Nucleation of Bainite on Allotriomorphic Ferrite/Austenite Interface in a Low Carbon Steel

2010 ◽  
Vol 654-656 ◽  
pp. 2326-2329 ◽  
Author(s):  
Hui Guo ◽  
Yin Bai ◽  
Shan Wu Yang ◽  
Xin Lai He
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Type I ◽  
Type Ii ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Type Iii ◽  
Forming Temperature ◽  
Allotriomorphic Ferrite

. A low carbon steel is austenitized and isothermally held at 680°C to form allotriomorphic ferrite and followed by a holding at lower temperature to form bainite. The morphology of allotriomorphic ferrite/bainite interfaces is studied using optical microscope. Three kinds of combination are observed: Type I: interface on one side is clear while on the other side, unclear; Type II: unclear on both sides; Type III: clear on both sides. Clear interface indicates a large difference in the orientation between the bainite and the ferrite, and unclear interface, a very small difference. The statistical counting shows that the ratio of Type I is about 80-82%, and that of Type II, 7-8%, and Type III, 9-11%. It is observed that this ratio does not change with the austenite grain size and bainite forming temperature. And the clear and unclear side of allotriomorphic ferrite may have different influence on the nucleation rate of bainite at allotriomorhic ferrite/prior austenite interface.

Corrosion Behavior of Al-Si-Cr-Cu Bearing Low Carbon Steel in A Cyclic Dry/Wet Laboratory Test

2009 ◽  
Vol 79-82 ◽  
pp. 1017-1020 ◽  
Author(s):  
Hui Shu Zhang ◽  
Dong Ping Zhan ◽  
Song Lian Bai ◽  
Zhou Hua Jiang
Keyword(s):  
Carbon Steel ◽  
Electrochemical Impedance ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Low Carbon ◽  
Rust Layer ◽  
Electrochemical Behaviors ◽  
Corrosion Rates ◽  
The Matrix ◽  
Corrosion Behaviors

The corrosion behaviors of Al-Si-Cr-Cu bearing low carbon steel and a reference steel Q235 were tested in a cyclic dry/wet environment containing 0.01mol/L NaHSO3 in laboratory. Rust layers were observed by optical microscope (OM), scanning electron microscopy (SEM) and XRD. The electrochemical behaviors of the steels were studied on the polarization curves and electrochemical impedance spectroscopy (EIS). The results indicate that after 120h corrosion test, the annual corrosion rates of the designed steels reduce 42 % than Q235 at least. The corrosion products are generally iron oxyhydroxides and oxides such as FeOOH, γ-FeOOH, α-FeOOH, γ-Fe2O3, Fe3O4. The α-FeOOH possesses good stabilization mainly exits and can improve the corrosion resistance. There are the enrichments of Cu, Cr, Si and Al in the rust layer close to the matrix, which make the rust layer be more compact and protected. The corrosion currents of the two designed steels are lower than that of Q235, the corrosion potentials are higher than that of Q235 after Tafel fitting. The rust layer impedances of the designed steels are higher than that of Q235.

Effect of Ti, Al and Mg Addition on the Impact Toughness of Heat Affected Zone in Low Carbon Steel

2009 ◽  
Vol 79-82 ◽  
pp. 143-146
Author(s):  
Jiang Hua Ma ◽  
Dong Ping Zhan ◽  
Zhou Hua Jiang ◽  
Ji Cheng He
Keyword(s):  
Carbon Steel ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Low Carbon ◽  
Welding Simulation ◽  
Mg Addition ◽  
The Impact

