alloyed low-carbon steels. This paper investigates the nucleation and growth of the surface texture by orientation contrast microscopy. It has been found that the surface texture is dominated by {001} oriented grains, which exhibit a remarkable orientation gradient from the centre of the grain towards the edge. The {001} oriented grain centre gradually rotates around a <110> axis in small incre¬mental steps when nearing the edge of the grain. Towards the edge the accumulated rotation angle has commonly reached a value of 30°. Underneath the surface grains (~30 µm) the bulk texture consists of a strong -fibre.

Surface Texture Evolution during α-γ-α Transformation in Mn and Al Alloyed Ultra-Low Carbon Steel

2007 ◽  
Vol 550 ◽  
pp. 503-508 ◽  
Author(s):  
Jai Gautam ◽  
Roumen H. Petrov ◽  
Leo Kestens
Keyword(s):  
Carbon Steel ◽  
Surface Texture ◽  
Surface Effect ◽  
Alternative Hypothesis ◽  
Texture Evolution ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Metal Vapour ◽  
Ultra Low Carbon Steel ◽  
Cold Rolled

This paper investigates the surface texture evolution during α−γ−α phase transformation. After austenite annealing of the cold rolled sheets a weak texture was formed at the surface of ultra low carbon steel alloyed with Mn and Al. This texture consists of <100>//ND and <110>//ND fiber orientations with an intensity of approximately 2 X random. This surface texture is confined to a mono-layer of surface grains which are in direct contact with the metal/vapour interface. In order to interpret this surface effect, two alternative mechanisms were considered: (i) one assumption attributes the occurrence of the specific surface texture to the minimization of the outer surface energy and (ii) according to an alternative hypothesis the release of elastic work parallel to ND in the surface area is responsible for the observed surface fibers. After analyzing the experimental data it is concluded that the evidence in support of hypothesis (i) is the more convincing in this experiment.

Effect of Soaking Time on Paste Carburizing of Carburized Low Carbon Steel

2017 ◽  
Vol 740 ◽  
pp. 93-99
Author(s):  
Muhammad Hafizuddin Jumadin ◽  
Bulan Abdullah ◽  
Muhammad Hussain Ismail ◽  
Siti Khadijah Alias ◽  
Samsiah Ahmad
Keyword(s):  
Carbon Steel ◽  
Carbon Content ◽  
Low Carbon Steel ◽  
Case Depth ◽  
Carbon Steels ◽  
Low Carbon ◽  
Soaking Time ◽  
Low Carbon Steels ◽  
Carburized Steel ◽  
Carburizing Process

Increase of soaking time contributed to the effectiveness of case depth formation, hardness properties and carbon content of carburized steel. This paper investigates the effect of different soaking time (7-9 hours) using powder and paste compound to the carburized steel. Low carbon steels were carburized using powder and paste compound for 7, 8 and 9 hours at temperature 1000°C. The transformation of microstructure and formation carbon rich layer was observed under microscope. The microhardness profiles were analyzed to investigate the length of case depth produced after the carburizing process. The increment of carbon content was considered to find the correlation between types of carburizing compound with time. Results shows that the longer carburized steel was soaked, the higher potential in formation of carbon rich layer, case depth and carbon content, which led to better hardness properties for carburized low carbon steel. Longer soaking time, 9 hours has a higher dispersion of carbon up to 41%-51% compare to 8 hours and 7 hours. By using paste carburizing, it has more potential of carbon atom to merge the microstructure to transform into cementite (1.53 wt% C) compare to powder (0.97 wt% C), which increases the hardness of carburized steel (13% higher).

Predicting the Effects of Cold Working on the Machining Characteristics of Low Carbon Steels

1987 ◽  
Vol 109 (3) ◽  
pp. 257-264 ◽  
Author(s):  
E. M. Kopalinsky ◽  
P. L. B. Oxley
Keyword(s):  
Flow Stress ◽  
Carbon Steel ◽  
Cutting Forces ◽  
Cold Working ◽  
Low Carbon Steel ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Steel Work ◽  
Machining Characteristics

Experiments show that the cold working of low carbon steel work materials can improve their machinability by reducing cutting forces and improving surface finish and tool life. The somewhat paradoxical result of reducing cutting forces by cold working a material so that its hardness is increased is explained in this paper by using a machining theory which takes account of the flow stress properties of the work material and can thus allow for the effects of cold working.

