Effects of Al, Si and N Content on the Formation of M-A Constituent and HAZ Toughness of Ti-Containing Low-Carbon Steel

2021 ◽  
Vol 1016 ◽  
pp. 42-49
Author(s):  
Kook Soo Bang ◽  
Joo Hyeon Cha ◽  
Kyu Tae Han ◽  
Hong Chul Jeong
Keyword(s):  
Carbon Steel ◽  
Impact Toughness ◽  
Low Carbon Steel ◽  
Charpy Impact ◽  
Coarse Grained ◽  
Low Carbon ◽  
N Content ◽  
Si Content ◽  
The Impact ◽  
Haz Toughness

The present work investigated the effects of Al, Si, and N content on the impact toughness of the coarse-grained heat-affected zone (CGHAZ) of Ti-containing low-carbon steel. Simulated CGHAZ of differing Al, Si, and N contents were prepared, and Charpy impact toughness was determined. The results were interpreted in terms of microstructure, especially martensite-austenite (M-A) constituent. All elements accelerated ferrite transformation in CGHAZ but at the same time increased the amount of M-A constituent, thereby deteriorating CGHAZ toughness. It is believed that Al, Si, and free N that is uncombined with Ti retard the decomposition of austenite into pearlite and increase the carbon content in the last transforming austenite, thus increasing the amount of M-A constituent. Regardless of the amount of ferrite in CGHAZ, its toughness decreased linearly with an increase of M-A constituent in this experiment, indicating that HAZ toughness is predominantly affected by the presence of M-A constituent. When a comparison of the effectiveness is made between Al and Si, it showed that a decrease in Si content is more effective in reducing M-A constituents.

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.

Developing High Strength-High Toughness Low Carbon Steel Using Combined V-Ti-Micro-Alloying and Different Thermo-Mechanical Treatments

2018 ◽  
Vol 786 ◽  
pp. 57-64 ◽  
Author(s):  
Ahmed Hamed ◽  
Mamdouh Eissa ◽  
Abdelhakim Kandil ◽  
Omnia Ali ◽  
Taha M. Mattar
Keyword(s):  
Tensile Strength ◽  
Carbon Steel ◽  
Impact Toughness ◽  
Low Carbon Steel ◽  
Chemical Compositions ◽  
Air Cooling ◽  
Low Carbon ◽  
Steel Alloys ◽  
Grain Sizes ◽  
The Impact

This work aims at designing and developing low carbon steel alloys to meet the high tensile strength, high ductility and high impact toughness properties. The effect of solid solution mechanism, precipitation hardening, as well as grain refinement were developed with different Manganese content (0.78-2.36wt%) combined with Vanadium(0.008-0.1wt%) and Titanium (0.002-0.072wt%) microalloying additions. The controlled thermo-mechanical treatments and chemical compositions play a big role in developing the microstructure and the corresponding mechanical properties. Therefore, the studied chemical compositions were treated thermo-mechanically by two different ways of changing start and finish forging temperatures with subsequent air cooling. The first way by start forging from 1050 to 830oC and the second from 950 to730oC. The second way of forging process developed finer grain sizes and higher ultimate tensile strengths for all the studied steel alloys. In spite of finer grain sizes, the impact toughness value was lower in the second regime due to detrimental influence of precipitation strengthening in the ferrite. A combination of 544 MPa yield strength, 615 MPa ultimate tensile strength, 20% elongation and 138 Joule impact toughness has been attained.

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

2010 ◽  
Vol 146-147 ◽  
pp. 1486-1490
Author(s):  
Jiang Hua Ma ◽  
Dong Ping Zhan ◽  
Zhou Hua Jiang ◽  
Ji Cheng He ◽  
Jin Yu
Keyword(s):  
Carbon Steel ◽  
Impact Toughness ◽  
Heat Affected Zone ◽  
Low Carbon Steel ◽  
Carbon Steels ◽  
Low Carbon ◽  
Welding Simulation ◽  
Type Test ◽  
Titanium Zirconium ◽  
The Impact

In order to understand the effects of deoxidizer such as titanium, zirconium and magnesium on the impact toughness of heat affected zone (HAZ) of steel, four low carbon steels deoxidized by titanium, zirconium and magnesium were obtained. After smelting, forging, rolling and welding simulation, the effects of Ti, Zr and Mg additives on the impact toughness of HAZ in low carbon steel were studied. The inclusion characteristics (size, morphology and chemistry) analysis, Charpy-type test and the fracture observation of the specimens after the Charpy-type test were carried out respectively. The following results were found. The density of inclusion in Ti-Zr-Mg deoxidized steel is maximal. With the increasing of Ti content in steel, the proportion of inclusions in diameter less than 0.5 μm decreases. The proportion reaches maximum 64.0% in Ti-Zr-Mg deoxidized steel. The addition of Ti-Zr-Mg can enhance the impact toughness of HAZ after welding simulation. The maximal impacting energy is 249J at 253K. The complex particles of MgO-ZrO2-TiOx-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.