In order to understand the effects of deoxidizer such as aluminium, titanium and magnesium on the impact toughness of heat affected zone (HAZ), three low carbon steels deoxidized by Ti-Al, Mg and Ti-Mg were obtained. After smelting, forging, rolling and welding simulation, the effects of Al, Ti and Mg addition on the impact toughness of HAZ in low carbon steel were studied. The inclusion characteristics (size, morphology and chemistry) of samples before welding and the fracture pattern of the specimens after the Charpy-type test were respectively analyzed using optical microscope and scanning electron microscopy (SEM). The following results were found. The density of inclusion in Ti-Mg deoxidized steel is bigger than Ti-Al deoxidized steel. The average diameter is decreased for the former than the latter. The addition of Ti-Mg can enhance the impact toughness of the HAZ after welding simulation. The maximal value of the impact toughness is 66.5J/cm2. The complex particles of MgO-TiOx-SiO2-MnS are most benefit to enhance impact toughness. The improvement of HAZ is attributable to the role of particle pinning and the formation of intergranular ferrite.

Study of Low Carbon Steel on Microstructe of Slag Film

2011 ◽  
Vol 284-286 ◽  
pp. 1253-1257 ◽  
Author(s):  
Xiu Li Han ◽  
Chang Cun Li ◽  
Li Na Liu ◽  
Run Ming Feng
Keyword(s):  
Carbon Steel ◽  
Glass Phase ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Mineral Component ◽  
Low Carbon ◽  
Slag Film ◽  
Main Structure ◽  
Mould Powder ◽  
Mineralogical Phases

Researched on the low carbon steel by mineral component ore phase structure of mould powder and its slag film under optical microscope. The result shows that the glass phase, quartz, and pyroxene in the mould powder helped to the slag film turn into glass. The melilite and wollastonite in the mould powder can promote the formation of melilite, and wollastonite can promote the formation of cuspidine in the slag film. The structure of the slag film is even and the main structure is glass phrase, the rate of crystallization is low, the crystallized mineralogical phases was melilite, the cuspidine did not appeared, which is good for lubrication. The content of glass phase, quartz and pyroxene in the mould powder of the low carbon steel should be increased, the content of wollastonite and fluorite should be reduced.

Austenite Grain Size Refinement of Multi-Microalloyed Low Carbon Steel Using Severe Plastic Deformation at High Temperature

2016 ◽  
Vol 838-839 ◽  
pp. 440-444
Author(s):  
Xiang Wei Kong ◽  
Tian Zhong Sui ◽  
Zhi Yong Hu
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Hot Deformation ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Size Refinement ◽  
Austenite Grain

The effect of hot deformation behavior on austenite grain size refinement of low carbon multi-microalloyed steel was investigated. The morphology of austenite grains was revealed by thermal etching and observed using optical microscope. The results showed that single pass compression can only marginally refine austenite grain size by dynamic recrystallization, even under severe plastic deformation. However, when the specimens were held for a while after hot deformation, the fine austenite grain size can be obtained due to static recrystallization behavior.

Influence of Austenite Grain Size on the Crystallography of Allotriomorphic Ferrite in a Low Carbon Steel

2012 ◽  
Vol 535-537 ◽  
pp. 605-610 ◽  
Author(s):  
Yin Bai ◽  
Hui Guo ◽  
Shan Wu Yang ◽  
Xin Lai He
Keyword(s):  
Grain Size ◽  
Prior Austenite ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
Allotriomorphic Ferrite ◽  
Austenite Grains ◽  
Prior Austenite Grain Size ◽  
Prior Austenite Grain

The influence of prior austenite grain size on the crystallography of allotriomorphic ferrite is investigated in a low carbon steel. The results show that as the prior austenite grain size decreasing, the fraction of allotriomorphic ferrites that do not keep K-S orientation relationship with any surrounding prior austenite grains is increased. It is observed that such ferrites usually form at the grain edges or grain corners. It is known that with the grain size decreasing, the fraction of grain edges and corners increases. It is suggested that the free energy of the defects at such nucleation sites is higher than that at grain faces, and the nucleation barrier of ferrite is lower. As a result, the possibility for the ferrite to form that does not have orientation relationship with all surrounding austenite grains is increased at such sites.