High Temperature Corrosion of Al Hot-Dipped Low Carbon Steels in N2/H2S-Mixed Gases

2016 ◽  
Vol 369 ◽  
pp. 59-64
Author(s):  
Muhammad Ali Abro ◽  
Dong Bok Lee
Keyword(s):  
High Temperature ◽  
Carbon Steel ◽  
Low Carbon Steel ◽  
Alloy Layer ◽  
High Temperature Corrosion ◽  
Carbon Steels ◽  
Low Carbon ◽  
Mixed Gas ◽  
Low Carbon Steels ◽  
Mixed Gases

A low carbon steel was hot-dip aluminized, and corroded in the N2/0.4%H2S-mixed gas at 650-850°C for 20-50 h in order to find the effect of aluminizing on the high-temperature corrosion of the low carbon steel in the H2S environment. A thin Al topcoat and a thick Al-Fe alloy layer that consisted primarily of Al5Fe2 and some FeAl and Al3Fe formed on the surface after aluminizing. The corrosion rate increased with an increase in temperature. Hot-dip aluminizing increased the corrosion resistance of the carbon steel through forming a thin protective α-Al2O3 scale on the surface. The α-Al2O3 scale was susceptible to spallation. During corrosion, internal voids formed in the Al-Fe alloy layer, where the Al5Fe2, AlFe, and Al3Fe compounds gradually transformed through interdiffusion.

scholarly journals Optimization of Niobium Content in Direct Quenched High-Strength Steels

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 807
Author(s):  
Jaakko Hannula ◽  
David Porter ◽  
Antti Kaijalainen ◽  
Mahesh Somani ◽  
Jukka Kömi
Keyword(s):  
Phase Transformation ◽  
High Strength Steels ◽  
Significant Loss ◽  
Carbon Steels ◽  
Optimum Level ◽  
Low Carbon ◽  
Niobium Content ◽  
Low Carbon Steels ◽  
Finish Rolling ◽  
Different Levels

This paper focuses on understanding the effect of niobium content on the phase transformation behavior and resultant mechanical properties of thermomechanically rolled and direct-quenched low carbon steels containing 0.08 wt.% carbon. Investigated steels contained three different levels of niobium: 0, 0.02 and 0.05 wt.%. The continuous cooling transformation (CCT) diagrams covering cooling rates in the range 3–96 °C/s constructed based on the dilatometer studies showed only a minor effects of Nb on the phase transformation characteristics. In addition, experiments were performed for reheating and soaking the slabs at 1050–1200 °C and the results revealed that for these low-carbon steels, Nb failed to prevent the austenite grain growth during slab reheating. In the case of hot rolling trials, two different finish rolling temperatures of 820 °C and 920 °C were used to obtain different levels of pancaking in the austenite prior to direct quenching. The resultant microstructures were essentially mixtures of autotempered martensite and lower bainite imparting yield strengths in the range 940–1070 MPa. The lower finish rolling temperature enabled better combinations of strength and toughness in all the cases, predominantly due to a higher degree of pancaking in the austenite. The optimum level of Nb in the steel was ascertained to be 0.02 wt.%, which resulted not only in marginally higher strength but also without any significant loss of impact toughness.

Oriented Nucleation and Selective Growth during Secondary Recrystallization in Ultra Low Carbon Steels

2004 ◽  
Vol 467-470 ◽  
pp. 941-948 ◽  
Author(s):  
Kim Verbeken ◽  
Leo Kestens
Keyword(s):  
Grain Growth ◽  
Texture Evolution ◽  
Secondary Recrystallization ◽  
Low Carbon Steel ◽  
Primary Recrystallization ◽  
Carbon Steels ◽  
Abnormal Grain Growth ◽  
Selective Growth ◽  
Low Carbon ◽  
Ultra Low Carbon Steel

After primary recrystallization, on further annealing, abnormal grain growth occurred in ultra low carbon steel. Texture evolution was studied by comparing the orientations after complete secondary recrystallization, with on one hand the nuclei for abnormal grain growth and on the other hand the selective growth products of the primary recrystallized matrix. The influence of both mechanisms could be identified in the final texture.

Texture Evolution in Si-Alloyed Ultra Low-Carbon Steels after Severe Plastic Deformation

2010 ◽  
Vol 12 (10) ◽  
pp. 1077-1081 ◽  
Author(s):  
P. Gobernado ◽  
R. Petrov ◽  
D. Ruiz ◽  
E. Leunis ◽  
Leo A. I. Kestens
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Texture Evolution ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels
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