Retained Austenite Control and Extra-Cryogenic Impact Toughness of Fe-3.0%Mn Low Carbon Steel

2020 ◽  
Vol 993 ◽  
pp. 520-525
Author(s):  
Xiang Tao Deng ◽  
Xiao Lin Li ◽  
Long Huang ◽  
Zhao Dong Wang
Keyword(s):  
Heat Treatment ◽  
Carbon Steel ◽  
Low Temperature ◽  
Impact Toughness ◽  
Retained Austenite ◽  
Uniform Elongation ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Low Temperature Impact Toughness ◽  
The Impact

The control of the retained austenite in Fe-3.0%Mn Low carbon steel by a three-step intercritical heat treatment and the low-temperature impact toughness evolution during the process were analyzed in the present study. The results indicated that the microstructure consisted intercritical ferrite, martensite/bainite and retained austenite. The distribution of carbon and manganese could improve the stability of the austenite located at the grain boundaries of prior austenite and lath boundaries of martensite. For the TRIP effect of the austenite, the excellent plasticity and low temperature toughness was obtained. The impact toughness could reach 200 J (impact energy) at －80 °C during the three-step heat treatment, and the uniform elongation could exceed at 16%.

scholarly journals Effect of Carbon Partitioning, Carbide Precipitation, and Grain Size on Brittle Fracture of Ultra-High-Strength, Low-Carbon Steel after Welding by a Quenching and Partitioning Process

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 747 ◽  
Author(s):  
Farnoosh Forouzan ◽  
M. Guitar ◽  
Esa Vuorinen ◽  
Frank Mücklich
Keyword(s):  
Grain Size ◽  
Carbon Steel ◽  
Weld Zone ◽  
Low Carbon Steel ◽  
High Strength ◽  
Precipitate Size ◽  
Low Carbon ◽  
Quenching And Partitioning ◽  
High Level ◽  
The Impact

To improve the weld zone properties of Advanced High Strength Steel (AHSS), quenching and partitioning (Q&P) has been used immediately after laser welding of a low-carbon steel. However, the mechanical properties can be affected for several reasons: (i) The carbon content and amount of retained austenite, bainite, and fresh martensite; (ii) Precipitate size and distribution; (iii) Grain size. In this work, carbon movements during the partitioning stage and prediction of Ti (C, N), and MoC precipitation at different partitioning temperatures have been simulated by using Thermocalc, Dictra, and TC-PRISMA. Verification and comparison of the experimental results were performed by optical microscopy, X-ray diffraction (XRD), Scanning Electron Microscop (SEM), and Scanning Transmission Electron Microscopy (STEM), and Energy Dispersive Spectroscopy (EDS) and Electron Backscatter Scanning Diffraction (EBSD) analysis were used to investigate the effect of martensitic/bainitic packet size. Results show that the increase in the number density of small precipitates in the sample partitioned at 640 °C compensates for the increase in crystallographic packets size. The strength and ductility values are kept at a high level, but the impact toughness will decrease considerably.

scholarly journals Relationship Between Bake Hardening, Snoek-Köster and Dislocation-Enhanced Snoek Peaks in Coarse Grained Low Carbon Steel

2016 ◽  
Vol 61 (3) ◽  
pp. 1723-1732 ◽  
Author(s):  
Weijuan Li ◽  
Shengshi Zhao ◽  
Hengyi Zhang ◽  
Xiaolong Jin
Keyword(s):  
Carbon Steel ◽  
Internal Friction ◽  
Dislocation Structure ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
Low Carbon ◽  
Bake Hardening ◽  
Maximum Value ◽  
Solute Carbon ◽  
Further Development

AbstractIn the present work, specimens prepared from coarse grained low carbon steel with different prestrains were baked and then, their bake hardening (BH) property and internal friction were determined. TEM was used to characterize the dislocation structure in BH treated samples. The measurements of internal friction in prestrained samples and baked samples were carried out using a multifunctional internal friction apparatus. The results indicate that, in coarse grained low carbon steel, the bake hardening properties (BH values) were negative, which were increased by increasing the prestrain from 2 to 5%, and then were decreased by increasing the prestrain from 5 to 10%. In the specimen with prestrain 5%, the BH value reached the maximum value and the height of Snoek-Köster peak was observed to be the maximum alike. With increasing the prestrain, both of the BH value and Snoek-Köster peak heights are similarly varied. It is concluded that Snoek-Köster and dislocation-enhanced Snoek peaks, caused by the interactions between interstitial solute carbon atoms and dislocations, can be used in further development of the bake hardening steels.

Sign in / Sign up

Export Citation Format

Share Document