Effect of Ti and Zr Deoxidation on Inclusions and Microstructure of Low Carbon Steel

2010 ◽  
Vol 146-147 ◽  
pp. 1434-1439
Author(s):  
Zhou Hua Jiang ◽  
Jiang Hua Ma ◽  
Dong Ping Zhan ◽  
Ji Cheng He ◽  
Jin Yu
Keyword(s):  
Carbon Steel ◽  
Linear Relationship ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Equivalent Diameter ◽  
Total Density ◽  
Low Carbon ◽  
Steel Microstructure ◽  
Zr Addition ◽  
Ti Content

In order to investigate the effects of Ti, Zr deoxidants on inclusions and microstructure of low carbon steel, the experiments by Ti and Zr addition were carried out. After smelting, forging, and rolling of the steel, the effects of Ti and Zr deoxidation on inclusions and steel microstructure were studied. The inclusion characteristics (size, quantity, morphology and composition) of samples were analyzed using optical microscope and scanning electron microscopy (SEM), and the grain size and density were measured. The following results were found. The diameter of most inclusions is less than 3 μm. A linear relationship exists between inclusions density and Ti content when Ti content ranges from 0.004% to 0.032%. With the increasing of the Ti content in steel, the proportion of inclusions diameter less than 0.5 μm decreases. The inclusions distribution changes a little when Ti content ranges from 0.01% to 0.03%. The typical inclusions are TiN and TiN-MxOy, with oxide core and MnS wrapper layer, and the components change with Ti content. The average grain equivalent diameter ranges from 11.8 to 15.9 μm in the experiments. The consistent linear relationship exists between grain density and the total density of the inclusions with the diameter range from 0.5 to 3 μm.

scholarly journals PENGARUH MEDIA QUENCHING TERHADAP KEKERASAN DAN STRUKTUR MIKRO PASKA HARDFACING

2018 ◽  
Vol 3 (2) ◽  
pp. 66-72
Author(s):  
Basori Basori
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Treatment Process ◽  
Low Carbon Steel ◽  
Optical Microscope ◽  
Heat Treatment Process ◽  
Low Carbon ◽  
Water Media

AbstrakHardfacing dengan proses SMAW merupakan salah satu teknik yang paling banyak digunakan, karena sangat mudah diaplikasikan seperti pada scoops lift buckets , Ripper Teeth, dan Dozer Blades.. Hardfacing pada komponen ini bertujuan untuk mencegah keausanan yang diakibatkan benturan atau gesekan saat penggalian tanah, pengumpulan tanah, pengangkutan tanah pada saat alat berat sedang bekerja. Setelah baja karbon rendah di hardfacing, kemudian dilakukan perlakuan panas dengan Quenching dengan tujuan lebih meningkatkan kekerasan dari material. Pembuatan spesimen dilakukan dengan teknik SMAW polaritas AC arus 100A menggunakan elektroda HV 450 kemudian spesimen di potong, di lakukan proses heat treatment. Setelah selesai kemudian speseimen di uji keras dan dilakukan pengamatan dengan mikroskop optik. Media air merupakan media yang paling optimal dalam menigkatkan kekerasan dari hasil hardfacing. Nilai kekerasan yang didapatkan dari hasil quenching dengan media air adalah sebesar 422.66 VHNKata kunci: Hardfacing, SMAW, Struktur Mikro dan Kekerasan AbstractHardfacing with the SMAW process is one of the most common techniques, because it is very easy to apply as in lift buckets Scoops, Ripper Teeth, and Dozer Blades. Hardfacing in this component for the situation caused by collisions or friction during excavation of land, transporting the soil when the machine is working. After low carbon steel hardfacing, then heat is done with quenching in order to increase the hardness of the material. The making of specimens was carried out using the SMAW technique using HV 450 electrodes and then the specimens were cut, and the heat treatment process was carried out. After completion, the experiment was carried out and an observation with an optical microscope was carried out. Water media is the most optimal media in increasing the hardness of hardfacing results. The value obtained from the quenching with water media is 422.66 VHN Keywords: Hardfacing, SMAW, Microstructure and Hardness

Sign in / Sign up

Export Citation Format

Share Document