Effects of Nb on Bainite Transformation Behavior and Mechanical Properties of Low‐Carbon Bainitic Steels

2019 ◽  
Vol 90 (8) ◽  
pp. 1900050
Author(s):  
Zhenye Chen ◽  
Jianxin Li ◽  
Jianjun Qi ◽  
Liqing Chen ◽  
Li Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Carbon ◽  
Transformation Behavior ◽  
Bainite Transformation ◽  
Bainitic Steels

The Influence of Oxide Inclusion on the Refinement of Bainite and Toughness in HAZ for Low Carbon Steels

2013 ◽  
Vol 651 ◽  
pp. 163-167
Author(s):  
Shu Rui Li ◽  
Xue Min Wang ◽  
Xin Lai He
Keyword(s):  
Mechanical Properties ◽  
Acicular Ferrite ◽  
Oxide Inclusion ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
The Core ◽  
Ti Oxides ◽  
Bainitic Steels

The influence of Ti oxide on the toughness of heat affected zone for low carbon bainitic steels has been investigated. The optical microscope, SEM and TEM were used to analyze the composition, size and distribution of the inclusions, and the microstructure and mechanical properties after welding thermal simulation were also investigated. The effect of Ti oxide inclusion on the transformation of acicular ferrite has also been studied. The results show that after the melting with Ti dioxide technique the inclusion is complex, in the core is Ti oxides about 1-3 micron and around it is MnS. It has been found the acicular ferrite can nucleate at the inclusions and the Ti oxide inclusion will promote the nucleation of acicular ferrite, and the acicular ferrite will block the growth of bainite. Therefore by introducing the Ti oxide in the steels the microstructure of HAZ could be refined markedly therefore the toughness of HAZ can be improved evidently.

scholarly journals Transformation Behavior and Mechanical Properties in Very Low Carbon Transformation-strengthened Steels

1984 ◽  
Vol 70 (10) ◽  
pp. 1429-1436 ◽  
Author(s):  
Masakazu NIIKURA ◽  
Sadahiro YAMAMOTO ◽  
Chiaki OUCHI ◽  
Isao KOZASU
Keyword(s):  
Mechanical Properties ◽  
Low Carbon ◽  
Transformation Behavior

The Influence of Thermomechanical Controlled Processing on Bainite Formation in Low Carbon High Strength Steel

2014 ◽  
Vol 783-786 ◽  
pp. 21-26
Author(s):  
Xiao Jun Liang ◽  
Ming Jian Hua ◽  
Anthony J. DeArdo
Keyword(s):  
Mechanical Properties ◽  
High Strength Steel ◽  
High Strength ◽  
Manganese Steel ◽  
Low Carbon ◽  
High Manganese ◽  
Bainite Transformation ◽  
High Manganese Steel ◽  
Cooling Rates ◽  
Controlled Processing

Thermomechanical controlled processing is a very important way to control the microstructure and mechanical properties in low carbon, high strength steel. This is especially true in the case of bainite formation, where the complexity of the austenite-bainite transformation makes the control of the processing important. In this study, a low carbon, high manganese steel containing niobium was investigated to better understand the roles of austenite conditioning and cooling rates on the bainitic phase transformation. Specimens were compared with and without deformation, and followed by seven different cooling rates ranging between 0.5°C/s and 40°C/s. The CCT curves showed that the transformation behaviors and temperatures are very different. The different bainitic microstructures which varied with austenite deformation and cooling rates will be discussed.

Effect of 0.06%Nb on the Microstructure and Mechanical Properties of Mn-Series Low Carbon Air-Cooling Bainitic Steels

2011 ◽  
Vol 284-286 ◽  
pp. 1191-1195
Author(s):  
Chun Feng ◽  
Bing Zhe Bai ◽  
Yan Kang Zheng
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Granular Bainite ◽  
Air Cooling ◽  
Low Carbon ◽  
Microstructure And Mechanical Properties ◽  
Bainitic Steels ◽  
Superior Mechanical Properties ◽  
Allotriomorphic Ferrite ◽  
Strength Improvement

The effect of 0.06%Nb on the microstructure and mechanical properties of grain boundary allotriomorphic ferrite (FGBA) / granular bainite (Bg) air-cooling bainitic steels has been investigated in this paper. The results indicate that the steel acquires superior mechanical properties by adding 0.06%Nb. Compared with Non-Nb steel, the addition of 0.06%Nb increases the tensile strength and yield strength about 37.1% (From 780MPa to 1070MPa)and 26.6%(From 557MPa to 705MPa) respectively, remaining 18.3% elongation and 97J toughness. The addition of 0.06%Nb not only promotes the nucleation of intragranular ferrite but also refines the allotriomorphic ferrite grain , both of which in turn contribute to the refinement of granular bainite cluster including its ferrite platelets and M-A islands. Under the synthetic roles of the microstructure refinement and precipitation strengthening, 148MPa yield strength improvement has been acquired in the low carbon air-cooling bainitic steel by the adding of 0.06%Nb.

Mn-Series Low Carbon Air Cooling Bainitic Steels Containg Niobium

2010 ◽  
Vol 89-91 ◽  
pp. 112-117
Author(s):  
Chun Feng ◽  
Bing Zhe Bai ◽  
Y.K. Zheng ◽  
Hong Sheng Fang
Keyword(s):  
Mechanical Properties ◽  
Volume Fraction ◽  
Small Addition ◽  
Granular Bainite ◽  
Precipitation Strengthen ◽  
Air Cooling ◽  
Low Carbon ◽  
Niobium Content ◽  
Bainitic Steels ◽  
The Impact

The effect of four different niobium(From 0-0.1%) addition on the mechanical properties of allotriomorphic ferrite (FGBA)/ granular bainite (BG) air cooling bainitic steels has been investigated in this paper. The results show that (1) The 0.06%Nb steel acquired superior strength and toughness combination by applying 1250°C×60min solution treated, finish rolling at 850°C, and air cooling. The corresponding mechanical properties of the thick plate(30mm) is: σb>1050MPa, σ0.2>700MPa,δ5>17%,Akv>90J. (2) The addition of niobium refine the grain size of FGBA, and promoted the transformation of bainite structure. With the increase of niobium content, the refinement of ferrite grain and bainitic cluster is improved. (3) More refined M-A island is acquired by the small addition of niobium. According to M-A Analysis tools and transversal methods, with the rise of niobium content, the volume fraction of M-A island increase from 21% to 35%, and the average size of M-A island decrease from 1.1μm to 0.7um. (4)It is suggested that 0.02-0.06% niobium can improve the mechanical properties of the steel obviously. However, excess addition of Nb (0.1%) deteriorates the impact toughness obviously. (5)Under the synthetic roles of the microstructure refinement and precipitation strengthen, 60-160MPa yield strength improvement has been acquired in the low carbon air cooling bainitic steel by the small addition of niobium. (6)This steel is with low production cost since the alloying element Mn is cheap.

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